Advances in Child Development and Behavior Volume 10

ADVANCES

IN CHILD DEVELOPMENT A N D BEHAVIOR

VOLUME 10

Contributors to This Volume Ann L. Brown Mary Carol Day Mary Fulcher Geis John W. Hagen

Robert H. Jongeward, Jr. Robert V. Kail, Jr. Boyd R. McCandless Alexander W. Siege1 Alice G. Vlietstra Sheldon H. White John C. Wright

ADVANCES IN CHILD DEVELOPMENT AND BEHAVIOR

edited by Hayne W. Reese Department of Psycho!ogy West Virginia University Morgantown, West Virginia

VOLUME 10

@

1975

ACADEMIC PRESS New York San Francisco London A Subsidiary of Harcourt Brace Jovanovich, Publishers

COPYRIGHT 0 1975,BY ACADEMIC PRESS, INC. ALL RIGHTS RESERVED. NO PART OF THIS PUBLICATION MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM OR BY ANY MEANS, ELECTRONIC OR MECHANICAL, INCLUDING PHOTOCOPY, RECORDING, OR ANY INFORMATION STORAGE AND RETRIEVAL SYSTEM, WITHOUT PERMISSION IN WRITING FROM THE PUBLISHER.

ACADEMIC PRESS, INC.

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United Kingdom Edition published by ACADEMIC PRESS, INC. (LONDON) LTD. 24/28 Oval Road. London NW1

LIBRARY OF CONGRESS CATALOQ CARD NUMBER:63-23237

ISBN 0-12-009710-9 PRINTED IN THE UNITED STATES OF AMERICA

Contents LISTOF COhTRIBUTORS

................................................

PREFACE............................................................

vii

ix

Current Trends in Developmental Psychology BOYD R . McCANDLESS AND MARY FULCHER GEIS . .................................................... I1. Journal Acceptance Rates ......................................... 111. Classification of Manuscripts ...................................... IV . Conclusions .................................................... V . Summary ...................................................... 1 Introduction

Reference ......................................................

1 2 3

7 8 8

The Development of Spatial Representations of Large-Scale Environments ALEXANDER W . SIEGEL AND SHELDON H. WHITE I . Introduction .................................................... I1 . Human Knowledge of Space: General Considerations . . . . . . . . . . . . . . . . . . III. Spatial Representations: Functions and Components ................... IV . How Adults Form Spatial Representations as a Function of Experience . . . . V . Main Sequences in Adaptation ..................................... VI . The Development of Children's Spatial Representations . . . . . . . . . . . . . . . . VII . Summary and Conclusions ........................................ VIII . Epilog: On Spatial Thinking About Nonspatial Matters ................. References .....................................................

25 30 37 45 47 48

Cognitive Perspectives on the Development of Memory JOHN W . HAGEN. ROBERT H . JONGEWARD. JR., AND ROBERT V . KAIL. JR . I . Early Research on the Development of Memory ....................... I1. Human Information Processing ..................................... 111. The Relevant Research ........................................... IV . Concluding Remarks ............................................. References .....................................................

57 59 63 94 97

10 11

21

V

vi

Conrents

The Development of Memory: Knowing. Knowing About Knowing. and Knowing How to Know ANN L . BROWN I . Introduction .................................................... I1. A Taxonomy of Memory Tasks and Processes ........................ I11. An Overview of the Developmental Literature ........................ IV . A Model of Developmental Changes in Memory ...................... V . Summary ...................................................... References .....................................................

104

105 110 134 145 146

Developmental Trends in Visual Scanning MARY CAROL DAY I . Introduction .................................................... 154 I1. Demonstration of a Systematic Strategy for the Acquisition of Visual Information ..................................................... 156 I11. Maintenance of a Strategy across Variations in the Content and Arrangement of Stimuli ........................................................ 158 IV . Focus on Aspects of the Visual Stimuli Most Informative for the Specific Task 163 V . Exhaustiveness and Efficiency of Visual Scanning ..................... 170 VI . Speed of Visual Scanning ......................................... 175 VII . Field of View ................................................... 182 VIII . Summary ...................................................... 186 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

The Development of Selective Attention: From Perceptual Exploration to Logical Search JOHN C . WRIGHT AND ALICE G . VLIETSTRA I . Introduction .................................................... I1. Development of Organized Observing Behaviors: Exploration vs . Search 111. Experimental Evidence ........................................... IV . Summary and Conclusions ........................................ References .....................................................

..

196 197 203 233 235

AUTHORINDEX. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

241

..................................................

250

CONTENTSOFPREVIOUS VOLUME...................................

253

SuarEcT INDEX

List of Contributors Numbers in parentheses indicate the pages on which the authors' contributions begin.

ANN L. BROWN Department of Psychology and Children's Research Center, University of Illinois, Champaign, Illinois (103) MARY CAROL DAY' Department of Psychology, Laboratory of Human Development, Harvard University, Cambridge, Massachusetts (153) MARY FULCHER GEE2 Emory University, Atlanta, Georgia (1) JOHN W. HAGEN Department of Psychology, The University of Michigan, Ann Arbor, Michigan (57)

ROBERT H. JONGEWARD, JR. Department of Psychology, The University of Michigan, Ann Arbor, Michigan (57) ROBERT V. KAIL, JR. Department of Psychology, The University of Michigan, Ann Arbor, Michigan (57) BOYD R. McCANDLESS Physiology Department, Emory University, Atlanta, Georgia (1) ALEXANDER W. SIEGEL Department of Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania (9) ALICE G . VLIETSTRA Psychology Department, University of Missouri-St. Louis, St. Louis, Missouri 095) 'Present address: The Learning Research and Development Center, University of Pittsburgh, Pittsburgh, Pennsylvania. 2Present address: Department of Psychology, University of North Carolina at Greensboro, Greensboro, North Carolina.

vii

viii

Contributors

SHELDON H . WHITE Department of Psychology and Social Relations, Harvard University, Cambridge, Massachusetts (9) JOHN C. WRIGHT Department of Human Development, University of Kansas, Lawrence, Kansas (195)

Preface The amount of research and theoretical discussion in the field of child development and behavior is so vast that researchers, instructors, and students are confronted with a formidable task in keeping abreast of new developments within their areas of specialization through the use of primary sources, as well as being knowledgeable in areas peripheral to their primary focus of interest. Moreover, there is often simply not enough journal space to permit publication of more speculative kinds of analyses which might spark expanded interest in a problem area or stimulate new modes of attack on the problem. The serial publication Advances in Child Development and Behavior is intended to ease the burden by providing scholarly technical articles serving as reference material and by providing a place for publication of scholarly speculation. In these documented critical reviews, recent advances in the field are summarized and integrated, complexities are exposed, and fresh viewpoints are offered. They should be useful not only to the expert in the area but also to the general reader. No attempt is made to organize each volume around a particular theme or topic, nor is the series intended to reflect the development of new fads. Manuscripts are solicited from investigators conducting programmatic work on problems of current and significant interest. The editor often encourages the preparation of critical syntheses dealing intensively with topics of relatively narrow scope but of considerable potential interest to the scientific community. Contributors are encouraged to criticize, integrate, and stimulate but always within a framework of high scholarship. Although appearance in the volumes is ordinarily by invitation, unsolicited manuscripts will be accepted for review if submitted first in outline form to the editor. All papers-whether invited or submittedreceive careful editorial scrutiny. Invited papers are automatically accepted for publication in principle, but may require revision before final acceptance. Submitted papers receive the same treatment except that they are not automatically accepted for publication even in principle, and may be rejected. I wish to acknowledge with gratitude the aid of my home institution, West Virginia University, which generously provided time and facilities for the preparation of this volume. I also wish to thank Drs. Edward C. Caldwell and Boyd R. McCandless for their editorial assistance.

HAYNEW. REESE

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CURRENT TRENDS IN DEVELOPMENTAL PSYCHOLOGY'

Boyd R . McCandless and Mary Fulcher Geis2 EMORY UNIVERSITY

I. INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11. JOURNAL ACCEPTANCE RATES

............................

Ill. CLASSIFICATION OF MANUSCRIPTS ........................ A. TYPES OF SUBJECTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. CONTENT AREAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. RESEARCH TECHNIQUES ...............................

IV. CONCLUSIONS.. ..........................................

1

2 3 3 4

6 7

...............................................

8

REFERENCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8

V. SUMMARY

I.

Introduction

In the January, 1970, issue ofDevelopmenta1Psychology, the senior author of this paper prepared an analysis of the first 500 articles that had been submitted to 'The authors appreciate the efforts of Professor Herbert Kaye and Mr. David Schwartz in laying the groundwork for the content analysis, and the editorial help that Ms. Julie Hatoff has given. The authors are deeply indebted to Professor John P. Hill and Professor Richard D. Odom, who have served as Associate Editors of Developmenrul Psychology. Professor Odom became editor of the journal in January, 1974. *Present address: Department of Psychology, University of North Carolina at Greensboro, Greensboro, North Carolina.

Boyd R . McCandless and Mary Fulcher Geis

2

the journal. This analysis led to the present paper, in which categories are more refined and more reliable. The paper is based entirely on submissions to Developmental Psychology, the official American Psychological Association publication outlet for this discipline. The present analysis was terminated on August 1, 1973, at which time 2108 articles had been received. During the period of time that is covered in the present analysis, the senior author of this paper was the journal’s editor. The reasons for limiting this paper to manuscripts that were sent to Developmental Psychology are implicit in the paragraph above: ( a ) The policy of the journal was to cover the life-span of a wide range of species. Therefore, articles about human subjects, from birth, through the life-span, to extreme old age and adjustment to impending death, have appeared in the journal. Many nationalities, races, and socioeconomic statuses have been included in the subject population. The range of species has been from mouse through goat to man, although it is possible that, in terms of hierarchy, the range should be ordered the other way. (b) These are the data that were available to us. (c) These are the data that tell us how psychologists define developmental psychology. Such an attempt to determine how developmentalists define developmental psychology is the purpose of this paper.

11. Journal Acceptance Rates Some of the story of developmental psychology in the United States is told in Table I. In the first year of the journal’s life, the acceptance rate was 6. As of the cutoff date for this paper (8-1-73), the acceptance rate had dropped to 28%. The present authors regard this decline as a function of three factors: ( a ) the increasingly high quality of research in the field, (b) the tightening of critical standards, and (c) the ever-growing expense of publication. The page limits of journals that are published by professional societies have been shrinking because of expanded costs. In the case of Developmental Psychology, the cut has been from a planned 1200 pages in 1974 to an actual 1000. -~ NUMBERS

TABLE I OF MANUSCRIPTS RECEIVED AND ACCEPTANCE RATES

Year 1968 1969 1970 1971 1972 1973 (submitted prior to 8-1-73)

Total period

Submissions

% Acceptance

226 319 410 389 460 304

-

2 108

39

-

61 54 36 30 34 28

Current Trends in Development Psychology

3

111. Classification of Manuscripts Each of the 2108 manuscripts was analyzed as to type of subjects studied, content area investigated, and research technique employed. The results of the analysis are presented here in three tables, corresponding to the three types of information that were obtained about each submission. We emphasize that each table represents a different breakdown of the total 2108 manuscripts and that the categories listed in each table are mutually exclusive and exhaustive, i.e., in the preparation of each table, every manuscript was placed in one and only one of the categories. During the first six years of the journal’s existence, the percentages that are reported in the tables remained about the same from year to year. Chronologically, the last 50% of the papers were reviewed blind, and almost all were handled by at least two reviewers. Moving to blind review made little difference in decision about papers by topic or author.

A. TYPESOF SUBJECTS The types of subjects studied by developmental psychologists, as represented by submitters to the Journal, are summarized in Table II. The areas of heaviest concentration were clearly the preschool ages (years 4 to 6), the early elementary school years (ages 6 to 9), and the intermediate school years (9 to 12 years). This age-span accounts for 30% of all submitted articles (see lines 3,4,and 5 of Table 11). If lines 9, 10, and 11 of Table I1 were analyzed by age group, this percentage would be much higher. Research workers continued to be quite interested in human infancy. Their subjects were usually babies from 1 to 8 days of age, whose socioeconomic status was typically low. Ordinarily, the infants were studied while they were still in the hospital after birth. By contrast, toddlers were much neglected. Only 2% of submitted manuscripts were devoted to this crucial age. However, they are a difficult age group to reach, since few are found in public facilities. The aged also were overlooked. Subjects of 60 years and older were included in only 1% of the manuscripts, perhaps because studies of aging are submitted primarily to the journals of the Gerontological Society. In the authors’ opinion, reasonably healthy percentages of developmentalists were working with animals (4% of all papers), with adults between 18 and 60 years of age (7%), and with special subject samples (7.3%, see lines 12, 13, 14, and 15 of Table 11). Research in which the subjects were described an emotionally disturbed, autistic, or schizophrenic was placed on line 15 of Table 11. Not only were developmental psychologists active in collecting new data, they also were interested in submitting literature reviews, critiques of research, and statistical papers ( 5 % of all submissions, see line 17 of Table 11). We note that the rates of acceptance were highest for authors dealing with infancy and with animals (see lines 1 and 16 of Table II), perhaps because these

Boyd R . McCandless and Mary Fulcher Geis

4

TABLE I1 SUMMARY O F SUBMISSION AND ACCEPTANCE RATES BY TYPES O F S s STUDIED’ Subject type 1. 2. 3. 4. 5. 6. 7. 8. 9.

10. 11. 12. 13. 14. 15. 16. 17. 18.

% Submission

% Acceptance

6 2 12 10 8 6

54 33 41 46 40 37

7 1

34 28

16

39

5 9 5 1 .3

46 34 31 33 50 8 56 38 3

Infants (0-2 years) Toddlers (2-4 years) Preschool and kindergarten (4-6 years) Early elementary (6-9 years) Elementary and preadolescents (9-12 years) Adolescents (12-18 years) Adults (18-60 years, college students included) Aged (over 60 years) General developmental 2 (a combination of two consecutively listed age groups, e.g., infants and toddlers) General developmental 3 (a combination of three consecutively listed age groups General developmental (broad age range) Retarded (all ages) Deaf (all ages) Blind (all ages) Behavior disorders (all ages) Animals Reviews, critiques, statistical papers Not available

1 4 5

2

‘Total number of manuscripts = 2108 (1-1-68 to 8-1-73). Entries in the first column sum to 100.3% because of rounding error. All lines in the table are mutually exclusive. Lines 1 through 8 represent research with single-age samples, while lines 9 through I 1 represent research with multiple-age samples.

authors tended to have experimental backgrounds and there was an editorial bias favoring experimental research (see Table IV). However, the acceptance rates were also high for multiple-age samples (see lines 9, 10, and I I of Table 11).

B. CONTENTAREAS The content-area classification of articles from 1-1-68 to 8-1-73 is given in Table 111. The most popular areas in developmental psychology seem to have been those that are concerned with experimental-manipulative-precise measurement (see lines 2, 4, 6 , and 12 of Table 111). A total of 29% of all submissions belongs to this category. The high rates of acceptance for such articles should be noted and may be another indication of the editors’ possible bias in favor of experimental studies.

5

Current Trends in Development Psychology

TABLE 111 SUMMARY OF SUBMISSION AND ACCEPTANCE RATES BY AREAS OF STUDYa -

Area 1. Personality, social development 2 . Sensory and perceptual processes, perceptual-motor development 3. Piagetian (moral development excluded) 4. Discrimination learning 5. Child-rearing patterns, parent-child interaction, father absence 6. Memory and verbal learning 7. Intellectual development 8. Language 9. Miscellaneous 10. Modeling, observational learning 11. Early experience 12. Reinforcement 13. Moral development, political development 14. Conceptual tempo 15. Creativity 16. Sex typing 17. Aggression 18. Therapy outcomes 19. Infancy miscellaneous 20. Not available

% Submission

% Acceptance

19

33

11 9 8

42 46

6 6 5 5 5 5 4 4 3 2 2 2 1 1 1 .5

38

50

43 46

38 .28 42 46

39 38 17 32 49 45

0 30 0

aTotal number of manuscripts = 2108 (1-168 to 8-1-73). Entries in the first column sum to 99.5% because of rounding error.

Personality and social development are included in the next largest category of submissions. Despite the Editors' favorable disposition to this field of study, the rate of accepting such manuscripts was not high. Piagetian papers constituted the third largest category of submissions and had a relatively high rate of acceptance (42%). It is the authors' impression that the quality of research in this area has sharply improved and that such cognitive developmentalists have made and will continue to make real contributions to developmental psychology. However, the present authors hope for more experimentation and manipulation and, thus, by definition, hope for less straight testing and normative work by Piaget-oriented investigators. In our opinion, psychologists are not doing enough with child-rearing patterns and parent-child interaction, language development, early experience, and moral and political development (see lines 5 , 8, I 1 and 13 of Table 111). Although the quantity of such research is insufficient, the quality of the research that has been completed is quite adequate.

6

Boyd R . McCandless and Mary Fulcher Geis

The editors of DevelopmentalPsychology and the present authors believe that it remains necessary to report the demographic variables of the Ss with whom investigators work, By demographic variables, the authors refer to sex, age, and, in some cases, organicity, race, socioeconomic level, degree of research sophistication, and so on. To dilate on this last point as an example, some children in university nursery schools have participated in so many studies of one sort or another that they want to “fool the experimenter.” In U.S.culture, it still means one thing to be Black, another to be Chicano, another to be Jewish, and another to be White Anglo Saxon Protestant. One simply grows up in different ways. Some 14% of submitters agreed with this point and conducted research in which subjects from varying socioeconomic levels and from different ethnic and racial groups were studied. The editors of the journal and the present authors also maintain that such information should be supplied about all research workers who have taken part in data collection for human subjects older than infants.

C. RESEARCHTECHNIQUES In Table IV, it can be seen that the plurality of research submitted to DevelopmentalPsychology was conducted in an experimental, manipulative fashion (48% of all manuscripts). In the classic tradition, the category next high in frequency was correlative, normative, and descriptive (33%). Within the discipline, there is still plenty of room for the latter type of research; for, as in astronomy and botany, there is still the need to classify and to relate variables.

TABLE IV SUMMARY OF SUBMISSION AND ACCEPTANCE RATES BY TECHNIQUES OF RESEARCfl Technique 1. Experimental, manipulative 2 . Correlative, normative, descriptive 3. Test development and validation, method development 4. Reviews, critiques, statistical papers 5 . Longitudinal 6. Not available 7. Ecolonical. observational 8. Projective, interview, case history I

-

% Submission

% Acceptance

48 33

46 31

6 5 3 2 1 1

43 31 52 4 40 19

‘Total number of manuscripts = 2108 (1-1-68 to 8-1-73). Entries in the first column sum to 99%because of rounding error. Manuscripts represented by line 17 of Table 2 were placed in line 4 of this table.

Current Trends in Development Psychology

7

The highest rate of acceptance was for longitudinal studies, because these data, while not always good, are precious and must be open for public inspection and, for this reason, must be preserved. Like the correlative-normative-descriptive approach, the longitudinal approach is often a source of suggestions for valuable further research. A few investigators continue to work in natural settings. It is a difficult area for research, but the authors believe that it should be maintained. Indeed, some of the more interesting research among the 2108 articles that were analyzed has resulted from studies in natural settings. There is no substitute for looking at human children and adults (or rhesus, or mice, or rats) as they behave in their living circumstances. The acceptance rate of this type of method had been moderately high. “Clinical type” articles have not been numerous, nor have their authors fared well as far as acceptance rate is concerned (a 19% rate of acceptance). This state of affairs probably reflects a preoccupation of the editors with precise methodology. Although it is notoriously difficult to be precise in “clinical settings,” the present authors would like to see more of such studies, and they also endorse test and method validation research (see the 43% acceptance rate for this category in line 3 of Table IV).

IV. Conclusions It is difficult to define developmental psychology. It is all sorts of things to people in all sorts of disciplines. Among the 2108 manuscripts that were analyzed for this paper, most have been submitted by psychologists. More have come from men than from women, but the ratio of women contributors is the highest among the scientific disciplines represented by contributors. Among those who have contributed papers (and this list is incomplete) are anthropologists, ecologists, general educators, primatologists, physicians (particularly pediatricians and psychiatrists), psychologists of all types, social workers, sociologists, special educators, and zoologists. The editor of this volume instructed the authors of this paper to give suggestions about the course of developmental psychology. They cannot do so. What they can say is that the interest of investigators is lively, that research workers (and editors) are concerned with many species (all mammalian for this journal), and the investigators are expedient, tending to study Ss that are easily available and neglecting those more difficult to reach. Concerns range from norms and description to elaborate and careful experiments and manipulations. More and more research and theoretical workers seem to be entering the field, and our conclusion is viable. After all, who can fail to be interested in how things grow, mature, and die?

8

Boyd R . McCandless and Mary Fulcher Geis

v.

summary

The authors of this paper concerned themselves with an analysis of 2108 papers that were submitted to the American Psychological Association’s journal Developmental Psychology, since its inception in January of 1968 to the cutoff time for analysis, August 1, 1973. High rates of submission and acceptance were noted for experimental-rnanipulative-methodologicalpapers. Areas of neglect as subjects in the field have been toddlers, adolescents (particularly those not in school), and the aged. Psychologists seem to pay little attention to language development. The present writers urge continued research upon and reporting of demographic variables. Blind handling of manuscripts apparently has not affected acceptance rates for the journal whose articles are the data base for this paper. REFERENCE McCandless, B. R. Editorial, Developmental Psychology, 1970, 2 , 1-4.

THE DEVELOPMENT OF SPATIAL REPRESENTATIONS OF LARGE-SCALE ENVIRONMENTS

Alexander W . Siege1 UNIVERSITY OF PI'ITSBURGH

and Sheldon H . White HARVARD UNIVERSITY

I . INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I1 . HUMAN KNOWLEDGE OF SPACE: GENERAL CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . PHILOSOPHICAL AND NEUROLOGICAL DISCUSSIONS OF SPATIAL KNOWLEDGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B . SYMBOLIZED SPACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . THE DEVELOPMENT OF SPATIAL KNOWLEDGE . . . . . . . . . . D . ON THE DISSOLUTION OF SPATIAL KNOWLEDGE . . . . . . . . E . SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10 11

11

16 17 17 20

111. SPATIAL REPRESENTATIONS: FUNCTIONS AND COM-

PONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . MODELS OF MACROSPACE ............................. B . THE FUNCTIONS OF THE MODEL ........................ C . THE ELEMENTS OF THE MODEL ........................

21 21 22 23

IV . HOW ADULTS FORM SPATIAL REPRESENTATIONS AS A FUNCTION OF EXPERIENCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . THE IMPORTANCE OF LOCOMOTION .................... B . LEARNING MECHANISMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . SUMMARY .............................................

25 26 26 30

V . MAIN SEQUENCES IN ADAPTION .......................... A . EVIDENCE FOR DEVELOPMENTAL PARALLELISMS . . . . . . . B . THE MAIN SEQUENCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

30 31 34 9

10

Alexander W . Siege1 and Sheldon H . White

VI. THE DEVELOPMENT OF CHILDREN’S SPATIAL REPRESENTATIONS .............................................

37

VII SUMMARY AND CONCLUSIONS.. ..........................

45

VIII EPILOG: ON SPATIAL THINKING ABOUT NONSPATIAL MATTERS ................................................

47

REFERENCES

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48

I. Introduction Consider a set of problems that people ordinarily solve through what we sometimes refer to as “knowledge of space.” A few anecdotal examples may serve to indicate the scope of these problems. Puluwat is one of a long chain of islands covering over a thousand miles of the Pacific Ocean north of New Guinea. The sailing canoe is at the very heart of the Puluwat way of life, and skilled navigators occupy the positions of highest status. There is quite a bit of drinking among men of Puluwat. A trip to Pikelot island, one mile wide and over 100 miles distant, is often launched at a drinking party. Someone jumps up and says, “I’m going to Pikelot. Who’s coming with me?” The navigator determines his sailing plan only after he is at sea; at no time is an overall plan developed for the voyage. Yet, without fail, at an average speed of 4.5 knots, the 26-foot sailing canoe with a now-sober crew arrives two days later at a one-mile wide island in the open Ocean (Gladwin, 1970). What is the nature of their knowledge about the sea and the sky and the islands and the canoe that makes this possible? Most mornings, every reader of this paper will find his way to the office, less exuberantly than the voyagers of Puluwat but no less decisively. He or she will walk, ride a bicycle, take the train, or drive. The route may be long or short, simple or complex; it may vary; it may be interrupted or accomplished around diversions. What system of habits, schemes, imageries, long- or short-term memories allows him to accomplish this? Most mornings, thousands of 6-year-old children will find their way to school. There will be protections along the way-street-crossing policemen-but there will be little fear on anyone’s part that the children will get lost. The children will find their way to the school building, within the building to their classroom, and after school, perhaps, to a friend’s house. However, most 3-year-olds do not typically engage in the same process. Is it that they are incapable of following routes and will thus get lost? It is quite possible that these very young children can recognize landmarks in a large-scale terrain, but have limited “route-knowledge,” and that adults are aware of this.

Development of Sputiul Representations

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These examples seem representative of one class of problem. They encompass different kinds of locomotion, different geographical extents, different actors in different cultures. Yet one would suspect that they can be given a common psychological analysis. One strong reason for believing this is impressionistic: they intuitively seem like the same kind of problem. In a more formal sense, certain analogies might be noted. In each: (a) there is a traveler who must find his way in a spatially organized set of markers-the traveler goes from Point A to Point B in this arrangement; (b) Point B is not directly perceivable from Point A; (c) the journey is ma& without a roadmap or compass; and (d) the traveler does not get lost (he takes some “least-effort’’ route). This paper deals with the organization and development of psychological systems that would make solution of this class of problems possible. Five bodies of literature and analysis will be reviewed. The question of how humans understand the arrangements of objects in space was a subject of scholarly interest before psychology, as a discipline, came into existence. It has been the subject of inquiry by philosophers and neurologists. A first part of the paper will be concerned with these inquiries. A second part of the paper will be concerned with research efforts on the part of psychologists and others to specify the nature, function, and components of human models of the environment. A third part of the paper will review evidence bearing on the question of how an adult constructs such models when he encounters a new terrain. A fourth part will introduce the notion of “Main Sequences” in the adaptation of adults and children. Finally, the paper will consider the development of spatial representations in children.

11. Human Knowledge of Space: General Considerations Descriptions of space, or allusions to space in language, must rest on two kinds of knowledge. The first appears to be based on models (maps, representations) which people construct to guide “spatial behavior” (Downs 8z Stea, 1973). The second appears to consist of a linguistic symbol-system that allows the models to be shared within a community of discourse. We are here concerned with the models, taking the question of their unification through linguistic or other formal address as a separate question.

A . PHILOSOPHICAL AND NEUROLOGICAL DISCUSSIONS OF SPATIAL KNOWLEDGE The central cognitive psychologies of today are constructionistic and treat knowledge as a matter of the assembly of meaning over real time. The information-processing analysis deals with knowledge constructed over intervals of microseconds or seconds; the Piagetian genetic epistemology deals with

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knowledge constructed over intervals of months or years. These forms of inquiry into the problem’of human knowledge are a realization, within the mainstream of contemporary psychology, of German idealistic philosophy initially formulated in the 18th and 19th centuries. Kant’s Rationalism lays the foundation for the contemporary constructionistic view of space. In his Critique ofpure Reason, Kant (1902 edition) argued that there is no way for humans to apprehend the nature of “reality” except as an interpretation of encounters with the world. Thus, it is impossible to separate completely the acts of knowing from the contents of knowledge. Knowledge can never exactly represent what is real. What we take to be real is a product of the act of knowing. A more “developmenta1” constructionism was subsequently set forth by Hegel. He saw the possibility that acts of knowing and, thus, reality, could change over time, One kind of conversion of this philosophical position to psychology came when Herbert Spencer blended Associationism, Rationalism, and Evolutionism, to produce what appears to be a modem psychological position expressed in archaic language. As early as his First Principles Spencer (1862), argued: We think in relations. This is truly the form of all thought. . . . Now relations are of two orders-relations of sequence and relations of co-existence; of which the one is original and the other derivative. The relation of sequence is given in every change of consciousness. The relation of co-existence . . . becomes distinguished only when it is found that certain relations of sequence have their terms presented in consciousness in either order with equal facility. . . . The abstract of all sequences is Time. The abstract of all co-existences is Space. Our consciousness of Space is a consciousness of co-existing positions [pp. 163-1641,

Henri Bergson (1922), influenced by Spencer, held as a fundamental tenet that whereas space is continuous, our model of it is created by ’mifically isolating, abstracting, and creating fixed states of consciousness and integrating them into a simultaneity. It is not the “states”, simple snapshots we have taken once again along the course of change, that are real; on the contrary, it is flux, the continuity of transition, it is change itself that is real . . . [p. 161. Radical instability and absolute immutability are . . . abstractions which the mind then hypostasizes into multiplesrares, on the one hand, into rhing or substance on the otherlp. 1841.

Our mind, which seeks solid bases of operation, has as its principal function, in the ordinary course of life, to imagine stares and things p. 2221.

Thus, for Bergson, space is an abstraction, successions fixed into a simultaneity. This argument had direct influence on Piaget, and determined his interest in studying the contrast between perception and conception. Cassirer (1944, 1955) posited three levels of spatial knowledge: active, perceptual, and symbolic space. One can construe this as an argument that spatial knowledge exists at three orders of temporal integration. At the first level, quick

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temporal co-occurrences make possible the manipulation of objects, hand-eye coordination, etc.’ At the second level, less close-packed sensory encounters allow the assembly of the routes and maps of spatial representations. Finally, the development of symbol systems allows construction of fantasy arrangements of line and space mapped out in angstroms or light-years. At the symbolic level, perceptua1 space is “re-modeled” in a way that permits coordination, communication, calculation, and extrapolation. Under the influence of the evolutionary thinking in the latter part of the 19th century, the contemporary philosophical psychology was actively coordinated with notions of the organization and function of the nervous system. John Hughlings Jackson, sometimes called the “father of modem neurology,” made repeated appeals to the evolutionary psychologies of Spencer, Bain, Laycock, and Lewes as justifications for his interpretation of function and dysfunction in the brain. Jackson was concerned with the evolution and dissolution of nervous system function. He borrowed heavily from Spencer’s Development Hypothesis in explaining the higher integrative functions of nervous system activity. The highest nervous processes (the anatomical substrata of consciousness) are evolved out ofall lower centres. Thus the highest nervous processes represent innumerable and widely separated movements; hence the discharge of them produces universal symptoms nearly simultaneously. Moreover, the highest nervous processes represent movements with innumerable intervals; hence discharge o f them produces the universal symptoms [of epilepsy] nearly contemporaneously. . . . The process by which it finally results that the highest nervous processes represent ( I ) the whole organism and represent its parts (2) simultaneously and (3) contemporaneously is a gradual one [Jackson, 1875, pp. 2 I6 -2 171.

Fundamental to Jackson’s thinking was the notion of knowledge and the evolutionary organization of the nervous system, constituted on a nested system of analyses of experience. As an example, we can consider Cassirer’s three levels of spatial knowledge in Jacksonian terms as arising out of a hierarchical nervous structure which allows space to be presented to the organism, then represented, then re-represented. At the level of active space, we have ‘A distinction like that of Cassirer’s was offered by Hart and Moore (1973), who separated fundamental spatial concepts and macrospatial cognition. These problems are not independent-they are merely two aspects of the same generic problem. Our primary concern in this paper is macrospatial cognition. The fundamental concepts of space include orientation and locomotion in proximate space, in which the objective can be directly perceived. This involves three organ systems and their movements--eyes (visual), head (vestibular), and the axes of movements about the torso (verticulomotor) (Shemyakin, 1962). The coordination of these three systems by the brain determines the individual’s knowledge of the three basic dimensions or axes about which all information is organized: up-down, front-back, and left-right (Harris, 1973). The general problem of proximate ‘‘way finding,” or orientation in proximate space, is dealt with extensively by Hart and Moore (1973). HowardandTempleton( 1966), LaurendeauandPinard(l970), PiagetandInhelder(1967). Pick (1970), Wapner et al. (1971), and Wapner and Werner (1957).

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“hardwired” programming which makes spatial calculations of experience sufficient to organize the organism’s movements in space. This level is, in Jackson’s terms, highest in “automaticity.” Constituted upon this lower level, with sufficient evolution of the brain, a higher-order analysis becomes possible. One then gets perceptual space. Finally, in man, with the possession of such featured as frontal and parietal cortex, one gets re-representation and the possibility of symbolic space. The notion of the structure of thought as built on presentation, re-presentation, and re-representation is Spencer’s; Jackson took it, with acknowledgments, in his Croonian Lectures (Jackson, 1884). In The Integrative Action of the Nervous System, Sherrington (1906) developed Spencer’s and Jackson’s theses further. He argued that in the line of evolution leading to man, the role of the distance receptors increases. In man the cerebellum is the “head ganglion of the proprioceptive system” while the cerebrum is the “head ganglion of the ‘distance-receptors.’” It is the long serial reactions of the “distance-receptors’’ that allow most scope for the selection of those brute organisms that are the fittest for survival in respect to elements of mind. The “distance-receptors” hence contribute most to the uprearing of the cerebrum [p. 3321.

With the development of the distance-receptors (eyes and ears), more and more of the spatial environment comes into the organism’s receptive range. The ascendancy of “distance-receptors” in the organization of neural function may be partly traceable to the relativefrequency of their use. . . . The frequency with which a receptor meets its stimuli is, other things being equal, proportionate to the size of the slice of the external world which lies within its receptive range. Although in a fish, for instance, the skin with its tango-receptors is much larger in area than are the retinae with their photo-receptors, the restricted “receptive-range”-the adequate stimulus requiring actual proximity-of the former gives a far smaller slice of the stimulus-containingworld to the skin than pertains to the eyes . . . the greater richness of the neural construction of the photo-receptive system than of the tango-receptive accords with this [p. 3331.

The extension of environmental knowledge is possible only because of the development of distance-receptors, whose anatomical location defines the ‘head’ of the organism. The animal’s receptive range is not equal in all directions as measured from the organism itself. The extension is greater in the direction about the ‘‘leading’’ pole. The visual receptors are usually near the leading pole, and so placed that they see into the field whither progression goes. . . . The elongated motor machinery of the rest of the body, is therefore from this point of view a motor appendage at the behest of the distance-receptor organs in front. The segments lying at the leading pole of the animal, armed as they are with the great “distance” sense organs, constitute what is termed the “head” [p. 3351. The head is in many ways the individual’s greater part. It is the more so the higher the individual stands in the animal scale [p. 3491.

Developmeni of Spaiial Representon’ons We see that the distance-receptors integrate the individual not merely because of the side ramification of their arcs to the effector organs through the lower centres; they integrate especially because of their great connexions in the high cerebral centres [p. 3521.

In effect, man is neurologically predisposed to gain knowledge of distal space. In The Evolution of Human Nature C . Judson Herrick (1956) argued that the construction of symbolized space is inherent in the design of the associational areas of the cortex. His argument may be paraphrased somewhat as follows: 1. Ideas of space and time are organized through experience. The newborn babe . . . lives in a world of space-time, just as the ameba does. Space and time, however, are individuated so early in his psychogenic experience of the surrounding world that in later life these ideas are regarded as intuitions, that is, as simple primary elements of experience-and this they certainly are not [pp. 275-2761,

2. The construction of three-dimensional extended space, abstracted from time, is a mental act or construction. In both phylogenetic and embryological development, unconscious action in fourdimensional space-time precedes our perceptual individuation of three-dimensional space and linear-dimensional time. . . . In perception the three dimensions of space are integrated in immediate experience because they can be measured in the same units of length. . . . Duration of time, however, cannot be measured in meters, and so the units employed cannot be perceptually integrated with the three dimensions of space. In naive experience, accordingly, space and time are separately apprehended as disparate elements of experience [p. 2761.

3. Since the construction of space is a mental act, perhaps unique to the primates and man, it is integrative in nature. All mental acts that we know anything about are total patterns of integrative type. The search for the origin and biological factors of mental evolution, accordingly, should begin with the general properties of the integrative apparatus. . . . Consciousness as we experience it seems to be a high-level integration of . . . nervous processes [p. 3221.

4. Integrative acts are patterns of association cerebral cortex. [There is a] fundamental difference between the analytic processes of the projection centers and the synthetic processes of the associational tissue. . . . The history of the evolution of the projection centers and the intervening areas of elaboration of sensorimotor experience shows that the former were localized in mosaic patterns from the beginning of cortical differentiation and that the integrative apparatus was progressively enlarged and structurally segregated in the areas between the projection centers. . . . There are . . . some ill-defined regions [association] which are concerned usually and by preference with different types of mental functions [p. 4301.

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Arising from a history of philosophical and neurological analysis, we have the development of an argument that knowledge of extended space is a mental construction. This construction is a kind of temporal integration which man is neurologically predisposed to create.

B. SYMBOLIZED SPACE How is this knowledge encoded in symbols? The form of the model of symbolic space is a product of a particular society and its conventionalizations. Just as the child develops cognitively in the direction of a closer approximation to a socially constructed reality, so the model of the environment is symbolized in coordination with this reality. Berger and Luckmann (1967), in The Social Construction of Realiry, argued that: In primary socialization . . . there is no choice of significant others. Society presents the candidate for socialization with a predefined set of significant others, whom he must accept as such with no possibility of opting for another arrangement. . . Since the child has no choice in the selection of his significant others, his identification with them is quasi-automatic. For the same reason, his internalization of their particular reality is quasi-inevitable. The child does not internalize the world of his significant others as one of many possible worlds. He internalizes it as the world, the only existent and only conceivable world [ p. 1341.

.

It is language that must be internalized, above all: The common objectifications of everyday life are maintained primarily by linguistic signification . . .. which I share with others in a taken-for-granted manner. . . . I encounter language as a facticity external to myself and it is coercive in its effects on me. Language forces me into its patterns. . . . Language provides me with a ready-made possibility for the ongoing objectification of my unfolding experience. . . . Language also typifies experiences, allowing me to subsume them under broad categories in terms of which they have meaning not only to myself but also to my fellowmen [pp. 38-39].

What one sees is based on exterior form, but how one scans and categorizes affects the decisions of perception. The Aleuts have no native names for the great vertical features of their landscape: ranges, peaks, volcanoes, etc. Yet the smallest aqueous feature-riffle, streamlet, or pond-has its own name because the tiny waterways are the features of the environment vital for travel (Lynch, 1960). The reference system on the island of Tikopia is tied to a particular edge of the landscape. The island is small and one is rarely out of sight or sound of the sea. The Tikopians use the expressions “inland” or “seaward” for all kinds of spatial reference. One man was overheard to say to another: “There is a spot of mud on your seaward cheek [Lynch, 1960, p. 1291.” Being a social animal and developing within a social context, man construes reality in the terminology of his culture. Part of this reality is symbolized space. With the re-representation of space in a symbolic form, particularly in the met-

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ricized symbols of Western culture, one has the basis for what we generally consider to be the most sophisticated understanding of space. Concrete operations can become formal operations. Calculations pertaining to perceived space, time, and causation can be extended productively by recourse to events occumng in fantasy spaces and times. We generally project the development of the child’s knowledge of space as a directional movement toward attainment of this symbolized knowledge.

c. THE DEVELOPMENT OF SPATIAL KNOWLEDGE Some developmental psychologists have consistently argued that children’s cognitive development proceeds through progressively more elaborate integrations of differentiated and “distanced” percepts. Werner (1948, 1957) argued that spatial knowledge is elaborated according to the orthogenetic principle: “Wherever development occurs, it proceeds from a state of relative globality and lack of differentiation to a state of increasing differentiation, articulation, and hierarchic integration [Werner, 1957, p. 1261.” Spatial knowledge is elaborated at three integrative levels, analagous to Cassirer’s three orders: action-in-space, perception-of-space, and conceptionsabout-space. These systems coexist in the adult. The latest to become fully elaborated, and the most conceptually sophisticated, arises out of symbol formation (Werner & Kaplan, 1963). The central notion in [an organismic theory of symbol formation] . . . is that of dynamic schematization . . ., characterized as a directive, regulative. form-building process . . . objects are given form, stmcture, and meaning through inner-dynamic schematization activity. . . . This inner-dynamic activity through which objects of cognition are formed must be considered genetically, that is, as an unfolding or “microgenetic” process: we hold that the formation of referential objects starts from a primordial matrix composed of affective, interoceptive, postural, imaginal elements, etc., that i s directed or channelized into a full perceptual articulation by the schematizing activity [pp. 17-18).

The developmental analysis of children’s knowledge of space will be discussed in some detail in the final section of this paper. It suffices for now to note that what has seemed “higher” in philosophical and neurological discussions has been taken as a directional principle in modern discussions of cognitive development. Child development is seen as the consummation of an evolutionary tendency. Using similar kinds of reasoning, there has been a consistent tendency among neurologists to interpret pathology as dis-evolutionary.

D. ON THE DISSOLUTION OF SPATIAL KNOWLEDGE The temporospatial background against which we register objects and events loses its constancy in psychotic states (Bert Kaplan, 1964), drug-induced states

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and their sequelae (Hall, Rosenberger, & Monty, 1974), and in states of meditation (Deikman, 1963, 1966a, 1966b). In these states our normally sharp, clear, and constant perceptions partially “dissolve” and lose their keenness. These kinds of data suggest that the cognitive construction of space and time are vulnerable. Dating back at least to Jackson (1884), there have been repeated suggestions that lesion or trauma of the cerebral cortex leads to dissolution of function. Dissolution is a term I take from Spencer as a name for the reverse of the process of evolution. . Evolution is a passage from . . .. the lowest, well organized, centres up to the highest, least organized, centres . . . from the most simple to the most complex, again from the lowest to the highest centres . . . and from the most automatic to the most voluntary. . . . The highest centres, which are the climax of nervous evolution, and which make up the “organ of mind” (or physical basis of consciousness) are the least organized, the most complex, and the most voluntary. So much for the positive process by which the nervous system is “put together”-evolution. Dissolution being the reverse of the process of evolution . . . is a process of undevelopment; it is a “taking to pieces” in the order from the least organized, from the most complex and most voluntary, towards the most organized, most simple, and most automatic. The symptomatology of nervous diseases is a double condition; there is a negative and there is a positive element in every case. Evolution not being entirely reversed, some level of evolution is left. Hence the statement, “to undergo dissolution” is rigidly the equivalent of the statement, “to be reduced to a lower level of evolution”. . . . Loss of the least organized, most complex, and most voluntary, implies the retention of the more organized, the less complex, and the more automatic. Now, suppose that from disease the normal highest level of evolution (the topmost layer) is rendered functionless. This is the dissolution, to which answer the negative symptoms of the patient’s insanity. I contend that his positive mental symptoms ar.e still the survivals of his fittest states, are survivals on the lower, but then highest, level of evolution [pp.

..

45-47].

The notion that spatial knowledge, specifically, is subject to dissolution, can be found in the literature of German neurology in the years between 1900 and 1940. For example, Potzl argued that the minor hemisphere (the right hemisphere in most right-handed people) produces the temporospatial background for “the constantly moving world image,” and that lesions or trauma of the right hemisphere produce disturbances in the spatiotemporal functions (Gloning & Hoff, 1969). Critchley (1953) documented disturbances in visuospatial functioning consequent to damage of the parieto-occipital region of the right hemisphere. Among these disturbances are topographical memory loss (loss of memory for familiar places), loss of map-reading ability, visual agnosia (inability to recognize objects), constructional apraxia, and prosopagnosia (loss of the ability to recognize faces).* *There is an enormous literature in the area of clinical neuropsychology relevant to knowledge of space. Disturbances in spatial knowledge often result from damage to the parieto-occipital region of

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Luria (1966) devoted several chapters to disturbances of higher cortical functions following lesions of the occipital and paneto-occipital regions, and provided an excellent history of the problem. The central apparatus of visual and tactile analysis is encompassed in the parietal and occipital regions of the cerebral cortex (Luria, 1966). The form of optic agnosia we have described is based neither on a disturbance of “memory images”, nor on a disturbance of the symbolic function . . .. Rather, . . . optic agnosia is a complex visual disturbance of the synthesis of isolated elements of visual perception, and of the integration of these elements into simultaneously perceived groups, the basic processes in the normal recognition of whole pictures [pp. 139-14q.

Luria (1966) stressed the importance of the parieto-occiptal region for spatial synthesis. We have seen that a lesion of the parieto-occipital divisions of the cortex may cause important disturbances in the “synthesis of individual elements into simultaneous groups,” as Sechenov [ 18911 originally pointed out. These disturbances lead to considerable changes in visual perception, in spatial orientation, in the performance of certain logical-grammatical operations, and in calculation functions evidently closely associated with disturbances of the complex forms of spatial analysis and synthesis [p. 164.

In The Man With a Shattered World, Luria (1972) gave an account of a man whose spatial synthesis had been disrupted. He described the area of damage thus: Naturally, other, more complex sectors of the cerebral cortex affect our simultaneous grasp of spatial relationships. These sectors are adjacent to the occipital, parietal, and temporal areas and constitute one of the mechanisms of the ‘‘tertiary” cognitive part of the cortex (at this point it could be termed the “gnostic” part). The function of the latter is to combine the visual (occipital), tactile-motor (parietal), and auditory-vestibular(temporal) sections of the brain. These sections are the most complex formations in the second block of the human brain. In the process of evolution they were the last part of the brain to develop, and only in man did they acquire any vigor. They are not even fully developed in

the right cerebral hemisphere. The pathology of spatial knowledge is discussed by: Anigoni and DeRenzi (I%), Benton (1967, 1972; Benton & Fogel, 1962). Brain (1941), Colonna and Faglioni (1966), Critchley (1953). DeRenzi er al. (DeRenzi & Faglioni, 1965, 1967; DeRenzi, Faglioni, Savoiardo, & Vignolo, 1966; DeRenzi, Faglioni, & Scotti, 1969, 1970; DeRenzi, Faglioni, & Spinnler, 196% Durnford and Kimura (1971), Ettlinger, Warrington and Zangwill (1957), Harris (1973). Hacaen. Penfield, Bertrand, and Malmo (1956; Hecaen & Assal, 1970), Levy (1969). Luria (1964, 1966). McFie, Piercy, and Zangwill (1950; McFie & Zangwill, 1960), Mountcastle (1%2), Newcombe and Whitty (1973). Paterson and Zangwill (1944, 1945a, 1945b). Piercy and Smith (1962), Reitan and Tarshes (1959; Reitan, 1955), Rude1 and Teuber (1971), Semmes, Weinstein, Ghent, and Teuber (1955, 1963; Semmes, 1%8), Smith (1966), Taylor and Warrington (1973). Teuber (19631, Vinken and Bruyn (1969), Warrington and lames (1967a. 1967b), Weinstein, Semmes, Ghent, and Teuber (1956; 1964), Whiny and Newcombe (1963, and Zangwill (1950, 1951, 1960).

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the human infant but mature gradually and become effective by ages four to seven. They are extremely vulnerable and even a slight impairment disrupts their function. . . It was precisely these ”tertiary” sectors of the cortex that the bullet fragment had destroyed in this patient’s brain [p. 301.

.

The quotes just given are representative of a mass of neurological writing that has consistently taken the Jacksonian principles as a useful general outlook on nervous system function. Within such an outlook it is assumed that such entities as spatial knowledge rest on a hierarchical establishment of higher-order cerebral function. Pathology is associated with dissolution or “undevelopment” of function. Assumptions much like these are at the core of the generally accepted psychiatric outlook on psychopathology.

E. SUMMARY Rationalistic philosophical arguments have consistently held that spatial knowledge arises through conceptual constructions elaborated upon the temporal integration of successive perceptions. This kind of philosophical analysis is most consistent with the constructionistic information-processing and genetic epistemological frameworks of current psychological inquiry. Evolutionary analyses of the organization of the brain have, in effect, given flesh to this kind of argument by holding that the human brain is organized to permit such complex constructions of space and time. These kinds of arguments rest on empirical elements, but generally the theses rest on the principle of consistency rather than the principle of proof. The arguments are designed to “hold together” a set of facts and intuitions, make a pattern out of them, and they do not arise out of a conventional hypothesis-andtest pattern. Nevertheless, it can be argued that this is a reasonable, and perhaps necessary, way of making headway on certain kinds of psychological issues (Overton & Reese, 1973). The gist of the picture so far developed is as follows. Spatial knowledge arises from the integration of successive perceptual experiences. There may be orders of such integration to elaborate an active space, a perceptual space, and a symbolic space. Symbolic space is a cultural creation. Generally, theorists have held that the direction of cognitive development in childhood is toward the capability to participate in the highest-order, symbolized knowledge of space. Depending, as it does, upon full function of the nervous system, higher-order spatial knowledge is vulnerable to pathologic dissolution, either temporarily as in altered states of consciousness, or permanently as in various forms of parieto-occipital insult.

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111. Spatial Representations: Functions And Components A. MODELSOF MACROSPACE Human models of large-scale environments have been given various names by researchers. In one of the earliest studies of the spatial images people carry around in their heads, Trowbridge (1913) referred to them as imaginary maps. Shemyakin (1962), in discussing Soviet literature on spatial orientation, used the term mental map. A number of city designers and geographers use the terms environmental image (Appleyard, 1969, 1970), spatial image (Boulding, 1956; Lynch, 1960), and spatial schema (Lee, 1968). Tolman (1948), Downs and Stea (1973), and S. Kaplan (1973) used the label most familiar to psychologists, cognitive map. The terminology has a tendency to suggest pictures or maps, but a variety of research indicates that “images” are not “maps” and are often not even maplike. 1. The representations are typically fragmented. Areas of considerable detail are linked with areas having little or no detail and are often separate from one another. Appleyard (1970) asked adults in an urban setting in Venezuela to draw a map of their local areas. He was able to distinguish eight different types of production. Only 3% of these productions resembled what one might call a “cartographic” map; 77% of the productions were fragmented, i.e., a few landmarks strung together with little detail in between. 2. The representations are often distorted. Lee (1970) has shown that if two urban facilities are equidistant from an urban resident, the one located on the “downtown” side is indicated as being closer than the one which is away from the center of the city. In the sketch maps drawn by residents, Appleyard (1970) and Lynch (1960) have found that even topological and projective relations are often not retained. 3. The representations are often several separate, but interlaced representations of smaller chunks of the environment. Ladd (1970) found that the sketchmap of one adolescent who had recently moved into the area contained streets and landmarks of the old neighborhood blending into streets of the new neighborhood. Schadler and Siege1 (1973) asked kindergarten children to reproduce a model of their classroom from memory. Clusters of furniture in the classroom were reproduced as a group, but the relation of these clusters to one another was neither topologically nor projectively isomorphic with the classroom itself. 4. The representationsdo not need to be entirely visual. Tolman’s (1948) kind of “cognitive map,” at least, referred to a “field map” of the environment, based primarily on tactile and olfactory inputs.

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Spatial models may allow an individual to draw a map, but in all likelihood the model in itself is not maplike. Successive links may be correctly reproduced, but the gestalt is typically not a good one (Appleyard, 1969, 1970; Downs & Stea, 1973; Lynch, 1960). To avoid the problem of the connotative meaning of map, we here use the term “spatial representation.” This term was chosen because of its lack of maplike connotation and because it seems to be a more generic taxonomic category, one of whose members could well be cognitive maps.3

B. THEFUNCTIONS OF THE MODEL The primary function of the spatial representation is to facilitate location and movement within the larger physical environment and to prevent getting lost. Lynch (1960) has argued that the original function of the image of the environment is way-finding. This is consistent with the positions taken by Boulding (1956), Menzell (1973), and Downs and Stea (1973). The second major function of the spatial representation is to act as an organizer of experience. According to Lynch (1960): In a broader sense [the image] can serve as a general frame of reference within which the individual can act, or to which he can attach his knowledge. In this way it is like a body of belief, or a set of social customs; It is an organizer of facts and possibilities. . . . The environmental image may go further, and act as an organizer of activity. . . At other times, distinguishing and patterning the environment may be a basis for the ordering of knowledge [p. 1261.

.

S. Kaplan (1973), in an excellent evolutionary analysis of cognitive maps, argued that the cooperative hunting of big game required a cognitive map. Perception, prediction, evaluation, and possible courses of future action can be represented in a cognitive map. Possible future situations are codable. Spatial representations provide frames of reference for understanding information for which locus is or could be an issue.

Information relevant to adults’ spatial representations of the large-scale environment is, with only minor exceptions, not found in the literature of psychology, but rather, in the literature of geography and urban planning. The single most recent and comprehensive statement of the “state of the art” can be found in Image and Environment, edited by Downs and Stea (1973). This book includes a fine review by Hart and Moore of the development of spatial cognition. Unfortunately, only a small portion of the bibliographical references provided in image and Environrnenr is concerned with truly large-scale environments. Among the most important of these are: Appleyard (1969, 1970), Blaut, McCleary, and BIaut (1970). Boulding (1956). Carrand Lynch (1968), Carr and Schissler (1969), Craik (1970). Downs (1970), Goodovitch (1967), Ladd (1970), Lee(1968, 1969, 1970), LowenthaI(l961), Lowrey (1970), Lynch (1960), Rand(1969), Stea(1965; Stea & Blaut, 1973; Stea & Downs, 1970), and Wohlwill (1970).

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c. THEELEMENTSOF THE MODEL Most theorists (e.g., Gladwin, Appleyard, Downs & Stea, etc.) essentially agree that landmarks and routes are the predominant elements of spatial representations. From a logical point of view it can be argued that landmarks and routes are perhaps the necessary and sufficient elements for “minimal” representations that allow “way-finding’’ to occur. 1 . Landmarks Landmarks are unique configurations of perceptual events (patterns). They identify a specific geographical location. The intersection of Broadway and 42nd Street is as much a landmark as the Prudential Center in Boston, the Eiffel Tower in Paris, or the billboard advertising Winston cigarettes. A person’s account of his spatial representations generally begins with landmarks, and these landmarks are the strategic foci to and from which the person moves or travels. For the child, “school,” “ballpark,” and “home” are the strategic foci; for the Puluwat navigators, Puluwat and Pikelot are the strategic foci. One’s conscious knowledge of where one is going is “landmark” knowledge. We are going to the park. We are coming from home. Landmarks are used as proximate course-maintaining devices. Not only do they identify beginnings and endings, but they also serve to maintain course. Gladwin ( 1970) wrote of the Puluwat navigators: The most common seamarks are reefs. , . . The reefs despite their depth can readily be detected from a canoe. . . . In the daytime a reef can often be detected a mile or two away by the whitecaps it creates, while at night it imparts a special uneasiness to the motion of a sailing canoe. . . . Every reef has its unique outline. . . . Thus reefs not only can serve as guideposts along the seaway to an island but also can provide a screen to arrest a canoe if it has strayed from its course, or even gone past its destination [p. 1621.

One uses landmarks as intermediate course-maintaining devices because their use makes the navigational directions conservative. Whenever possible a course is set so that reefs, or better still, islands which can be seen from afar, lie in a direct line k y o n d the destination, a screen to catch the canoe if it should miss its mark. . . . This illustrates an essential characteristic of Puluwat navigation: sailing directions are always conservative, incorporating every precaution the seaway can offer [pp. 162-1631,

Landmarks are unique patterns of perceptual events at a specific location, they are predominantly visual for human adults, they are the strategic foci to and from which one travels, and they are used as proximate or intermediate coursemaintaining devices.

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2. Routes Whereas landmarks were considered as being predominantly visual, routes are predominantly sensorimotor. Routes are nonstereotypic sensorimotor routines for which one has expectations about landmarks and other decision points. If one knows at the beginning of a “journey” that one is going to see a particular landmark (or an ordered sequence of landmarks), one has a route. Routes are partly indexed by their termini, which are landmarks. Between any two landmarks there is probably a huge number of potential routes. However, efficiency (i.e., least effort) and physical plausibility reduce the number of “functional” routes between two landmarks to a very limited number. Route knowledge is to some extent sequence knowledge. If the expected landmarks do not occur the question is raised as to “what am I doing here? Am I on the right road?” Routes give shape to the spatial representation. They represent habitual lines of movement and familiar lines of travel (Lynch, 1960; Zaporozhets, 1965, 1969), and thus they constitute a first-order, “enactive” representation of the terrain. One can conceive, then, of the environment consisting of potential landmarks connected by potential routes. One can picture a spatial representation as landmarks (visual ‘‘pegs”) connected by routes (sensorimotor “lines”), to some extent guided by sequence learning. 3. Conjigurations In addition to landmarks and routes, a third useful and often-present element of a spatial representation is constituted by gestalt knowledge. Knowledge of configuration gives something more than a minimal map. It is a sophisticated wrinkle that gives its owner an advantage in way-finding and organizing experience. There seem to be at least three types of such knowledge of configurations: A perceived outline of a terrain (e.g., the outline of a United States map); a graphic skeleton (e.g., a schematic portrayal, a spatial representation of London as a set of routes leading from a diagrammatic image of the subway system); and a figurative metaphor (e.g., the “boot” of Italy). These “configurations” enhance way-finding, and they may be a necessary condition for inventions of new routes. We would argue that all spatial representations are functionally “landmarksconnected-by-routes,” but that there are varying degrees of integration or gestaltness of the spatial representation. [It is quite possible that these integrated spatial representations are analagous to the mental representation which makes face-recognition as quick a process as it is (Freedman & Haber, 1974; Haber & Hershenson, 1973).] A number of authors have discussed two levels of maps and have discussed route maps as being developmentally prior to survey maps. Shemyakin (1962) has made this distinction in maps produced by children, and has argued that the

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survey maps are characterized by configurational-gestalt elements. Appleyard (1969, 1970) had adults in Ciudad Guyana (an urban setting in Venezuela) draw maps of both the whole city and their local areas. He distinguished two main categories of production; drawings which were sequentially dominant and drawings which were spatially dominant. He noted that many subjects would build up their drawings along paths of movement, “hesitating at intersections as if mentally travelling the journey [Appleyard, 1970, p. 1101.” He found that with increasing familiarity with the area (i.e., length of residence) the use and frequency of spatially dominant maps increased. For example, whereas only 20% of the newcomers (less than one year in residence) produced spatially dominant maps, 40% of the older residents did. The existence of spatially dominant maps may depend on amount, directness, and quality of experience. The maps of residents who traveled to and from the city entirely by bus were compared to another group of residents who traveled to and from the city entirely by car (education levels of the two groups were equated). Of the “bus” travelers, only 20% drew coherent maps of the urban road system, whereas almost all of the “car-travelers’ ’ drew maps which were coherent and continuous. Evidence supporting a distinction between route vs. survey spatial representation comes from the literature of neuropsychology. Kolodnaya has claimed that parietal lobe damage destroys both route and survey representations, while temporal lobe damage destroys only survey-type representations (Shemyakin, 1962). Critchley (1953), Paterson and Zangwill (1944), Luria (1966), Zangwill (1951) and others have found that lesion or trauma in the parieto-occipital region of the right hemisphere destroys the ability to produce a “survey” representation. Warrington and James ( 1967a) have provided evidence that patients with right hemispheric lesions do significantly more poorly on recognition of familiar and unfamiliar faces than do patients with left hemispheric lesions or normal adults. This effect was particularly striking for patients with lesions of the right parietal lobe. The loss of topographical memory (survey representations) and prosopagnosia seem clearly related and seem to be dual functions of the right parieto-occipital region.

IV.

How Adults Form Spatial Representations as a Function of Experience

How does an adult construct a spatial representation of a new geographical terrain or macrospace? Generally, spatial representations appear to be figurative constructions arising out of a foundation of perceptions and practical activity (Piaget, 1968; Piaget & Inhelder, 1967; Piaget, Inhelder, & Szeminska, 1960).

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They are typically the result of intersensory connections, primarily visual-motor-kinesthetic, and are not the result of any one modality of sensations (cf. Stea & Downs, 1970; Tolman, 1948).4

A. THE IMPORTANCE OF LOCOMOTION Actual locomotion in space appears to be an almost essential condition for the construction of spatial representations (Carr & Schissler, 1969; Lee, 1968; Lynch, 1960). Lee (1968) argued that spatial representations arise and “jell” as a result of practical activity. Gladwin (1970) found that the Puluwat navigators learn the spatial arrangement of islands through an apprenticeship-experienceof traveling the seaways between islands. Appleyard (1970) found the degree of direct contact with an environment (driving a car as opposed to being driven in a bus, or the length of residence) was related to the quality of the produced spatial representation. Ladd (1970) studied the maps black urban adolescents drew of their neighborhoods and found that the quality of the map and richness of detail increased as experience in the environment and the functional activity sphere of the children increased. She argued that “. , . Walking is intimate to the environment and therefore articulates the schema [p. 971 .” Thus, action or locomotion in the locale adds to, enhances, and articulates the spatial representation. An important point is that spatial representations arise in systems that one would generally characterize as enactive or figurative. The kinds of production elicited in studies require the subject to portray this level of knowledge in a symbol system. In doing so, it is likely that much is not captured. A drawn map is a representation of the enactive or figurative in a performance system. So also is a person’s verbal description of his spatial representation.

B. LEARNINGMECHANISMS Established sequences in adult learning suggest that certain kinds of learning mechanisms must be involved in the process. The organizations around landmarks suggest that a “recognition-in-context-memory”is an early learning mechanism. The dependence of route learning on activity suggests that some kind of sensorimotor sequencing is being established. Finally, the tendency of route maps to become interorganized as survey maps suggests that there is a sequence from association to structure.

‘As a kind of tour de force, one person can “develop” a spatial representation in the mind of another through presentation of entirely auditory-verbal instruction or entirely visual diagrams or maps. However, in our judgment, this is possible only with highly symbolized intellectual development, e . g . , children who can receive extended verbal or graphic instruction. In the process, one probably engages, through symbolism, figurative and sensorimotor structures which are intrinsically intersensory .

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1 . Recognition-in-Context-Memory: The ‘‘Now Print!” Mechanism The prominent role of landmarks in early spatial representation seems to require a special kind of figurative memory. We may call this a “recognition-in-context” memory. It is insufficient when one sees a landmark to know, “I’ve seen that before.” One must know something about that landmark, what it implies, what it is next to, when it last occurred, what its connection is with other landmarks. Such a memory might be derived from a “Now Print!” mechanism proposed by Livingston (1967a, 1967b) as a neural basis of reinforcement in learning. Since a number of investigators are persuaded that learning occurs as a result of growth processes taking place at cellular junctions, Livingston suggested that such growth is induced as a result of the brain’s being further aroused through its pickup of “biologically meaningful novelty”: Any novelty has potential biological significance, and is signaled by initial reticular activation. The function of the ventricular lining and front-limbic systems is to evaluate significance of the new message. Limbic-induced discharge enters a particular part of the reticular formation and thereby induces a generalized arousal. I have proposed that a consequence of this particular reticular discharge pattern is a generalized order, “Now Print!”-an order for all neurons recently activated to undergo growth. Whatever patterns-sensory , motor, associational-are active whenever any biologically important event is repeated, will be printed, reprinted, and overprinted into habit through the exercise of this limbic-reticular “Now Print!” discharge consequent to the indentification of novelty and its assignment of biological significance [ Livingston. 1967a. pp. 514-515].

Livingston (1967b) proposed the following sequence of the operation of “Now Print !”: The steps are postulated to occur as follows: ( I ) reticular recognition of novelty; (2) limbic discrimination of biological meaning for that individual at that moment; (3) limbic discharge into reticular formation; (4)a diffusely projecting reticular formation discharge distributed throughout both hemispheres, a discharge conceived to be a “Now Print!” order for memory; and finally ( 5 ) all recent brain events, all recent conduction activities will be “printed” to facilitate repetition of similar conduction patterns [p. 5761.

Livingston argued that only biologically meaningful events, only events receiving reinforcement (by a sensory reinforcing, by a sensory approach, or by a central reinforcement signal) can contribute to the last three stages of the “Now Print! sequence. Probably most adults today will remember precisely where they were on November 22, 1963, when they received the news that President Kennedy had been assas~inated.~ It is highly likely that most adults can remember where they ”

%e notion of one-trial learning under the influence of strong emotion. or its possibility, is not a new idea. Warren (1921) has traced its ancestry to the British Empiricists of the 18th century. For a variety of reasons, the notion was not carried forward in time, and does not appear in the writings of contemporary leaning theorists in the 20th century. Livingston’s “Now Print!” mechanism reintroduces the concept in the literature of the neurosciences.

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were and with whom, whether they were standing, sitting, or walking, and how they felt. The essence of Livingston’s argument is that, at the time of a biologically meaningful event, the nervous system is stimulated to take a picture of itself. This would include registration of the event, its context, and the state of the organism at that moment. Suppose that landmarks are meaningful events and that the nervous system is continually taking pictures of landmarks. The clarity of the photograph and the extent of the landmarks’ spatial and temporal context included is determined by the degree of meaningfulness, novelty, and/or “emotion-value” of that event for that person at that point in time. The photographs taken in such a scheme would be multimodal. Perceptual, cognitive, motor, and affective components would be included. One would have to suppose that: (a) Among the biologically meaningful events sufficient for a “Now Print!” would be the execution of a decision in locomotion (a change in bearing or heading) and (b) The context cues provided in individual pictures would provide extra information sufficient to link such pictures in systems of routes or survey representations. These do not seem unreasonable assumptions to attach to Livingston’s hypothesis. If such assumptions were true, “Now Print!” events could serve as the basis for the establishment of landmarks in human spatial representations. Thus, the figurative core of a spatial representation could exist on the basis of a flashbulb going off (an orienting response made, a photograph taken), leading to “recognition-in-context” memory of landmarks. Spatial representations would then develop by organizing a choice-point decision-system between landmarks. Let us consider this aspect further.

2. Route Learning One can consider a route as a conventional sensorimotor system. Although we are not in the position of providing a formal analysis of what this system is, it is possible to point to likely elements or characteristics of what the system must have. 1. A route must involve a sequence of decisions-generally, changes in heading. In several attempts to set up models of route making, we have been unable to project a reasonable kind of route learning without entering into the knowledge system some such entry as “bearing” or “heading.” Unless the organism steers its way through a route by a sequence of line-of-sight approach movements, a kind of process that seems unlikely for all route learning, the organism must compute its decisions in terms of an orientation of the direction of the organism with regard to some feature of the environment. 2. The knowledge of a route could then conceivably exist through a kind of serial learning, a memorized series of decisions. However, it seems much more

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likely that a memorized route would be somewhat more akin to paired-associate learning, changes in bearing associated with the arrival at “stimulus” landmarks. 3. Learning between landmarks is, to some extent, incidental and irrelevant except to the extent that intermediary landmarks serve as course-maintaining devices (and thus as landmarks associated with no change in heading). A conservative route learning system would then be, in effect, “empty” between landmarks. All of the learning would be organized around the nodes of the decision system, the landmarks. In the adult’s construction of a spatial representation, routes become scaled by landmarks in an ordinal and roughly interval sense. Gladwin (1970) described an excellent example of this “scaling” process which he found in “Eruk”-part of the Puluwat navigational system for estimating the distance already travelled on a long journey. For the Puluwat navigators, star positions serve as landmarks under which one passes during a journey. A reference island 50 miles or so to one side of the line of travel and roughly opposite the midpoint of the seaway connecting the islands of origin and destination is chosen. The star bearings of the reference island from both the starting and ending points of the trip are known. In between there are other navigation star positions under which the reference island will pass as it “moves” backward. For the Puluwat navigator . . . [the moving island] is a convenient way to organize the information he has available in order to make his navigational judgments readily and without confusion. This picture he uses of the world around him is real and complete. All the islands which he knows are in it, and all the . . . navigational stars and the places of their rising and setting. Because the latter are fixed, in his picture the islands move past the star positions, under them and backward relative to the canoe as it sails along [pp. 182- 1831.

The number of star positions which lie between the reference island’s bearing as seen from the origin island and its bearing as seen from the destination island determines the number of etuk (segments) into which the voyage is divided conceptually. When the navigator mentally envisions the reference island’s passing under a particular star he notes that a certain number of etuk have been completed, and thus a certain proportion of the voyage has been traveled. A trivial example of this in our modem technological society, where we measure distance in interval units of miles and hours, is the way in which we estimate the portion of the journey already traveled by the number of turnpike exit signs we have passed or by the numbered streets we cross when traveling through a city. To some extent, then, the “empty” space between landmarks receives “scaling” during extended experience with the routes. This may be of significance in the ultimate elaboration of the survey representation.

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3. Pattern Learning Once one locates oneself along a number of routes by a system of landmarks, these routes with termini become interrelated into a networklike assembly as a function of repeated experience, temporal integration, and sustained meaningfulness. Taxi drivers, for example, organize such networklike knowledge of American cities. They associate conditions of time, traffic, road conditions, etc., to components of the network. With such knowledge a taxi driver can plan a route through the maze of city streets which will be both as short as possible, and which will optimize speed of travel under prevailing conditions. To do this he must have in his mind a plan of the city which is not only detailed and complete but has superimposed upon it the flux of traffic as this is governed by the time of day and day of the week. He must be able to superimpose himself on this dynamic map and project his course from start to finish upon it . . . in many ways both the taxi driver and the Puluwat navigator think alike [Gladwin, 1970, p. 2241.

Once routes with termini become interrelated into a networklike assembly, the gaps are gradually filled in [and become Lynch’s (1960) “districts,” “edges,” and “nodes”] . The landmark-connected-by-routes spatial representation becomes more gestalt-like.

C. SUMMARY To sum up our arguments on how an adult constructs a spatial representation of a new terrain: Spatial representations appear to be enactive and figurative constructions arising out of a foundation of perceptions and practical activity. Their development might be seen as requiring three kinds of learning systems. First, landmark knowledge might be based on a “recognition-in-context” memory. Second, route learning might develop initially through a kind of paired association of changes of bearing with landmarks. Some evidence suggests that “scaling” of routes might then metricize them to begin to give survey-like representations. Finally, the routes become interrelated into a networklike assembly, which is or becomes “configurational.”

V. Main Sequences in Adaptation Given the fragmentary nature of our current research information on spatial representation derived from either children or adults. it is tempting to address the interpretation of the child development data using preliminary estimations deriving from both bodies of literature. There is a basis for doing so. There are some formal similarities between adult learning and child development deriving

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from the fact that both children and adults must conform to an essential “Main Sequence” in their organization of spatial representations. One reason for believing this is specific to the issue under discussion. As one confronts analyses of adults, the data that have been discussed, and analyses of child development, the data to be discussed, one is struck by resemblances in the patterns of the two bodies of data. Another reason is more general. This type of sense-of-likeness is a rather familiar experience to the developmental psychologist. One repeatedly senses such similarities across diverse bodies of data. Indeed, the literature of developmental psychology is full of instances of developmental parallelism, recapitulations, and regressions, intuitively and speculatively avowed by one writer and then rationally and scientifically disavowed by the next. It is possible that this tantalizingly recurrent kind of hypothesizing rests on a genuine phenomenon in learning and development-the fact that both adult learning and child development can occur only through certain sequences of behavioral organization, what we here call “Main Sequences.” Because the data on spatial representation suggests the governance of a Main Sequence, it seems worthwhile to digress for a few moments to consider a significant body of data and theory that now supports the tenability of this kind of hypothesis.

A. EVIDENCE FOR DEVELOPMENTAL PARALLELISMS

In the early days of Child Study in the United States, G. Stanley Hall based much of his thinking about child development on a recapitulation of phylogeny in ontogeny . His hypothesis, romantically and incautiously elaborated, was rapidly set aside (Grinder, 1968). Nonetheless, Hall’s argument reflected a more sober analysis of the design features of organizations of behavior that preceded him and that were to continue on after him. The evolutionary biologists (Coghill, 1929; C. L. Herrick, 1904) have characteristically rejected the doctrine of strict recapitulationism, arguing that the laws of organization of a higher level could not, in principle, be completely understood by a complete knowledge of the laws of organization of the lower level. However, they have argued that a number of formal parallelisms exist between simpler and more complex organizations of behavior, parallelisms that can be conceptualized within a framework of “integrative levels” (C. J. Herrick, 1949; Novikoff, 1945; Schneirla, 1957, 1959). C. J. Herrick (1956) wrote: The general principles of integration are the same in the inorganic and the organic realms of nature, but in the animal world these factors are organized in very distinctive patterns which show a remarkable series of changes in complexity and efficiency as we pass them in review from the lower to the higher ranks of animals [p. 104). In our search for the evolutionary factors of animal behavior the ancestry of the species of

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animal in question must be taken into account. Its phylogenetic history must be known because very similar patterns of behavior have been evolved independently in various branches of the phylogenetic tree. In a similar way [to structural homologies] various patterns of behavior which resemble each other may be homologous or analogous or a mixture of the two. We must be careful not to homologize the distinctively human patterns of social organization with the superficially similar patterns seen, for example, in insects, for there is no genetic connection between them. But there are some biological factors which these two series of evolutionary development have in common, and the specifically human traits have arisen naturally by further elaboration of simpler patterns of performance of the primary ancestors of the human race. We can find the precursors of all human symbolisms, human values, and human ethics in the behavior of other animals, although at a much lower level of organization and vastly inferior in efficiency [pp. 106-107l.

Other kinds of parallelisms have been noted in psychological writings. Cassirer (1944) and Werner (1957) have suggested extensive parallels between staged organizations in ontogenesis and microgenesis, and staged disorganizations in pathology. Their writings are related to the work of Schilder, and to those of a group of German writers concerned with Aktualgenese. Schilder (1951) did extensive work in the 1920’s on the development of images and thoughts. He argued that images and thoughts “developed” over relatively short periods of time. Images and thoughts have a development, a pre-history . . . Image and thought development progress from the indefinite to the definite . . . incompletely evolved thoughts contain presentation-fragments from various phases of development . . and are particularly amenable to affective transformation [ p. 5071.

.

Krueger (1928) and his group dealt with the temporal development of percepts and viewed normal cognition as a “microdevelopmental achievement of the organism”; deviations from normal cognition were viewed as developmental arrests. On the basis of experimental work, Sander (1930) provided a detailed description of the microgenesis of perception. Sander believed that perception is a developmental process consisting of a number of conceptually distinct phases, and that percepts following brief exposure are the transitory percepts which precede the final percept under normal exposure conditions (cf. also Werner, 1957). He described the course of perceptual microgenesis-from the initial percept of a diffuse undifferentiated whole, to figure-ground differentiation, to distinct detail in a loose configuration, to a final modified and elaborated gestalt. Both Sander’s (1930) account of the microgenesis of perception and Schilder’s (195 1) account of the microgenesis of thought show interesting similarities to the developmental sequences of perception and thought described by Werner ( 1948) and Piaget (1968; Piaget & Inhelder, 1969). In their review of the literature on the microgenesis of perception and thought, Flavell and Draguns (1957) also pointed out extensive parallels between the

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microgenesis of the two, their development in children, and the pathogenesis demonstrated in schizophrenic adults and normal adults under conditions of stress and time pressure (Flavell, Draguns, Feinberg, & Budin, 1958). Another kind of parallelism has been explored by Teitelbaum and his associates. In a series of animal experiments, they have tested the principle that “recovery recapitulates ontogeny.” Cheng, Rozin, and Teitelbaum (197 1) used semistarvation to slow down development. They found that the stages of recovery from the lateral hypothalamic syndrome [ aphagia and adipsia, anorexia and adipsia, adipsia, recovery, normality (Teitelbaum, Cheng, & Rozin, 1969b)] in the adult rat exactly paralleled the stages of feeding and drinking in the development of the weanling rat. They proposed that, just as development is a process of encephalization, recovery is a type of reencephalization. Teitelbaum (1967) and Teitelbaum, Cheng, and Rozin (1969a) specifically discussed the relationship between the development of reflexes in the infant and their recovery in patients with frontal lobe damage. Peiper (1963) and Milner (1967) have argued that a human infant at birth is very much like a decerebrate animal, whose behavior consists primarily of automatic reflexes of approach and withdrawal. The work of Denny-Brown (1958; Denny-Brown & Chambers, 1958) has shown that infantile reflex patterns reappear after the appearance of cortical damage in the adult. After damage to the frontal lobes, one can observe release of automatisms of approach. Touching or stroking the side of the patient’s cheek near his mouth often elicits mouthopening, head-turning toward the stimulus, and if the mouth makes contact with the stimulating finger, sucking. If the patient is asked why he is doing this, he may show surprise and embarrassment, answering that he was not aware of his action. He might even deny it, yet he may be unable to stop [Teitelbaum, 1967, p. 5611.

The recovery of voluntary control of the hand after frontal lobe damage also parallels the development of such voluntary control in infancy. The progression is the same in both. There have been a number of suggestions that pathogenesis reverses ontogenesis as regards spatial functions. According to Critchley (1953) and Luria ( 1 966) the main defects arising from right parietal (or parieto-occipital) disorders are: (a) “neglect” of the left side of space; (b) right-left disorientation; (c) an inability of the patient to find his way about in a familiar environment, to read maps, or to appreciate spatial representations in plans; and (d) constructional and drawing defects so that the patient has trouble judging distances or comparing dimensions, confuses planes, and adopts a piecemeal approach to the task. Rochford and Williams (1962a, 1962b), Williams and Jambor (1964), and Woodward (1962) argued that‘ signs which are suggestive of parietal defects in adults may often be seen as reconstituting a normal phase in the development of children and further, that such signs may not be fundamentally different from

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those which might occur in normal adults under conditions of stress or distraction. For example, it could be argued that left-sided neglect can be experimentally produced in normal adults. Wyke and Ettlinger (1961) have shown that more pictures are recognized in the right visual field than in the left visual field when pictures are presented tachistoscopically to normal adults. Williams and Jambor (1964) noted that although the dissolution of topographical orientation in patients with right-sided parietal lesions is fairly well documented. The manner in which topographical orientation is developed in children and the stages through which it passes, are not altogether clear from past work. Piaget’s studies have been concerned with elucidating the development of “concepts of space,” rather than the manner in which children find their way about in it [p. 561.

B. T H E MAIN SEQUENCE In view of the crisscrossing parallelisms that have been discussed, it seems reasonable to believe that the progressive organization of a human behavioral adaptation over time and experience has some generally systematic characteristics. There may be one or several Main Sequences identifiable in time sequences of perception, cognition, learning, development, and recovery and, in addition, governing the way in which temporary or acute disturbances of psychological function will manifest themselves. The limited amount of data presently available allows only the broadest suggestions to be made of the nature and form of a Main Sequence, but these data suggest that something like the following may hold with regard to a recurring environmental problem: 1. Human sensorimotor organization can exist only in a fixed and relatively limited number of systematic states. The system-properties of these states are often referred to as “structural” features of cognition. The states themselves are characteristically referred to as “stages” in discussions of child development (although not all the “stages” of contemporary developmental discussions are state systems, as indicated below). 2. The states are ordered for the adapting organism, and this ordering applies to time series as widely diverse as those obtaining in the constitution of a perception over a few seconds or a cognitive organization over a period of months or years. There must be A before B, B before C, C before D, etc. 3. To indicate that a sensorimotor organization is in a state is to describe something about it, but not everything. That something will generally consist of a set of adjectives or functional arguments about the organization, indicating something about its design but not completely describing it. States are partial lists of system properties. Suggestions about parallelism, recapitulation, regression, of the kind noted above, rarely prove out upon examination to lead to exact correspondences. Nevertheless, the hypothesis that there are general states has some

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distinct scientific value. It reduces uncertainty. If one argues that there may be correspondences between the early stages of cognitive development and the early moments in the microgenesis of a thought, one has some basis for expectations, hypotheses, interpretation, even if one does not have the basis for an exact and testable prediction. 4. The notion that there is an ordered time series of states in adaptation applies in a “competence” rather than “performance” view of the adaptation. If one examines human performance over real time, one finds variation in state-level upward and downward as temporary factors of stress, anxiety, lability, etc., variably upgrade or downgrade the choice of states. 5 . It is likely that the existence of Main Sequences in human adaptation depends upon two substrate kinds of design features. One has to do with nervous system construction, e.g., a principle that subcortical adaptations must be established as bases for secondary cortical adaptations. These design features themselves might be related to a second basis. There may be broad systems-analyticproperties (von Bertalanffy, 1968) governing any entity that one would characterize either as “adapting” or “persisting in characteristic organization through change” or “developing. ” This latter consideration would tend to explain why writers like Herbert Spencer and Heinz Werner attributed so many diverse phenomena to the development hypothesis. 6. Some but not all of the diverse “stages” proposed in contemporary developmental theorizing might be related to kinds of Main Sequences being discussed here. Piaget’s six-stage systematization of the development of sensorimotor intelligence would constitute a Main Sequence. His “stages” of sensorimotor intelligence, concrete, and formal operational thought would not. They would represent reestablishments of his basic Main Sequence in successive domains of intellectual organization. Characterizations of the successive states of a Main Sequence may now be becoming possible. The most detailed description of such a sequence may be, as just noted, the sequence identified by Piaget in the first two years of infancy. Using the notion of “vertical decalage,” Piaget posited the reconstitution of this series as a Main Sequence governing figurative, concrete operational, and formal operational adaptations. In other writings, he argued that the construction of reality in the child may be paradigmatic for the social construction of reality in the history of science. Possible Main Sequences in learning have been suggested by Mandler (1962) and Fischer (1971). Mandler (1962) assumed that there is a continuous line of elaboration from associations to cognitive structures: “Structures are temporal and probabilistic linkages of inputs and behavior which are available in functional units. These units . . . may be as simple as a reflex arc . . . or as cognitive as a means-end relationship [pp. 415-4161 .” In this paper Mandler was concerned with the conditions under which structures are developed. He maintained

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that cognitive characteristics of the organism may, in some limited cases, be developed out of associationist processes, He further suggested that “ . . . overlearning experience with the old response and the formation of an analogic structure permits the subject to manipulate that response, to ‘think about’ [p. 4201 .” Thus, Mandler suggested that during the development of learning, separate associations or responses get transformed into structures, as a function of overlearning. These may, in turn, serve as larger functional units in a subsequent learning process. Fischer’s (1971) dissertation research was done with animals and was directed toward the problem of how an organism organizes a linked series of responses into a “seamless whole” or, as Lashley (1951) would put it, an ‘‘arpeggio.” He identified similar stages of organization in the learning of pigeons and rats faced with moderately complex tasks. At first, the animals showed a preponderance of unit responses or elements, disorganized, fragmentary, easily prone to disruption, accompanied by some emotionality. Then, an awkward linked system of motor unit responses appears. It develops slowly and is prone to disruption; the units can easily branch and be reassembled. In a third phase, the behavior is organized and the response system exists, but the performance is stereotypic and ritualistic, given without the possibility of disruption or variation. Finally, in the full development of the learning, the chain of responses has become a unit permitting more flexible adaptation. This last stage in Fischer’s sequence may be the counterpart of that point in the Mandler sequence when association has become structure, or that point in Piagetian developmental sequences when the organized cognitive structure is said to become “flexible” and “mobile.” This kind of sequence could account for the argument that mediational outcomes of learning emerge as a result of overtraining (cf. Reese, 1962). More recently, Fischer (1974) has been concerned with children’s developmental stages in the organization of the ability to seriate. He argued that: These stages depict more than just stages in intellectual capacity. They describe phases in the solution of a problem o f a parficukzr type. The stages that he shows in the task are stages in the solution of seriation and are produced jointly by his cognitive capacities and the difficulty of the specific task. Intellectual development and problem-solving involve essentially the same process. Intellectual development can be treated as problem-solving, and problem-solving can be treated as a developmental process in miniature [termed ‘microgenesis’ by Werner and Kaplan, 19631 [p. 31.

The assertion of parrallelism, of states and Main Sequences governing adaptational phenomena, all constitute a reassertion of an argument advanced some time ago by Bernard Kaplan (1967). In his “Meditations on Genesis” he argued that the concept of development, and the developmental analysis of psychological phenomena, needs to be considered in contexts other than its most customary context, the analysis of age-related and growth-related phenomena.

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VI. The Development of Children’s Spatial Representations With regard to children, the following sequence in the development of spatial representations of the large-scale environment has been identified in the research literature. The sequence is the sequence with which we have become familiar in discussions of adult learning. It is thus, conceivably, a “Main Sequence.” However, within the sequence, the details and parameters are not quite the same as for adults. Within the context of the “Main Sequence,” these differences will be discussed. 1. Landmarks are noticed and remembered.

Insofar as landmarks may be nodes of activity and emotion for children, they constitute the core of the “Now Print!” photograph. The content of the photograph probably changes with age. If one accepts current arguments that the nature of representation changes with development (cf. Bruner, 1964; Piaget & Inhelder, 1969; Werner, 1948), it follows that the photographs taken by children and adults may have different sensory distributions. The photographs of adults are likely to include some interpretive information derived from vague place knowledge. In younger children the photograph is likely to be more “iconic” in the sense that relatively little interpretive information is included. Shemyakin (1962) had children draw maps of their neighborhood, and found that young children tend to draw local objects (e.g., homes, trees) whereas in the productions of older children, these “iconic” drawings disappear and points begin to be substituted for them. In a different vein, the literature in eidetic imagery (Haber & Hershenson, 1973; Kluver, 193 1) seems to indicate a decrease in eidetic imagery with development. Thus, with development the photograph should become less iconic and more “cognitively organized.” The photographs of children relative to adults could entail a proportionately larger motor component. Earlier, the point was made that spatial representations arise and jell out of practical activity. Some recent evidence supports this contention. Shantz and Watson (1971) found that the ability of a young child to predict the location of objects on a mock landscape after he has physically moved around the landscape is positively related to his ability to identify object locations from another’s (a doll’s) point of view. There were no age trends between 3% and 6% years; generally, predicting object sites when the child himself moved was an easy task, but identifying object locations from another’s point of view was not. Munroe and Munroe (1971) and Nerlove, Munroe, and Munroe (1971) studied the relationship between activity range and spatial ability. Their results indicate that African children who spent a relatively greater amount of free time further from the home (i.e., children who had a greater normal activity range) did significantly better than their age-matched counterparts on tests of spatial ability (i-e., copying block patterns). Huttenlocher and Presson (1973) found that chil-

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dren’s performance on predicting the outcomes of object rotations were facilitated by allowing them to walk around the model. Ladd (1970) asked urban adolescents to draw maps of their neighborhood, and found that the quality and detail of the productions were positively related to the extent of the children’s normal activity range. The evidence from these studies seems to indicate that the development and utilization of spatial representations is greatly facilitated (and may well be dependent upon) locomoting in the environment. The importance of motor patterns in the formation of children’s spatial representation is a recurrent theme in the Soviet literature. Shemyakin (1962) wrote: That fact that the “route-map’’ originates and develops on a foundation of real movements in space permits of the assumption that motor patterns play a dominant role in this type of representation. The development of “route-map” representations paves the way for the emergence of “survey-map’’ types of representation. The origins of “surveymap” types of representations would not be possible without the accumulation of a certain quantity of “route-map’’ types of representations; with the help of the latter a given locality is, as it were, presented as a system of roads leading “there” and “back.” It may be assumed that motor patterns likewise necessarily play a part in this type of representation [p. 2201.

The foregoing is not to be mistaken as an argument that the visual component of the “landmark photograph” is minimal in children. This is certainly not the case. In fact there is some considerable evidence indicating that the core of spatial representation is visual recognition memory. from which is derived recognition-in-context memory. Although spatial representations arise and jell out of practical activity, that which is “jelled” has a massive visual component in normally sighted individuals. Smothergill (1973) had 6-7 and 9- 10-year-olds and adults localize spatial targets by pointing with the index finger of their unseen hand. Spatial information was provided visually, proprioceptively, or both visually and proprioceptively. The localization response was made either while the target was present or some number of seconds after it had been removed. Analysis of accuracy and variability indicated no age differences when the target was present, but older subjects did better than younger subjects when pointing at absent (but remembered) targets. Generally, performance in the proprioception condition was worse than in either of the other two conditions. A series of studies by Keogh (1969, 1971; Keogh 8z Keogh, 1%8), in which 8-10-year-old boys were asked to copy patterns by walking, indicated that the pattern-walking of these boys improved across conditions as more visual cues were added. Blackstock and King (1973) demonstrated that the ability of 4-5-year-old children to recognize a seriated configuration clearly preceded the ability to reconstruct one. The results of these studies suggest the important role of vision in spatial relations, and they may bear on the nature of memory for landmarks. Blackstock

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and King found that visual recognition memory developed prior to visual reconstructive memory, while Smothergill found that visual evocative memory developed latest. This is congruent with Piaget’s (1968) suggestion that recognition memory is the most primitive kind of memory, depending only on sensorimotor schemata. In reconstructive memory, the child must have a schema or image which can be activated with much less stimulus support. Evocation memory, somewhat akin to free recall, is the most demanding, as it requires the ability to activate a scheme or produce an image in the absence of any stimulus support. Asso and Wyke (19701, for example, found that visual discrimination of spatial relations is easier than verbal comprehension of spatial relations between ages 4% and 795, and there was no correlation between individual performances on the two tasks. These studies together provide evidence for the assertion that the core of spatial representation is a process of visual recognition memory, relatively independent of verbal processes. [Cf. Siegel, Babich, and Kirasic (1974) for a fuller discussion of the independence of visual recognition memory and verbal processes]. The photographs of children could conceivably have a narrower spatial and temporal context and a larger affective component than those of adults. There is no direct support for this assertion; however, there have been repeated suggestions that the sensory balance in children’s perception differs somewhat from that of adults. von Uexkull (1957) has argued that the Umweft of the adult has a broader spatial-temporal context than that of the child, and Schilder (1951) has contended that early transitory percepts (and the percepts of children and “primitives”) have a considerable affective loading as compared with the final percepts (and the percepts of adults). Landmarks may vary from culture to culture. These landmarks may be taught to children either deliberately or implicitly as significant, distinctive, or contrastive features of the environment (Gibson, 1969). One culture’s differentiated environment is another’s trackless expanse. Lynch (1960) wrote: Jaccard speaks of a famous Arab guide in the Sahara, who could follow the faintest trail. and for whom the entire desert was a network of paths. . . . In quite another landscape, the seemingly impenetrable African forest, the jungle is intersected by elephant paths, which natives learn and traverse as we might learn and traverse city streets [p. 1291.

Children must be ‘‘taught” those landmarks that are peculiarly distinguished by their cultures. As Gibson, Gibson, Pick, and Osser (1962) have shown, the process of detecting distinctive features (i.e., perceptual learning) is slower in young children. Thus, it would be expected that “landmark learning” involving acquired distinctive features would be a more rapid process in older children.

2. Once landmarks are established, the child’s acts are registered and accessed with reference to them. The noticing and distinguishing of landmarks is taught, deliberately or implicitly, so that they serve as organizers and guides to the child’s visual and

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motor exploration of the terrain. The organization of visual (Day, 1974; Yarbus, 1967) and motor (Zaporozhets, 1965, 1969) scanning provides the basis for a decision system governing encounters with the environment about where to look or move next. Concomitant with the development of this decision system, of which landmarks are the anchor points, the child’s acts and “route knowledge” are registered and accessed with reference to these anchor points. Piaget’s work contains a series of studies concerned with children’s representations of the large-scale environment (Piaget 8t Inhelder, 1967, Ch. XIV; Piaget et al., 1960, Ch. I). While these are not reported in great detail, the studies do provide evidence that children are apt to notice and remember landmarks first, subsequently establishing routes connecting these landmarks. In one study (Piaget et al., 1960) children 4- 12 years old were asked to draw and then construct from their drawing a three-dimensional model of the school buildings and the principal features in the immediate locale, to reconstruct the route from school to a well-known landmark, and to change the location of geographical features when the school building was turned through 180”. Piaget characterized Stages I and I1 as ones in which landmarks are uncoordinated and changes of position cannot be described. In constructing the plan of the locale, younger children described changes of position in terms of end-position only, while older children compared paths of movements. That is, landmarks get laid out and described prior to routes connecting them. Younger children make no attempt to link end-point (Landmark A) with starting point (Landmark B). They do not consider both in terms of a more comprehensive system of reference. During Stages I and I1 children give three kinds of responses, all of which seem interrelated: (1) When dealing with a route, they think of their own actions first . . . and the various landmarks are fixed in terms of them. . . . (2) Their landmarks are not organized in tern of an objective spatial whole; the links between any two are conceived of as being independent of the system as a whole. . . . (3) Subjects cannot rotate a plan through 180”. nor can they reconstruct a route in the reverse direction [p. 61.

In congruence with this is Shemyakin’s (1962) finding that drawings prepared by the “survey-method,” typically the productions of older children, failed to accentuate the initial and terminal sections of the route (landmarks), in contrast to drawings prepared by the “route” method. It appears that once landmarks are noticed and remembered in a way that retains decision-relevant distinctive features, and children’s acts are made in the midst of such landmarks, route formation is probably fairly automatic. A basis for a temporal sequence of routes and landmarks then exists. At later stages in the development of landmark-based decision systems, routes are created more and more easily and automatically.

3. Given landmarks, action-sequences, and organized decision systems about where to look next, the child forms clusters of landmarks and “minimaps.”

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These may represent no real elevation in the child’s understanding, and may even be formed inadvertently. In Piaget et al.’s (1960) model construction task, children in Stage IIIA reconstruct routes. They use subsystems of reference which are not coordinated as a whole (i.e.. multiple minimaps). “Their plan of the district is made up of several portions which are correct in themselves but do not agree with one another [p. 8] .” Thus, it seems that Piaget’s research provides evidence for the primacy of landmarks, followed by landmarks getting connected by routes, followed by coordination of a series of routes with termini making up a configuration. Schadler and Siegel ( 1973) asked kindergarten children to construct from memory a three-dimensional model of the arrangement of furniture within their classrooms. It was found that these children tended to produce multiple “maps”. Clusters of furniture in the classroom were reproduced accurately, but the relations between clusters or areas were not properly reproduced. Schadler and Siegel argued that the representations of these children of their classrooms consist of several ‘‘mini-spatial-representations,” and that the children were not able to build up a representation of the environment as a whole. These results accord with Piaget’s description of Stage IIIA in the development of topographical representations found in the “model” experiment. Both sets of results imply that children’s spatial representations of a landscape or large terrain are partially coordinated by the use of landmarks, but the children have uncoordinated spatial representations for different parts of the landscape.

4. A key issue in the development of spatial representation is the child’s formation of some kind of objective frame of reference, and a concomitant organization of outside features into systems in space. Part of what is involved in this process appears to be a progressive differentiation of self-orientation from outside-orientation, and the development of a notion of objective bearing. In one of the earliest studies of children’s reference systems, Freeman (1916) observed that as children grow older they move from orientation with reference to the position of some fixed object or some fixed direction of an object. A child thus achieves a “detached view of a region as though it were seem from a distance [p. 1651.” Pick (1970) argued that the adoption of frame-of-reference defined systems is a developmentally related process, and that the existence of such systems often implies the coordination of perspectives. Dubanoski (cited by Pick, 1970), for example, was interested in the answer to the following question: “If an experimenter stood in front of a blindfolded subject, and tactually traced a ‘d’ on the subject’s forehead, would the subject perceive this as a ‘d’ as if he were viewing it as the experimenter did, or would the subject perceive this as a ‘b’ as if he were viewing it from inside his own head [pp. 199-2001.’’ In studying 6-15-year-old children, Dubanoski found that older children had a frame of reference as if they were standing behind their head and looking forward; young children showed no consistent frame of reference. Additionally, older children

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were able to adopt another frame of reference when told to try to perceive the figure from the experimenter's point of view, whereas younger children could not. This finding is congruent with recent unpublished results obtained by Schadler and Siegel who found that kindergarten children can construct a reasonable facsimile of their classroom from memory if the orientation of the model is congruent with their preferred or typical perspective. When the model was rotated 180" from their (inferred) perspective, the quality of the models produced was drastically reduced. Using a similar procedure, Lyublinskaya (cited by Shemyakin, 1962) gave kindergarten children a model of their group room and told them to arrange in it, from memory, models of furniture where they belonged. In one experiment the room model was turned at 180" in relation to the direction of the room as the child perceived it on joining the other children. Lyublinskaya found that the task was much too difficult for the Cyear-olds, and as Schadler and Siegel had found, only a few of the 5- and 6-year-olds were able to cope with it. Kershner (1971) and Duncan and Eliot (1973) asked kindergarten children to copy a route that the experimenter's truck had just traveled. Significantly more errors were made when the dominant feature of the subject's array was a mirror image of that feature in the experimenter's array, than when it was aligned with the experimenter's array. In addition, more errors were made when the discrepancy was 180" than when it was 90" left or right. The initial form of the spatial representation may exist in only one perspective. With repeated encounters with the terrain the adult, and with development the child, may be able to take a number of perspectives on it, coordinate them, and then use this coordinated set of perspectives adaptively to pose that frame of reference which a particular problem requires. Wapner, Cirillo, and Baker (1971) reviewed their research on the perception of verticality (Wapner, 1968), straight-ahead, eye-level, and autokinetic motion. They concluded that with development there is increasing differentiation between the body spatial reference system and the external spatial reference system: The relation between apparent vertical and apparent body position is of great significance for the development of spatial location because it bears on the differentiation between body and object space which . . .. is reflected in the angular discrepancy between apparent vertical and apparent body position . . .. which is markedly less in children than in adults [p. 1751.

A number of recent studies have been concerned with the problem of perspective-taking in young children (Fishbein, Lewis, & Keiffer, 1972). Huttenlocher (1967a, 1967b) found that 4- to 5-year-old children's orienting and ordering of objects, and the discrimination of this orientation, were easier when the

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array was organized along the up-down dimension than when it was organized along the left-right dimension. Minnigerode and Carey (1974) asked third and fifth graders to take different perspectives on single and multiple object arrays, and found that before-behind relationships were more salient in both cases than were left-right relationships. Coie, Costanzo, and Farnill (1973) studied the development of spatial perspective-taking ability on a simplified version of Piaget’s mountain task. Children 8-10 years old were asked to infer the perspective of a doll at each of eight positions around the array. Left-right errors did not decrease with age, but before-behind errors did. Coie et al. interpreted their data as indicating that a sequence of successive spatial reconstmctions involves a movement from what is seen (the visibility and occlusion of objects), to how objects are seen (their appearance or aspect+orner, side, or frontal view), to where the objects are seen (right or left side of the visual field). As would be expected from Piaget’s theory, distance errors decreased only gradually with age [possibly, because “scaling” of route maps occurs with their use (cf. Section IV, B, 211. These findings, taken as a whole, seem to indicate that the nature of spatial representations in young children might well be more accurate along the front-behind axis, while accuracy in representation along the left-right dimension might be expected to develop later. Harris and Strommen (1972) provided some confirmation of this. Children from 444 to 7% years made a series of “in front,” “in back,” and “beside” placements of common objects. Of seven pairs of objects, three pairs lacked front-back features, four pairs had such features. Each child made two kinds of judgments: object-referent (the subject was asked to place an object in front, or in back, or beside another), and self-reference (the subject was asked to place one member of the pair in front of, behind, or beside himself). Generally, children made more accurate “front-back” placements than “beside” placements, and this was particularly marked in the object-referent condition. Thus, the development of spatial representations in which landmarks and routes are coordinated, is in large measure tied to the development of an objective system of reference which takes place in childhood. This, in turn, is dependent on the development of a notion of objective bearing. 5 . Survey maps appear as coordinations of routes within an objective frame of reference. That is, survey maps become possible only after both routes and an objective frame of reference exist. Piaget et al. (1960) argued that children at Stage IIIB can construct “. . . a topographical schema in line with a two-dimensional coordinate system, though the various intervals are not always strictly proportional to each other . . .. a complete coordination is achieved at level IIIB [p. 191.” In “sketching” their journeys, these children reproduce a coordinated whole. “What began as a sketch-plan of a route finishes as a general map of the district [p. 201.”

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Ala (8;3) thinks of 24 separate features and arranges them correctly. Now and again, in bringing in a new object, he is driven to build up a subgroup involving fewer relations, but each time he succeeds, almost immediately, in integrating this subgroup with the main plan [p. 19.

Shemyakin’s ( 1962) account of the development of topographical representations largely accords with that of Piaget. Shemyakin had children and adults draw sketch-maps of their neighborhoods. Children 6-7 years old usually drew only those routes over which they really and frequently traveled. They accurately presented the turns of the street on the route “home from school,” but reproduced only those sections of the route over which they actually traveled without reproducing the street as a whole, still less the streets adjacent to it. Children 9-10 years old produced more complex drawings, and “offshoots” from the main route appeared-these offshoots were still not connected with each other. By 12 years of age, drawings appeared which presented the locality in the form of a “closed aggregate.” The presentation of a locality by the “survey” method begins with the drawing of local objects (e.g., homes, trees, buildings) in “iconic” form. (By survey maps, Shemyakin means representationsof the “general configuration of schema of the mutual dispositions of local objects [p. 1761.” This seems equivalent to Piaget’s description of a true topographical representation utilizing a coordinate reference system). Later, drawings of the local objects disappear and local points (now less “iconic” and more schematic) begin to be presented in a row, or in the form of “sections” of the localityas a whole (cf. Schadler & Siegel, 1973). Following this, children shif;to a more systematic presentation of the “relations” of the locality. At first, however, they can present the locality only by taking some specific point in it as the initial-point; they require a fixed perspective. Shemyakin (1962) argued that: A topographical representation of a “route-map’’ type which reflects a locality in the form of mentally traced routes of locomotion, corresponds to the first of these methods. A topographical representation of the “survey-map’’ type which reflects a locality in the form of a system of the mutual disposition of local objects, corresponds to the second method. . . . Representations of the “route-map” type develop earlier than do the “survey-map” type of representation [p. 22q.

It is likely that there are a number of levels of sophistication of survey maps, levels of integration which allow for progressively increasing flexibility with which the representation can be used. The level of sophistication is probably related to the degree to which the representation is “association” or “structure,” is successive or simultaneous: “Simultaneity or survey,” that is the simultaneous embracing of a multitude of details, is characteristic of these representations. It is customary to regard simultaneity as a distin-

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guishing characteristic of visual perceptions and representations. And it is this characteristic which is at the basis of the assumption that visual representations play a dominant role in the “survey-map” type of representation [Shemyakin. 1962, p. 2261.

The extent to which simultaneity can be derived from successivity, or structure derived from associations of elements, seems to be directly related to the information-processing capacity of the organism. There have been repeated suggestions in the literature that this capacity increases with development, independent of ‘‘verbal skills.” Perhaps the most sophisticated statement of this argument is Pascual-Leone’s (1970; Pascual-Leone & Smith, 1969)construct of “M space.” Whenever the task requires the subject to process or transform information conforming to a plan (or operative superscheme) in order to obtain new information . . . the processing is carried out as follows: Placing each one of the different relevant subschemes in one of the channels or “centration” places of the central processing [or computing space] together with the schemas representing the task instructions and the general task situation. The set measure of M, i.e., the maximum number of schemes or discrete ‘chunks’ of information that M can attend to or integrate in a single act, is assumed to grow in an all-or-none manner as a function of age in normal subjects. This M measure is considered as a quantitative characteristic of each developmental stage [ Pascual-Leone. 1970, p. 3071.

An increase in the capacity of M space with development would allow for the simultaneous entry of sufficient discrete chunks of the environment (i.e., landmarks) to be encoded, transformed, and coordinated, in order for a survey-type of representation to be constructed.

VII.

Summary and Conclusions

A long succession of neurological and philosophical discussions has provided

consistent suggestions that space is a model of the environment, constructed from the temporal integration of successive perceptions, which model man is neurologically disposed to create and organize. The model is coordinated to social conventions. It develops and is vulnerable to dissolution. Studies of adults’ knowledge about their macroenvironment suggest that human “maps” are not literally maps, Rather, they tend to be fragmented, distorted projectively, and are often several multiple “mini-spatial-representations.” Landmarks and routes are the minimal elements of spatial representatioy they lead to what has been termed route-representations. Survey-representations incorporate configurational elements (outlines, graphic skeletons, figurative metaphors) and may be the final derivative of very dense and richly interconnected and hierarchically organized route maps.

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The spatial representation, although coordinated to conventional symbolizations, are figurative and enactive. Their construction seems to require a “recognition-in-context” memory which could be derived from a “Now Print!” mechanism proposed by Livingston (1967a, 1967b). The multimodal photographs of landmarks which result from the operation of this mechanism could form the figurative nodes of spatial representations. Following the establishment of landmarks, route learning and the learning of patterns of landmarks-connected-by-routes ensue. The notion of “Main Sequences” was introduced as a potential explanation for the extensive parallelisms identified among ontogenesis, microgenesis, the course of pathology, and the recovery of function following pathological insult. There may be a standard sequence of states governing the organization of any human adaptation over time, regardless of age, time span, or circumstances. This sequence would be similar to a stage sequence, but it would be only partly prescriptive of the system properties of the successive states. The development of the sequence of spatial representations in children conforms to the “Main Sequence” identified in the construction of spatial representation in adults. Landmarks are first noticed and remembered. The child acts in the context of these landmarks, and given landmarks and action-sequences, route formation is accomplished. Landmarks and routes are formed into clusters, but until an objective frame of reference is developed, these clusters remain uncoordinated with each other. Survey representations appear as a system of routes arising from and embedded in an objective frame of reference. There are significant differences in detail between the spatial representations of adults and the development of these representations in children, though the “stages” follow the main sequence identified in adult learning. There is probably a different sensory distribution in the photographs of the landmarks, with the photographs of children having a larger motor, iconic, and affective component and a narrower spatial and temporal context. The process of route learning in children is probably slower insofar at this process depends on the development of a tendency to “notice” decision-relevant cues, and to then photograph landmarks in such a way that they register features that are distinctive for decisions. The objective frame of reference and objective sense of bearing necessary for the development of survey representations develops slowly in children. Finally, information-processingcapacity (e.g., M space) limited in children relative to adults, determines the derivation of simultaneity out of successivity (a survey representation), Nonetheless, the development of children’s spatial representations conforms to the “Main Sequence” identified in adult learning: The process of going from landmarks, to route-maps, to survey-maps is a process of going from association to structure, and of deriving simultaneity from successivity.

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VIII. Epilog: On Spatial Thinking About Nonspatial Matters In this paper we have discussed human knowledge of space and things in space. However, there is good reason to believe that spatial knowledge may be paradigmatic for the way in which humans know things and events that are not spatial but that are, in effect, “spatialized” by the human in order for certain relationships to be grasped or remembered. A number of human frames of reference are created by quasi-spatial organizations of information. That is, there are a number of nonspatial domains of human experience that are made into a pattern or picture by a spatial interpretation. Memory may be facilitated if the items to be remembered are seen as an arrangement in space. For example, the “method of loci” is a mnemonic device for organizing, storing, and retrieving lists of items. The power of the method as a list organizer is demonstrated in The Mind of the Mnemonist (Luria, 1968): When S. read through a long series of words, each word would elicit a graphic image. And since the series was fairly long, he had to find some way of distributing these images of his in a mental row or sequence. Most often . . . he would “distribute” them along some roadway or street he visualized in his mind. Frequently he would take a mental walk along Gorky Street in Moscow-beginning at Mayakovsky Square, and slowly make his way down, “distributing” his images at houses, gates, and store windows. . . . This technique . . . explains why S. could so readily reproduce a series [often 50 items in length] from start to finish or in reverse order; how he could rapidly name the word that preceded or followed one I’d select from the series. To do this, he would simply begin his walk, either from the beginning or from the end of the street, find the image of the object I had named, and “take a look at” whatever happened to be situated on either side of it [pp. 31-33]. What is important to notice in this example is the power of a spatial treatment as an organizer, and that this treatment has both visual (“landmark”) and motor (“route”) components.

Huttenlocher ( 1968) has elegantly demonstrated that our understanding of verbal syllogisms and our mental manipulation of them is fundamentally a visual-spatial process. Huttenlocher proposed an explanation of how adults solve three-term series problems of the form: “Mary is taller than Lois, Marsha is taller than Mary. Who is the tallest?” She argued that the mental operations involved in obtaining answers to these reasoning problems are analogous to those involved in making actual spatial arrangements of real objects when given similar types of verbal descriptions. Subjects conceive of certain nonspatial dimensions as having particular spatial orientations, and this spatial imagery determines how they set up ordering problems. An analysis of the S’sintrospective reports corroborates this: They claim that they first imagine arranging the two items from the first premise, and then imagine placing the third item with respect to these fixed items according to the description in the second premise. Hutten-

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locher also provides data which support the contention that the construction of spatial images in word syllogisms parallels the adults’ procedure of arranging real objects spatially according to some dimension that will facilitate retrieval. Such rules of correspondence between spatial and nonspatial dimensions enable one to find particular items without searching through an entire collection, and they preserve order without requiring that items be individually marked. A final example of how humans understand nonspatial domains of experience by coordinating spatial representations to them can be found in everyday language, as well as in psychological terminology. We speak of “dimensions” in our discussions of analysis of variance, conceptualizing variables as being represented in rows, columns, and layers. We organize our understanding of bipolar adjectives (e.g., good-bad, strong-weak, etc.) in terms of a spatialized continuum, and in Osgood’s semantic differential technique we locate words in a three-dimensional semantic space. We often speak of time sequences as if the events lay on a dimension whose endpoints are “past” and “future.” These are but a small sample of instances of the spatializationof nonspatial domains for the purpose of understanding. There are undoubtedly many others. Analysis of the development of spatial representations could provide a basis for modeling the sequences of human adaptation of a variety of knowledge organizations. A logical next step would be to begin to consider the “Main Sequences” in the learning of adults and in the development of children in quasi-spatial representations. REFERENCES Appleyard, D. Why buildings are known. Environment and Behavior, 1969, 1, 131-156. Appleyard, D. Styles and methods of structuring a city. Environment and Behavior. 1970. 2, 100- 118. Arrigoni, G., & DeRenzi, E. Constructional apraxia and hemispheric locus of lesion. Correx, 1964, 1, 170-197. Asso, E., & Wyke, M. Visual discrimination and verbal comprehension of spatial relations by young children. Brirish Journal of Psychology, 1970, 61, 99- 107. Benton, A. L. Problems of test construction in the field of aphasia. Cortex, 1967, 3, 32-58. Benton, A. L. The “minor” hemisphere. Journal of the History of Medicine and Allied Sciences, 1972, 27, 5-14. Benton, A. L., & Fogel, M. L. Three dimensional constructional praxis. Archives of Neurology, 1962, 7, 347-354. Berger, P. L., & Luckmann, T. The social construction of reality. New York: Anchor, 1967. Bergson, H. The crearive mind. 1922. (Transl. by M. L. Andison) New York: Philosophical Library, 1946. Blackstock, E. G ., & King, W.L. Recognition and reconstruction memory for seriation in four- and five-year-olds. Developmental Psychology, 1973, 9, 255-260. Blaut, J. M., McCleary, G. S., & Blaut, A. S. Environmental mapping in young children. Environment and Behavior, 1970, 2, 335-349. Boulding, K. E. The image. Ann Arbor: University of Michigan Press, 1956.

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COGNITIVE PERSPECTIVES ON THE DEVELOPMENT OF MEMORY

John W . Hagen, Robert H . Jongeward, Jr., and Robert V . Kail, Jr. THE UNIVERSITY OF MICHIGAN

I. EARLY RESEARCH ON THE DEVELOPMENT OF MEMORY

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11. HUMAN INFORMATION PROCESSING. ...................... A. THE BASIC TENETS .................................... B. MODELS OF MEMORY ..................................

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111. THE RELEVANT RESEARCH ............................... A. ENCODING AND REPRESENTATION IN MEMORY . . . . . . . . . B. STRATEGIES IN ACQUISITION AND RETRIEVAL . . . . . . . . . . C. THE DEVELOPMENT OF SELF-AWARENESS IN MEMORY SKILLS ................................................

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IV. CONCLUDING REMARKS REFERENCES

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Early Research on the Development of Memory

h o r to the past decade, little research was focused on the development of memorial processes in children, but of late the situation has been changing dramatically. The advent of information-processingmodels that gave memory a key role in their formulations, and the movement identified as “experimental child psychology” are largely responsible for this expanding interest in memory development. There were, however, some early developmental studies of memory. Hunter (1913) made some phylogenetic as well as developmental comparisons of the 57

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ability to deal with absent stimuli. His paradigm employed the delayed reaction technique, in which various positive and negative reinforcement boxes were used. After learning a discrimination, delays of various lengths of time were introduced from the offset of a light in the positive reward box to release of the animal from the release box, If the animal maintained a motor set, he could select the correct box with delays of a few seconds; otherwise the animal’s “memory” appeared to be very poor. Dogs were found to do no better than rats, but raccoons were able to recall for longer periods of time and did not need to maintain a motor set in order to do so. Then Hunter (1917) used his infant daughter in a study. The child sat in front of the apparatus while he placed the stimulus in her hand. The object was then taken from her and placed in one of three boxes in front of her and the lid was closed. She was distracted during the delay interval, and then placed back in front of the boxes and left alone. She did show seeking behavior, and her success was a direct function of the length of delay. Further, if permitted, she would watch the box during the delay, suggesting that a motor set was facilitative. Hunter reported that similar results were found for other children. Delay experiments also have been conducted with monkeys, and delays up to several hours can be mastered by at least some species of primates (Harlow, Uhling, & Maslow, 1932; Tinklepaugh, 1928). Another approach to studying memory in young children was eeported by Buehler and Hetzer (1935). A ball was used that contained a chicken that popped out when squeezed. When the ball was presented again, infants of 15 months remembered the chicken, as judged from “surprise” and “looking” behavior, for intervals up to 3 minutes, while 2-year-olds could remember for intervals as long as 17 minutes. Tests of memory have been a part of intelligence measurement since the first standardized intelligence test was introduced (Anastasi, 1968). The constructors of the first test to achieve prominence, the Stanford-Binet (Terman, 1916), based their test on the premise that intellectual abilities followed a developmental course. Thus, they sought items that showed an age progression. Memory spun was found to be related directly to chronological age. In this task, a series of letters or numbers is presented and the subject is asked to repeat the series. Additional items are included on successivepresentations. With auditory presentation, the number of digits recalled averages about four between 4 and 5 years, five between 6 and 8 years, six from ages 9 to 12, and seven beyond this age. Several other items on the Stanford-Binet test incorporate measures of memory. For example, in one item a story is read to the child, and then a series of questions is asked concerning the story. In another item, an object is hidden beneath a small box and the child must recall the hidden object from an array of objects. In still another, the child is given a series of simple commands, such as “pick up a pencil,” “put it on a chair,” and then “close the door.” Performance is scored on how many of these acts the child does in proper sequence.

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In developing his test of Primary Mental Abilities, Thurstone (1938) used factor analyses on 56 different test items, and Memory was one of the six predominant factors that emerged. The items used in his test concern immediate recall for words, digits, and designs. Memory, then, has been used as a measure of the development of intelligence for over 50 years, because it exhibits clear and reliable developmental properties over a wide age span and because it appears to be related to accepted criteria of cognitive ability. It has also been noted by those working with intellectually impaired subjects that these individuals frequently have deficits in memory (Anastasi, 1968). A number of clinical tests have been devised using measures of memory. In the Benton Visual Retention Test (Benton, 1963), for example, a card is exposed briefly and then removed, and the subject is instructed to draw the figure just seen. Then, delays between exposure and drawing of 5 and 15 seconds are introduced. Norms have been devised and the test is apparently useful in diagnosing brain injury as well as other diagnostic categories in children. Typically, however, there has been little clinical concern with why these types of children (or adults) evidence performance decrements in memory.’ We see, then, that historically the development of memory has been of interest to the researcher, the differential psychologist, and the clinician. The fact that memory does follow a predictable developmental course has led to its utility in the formulation of a wide variety of measuring instruments. Yet, the attempt to understand how and why these developmental changes occur in memory is quite recent. Because the information-processing model has provided a useful framework for the study of memory and its development, we shall describe the basic aspects of this approach in Section 11. This framework will, then, provide the organization for a review of recent research on the development of memory in Section 111. It will become evident that memory is an exceedingly complex phenomenon, closely linked to many other aspects of cognitive processing, and its development is dependent upon many factors that are just beginning to be understood.

11. Human Information Processing A. THEBASICTENETS The information-processing approach to psychology is a mentalistic one, a modern-day descendent of the early act psychology of Brentano and Kulpe (Boring, 1950). That is, this approach has attempted to “look inside the S-R ‘Recent work by Belmont and Butterfield (1971a) and Brown (1974) on memory processing in retardates are notable exceptions in this regard.

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psychologist’s black box.” For associationistic psychology it is sufficient to examine the relationship between stimulus and response. In contrast, the focus of the information-processing approach has been to specify the mental processes that determine specific sets of input-output relationships. The task of the psychologist using this approach is akin to the physiologist’s attempts to describe the functioning of the central nervous system. However, instead of describing the transmission and transformation of information at the neural level, the information-processing psychologist attempts to analyze these phenomena within the framework of a functional cognitive system. The input-output metaphor borrowed from the computer sciences suggests a second aspect of the information-processing approach. As he seeks to describe the cognitive system, the information-processingpsychologist believes that the appropriate question to be asked is “How is the human organism programmed?” This approach assumes that the cognitive activities of the organism form a systematic, well-organized pattern analogous to the program that directs the activities of the computer. That is, the flow of information through the system can be characterized by a series of potentially identifiable operations similar to the subroutines in a computer program that perform specific operations with data. Finally, the information-processing approach assumes that many of the subroutines in the “mental programs” consist of different ways of transforming the data handled by the system. Thus, this approach emphasizes the transformation of external events during entry of these events into the system. At the same time there is a similar emphasis on the transformations necessary for the successful subsequent retrieval of these events when they are to be used by the organism. Clearly, in any description of cognitive functioning from an information-processing point of view, memorial processes must play a crucial role. Even such a “simple” cognitive act as recognizing a single letter requires contact with a representation of that item in memory for a correct identification. At the other extreme, when solving the most complex problems the subject must continually retrieve stored information from memory to achieve a solution. Given this central role of memory in many cognitive activities, knowledge of memorial processes will provide some critical insights for our understanding of cognitive functioning at a more general level. Accordingly, in the following section several models, derived from research with adult subjects, will be reviewed to illustrate the application of information-processing models to the explanation of memory processes. Our primary purpose is to present a few exemplary models that will demonstrate the shift in emphasis from specification of the structural features of the human memory system to the current emphasis on mnemonic processing, especially that which is under the subject’s direction and control.

B. MODELSOF MEMORY While the analysis of memory within the framework of the information-processing approach has a history dating only to the early 1960’s, many of the

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seminal ideas in this approach have an intellectual history dating to much earlier periods. In particular, William James’ (1890) proposal that memory consists of two components, primary and secondary memory, anticipated quite well the developments that were to mark the field in the Mid-Twentieth Century. James proposed that an item in primary memory is presently in conscious awareness. Items in secondary memory have left such awareness and need to be retrieved from the past. Although Broadbent (1958) incorporated a short-term memory store in his model of selective attention, and Sperling (1960, 1963, 1967) has presented a series of models describing very short-term storage of sensory information, Waugh and Norman (1965) were the first contemporary theorists to propose a model dealing specifically with memory. They argued, after James, that memory can be subdivided into two separate storage systems: primary memory and secondary memory. Primary memory is a storage structure with limited capacity. Information in primary memory is lost rapidly, being displaced by new, incoming information rather than merely decaying. The loss of information from primary memory can, however, be delayed indefinitely by means of rehearsal, a process they described as “the recall of a verbal item-either immediate or delayed, silent or overt, deliberate or involuntary [Waugh & Norman, 1965, p. 921.” In essence, rehearsal is a process by which the subject continually represents the information to himself. In addition to maintaining information in primary memory, rehearsal also serves the function of transferring information to secondary memory, a more stable, permanent store of much greater capacity. However, the two stores are not mutually exclusive. An item can be retained in one or both stores at the same time. Atkinson and Shiffrin (1968) have presented a comprehensive multistore model that extends the model proposed by Waugh and Norman (1965) in some important ways. Perhaps the major contribution of this new model is to make explicit the distinction between structural features and control processes in human-memory. The structural features include both the physical system and those built-in processes that are fixed and invariant. Control processes refer to those processes that are under the direction and control of the subject. They can be selected, modified, and used at the subject’s option to fit the demands of a specific situation. Using a computer analogy, the structural features correspond to the hardware and systems programs, while the control processes correspond to those program sequences that can be established and modified at will by the programmer. The model divides memory into three structural components: the sensory register, the short-term store, and the long-term store. Sensory information first enters the sensory register. Information in this store provides a relatively complete, literal copy of the physical stimulation, but is subject to rapid decay (less than 2 seconds). The short-term store is considered to be the subject’s working memory. Selected inputs from both the sensory register and the long-term store are held here, presumably in an auditory, verbal, or linguistic form. The capacity

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of the short-term store is severely limited (5-9 units) and unattended information is likely to be displaced rapidly by new, incoming information. However, the loss of information from short-term store can be delayed indefinitely be means of rehearsal. With some probability, information can be transferred from short- to long-term store. The capacity of the long-term store is considered to be unlimited. Once an item is stored there, it remains permanently. The inability to recall informafion from long-term store is attributed to unsuccessful attempts to retrieve information from the store rather than to the actual loss of information. The more interesting aspect of the Atkinson and Shiffrin (1968) model lies in its description of the control processes used by subjects. These processes control the flow of information both within and between various structural components. Control processes do not constitute a well-defined set of procedures. Instead, they are ‘‘. . . transient phenomena under the control of the subject; their appearance depends on such factors as instructional set, the experimental task, and the past history of the subject [Atkinson & Shiffrin, 1968, p. I061.” For example, the subject is able to prevent the loss of information from the short-term store by means of rehearsal. He decides what information needs to be rehearsed, how long to rehearse it, and when to divert his attention to other information or activities. In general, the control processes increase the flexibility of the entire system. The role of subject-controlled processing in memory becomes even more important in a model proposed by Craik and Lockhart (1972). In fact, they have abandoned the multistore characterization of memory in favor of an approach that stresses the depth or level of processing incoming information. They argued that the original distinctions between short- and long-term stores, with reference to capacity, coding, and forgetting characteristics, have become obscure. Craik and Lockhart took the view that perceptual analyses of incoming stimuli proceed through a number of levels. The memory trace is a product of these analyses and the persistence of that trace is a function of the level of processing. The initial levels involve the analysis of simple physical or sensory features and are highly dependent on stimulus properties. The result is a highly transient memory trace. Deeper levels of analysis are concerned with pattern recognition and the extraction of meaning. These subsequent analyses are more cognitive, more semantic and may involve elaboration and enrichment of the stimulus. This deeper processing results in a trace that is more resistant to forgetting. Craik and Lockhart (1972) described rehearsal as a process in which continued attention is directed toward some set of information. Rehearsal may take one of two forms. On the one hand, attention for an item may be maintained at a given level of analysis. This maintenance rehearsal prevents forgetting but does not strengthen the memory trace. Once attention is diverted, the information will be lost at the rate characteristic of that level of analysis, independent of the length of time the information was rehearsed. On the other hand, rather than maintaining

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attention at a given level of analysis, the subject may continue to elaborate and carry on increasingly deeper modes of analysis. This elaborative rehearsal might take the form of relating new information to that which has previously been stored, incorporating information into a sentence, or developing a visual image. These processes have the effect of strengthening the resultant memory trace. Finally, it should be noted that processing in this model is largely under the direction of the subject. He decides how much and what type of processing to do in response to the demands of a given situation. Brief mention should be made of two other theorists whose views are consistent with those of Craik and Lockhart (1972). Central to a model proposed by Bjork (1974) is the existence of a central processor. This processor is viewed as a conscious mechanism that directs attention, storage, rehearsal, retrieval, and a host of other mnemonic activities. All those activities that have previously been termed “control processes” are considered to be under the direction of this central processor. Similarly, Mandler (1974a, 1974b) viewed consciousness as being equivalent to the contents of attention and maintained that the use of mnemonic devices, storage strategies, and retrieval processes all require the intervention of the conscious system. In summary, even in the brief period of 10 years there has been a definite change in emphasis on models proposed to explain adult memory behavior. While Waugh and Norman (1965) dealt almost exclusively with the specification of two distinct storage structures, subsequent formulations have increasingly stressed the role of conscious mnemonic activities on the part of the subject. This theoretical shift fits nicely with the recent research on memory development. In the review that follows, it will become clear that important changes in memory development can be attributed, not to changes in the characteristics of the structural components, but rather to changes in the type of processing done by children.

111. The Relevant Research A. ENCODING AND REPRESENTATION IN MEMORY In Section 11, A, we noted that the correct identification of a simple object such as a letter may require the use of stored information from memory. This is not an isolated instance, but rather an example of a more general phenomenon. To the information-processingtheorist, entry to and subsequent retrieval of information from a system is dependent to a very great extent on the nature of the existing stored information. Consequently, in this initial section a review will be made of the developmental changes that occur in the representation or “memory trace” of an item. When discussing such developmental differences in representation, Bruner’s (1964) typology of enactive, ikonic, and symbolic modes of repre-

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sentation comes to mind. While not denying the importance and influence of Bruner’s framework, attempts to distinguish the three modes of representation have not been particularly successful (e.g., Corsini, 1969a, 1969s). In the present review a current conception of representational processes that has been derived from research with adults will be examined instead. 1. The Attributes of Encoding If one were to ask a child to characterize his teacher he presumably could generate a list of attributes. The teacher is an adult, a man or a woman, a disciplinarian, and a source of new information. Other attributes connoted might be “warm,” “active,” and “helpful.” Such a characterization may also function when the child encodes the word “teacher” into memory. Bower (1967) has described a detailed analysis of encoding that is similar to this informal description of a familiar stimulus. He proposed that a memory trace is “an ordered list of attributes with their corresponding values [Bower, 1967, p. 2331.” Subsequent papers (Underwood, 1969; Wickens, 1970, 1972, 1973) have concurred with the conception of a word’s encoding as a vector with a value determined by numerous components. a. The detection ofattributes. By far the most extensive work on the attributes of encoding in memory has come from Wickens (1970, 1972, 1973) and his students. Using Keppel and Underwood’s (1962) finding of proactive inhibition in the Brown-Peterson paradigm, Wickens devised a technique to determine those formal categories that also function as psychological encoding categories. Because this paradigm has been used in several experiments with children, the basic procedure will be described here. A trial consists of presentation of stimuli followed by a distraction task for 15-20 seconds, and then a recall interval. On the first trial recall is nearly perfect. When stimuli on subsequent trials are selected from the same category as those presented on the first trial, performance declines. This decline has been interpreted as proactive interference caused by similar encoding in memory (Wickens, 1970). If items presented on a later trial are selected from a different category, an increase in recall or “release from proactive interference” effect may occur in comparison to a control group that does not change material. The absence of interference following such a category shift suggests that the words from the new category are encoded differently in memory. All encoding categories need not be independent; the amount of release from proactive interference following a category shift may indicate the psychological independence or importance of a category for encoding in memory (Wickens, 1972). In experiments using this paradigm Wickens (1970, 1972, 1973) and his colleagues have investigated the dimensions adults use for encoding in memory. The results of these experiments are summarized in Fig. 1. The dependent variable, the percent release from proactive interference, is obtained by first measuring the decline in recall in the control group from the first trial to the shift

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trial. This value is divided into the difference in performance between the experimental and control groups on the shift trial. Multiplying the resulting quotient by 100 yields the percent proactive interference release index. For those studies presented in Fig. 1 a release of approximately 20% is necessary for significance at the .05 level.

6 "-SEMANTIC

MARKINGSYNTACTIC

PHYSICAL

OTHER

Fig. I . Percentage release from proactive inteflerence (PI) as a function of various shifs. (From Wickens, D . D . Characteristics of word encoding. In A. W . Melton & E . Martin (Eds), Coding processes in human memory. Washington, D . C . : Winston. 1972. P . 195. Fig. 3 . Reprinted by permission of Hemisphere Publishing Corporation.)

The data in Fig. 1 have been grouped into four general types of attributes. For each of the semantic shifts tested, a strong release effect was obtained. That the taxonomic category and value on the semantic differential of a word are encoding categories is not surprising, as these attributes constitute much of the meaning of a word. However, connotative aspects of a word's meaning, such as the sense impression conveyed, are also encoded. In contrast, little information of the next two general types, syntactic or physical attributes, appears to be encoded.* The 2The single exception here involves category shifts between two modalities, and the data are ambiguous in this respect. The higher value on this bar represents data from an experiment by Rubin (1967) in which evidence was produced of a strong release effect when shifting between auditory and visual modalities. The lesser value comes from a study by Wittlinger (1967) in which a small, insignificant, release effect was obtained.

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set of attributes marked “other” indicates that the language of presentation (for bilinguals), the frequency of occurrence in the language, and the representational symbol of the stimulus (e.g., 3, 9, 7 vs three, nine, seven) are all parts of the encoded representation of a stimulus in the adult’s memory. Because of their importance in adult coding processes, several experiments have been conducted to investigate the development of the semantic encoding attributes. One important type of semantic encoding is taxonomic or conceptual encoding. To detect taxonomic encoding, stimuli from one conceptual category (e.g., animals) are presented and later a shift is made to another category (e.g., body parts). In four separate experiments taxonomic encoding has been demonstrated in children between the ages of 6 and 12 years (Kail & Schroll, 1974; Libby & Kroes, 1971; Pender, 1969; Wagner, 1970). Thus, this important coding attribute has been found in children as young as have been tested with this paradigm. A second semantic encoding attribute noted with adults is the value of the stimulus on the semantic differential (Osgood, Suci, & Tannenbaum, 1957). This component involves three distinguishable dimensions: evaluation, activity, potency. Data for these dimensions have been combined in Fig. 1. The child’s use of the evaluative dimension as an encoding category has been tested in three experiments with ambiguous results. The stimuli were words that were valued positively (e.g., true, open) and negatively (e.g., no, hate) on the evaluative dimension, but were relatively neutral on the activity and potency dimensions. Eleven- and twelve-year-olds were found to use this dimension (Cermak, Sagotsky, & Moshier, 1972; Kail & Schroll, 1974; Pender, 1%9), but the developmentof encoding along this attribute is unclear. In the Cermak et al., and Kail and Schroll studies the recall of children aged 10 years and younger did not improve on the shift trial, thus indicating that the evaluative dimension was not a functional attribute for these children. However, in the Pender (1969) study a release effect was obtained on this dimension for second-grade children. The source of differences between these studies is unclear. Pender (1969) also tested the development of coding along the activity and potency dimensions and found little evidence for the use of either dimension with second and sixth graders. These general findings are consistent with analyses of children’s semantic differential ratings showing that the activity and potency dimensions are not detected wtil late childhood, while the evaluative dimension is present much earlier (DiVesta, 1966). An additional semantic encoding category for adults involves the “sense impression” conveyed by the stimulus. In these experiments the stimuli are categorized on the basis of a shared physical characteristic such as “roundness” or “whiteness. ” In experiments investigating the development of this dimension the performance of college students improved on the shift trial, and there was some indication of improvement following a shift for 1 1-year-olds (Wagner,

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f970), but no increase in recall for younger children (Kroes, 1973; Wagner, 1970). Apparently this dimension, in addition to being less salient with adults, develops later than some of the other semantic attributes. A final semantically based encoding category that has been studied is the masculine or feminine connotation of a stimulus. While not a particularly salient dimension for adults, the development of sex role knowledge and preference might influence the importance of these coding processes, and this possibility has been investigated recently (Kail & Levine, 1974). In this study the stimuli were words representing games and objects that children had judged in pretesting to be appropriate for boys (e.g., hunting, airplane) or girls (e.g., hopscotch, dolls). Seven- and ten-year-old boys and girls were tested first on the memory task, then on a sex role preference task (Nadelman, 1974). The performance of 7- and 10-year-old boys and the 7-year-old girls improved on the shift trial, when the stimuli changed from one sex type to the other, while the recall of control subjects did not change. These findings were similar to the sex preference data in that these three groups (the boys of both ages and the 7-year-old girls) were also the most extreme in their preference for stimuli of their own sex. However, the older girls were less extreme in this regard and their performance did not improve on the shift trial of the memory task. In the last portion of the sex preference task, the child was required to select the one item that was his or her favorite. When the older girls were divided into those selecting a masculine item as their favorite and those selecting a feminine item, it was found that the recall of the latter group improved on the shift trial, but the recall of the former did not. Apparently for the boys and the younger girls the masculine-feminine connotation of an item was a salient attribute that was reflected in both the memory and preference data. With the older girls there were marked individual differences. This dimension was salient for some older girls, as it was for younger girls. However, this dimension was not detected in the performance of girls who showed less rigid sex-typing by selecting a masculine item as their favorite. Thus, children’s preference data were consistent with the detected encoding attributes, as one would expect of an organized cognitive system. A single nonsemantic coding attribute, acoustic similarity, has been studied (Pender, 1969; Wagner, 1970). Pender selected two sets of words as stimuli. One group of words rhymed with “care” and another group rhymed with “blue.” Recall improved on the shift trial for second and sixth graders as well as college students in Pender’s study. However, Wagner’s data indicated a release effect for college students, but not for 8- and 10-year-olds. Several conclusions are evident from this growing body of research. Perhaps most importantly, the pattern of results from studies with children is generally consistent with the data from adults. Semantic categories are important features in the encoding processes of very young children, while the role of acoustic

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features is ambigous. To a certain extent the developmental differences noted reflect the salience of the attributes in the encoding of adults. Those attributes that are dominant in the adult’s representation of a stimulus are detected in very young children. Less salient attributes are not detected until later in the child’s development. The basic model of an encoded stimulus as a trace with numerous semantically based attributes seems appropriate for children as young as 6 years of age. What does change with age is the richness of this representation as stimuli are encoded into an increasingly large number of semantic categories. b. The dominance of attributes. A problem with the Wickens’ paradigm is that it generally tests the presence of a single attribute at a time. While the Bower (1967) model describes (and Wickens also assumes) encoding along multiple dimensions, this paradigm does not lend itself easily to the detection of encoding along each of several dimensions simultane~usly.~ As Underwood (1972) has noted, these experiments may indicate psychologically differentiated categories that could potentially function in the encoding process rather than detecting the number of attributes that are actually used. The number of attributes that are uctually used during encoding processes may be overestimated by this paradigm. Instead of the multiple simultaneous encoding processes suggested by Wickens (1972), Underwood (1969) has proposed a possible developmental sequence of attribute dominance. The attributes which are established as a memory during learning may differ as a function of the developmental stage. In a very young child, the associative attributes may be subordinate to other attributes, particularly the acoustic and spatial. . . As a child ages, and particularly as he concomitantly is exposed to successive learning experiences in the school systems, the primary attributes developed in learning may change, with the associative verbal attributes becoming more and more common [UnderWood, 1%9, p. 5711.

.

To test for the possibility of developmental changes in encoding processes, Underwood and others have used the false recognition procedure. In this procedure, several key stimuli are first presented to the subject. Then a recognition test is administered that includes these key words, new words that bear some relationship to the original stimuli (e.g., synonymity), and control words. The dependent variable of interest is the number of times that a subject falsely “recognizes” words that were not shown in the original list. The logic behind this paradigm is that after a child initially encondes a word, he will be more likely to confuse that word with subsequent words if they share common coded attributes. Thus, if the stimulus in the original list were “boat,” and the child incorrectly “recognized” the word “goat,” this would indicate acoustic encoding in memory. However a false recognition of “ship,” would be evidence for semantic encoding. An encoding attribute is detected when the child )Efforts have been made to revise this paradigm for use in detecting coding along multiple dimensions (see Goggin & Wickens, 1971).

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consistently makes false recognition errors to words that have a particular relationship to the key stimuli. If one specific type of false recognition error predominates then that attribute reflected by this error is presumed to be dominant. To test the hypothesized developmental changes in the dominance of encoding attributes, Bach and Underwood (1970) generated recognition test lists that contained words similar to the key words along one of two dimensions. The words were either highly associated with, or acoustically similar to, the key words. The data were consistent with the hypothesized change in that 7-year-olds made more false recognition errors to acoustically similar words than to associates. The pattern was reversed for the 12-year-olds who made more recognition errors to associates than to acoustically similar words. Freund and Johnson (1972) noted that acoustic similarity was confounded with orthographic similarity in the Bach and Underwood study. Consequently, they generated a test list of words that were either associates to, acoustically similar to, or orthographically similar to, the key words. Six-year-olds, eight-year-olds, and college students were tested in this experiment. For 6-year-olds, false recognition of orthographically similar words predominated. For both the 8-year-olds and college students, all three categories of related words were falsely recognized more than the control words, but did not differ from one another. In these two experiments, the materials were presented visually, and the child was required to read the words. Such a procedure might enhance the encoding of orthographic attributes, as was found in the Freund and Johnson (1972) experiment. In like manner, one might predict an increase in the amount of acoustic encoding if the stimuli were presented auditorily to the child. Hall and Halperin (1972, Experiment 111) tested this possibility with 4- and 5-year-old children. In their experiment, associated words and acoustically similar words both were falsely recognized more than controls, but did not differ from each other. There were no age differences in performance. In a similar experiment with slightly older children, Cramer (1972) included words in the recognition test that were either synonyms or homonyms of the original words. For both 6- and 10-year-old subjects, she found a slight tendency for children to make more recognition errors to homonyms than to synonyms following auditory presentation. A final experiment using this paradigm was reported by Felzen and Anisfeld (1970). They accurately illustrated the need to differentiate between the various types of semantic relationships that can occur between words, a variable that was not controlled in the experiments by either Bach and Underwood or Freund and Johnson. Present in the recognition test were four classes of associative relation obtained by crossing two factors: type of associate (synonym versus antonym), and degree of association (high versus low). In addition, words that were acoustically similar to the words originally presented were included in the recognition test. For 8-year-old subjects, a significant number of false recognitions occurred only to highly associated synonyms and acoustically similar words. With the 12-year-olds, confusion errors occurred with all five categories.

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A summary of these data indicates findings complementary to those obtained with the proactive interference release paradigm. The role of semantic encoding processes appears to be established with children as young as 4 years. The development of nonsemantic coding attributes, in particular orthographic and acoustic characteristics, is less clear from the available data. The use of these attributes seems to be dependent upon the specific manner in which the stimuli are presented. The emerging picture is one of a flexible coding system, even with young children, in which semantic information about a stimulus is stored, as a rule, while other nonsemantic characteristics may be stored under particular circumstances. 2. Encoding as Semantic integration One severe limitation with the research presented thus far in this section is that the concern has been with memory of single words. Such procedures have been invaluable in the detection of various attributes of encoding, but the generalization of these data to the processing that occurs during the everyday use of words within sentences must be tenuous indeed. One might presume that when words are presented in sentences the syntactic characteristics of a word would be encoded, in contrast to the data in Fig. 1 obtained with the Wickens paradigm.“ Furthermore, a great deal of semantic information is conveyed in a sentence beyond that represented in the words individually. From the semantic standpoint a sentence is clearly greater than the semantic sum of its constituent parts. In a similar manner, the meaning and memory of several sentences may be greater than the meaning and memory of the individual sentences. Such a phenomenon has been demonstrated in experiments by Bransford and Franks (1971). In these experiments adults first heard a series of sentences that were related thematically. In a later phase of the experiment the subject’s recognition of these sentences was tested. The most important finding was that subjects confidently recognized sentences which had not actually been presented, but which integrated the semantic content of several shorter sentences that had been presented. In fact, subjects generally “recognized” such sentences with more confidence than the originally presented sentences. These findings are not attibutable to generally poor performance because subjects were also quite confident that they had not heard sentences concerned with the same ideas but with changed semantic relationships. Apparently, “. . . Ss acquired something more general or abstract than simply a list of those sentences experienced during acquisition. Ss integrated the information communicated by sets of individual sentences to construct wholistic semantic ideas. Memory was a function of these ideas acquired during acquisition [Bransford & Franks, 197 1, p. 3481.” The notion of constructing semantic ideas is suggestive of the Piagetian forma‘However, Wickens (1972) has presented evidence from the release-from-proactive-interference task that no release effect is obtained when the words to be remembered are presented in a sentence.

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tion of schemas. It would be reasonable to suppose that developmental changes might occur in the processes of representing semantic material in memory. In separate experiments, Paris (Paris, 1973; Paris & Carter, 1973) tested children ranging in age from 7 to 11 years. The acquisition portion of these experiments consisted of the oral presentation of “stories” consisting of three simple, active declarative sentences. For example, one story consisted of the following three sentences: (1) The bird is inside the cage.

(2) The cage is under the table. (3) The bird is yellow.

In each story the first two sentences were premises, while the final sentence was a filler sentence. During the recognition sequence, sentences were read to the child, who judged whether he had heard each one previously. Four types of sentence for each story were read: A true premise; a slightly altered (hence, false) premise; a sentence that was a true inference from the two premises; and an inference that would be false from the two premises. The semantic integration hypothesis of Bransford and Franks (1971) would predict few errors on the recognition test except for the true inferences. Representative data (from Paris & Carter, 1973) are presented in Fig. 2. The semantic integration hypothesis was upheld for children at both ages. The older children made fewer errors overall, but both age groups showed a strong tendency to report having heard sentences that were true inferences from the sentences they had heard. Children made relatively few errors on the three other types of sentences. These results have been confirmed in an experiment by Barclay and Reid (1974). They examined the accuracy of the semantic integration hypothesis in predicting the recall of sentences with different passive structures. During acquisition passive sentences were embedded within a brief story. The target sentences consisted of (a) full passive sentences; (b) truncated passive sentences in which the actor was introduced later in the story; and (c) truncated passive sentences in which the actor was never mentioned in the story. Examples of each are: (a) On thefirst day of school Bob was introduced to his new teacher by the principal. The principal was very nice. (b) On thejrst day of school Bob was introduced to his new teacher. The principal who introduced him was very nice. (c) On thefirst day of school Bob was inrroduced to his new reacher. All his friends were glad to see him.

Following the presentation of each story the children were asked to recall the stories verbatim, The semantic integration hypothesis would predict that truncated passive sentences in which the actor is introduced later in the story would be recalled more often as active or full passive sentences than as truncated

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12 100

@a

7-YEAR-OLDS

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10-Y EAR -0LDS

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30 20 10

0

Fig. 2. Percentage recognition errors. (From Paris, S . G . , & Carter, A. Y . Semantic and constructive aspects of sentence memory in children. Developmental Psychology, 1973, 9,111, Fig. 1 . Copyright 1973 by the American Psychological Association. Reprinted by permission.)

passives. For those truncated passives in which the actor is not introduced, the sentences would most often be recalled in their original form. The data were in clear support of the semantic integration hypothesis. The most significant finding, however, concerns the comparison among the four groups tested. There were no differences in the types of recall responses given by the children, ranging in age from 5 to 10 years. Truncated passives were frequently recalled as active sentences when the actor was supplied later in the passage. When the actor was not supplied the truncated passives were almost always recalled in their original form. The truncated passive serves the important semantic function of indicating that the actor is unknown or irrelevant, and only when this is the case is the syntax of the truncated passive sentence maintained. These investigations of the semantic integration hypothesis contribute to the emerging picture of the young child’s ability to encode information. That he can extract much semantic information from stimuli has been documented throughout this section. Wickens has characterized adults “as extraordinarily efficient, fertile, and rapid processors of an almost unbelievable amount of information [Wickens, 1973, p. 4851.” This description seems appropriate for the young child as well, a not surprising conclusion given the ease with which the child engages in the complex processing required of everyday conversation. However, this ability is not necessarily typical of all aspects of the development of memory, as will become clear in the sections to follow.

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STRATEGIES IN

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ACQUISITION AND RETRIEVAL

The developmental course of subject-employed strategies in memory has been charted in a number of different ways by various investigators (e.g., Belmont Br Butterfield, 1969, 1971b;Flavell, 1970; Hagen, 1971, 1972). Various strategies have been described. While differing in many aspects, they all involve some activity on the part of the subject aimed at improving subsequent recall. Children from preschool age through adolescence have been studied, and striking changes have been observed as a function of age, both in performance on a variety of memory tasks and in the use of strategies. In the remaining sections of this paper, it will be argued that these strategies are responsible for a major part of the age-related improvement in memory. While strategies are general by their very nature, i.e., they are applicable to a range of tasks, no doubt certain task characteristics determine which strategy (or strategies) is appropriate for a particular type of task. Thus, as the child gains a repertoire of strategies he must also become proficient in linking these with the particular task he is undertaking at a given time. Further, it has been pointed out very well by Belmont and Butterfield (1969) that different strategies may or may not be used at various phases in the memorial process. Certain strategic activity may be employed during acquisition, when the to-be-remembered information is initially processed, while other strategies may be specifically suited for facilitating retrieval at the time of recall. Both of these possibilities are considered in the sections that follow. In the course of this review, it will become clear that certain strategies for improving memory are characteristically used by older children but appear to be nonexistent in younger children’s behavior. There also appears to be an identifiable transitional stage during which the child can use a strategy under certain conditions or can learn to use it during a relatively brief training session. However, the strategy is not used spontaneously nor does it show the characteristics of durability or generality. Some of our important insights have resulted from experiments that have focused on this transitional period. From the results of these studies it appears that learning, whether it be through spontaneous experience, informal education, or formal training, is critical in the development of the use of strategies. It should also be pointed out that although these periods may occur at different age levels for different strategies, our concern is not for the specific age levels but rather for the developmental progressions identified and described. 1. Acquisition a. Verbal mediation: Production or mediation dejciency? For almost three decades there has been research aimed at demonstrating the mediational role played by verbal productions in a wide variety of cognitive tasks (for a review of this literature see Stevenson, 1972). Simple verbal labeling of stimuli was found

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to enhance discriminability for children at certain age levels but not others (Spiker, 1963). Furthermore, while children as young as age 4-years may have appropriate verbal responses to stimuli in their repertoire, these responses serve as mediators only for older children (Reese, 1962). In order to explore the mediational deficiency hypothesis in a memory task, Flavell, Beach, and Chinsky (1966) showed pictures of to-be-remembered objects to 5-, 7-, and 10-year-old children. Seven pictures were shown in a circular array and the experimenter pointed to three of them as the ones to remember on that trial. A clever procedure was used to measure the child’s spontaneous verbal activity during a 15-second delay period between presentation of items and the test for recall. The child wore a space helmet which had a visor that was pulled over his eyes during the delay so he could not see the pictures. However, his lips were visible and the experimenter, who could lip read, recorded lip movements during this time. After 15 seconds, the visor was lifted and the child was asked to point to the three pictures in the order in which they had been designated as the ones to remember. Only two of twenty 5-yearold children showed any evidence of verbal naming or rehearsal during the delay. However, for the older age groups, verbal activity increased so that for the ten-year-olds, 17 of the 20 showed detectable verbal activity. Further, those subjects who verbalized during the delay period typically recalled more than those who did not. Did this verbal rehearsal actually facilitate memory? Could those children who did not rehearse be induced to do so, and would their memory be improved if they did? To answer these questions, another study (Keeney, Cannizzo, & Flavell, 1967) was performed using basically the same procedure as in the study just described. First-grade subjects were used, because if was known that some would engage in verbal activity during the delay and some would not. For those children who did engage in verbal activity, recall was higher than for those who did not. Then, those who did not show evidence of rehearsal were instructed to whisper the names of the pictures to be remembered during the delay and were tested again. These children learned to rehearse with ease and their recall was as good as the recall of those children who engaged in rehearsal spontaneously. However, upon subsequent testing, when no request to whisper was made, these “induced” rehearsers did not continue to do so, and their recall also declined. These findings led the authors to conclude that a production deficiency characterizes the way these children approach a memory task. They do not use skills they have available to facilitate or mediate their recall. There is no deficiency in mediation ability per se, because they do use this skill when instructed to do so, and memory is improved. Whether still younger children would have been able to show mediation when instructed to rehearse verbally is not known. It is clear, though, the children at the 6- to 7-year age level do seem to show a production deficiency in a simple short-term memory task.

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b. Verbal labeling, rehearsal, and the serial recall task. Another task has been used to study the mediational effects of verbal processes on memory. Hagen and Kingsley (1968) administered a serial recall task (adapted from Atkinson, Hansen, & Bernbach, 1964) in which a series of eight picture cards, each depicting a familiar animal, is shown to the child. The first card is shown briefly, then placed face down in front of the child. The second is then shown and placed next to the first, and this procedure is continued until all eight cards are in a row in front of the child. Then a cue card is shown by the experimenter, and the child's task is to point to the face-down card in the row that matches the cue card. On each trial, the same pichtres appear but rhe order is varied, so it is not possible for the child to learn locations of particular pictures. Across trials, each child is tested on each of the eight card positions. Thus, it is possible to determine not only how many pictures the child remembered, but whether the order of a card's appearance in the series made a difference. The initial cards occupy the primacy positions, while the last cards presented just before recall is assessed occupy the recency positions. In the Hagen and Kingsley study (1968) children at the ages of 4, 6, 7, 8, and 10 years were included. In the label condition, the children were required to say aloud the names of the pictures as they were 5c ln W ln

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presented. In the no-label condition, overt naming of the pictures was not required. As illustrated in Fig. 3, recall improved sharply with age. At the middle age levels, children who labeled recalled more pictures than those who did not, but the recall by 4- and 10-year-old children was not affected. Clearly, it cannot be concluded that labeling is necessarily advantageous in recall. Next, the serial-position data were analyzed. A score was computed for each of the eight list positions for each child. Two findings emerged that help to explain the overall findings for the labeling vs. no-labeling manipulation. First, recall for pictures in the primacy positions in Fig. 4, the left-hand portion of each curve, was not facilitated by labeling. In fact, for the oldest age group, 10 years, recall was significantly poorer when labeling was required. Second, at the extreme right, or recency positions of each curve, it is evident that at all age levels labeling provided a decided advantage for correct recall, It should be noted that at age 10 years, the improvement due to labeling at the recency portion was negated by the detriment due to labeling at the primacy portion. Thus, even though overall recall was not affected, it should not be concluded that labeling had no effect on recall for the 10-year-old subjects. From these findings, it might be argued that 4-year-old subjects displayed a mediation deficiency because their performance did not change even when they

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labeled the stimuli. At ages 6 through 8, aproduction deficiency is evident for the recall of primacy items, the same age level where this deficiency was identified by Keeney et al. (1967). The 10-year-old subjects performed the task considerably better than any of the younger groups. From the findings at the primacy portion of their recall curves, it was concluded that they engaged in spontaneous, covert rehearsing of the names of the pictures to be recalled. For example, as the first picture was shown, the child would say to himself, “fish.” As the second was shown he would say, “fish, bear.” This type of cumulative rehearsal becomes difficult as the list gets longer. Consequently, rehearsal should facilitate primarily the recall of the primacy pictures. The results for the oldest children in the no-labeling condition are consistent with this “rehearsal strategy” hypothesis. When labeling is required, though, covert rehearsing should be more difficult, and recall at the primacy positions should suffer, which it did for those 10-year-olds. In order to test this hypothesis more definitively, 5-year-old children, well below the age of spontaneous rehearsing, were tested in an induced rehearsal condition (Kingsley & Hagen, 1969). They were trained to rehearse aloud cumulatively the names of pictures as they were presented. Only five pictures per trial were used. They learned to rehearse with no difficulty, and compared to children in the standard label and no-label conditions, their recall was facilitated. Further, they showed a striking improvement at the primacy portion of the serial-recall curve. Hence, children at this age level can be classified as exhibiting a production deficiency in this task too: They do not use rehearsal spontaneously; but when they are induced to do so, recall is improved. It appears that, while labeling has a direct facilitative effect on recency, cumulative rehearsal of the labels is responsible for the improvement in recall found at the primacy portion of the serid-position curve. In a recent study, the properties and durability of induced rehearsal were explored further (Hagen, Hargrave, & Ross, 1973). Five- and 7-year-old subjects were given training in rehearsal similar to that used by Kingsley and Hagen (1969). It was found that this rehearsal facilitated recall at both age levels. On a posttest one week later, however, the improved recall due to induced rehearsal was found to have disappeared. This latter result is not surprising in view of the Keeney et al. (1 967) finding of no transfer effect for induced rehearsal even in an immediate posttest. The serial-recall task was administered to subjects at the teenage and collegeage level (Hagen, Meacham, & Mesibov, 1970). Here eight serial positions were used, and it was found that required overt labeling resulted in lower recall at the first six serial positions; only at the last two, or recency positions, did recall improve. It appears, then, that for performance at the recency positions, labeling has a direct facilitating effect, perhaps acoustical in nature. For the slightly longer-term memory for items in the primacy positions an active “strategy for remembering” must be used in order to improve recall, and it is only this latter type of memory that shows clear developmental changes with increasing age.

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A design was employed in which it was possible to manipulate the relative ease with which children could use their recall strategies or mnemonic devices (Hagen & Kail, 1973). In this study a serial position recall task, with seven items, was used. A 15-second delay between the presentation of the final to-beremembered item and the presentation of the cue card was imposed. In the facilitation condition, the children were instructed to ‘‘think about the pictures” during the delay period. In the distraction condition, the subjects counted aloud during the delay. Seven- and eleven-year-old ch;ldren were tested in each of these two conditions, in addition to a control (no-delay) condition. There was no difference in overall recall between the facilitation and control conditions for the 11-year-old children. However, for these children, recall of the primacy items increased in the facilitation condition, while recall of the recency items declined. In the distraction condition, where rehearsal should be difficult, recall of primacy items declined significantly for the older children but did not change for the younger children. Total recall was virtually identical for the two age groups in this condition, and their serial position curves were very similar. An additional analysis also proved revealing. The data from those younger subjects who performed as well as, or better than, the mean performance of the older subjects were analyzed separately. No evidence of a primacy effect was found even for these superior 7-year-olds. It was concluded that “. . . children in the seven year age range do not yet characteristically engage in rehearsal to improve recall, but by age eleven years children are proficient in using this strategy [Hagen & Kail, 1973, p, 8351.’’ The findings of another study provide supporting evidence. Locke and Fehr (1970) used electromyographical recordings to detect verbalizations in 5-yearold subjects. Electrodes were attached to their lips and chins. Pictures were shown, three at a time, followed by a 12-second delay interval. During presentation, the children did verbalize, but no verbal activity was detected during the delay interval. Rehearsing in the absence of the stimuli appears to be an activity that does not emerge until a later developmental period.

c. Evidence for other acquisition strategies. While it seems clear that verbal rehearsal is a mnemonic that comes to play an important role, it is no doubt just one component in the developmental changes associated with the acquisition of information to be remembered. The child learns a complex set of skills that allows him to control, to a large degree, just what he will learn and retain. Three studies that provide additional insight into the components of these skills are now considered. In a study by Flavell, Friedrichs, and Hoyt (1970) the,children were given control of both the length of study time and the number of exposures of the to-be-remembered stimuli. Black and white drawings were shown, each of which was mounted in a window that could be illuminated by pressing a button. Children in nursery school, kindergarten, and second and fourth grade were told that their task was to learn which picture was located in each of the ten windows, and

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that they could expose each picture by pressing the corresponding button as long and as often as they wished. The experimenter left the room while the child was preparing for the recall task. When the child thought he was ready, he called the experimenter back to the room. The frequency and duration of exposure of each stimulus by the child were recorded. Even when given this opportunity to master the task, accuracy of recall was directly related to the subject’s age. Further, this age-related improvement in recall was attributed in part to the finding of a dramatic increase with age in the amount of time spent in preparation for recall. The child’s verbal and nonverbal activities were also recorded by an observer viewing the child through a one-way mirror. Four different task strategies were observed. Overt naming of the pictures was done very little by the three younger groups, but was used frequently by the fourth-grade children, especially early in the study period. At the same time, rehearsal increased over the duration of the study time for the fourth graders and, to a lesser extent, for the second graders. There was no change over study time in this measure for the two younger groups. Another strategy observed was anticipation, testing one-self prior to illuminating a picture. This technique was used primarily by fourth-grade children and to a lesser extent by some second graders. A final behavior, pointing to the actual location of the stimuli, was used increasingly over trials by the fourth-grade children only. Thus, only at the fourth-grade level were the various task-appropriate strategies used consistently to aid in subsequent recall; and only these children showed regular changes over study time in the employment of these strategies, suggesting that they were actually monitoring their performance and making corrective changes in the strategies as their study progressed toward the goal of mastery. The use of study time was investigated in a subsequent study by Masur, McIntyre, and Flavell (1973). Seven-, nine-, and twenty-year-old subjects were given a list of pictures to memorize over a series of five trials, each trial consisting of a study period of 45 seconds followed by a recall test. After each trial, the subjects were allowed to study half of the total number of items they were attempting to recall, and they could choose the items to include in this set from the total array. The major finding was that both the 9- and the 20-year-old subjects chose, significantly more often than the 7-year-old subjects, those pictures that they had been unable tb identify during the preceding recall test. In fact, the youngest group did not show this tendency at all. Other analyses indicated that, while the 9-year-old children did use this strategy (as much as the 20-year-olds), it did not appear to facilitate their recall. These findings suggest that a strategy of giving special attention to information that is less-well mastered in a task emerges with development. Further, this strategy is employed for a period of time before it is perfected. Because there was such a large difference in age between the two older groups of subjects in this study, the course of the development of this strategy cannot be described very accurately at this time. In another task, stimuli are presented which may be grouped into common categories by the children during a study period. Moely, Olson, Halwes, and

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Flavell(l969) presented, in a random arrangement, pictures of common objects belonging to four different categories to children from 5 years through 9 years of age. After the child named each picture, he was given 2 minutes to look at the array and to rearrange the pictures if he wished. Then the pictures were removed from view and the subject was asked to recall as many of them as possible. This procedure constituted the control condition. There were also two experimental conditions used at each age level. In the first condition, the experimenter named the four categories (animals, furniture, vehicles, and clothing) in addition to having the child name each picture. In the second experimental condition, in addition to being given the names of the categories, the child was taught how to sort the pictures into these groups. It was further suggested that it might be helpful if he first remembered a category and then the items in that category. During the 2-minute study period, an observer, watching through a one-way mirror, recorded the child’s manual manipulations of the pictures. The child’s verbalizations were tape-recorded. The results for the 5- to 6-year-old children were very clear cut, as shown in Fig. 5 . Organizing the pictures into categories occurred with high frequency in the teaching condition, but this behavior was almost nonexistent in the other two conditions. For the 6- to 7-year-old children, the use of categories occurred with somewhat higher frequency (although not significantly)in the naming condition, but again the teaching condition resulted in their highest use. By 8- to 9-years of age, the frequency of categorization in these two experimental conditions did not differ. Subsequent recall was found to be higher for those subjects who used manual groupings than for those who did not, regardless of age level. Further, when verbal behavior during the study period was analyzed, it was found that only the older subjects spontaneously moved pictures and verbalized in a way that permitted self-testing. A group of 10- to 1l-year-old subjects was tested in the control condition only, and their spontaneous use of grouping and subsequent recall was found to be at the same level as that for the younger children in those conditions which facilitated their use of grouping during the pre-recall period. Thus, when children organized or grouped stimuli into categories during study, their recall performance was higher than that of children who did not do such organizing. These results have been replicated in a subsequent study by Neimark, Slotnick, and Ulrich (1971) in which the age range of the subjects was extended to include the college-age level. The evidence points strongly to the importance of strategies employed while information is being initially acquired for subsequent recall. These strategies show a consistent developmental progression in their implementation, and they are not well developed until several years after the onset of formal education. Just how and when strategies may be used once information has been acquired is addressed next. 2 . Organization and Retrieval Processes We have attempted to show (in Section 111, A) that information stored in memory

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CONTROL

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Fig. 5 . Prerecall organization as a function of experimental group and age level. The dependent variable is the number of times two items from the same category were placed next to each other during the study period relative to the possible number of such adjacent placements of i t e m from the same category. (Datafrom Moely. B . E . Olson, F . A . , Halwes. T . G . , & Flavell. J . H . Production deficiency in young children’s clustered recall. Developmental Psychology, 1969, 1,29, Table 2 .) ~

is contained within an organized structure and that the storage of new information involves incorporating it into the existing organized system. Given that memory has a detectable organization, it seems reasonable that research has focused on how the subject utilizes that structure to aid him in retrieving information from memory. More recently, developmentalists have asked whether there are age-related changes in such retrieval processes. a. Free recall ofcaregorizable stimuli. It is, of course, well established that many characteristics of stimuli affect the ability of persons to recall them, as we have seen. Words that are related to each other may be recalled together. For example, if an adult is asked to remember the words, “apple, dog, orange, pear, snail, rabbit, plum, and horse,” a typical response would be, “dog, snail, horse, apple, orange, plum.” It is evident, first of all, that his recall is not perfect. Of more interest, though, is the organization that is evidently imposed on the list, a group of animals and a group of fruits. The words were clustered into groups; this tendency to organize stimuli has been shown to be a typical strategy used by adults in memory tasks, and it facilitates total recall (Bousfield, 1953; Bousfield, Cohen, & Whitmarsh, 195Q5 5Numerous measures have been developed to indicate the amount of clustering in a subject’s recall protocol. In general, these measures indicate whether the adjacent occurrence, in the protocol, of two words from the same experimenter-defined category is more frequent than would be expected by chance. Jablonski (1974) and Moely and Jeffrey (1974) have recently reviewed the various clustering measures and discussed the appropriateness of the different measures for developmental research.

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To see if the presence of categories in the stimulus list would facilitate children’s recall, Vaughan (1968) tested first, fourth, and seventh graders. She used two lists in her experiment. One list consisted of 16 pictures of objects bearing no particular conceptual relationship to one another. The second list included pictures of four objects from each of four different conceptual categories. Subjects were given a standard free recall test. They were asked to recall as many of the stimuli as they could in any order they wished. Overall recall increased with age; subjects recalled more words from the categorized lists; and seventh graders clustered significantly more than first graders. However, children at all ages tested showed clustering significantly greater than chance. Rossi and Rossi (1965) have shown that the same improvement in recall with a clusterablelist is obtained with subjectseven younger than the school-age-subjects in the Vaughan (1968) study. They presented lists of 12 pictures to subjects between the ages of 2 and 5 years. Each list consisted of three exemplars from each of four different categories. They found that both recall and the amount of clustering increased as a function of age, but even at the youngest age level, 26 of the 30 2-year-olds clustered above chance. Thus, children as young as age 2 can benefit from the presence of categories in free recall lists, but older children profit more from their presence than do younger children. Such a developmental improvement, however, may merely be an artifact of the particular stimulus lists,that were used. It is possible that younger children cluster as much as older children but according to different criteria or rules. To test this hypothesis, Rossi and Wittmk (1971) presented 12-word lists to children ranging from 2 to 5 years of age. Each list consisted of two pairs of each of three different types of pairwise relationships. Words were either phonemically similar (sun, fun), syntactically related (dogs, bark), or taxonomically related (peach, apple). Syntactic clustering in recall was not dominant at any age. Phonemic clustering was dominant for 2-year-olds but was infrequently noted thereafter. Taxonomic clustering was dominant from age 3 to age 5 , where serial order (input-output correspondence) was the most frequent basis of organization. It should be noted that clustering of wordpairs was examined in this study. Therefore, it may be more appropriate to view this task as retrieval based simply on inter-item associations than as an example of retrieval based on categorical relationships. That is, the data may reflect developmental changes in the dominant associative responses at different ages rather than changes in the hierarchical structure of information in memory. Most of the studies of organizational processes in children’s memory have confounded the categorical relationships within the stimulus list and associative relationships among items within these categories. One notable exception is a study conducted by Lange (1973) in which he presented lists of 16 items to 5%-, 11-, and 15-year-old children. The lists contained four conceptual categories but the four items within each category were not high associates of one another. For example, “pig, squirrel, horse and giraffe” are all in the same category

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(animals) but are not highly interassociated. Using such lists, only 15-year-olds demonstrated clustering significantly higher than would be expected by chance. Thus, previous demonstrations of “categorical clustering” in very young children (see Rossi & Wittrock, 1971) may instead “reflect skills of a lower cognitive order than has been assumed [Lange, 1973, p. 4031 .” Regardless of the exact basis of organization, be it associative or based on taxonomic categorization, it seems that recall by children as young as 2 years can be increased by the presence of categorical relationships in to-be-learned lists. Several attempts have been made to enhance the child’s sensitivity to the presence of such relationships. One such manipulation is to present the to-beremembered materials in a way that increases the likelihood that the child will notice the categorical nature of the material. For instance, Cole, Frankel, and Sharp (1971) contrasted recall of lists in which all of the exemplars of a given category were presented together, in blocked fashion, with lists in which category exemplars were distributed randomly throughout the list. The children tested were in first, third, and eighth grade, and at all ages, blocked presentation resulted in higher clustering and recall. However, in testing children in the 4- to 10-year range, Yoshimura, Moely, and Shapiro (1971) found that blocked presentation of category members resulted in higher clustering than random presentation only for 9- to 10-year-olds.The reason for the discrepancy in the age level at which blocked presentation first facilitates recall is not clear at present. In other studies, more direct means were used to draw the child’s attention to the categorical structure of to-be-remembered materials. In an experiment with kindergarten, third-, and fifth-grade subjects, Kobasigawa and Middleton ( 1972) presented categories in either blocked or random fashion and, in addition, at each age level, half the children were told the categorical nature of the lists. At all three grades, blocked presentation resulted in higher clustering and recall performance. Telling the children about the presence of the categories, however, had no effects on clustering, nor did it interact with the type of presentation method. Apparently, if children note the presence of categories, which they seem to do quite readily, their recall improves. The relative ease with which children detect and use the categorical nature of to-be-learned materials is further illustrated by additional results from the Vaughan (1968) study introduced earlier. Half of the subjects were explicitly instructed to memorize the lists, while for the remaining subjects, the recall test came as a surprise, after they had used the words in constructing an irrelevant story. The findings of an age-related increase in recall and better recall for categorized lists than lists of unrelated words were nol affected by the nature of the instructions. Finally, several investigators have examined the facilitative effects on recall of presenting category cues at the time of testing. Typically, the free recall of categorized materials has been viewed as a two-step process. First, subjects must gain access to a category and second, they must recall the contents of that category. Furthermore, studies with adults (see Cohen, 1966; Tulving &

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Pearlstone, 1966) have indicated that most of the variance in forgetting a categorized list is attributable to forgetting category labels or cues rather than to forgetting items within categories. For example, Cohen (1966) demonstrated that if one item is recalled from a category, then there is a high probability that the subject will recall a stable number of other items from that category, independent of list length and number of categories present (within limits). Because access to a category is such a critical factor, it seems reasonable to expect that supplying category labels at recall, given that those labels were stored with the items at the time of acquisition, will increase the amount recalled. To test this notion, Scribner and Cole (1972) presented categorized lists of 20 items to 7-,9-, and 11-year-olds. Half the subjects were given the category names at presentation and recall (cue condition). In addition, the remaining subjects were also required to recall all the exemplars of one category before moving on to the next (constrained condition). Recall was higher for the subjects in the constrained condition at each age, even on the fourth trial when all subjects were merely asked to recall the list without being given any category information. In a similar study, Halperin (1974) tested 6-, 9-, and 12-year-old children on a 36-item list consisting of nine different categories. Presentation of the categories in the list was blocked and the experimenter said the category name prior to naming the examplars. Subjects in the control condition were given standard free recall instructions. Those in the cue condition were required to recall all the items within a category after the experimenter named the category (thus replicating the constrained condition of Scribner and Cole, 1972). When the category labels were provided, there were no differences among age groups in their recall of the different categories (recalling at least one examplar of a category) but there were strong age differences in the noncued condition. Apparently, the categories were available to children of all ages, but only the older children were able to rely upon their own retrieval strategies to gain access to these categories when the experimenter did not provide the category cue. Further, presenting cues at the time of test facilitated category recall rather than within-category recall. While older children typically remembered more items per category, the two cuing conditions did not affect the recall of these items. A recognition test was administered after two presentation-and-recall trials. Children in the noncued condition recognized seven to nine more words than they recalled on the second trial. Assuming that recognition does not involve a retrieval or search process (Kintsch, 1970), this finding suggests that there were seven to nine additional words that were available in long-term memory but that could not be recalled by the child. A similar comparison for subjects in the cued groups suggested that for the two oldest groups, all the available words were also accessible for recall. For these subjects, cued recall on the second trial approximated recognition performance (and this finding could not be attributed to a ceiling effsct). However, for the 6-year-olds in the cued condition, there were approximately five words that were available but could not be recalled, as evi-

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denced by the difference between recognition and trial 2 recall scores. Thus, the younger children, even in the cued condition, were not as adept at exhaustively recalling all words whose presence in memory was detected by a recognition test. In summary, there are consistent developmental increases in the ability to use taxonomic and associative relationships, but it appears that the recall of children even as young as 2 years is affected, at least to a limited extent, by the presence of such relationships. It seems that children not only are sensitive to the semantic aspects of words (as shown in Section 111, A), but also that they are able to use these aspects to aid recall. As the child grows and his experience with the semantic relationships in language increases, his ability to make effective use of them also increases. b. Subjective organization. Instead of providing the subject with an experimenter-defined categorical structure, an alternative approach to the study of organizational processes is to supply the subject with lists of “unrelated” words and see if he imposes a structure of his own. One method of observing such subjective organization is to present the subject a series of alternating presentation and free-recall trials with the same list of words. Each presentation is a new random order of the list. If the subject tends to recall the same words together as groups on successive trials, the groupings must be independent of the input order of the list, which varies from trial to trial. Thus, the subject must have imposed his own organization on the materials (Tulving, 1962). In an early experiment on subjective organization (Laurence, 1966) 5-through 10-year-olds were tested as well as adults. The important finding was that adults demonstrated greater amounts of subjective organization than did any of the groups of children, which did not differ from one another. For the adults and the two oldest groups of children there was a positive correlation between the amount of subjective organization and the number of words recalled, but there was no such relationship for 5- or 6-year-olds. Thus, there is little indication that young children spontaneously impose any organization on the stimuli, and only a suggestion that the older children do so. Similar low levels of subjective organization, when compared with adult performance, were reported for subjects as old as 12 years in a study by Shapiro and Moely (1971). In addition, attempts to induce subjective organization in young children have not been entirely successful. In one condition of a free-recall experiment, Rosner (1971) told children in the first, fifth, and ninth grades to “chunk” items together by making up ways that the picture stimuli could go together. For first graders, instructions to chunk resulted in slightly higher subjective organization as measured by a sorting task following the recall trials, but it did not increase actual recall when compared to a standard free recall condition. Recall and subjective organization increased with chunking instructions at Grades 5 and 9, although only slightly for the latter group because they were probably organizing the material even without the specific instruction to do so. The fifth graders, while

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they generally do not engage in such spontaneous organization, do benefit from the chunking instruction. Even though the chunking instruction increases the amount of subjective organization for first graders, it does not improve their recall performance. In summary, although even young children are able to use experimenter-imposed categories to facilitate recall, typically they are unable to construct an organizational scheme that will aid them in recalling lists of unrelated words. The construction of such a scheme involves a more active, planful form of processing, a strategy that no doubt develops later than the ability to make use of experimenter-supplied, and usually quite obvious, relationships within the tobe-learned material. c. Organization as memory. The organizational indices in both clustering studies and subjective organization studies rely on the adjacent recall of related pairs of items. Such measurements are not sensitive to higher levels of organization. To circumvent this problem Mandler and Stephens (1967) used a third approach to the study of organization and memory. Girls at ages 7 , 9 , 11, and 13 years were presented 15 high-frequency words. Subjects in a free-sorting condition sorted the words into two to seven categories of their own choosing on successive trials, until they had sorted the words identically on two consecutive trials. Subjects in a constrained-sorting condition were each paired with a child of the same age in the free-sorting condition and were required to duplicate their free-sorting partner’s final arrangement. The placement of each word into a group by the constrained-sortingchild was corrected by the experimenter if it did not correspond to the placement of that word by the child’s free-sorting partner. This procedure was repeated untiI the subject made two errorless sorts in succession. Then all subjects were given a surprise free recall test. Children at all ages in the free-sorting condition made fewer errors and took less time in reaching the sorting criterion than the children in the constrained-sorting condition. However, on the recall task, while the older subjects recalled more total words, there were no differences between the two sorting groups in the amount recalled. Once a stable organization was achieved, regardless of the number of trials necessary, the recall performance was the same. Although Mandler and Stephens (1967) found no developmental differences in the number of categories used by the free-sorting subjects, Lange and Hultsch (1970), in a similar experiment, reported that younger subjects used more categories than older subjects. Since this number was greater than the optimal number of categories, at least for adults (Mandler, 1967), it may be that their organization was not as ‘‘good” as that of adults. Even though they sorted to the same criterion as older subjects, the young child’s organization may have been less efficient in aiding retrieval. Such a conclusion is supported in an experiment by Liberty and Ornstein (1973). The subjects were fourth graders and college students (mean ages 9.8 and 19.3 years, respectively). Each subject was present-

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ed with 28 stimuli. Half the subjects at each age were tested in a free-sorting condition similar to that employed by Mandler and Stephens (1967), except that there was a recall test after each sorting trial. Half of the remaining subjects at each age were paired with a fourth grader in the free-sorting condition and were required to reproduce their partner’s sorting pattern. The other half of the remaining subjects at each grade were paired with a college student and were required to reproduce that subject’s pattern of sorting. Subjects in the constrained-sorting condition also had a free recall test after each sorting trial. The important result is that at both age levels subjects in the constrained condition who were paired with college students recalled more words than subjects paired with fourth graders. The data reported by Liberty and Ornstein suggest that the organizational schemes of younger subjects do not facilitate recall as effectively as the organizational schemes generated by older subjects. Liberty and Ornstein analyzed the structures of the groups formed by subjects during the sorting task, and found that adults grouped together words that were semantically related. Children sorted words according to meaning much less frequently and used other dimensions, such as phonemic similarity, to sort words into groups. The semantically based organization of adults may have resulted in more effective rehearsal, thereby increasing recall; alternatively, these content-oriented groups may have facilitated retrieval processes. d. Development of retrieval processes. In the preceding sections it was assumed that the contents of memory can be characterized by some form of systematic organization and that successful retrieval is dependent upon use of this structure. However, this discussion has been predicated upon the notion that subjects do, indeed, have some conception of the act of retrieval. That is, the child must be aware that he does, in fact, possess the information that is being requested of him and that his task is to retrieve that information for the experimenter. At a more advanced level, the child should be aware of the various ways that one can assist this process of retrieval other than just “brute-force” willing the information into existence. The development of retrieval strategies in young children was examined in a study conducted by Ritter, Kaprove, Fitch, and Have11 (1973). The subjects in this experimentwere from 3 to 5 years of age. The stimuli consistedof duplicate sets of pictures of six different persons, plus six small toys, each toy being closely associated to one of the persons depicted in the pictures. There was also a row of six house-toybox units. In the first task the experimenter “put the first picture to bed” in a house and put the associated toy in the adjacent (open) toybox. The experimenter then asked the child how the matching picture could find its twin, who was now asleep. In this task the toys were designed to serve as the retrieval cues for the location of the pictures. Prompts of varying strength (three verbal and two modeling) were given if the child did not spontaneously suggest using the toys in the boxes. After completion of the first task, the experimenter left the

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room with the toys and then returned to ask the subject how many names of the now-absent toys he could remember. In this second task the pictures were designed to function as retrieval cues for the names of the toys. Again, there was a series of five graded prompts to be used if the child failed to utilize the appropriate retrieval cues. In the first task there were no age differences. More than half of the children used the toys spontaneously as cues and following the strongest prompt, only one child failed to use the toy as a retrieval cue. In the second task, most of the older children (about 75% of the subjects) used the pictures as retrieval cues for the toys with either no prompting or minimal prompting. In contrast, nearly half of the 3- to 4?4-year-olds required the strongest form of the prompt before they used the retrieval cues. In addition, approximately one-third of these younger children completely failed to use the pictures as retrieval cues in the second task. In the second task, the use of retrieval cues was not strongly suggested by the stimulus display (as was the case in the first task). Thus, the data from the second task support the hypothesis that there are developmental changes in the child’s understanding of and approach to the problems of retrieval. In a related experiment, Kobasigawa ( 1974) tested the hypothesis that children of different ages would differ in their utilization of retrieval cues in the recall of categorized lists. Twenty-four stimuli representing eight different categories were mounted on a board, with a picture of an appropriate retrieval cue mounted adjacent to each stimulus. For instance, a picture of a zoo accompanied each of the three animal pictures. During the presentation sequence the experimenter explicitly referred to the stimulus-cue relationship. Following presentation, 6-, 8-, and 11-year-old subjects received different recall instructions depending upon the experimental group. A control group was given typical free-recall instructions. In a cue condition, the children were given a deck of cards that were identical to the cues initially presented with each stimulus. The subjects were told that they could use these cards to help them remember. Finally, in a directive-cue condition, cards from this same deck were shown individually to the subject, who was required to name all the category exemplars related to that cue before proceeding to the next card. Analysis of the recall data, which are presented in Fig. 6, showed that “the cue versus free-recall differences become progressively greater with increasing grade level, and the cue versus directive-cue recall differences become progressively smaller with increasing grade level [Kobasigawa, 1974, p. 1291.” The directive-cue condition effectively eliminated developmental differences in recall, indicating that the information was stored and retrieved equally well by subjects of all ages. (Confidence intervals computed for each of the means shown in Fig. 6 in no case included 100% correct recall; thus the lack of an age effect in the directive cue condition probably is not attributable to a ceiling effect.) In contrast, a large increase in recall with age was noted in the cue condition. Even

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at the eight-year-old level where there is a slight (statistically insignificant) superiority of the cue condition as compared to the free-recall condition, subjects were not using the cues as efficiently as they could (directive-cue condition). However, recall by the 1 I-year-olds in the cue and directive-cue conditions did not differ. These subjects were able to recall exhaustively all the members of a category whether required to do so (directive-cue condition) or not (cue condition). Analysis of the clustering data for subjects in the cue condition complements these findings. High clustering scores were obtained for 1 1-year-olds, indicating that they recalled all the items they could from one category before moving on to the next. In contrast, younger subjects yielded low clustering scores. Kobasigawa reported that these subjects often went through the deck of cue cards several times, each time attempting to recall only one exemplar of a category before proceeding to the next.

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Fig. 6 . Percentage correct responses as a function of age and recall condition: Solid line, directive-cue; broken line, cue; dotted line, free recall. (Redrawnfrom Kobasigawa, A. Utilization of retrieval cues by children in recall. Child Development, 1974. 45,130. Fig. 1.)

That the strategy of exhaustively recalling all the exemplars of a category develops with age has been convincingly demonstrated in a study by Tumolo, Mason, and Kobasigawa (1974). A 24-item list was presented to first- and third-grade children. The list consisted of pictures of three objects from each of

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eight conceptual categories. The picture of an appropriate category cue accompanied each of the three pictures from that category. At the time of recall, a deck of category cue cards was given to the subject and he was told that they might be helpful for recalling the names of the pictures that had been presented. Printed on the cue cards in an informed condition, in addition to the picture of the category cue, were three blue squares indicating the number of exemplars of that category to be recalled. Subjects were told that the blue squares should remind them that there were three pictures in that category. Only the picture of the category cue appeared on each cue card for the subjects in an uninformed condition. Overall recall was higher for third than first graders. More importantly, for third graders, there was no difference in recall between the two cuing conditions. In either situation, they were equally adept at exhaustively recalling most of the examplars of a category. For first graders, however, recall was significantly higher in the informed condition. Without the additional information about category size, they did not exhaust their memory for the elements of one category before proceeding to the next. The notion that many developmental differences in memory performance can be attributed to the child’s increasing ability to use retrieval strategies effectively would be further supported if developmental differences did not appear in tasks in which successful performance did not require the use of such retrieval strategies. A recognition memory task is one such task in which it is assumed that retrieval processes are largely bypassed (Kintsch, 1970). Both Corsini, Jacobus, and Leonard (1969) and Brown and Scott (1971) have found very high recognition performance in preschoolers when they are asked to indicate, for each picture in a long series, whether or not that picture had appeared previously in the series. A closely related task is one in which subjects are required to make judgments of relative recency. In this task a long list of words is first presented. Then, on a subsequent test, subjects are presented a pair of words, both of which appeared in the initial list, and they are required to indicate which word was presented more recently. Brown (1973) found that, while performance increased both as a function of the separation of the two words in the initial list and the “nearness” of the second word to the end of the list, there were no developmental differences for subjects ranging from 7 to 18 years of age. She concluded that in a task such as this, in which no deliberate mnemonic strategy will contribute to successful performance, no developmental trend will be found. This contention was supported in a later study (Brown, Campione, & Gilliard, 1974) where an age effect was found only when the task was such that performance could be facilitated by the deliberate use of a strategy.

c. THE DEVELOPMENT OF SELF-AWARENESS IN MEMORYSKILLS A paradoxical finding that has consistently reappeared in the discussion of the development of memory is that young children can perform many complex

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memorial activities when induced to do so by an adult, but rarely do so spontaneously. For example, young children may not spontaneously rehearse or organize, but these skills can be taught to children rather easily (see Kingsley & Hagen, 1969; Moely et al., 1969). Thus we are left with the question of why the younger child does not engage in these behaviors, even though he is capable of doing so. The emphasis of the information processing approach on an active, “strategy-using” organism suggests one possible answer to this question. Presumably, the child’s awareness of himself as an active organism may have its own developmental course. If the child does not view himself as an active memorizer, then he will be unlikely to initiate spontaneously the deployment of strategies in various memory tasks. In like manner, the child’s knowledge of all things mnemonic probably follows some ontogenetic course. That is, the acquisition of all the facts of memory that are known to the typical adult human (either explicitly or implicitly) must occur over some developmental span. To the extent that the child does not have knowledge of either his “mnemonic self’ or of various memory phenomena, one would not expect the child to engage in any task appropriate mnemonic behavior. One implication of this point of view is that there should be an age at which the child does not realize that a memory task demands a specific set of behaviors for its successful completion. If this hypothesis is correct, then children of this age who are given instructions merely to look at stimuli should not behave differently from children who are given more explicit mnemonic instructions. To examine this notion Appel, Cooper, McCarrell, Sims-Knight, Yussen, and Flavell (1972) tested the recall of 4-, 7-, and ll-year-old children following either looking or remembering instructions. The stimuli were 15 pictures, three from each of five categories. Following presentation of the stimuli there was a 90-second study period during which the children were permitted to manipulate the still-visible stimuli in any manner they desired. Then all subjects were required to recall the pictures. The results indicated that only at the 1I-year level was recall in the “remember” condition higher than in the “look” condition. Further, identical results were obtained’when the child’s clustering scores were analyzed. Observations of the child’s behavior during the study period revealed that only the 11-year-olds rehearsed more in the remember condition than the looking condition. Thus, there is support for the hypothesis that “memorizing and perceiving are functionally undifferentiated for the young child, with deliberate memorization only gradually emerging as a separate and distinctive form of cognitive encounter with external stimuli-a form that naturally includes but also goes beyond mere perceptual contact with those data [Appel et al., 1972, p. 13651.” The differentiation of mere perceptual processing and memorizing in the older child may consist, in large part, of the acquisition of knowledge and awareness of a variety of mnemonic phenomena. Kreutzer, Leonard, and Flavell (in press) have coined the term “metamemory” to describe this knowledge about all things mnemonic. Further, Kreutzer et al. suggested that children might acquire knowl-

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edge about various classes of memory phenomena. First, there is knowledge about one’s abilities. With development children may become increasingly proficient at estimating their own mnemonic capabilities. Clearly, this is an important aspect because to the extent that the child is inaccurate in his assessment of his own memorial abilities, he will be less likely to reatize when those abilities are being challenged, and consequently, will fail to utilize appropriate mnemonic strategies to improve his performance in such a situation. Evidence to this effect has been provided in a study conducted by Flavell et al. (1970) described, in part, previously (Section 111, B, 1). In addition to the findings already reported, the accuracy of the child’s estimate of his own memory span was assessed in these subjects of nursery school, kindergarten, second-, and fourth-grade levels. The child was asked first how many items he thought he could remember from a list of ten pictures. Then the actual number of pictures that the child could recall was tested. The estimates of the two younger groups of children were consistently higher than the estimates from the second and fourth graders. The percentage of subjects who predicted that they would be able to recall all of the items from the ten-item list decreased from 57% at the nursery school level to 21% at the fourth-grade level. The younger children were obviously much less aware of the limitations of their own memorial abilities. Kreutzer et al. (1974) also pointed out that subjects acquire information about items and relationships between items that make them easier or more difficult to remember. From Section 111, B, 2, it is evident that one of the most powerful ways of making items easier to remember is to present them in conceptual categories. Moynahan (1973) investigated the development of this knowledge of the facilitating effects of categorization upon free recall in 7-, 9-, and 10-yearolds. The child viewed several pairs of cards. One card of each pair contained several pictures from conceptually related classes, while items on the other card were not related. The child’s task was to select the set of items that would be easier to remember, and to indicate why he believed them to be easier. Those children who failed to mention the categories in at least seven of their explanations were asked a subsequent question to determine if they had, in fact, detected the categorized nature of the cards. The results indicated that the two older groups did not differ in the number of times they chose the categorized items as easier to remember. Both groups selected the card with the categorized items more frequently than did the 7-yearolds. However, even these youngest children selected the categorized items more frequently than chance. A similar pattern of results was obtained for the explanation scores as well. Furthermore, these differences were maintained when the analyses were restricted to only those subjects who detected the categories. The overall superiority of the older children and the greater-than-chance performance of the youngest children in the Moynahan study are similar to data obtained in the clustering experiments reviewed in Section 111, B, 2. Consistent

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with the developmental differences noted in that section, it would seem plausible that a task that placed more of the burden of creating and using an organization on the child might yield more striking developmental differences. Tenney (1973) investigated the lists that kindergarten, third-, and sixth-grade children generate when asked to choose words that would be easy to remember. Children generated lists of words following one of three sets of instructions. The experimenter first told the child a key word. Then the child was asked to generate a list of words that: (a) would be easy to remember with the key word; (b) consisted of words that were members of the same category as the key word; or (c) consisted of free associates to the key word. The analyses of these lists showed that the kindergarten children generated essentially the same list whether the instruction was to give free associates or to generate items that would be easy to remember. At the two older age levels, however, the lists of easy-to-remember words were very similar to the lists of category items. Thus, only the older,children had sufficient knowledge of the effects of categorization to produce spontaneously such a categorized list. By far the most comprehensive study of the child’s knowledge of different memory phenomena was conducted by Kretzer ef al. (in press). In this study children from kindergarten, first, third, and fifth grades were interviewed to determine their knowledge about a wide range of different aspects of memory. The interview was organized around five central components that are critical for one’s knowledge of memory processes. These included knowledge about (a) the individual as an habitual user of mnemonics; (b) properties of data that affect the ease with which they are remembered; (c) acquisition strategies that facilitate subsequent retrieval of stimuli; (d) ways to cope with the problem of retrieving stored information; and (e) the differing nature of the mnemonic demands placed on an individual in different retrieval situations. Rather than review all of the data from this study, certain aspects that illustrate some of the developmental differences found in metamemory will be presented. For example, one of the facts about one’s memory that has practical consequences for mnemonic behavior is the rapid decay from short-term store. To test for knowledge of this fact the child was asked, “If you wanted to phone your friend and someone told you the phone number, would it make any difference if you called right away after you heard the number or if you got a drink of water first? [Kreutzer et a l . , in press, p. 231.” Children in the first through fifth grades said consistently that one should phone immediately, while kindergarteners said one could phone or get a drink of water with almost equal frequency. In a subsequent question Kreutzer et al. probed the child’s knowledge of the facilitating effects on paired associate learning of relationships between the paired stimuli. To insure that the child understood the requirements of the task, he first learned a list of three pairs. Then he was shown two different lists of pairs. The experimenter showed that in one list the words were opposites (e.g.,

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boy-girl), while in the second Iist the pairs consisted of names of people and things they do (e.g., Mary-walk). The child then was asked which list would be easier to learn. After he had responded, the experimenter added another pair to the list that the child had judged to be easier and asked the child to select the list that was easier now. This procedure of adding items was continued until the child finally indicated that the originally more difficult list would now be easier. The responses to this question showed striking developmental differences. Kindergarteners were more likely to say that the arbitrary pairs would be easier to learn, and the first-grade children selected the two types of pairs with equal frequency. Only the third- and fifth-grade children seemed to know that the invariant associative relationship between items in the list of opposites would facilitate learning. Furthermore, only the older children were steadfast in maintaining their selection of the easier list. For the two younger groups, a list became automatically more difficult when just one more pair was added. Most older children did not switch their list preferences until more than three pairs had been added to the original list. They seemed to be quite certain of the importance of the relational structure in a list. Thus, there is impressive evidence that metamemory exhibits a developmental course. It is not as clear, however, just what the relation is between the development of this self-awareness of the memory process and actual performance in memory stiuations. Studies should be pursued with the aim of determining whether the suspected causal links do indeed exist.

IV. Concluding Remarks Since almost the beginning of scientific psychology there has been a curiosity about the age-related changes found in memory. The early knowledge of memory development was quickly put to use in tests of intelligence; thus, almost immediately memory was considered a part of the larger sphere of intellectual functioning. However, memory was treated more or less as a unitary construct and was not analyzed further by these differential psychologists. Experimental psychology did recognize that memory performance is, to a large extent, a function of the technique of measurement; but not until the advent of the information-processing models was memory pursued vigorously as a construct in its own right. The sheer volume of the research reviewed in Section I11 of this paper attests to the magnitude of interest in recent years in the development of memory, and the orientation of this research reflects the theoretical bias that has influenced the majority of the investigations. The information-processingmodel suggests critical points in the memorial process where developmental changes occur-initial

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encoding, acquisition, storage, and retrieval-and where this process may be linked to other important aspects of cognition (see Reese, 1973). Initial encoding, not surprisingly, involves language even in preschool-age children, as shown in Section 111, A. Semantic information is coded for storage in a wide variety of experimental tasks across a wide age range. Other types of features of stimuli may be used depending on the circumstances. Further, children as young as 5 years can deal effectively with semantically integrated information, such as a series of short sentences. They can encode and use the semantic information presented in ways that are independent of the original formal structure. The lack of age differences, across a rather wide range (preschool to adolescence), points to the early (and seemingly automatic) abilities children have in encoding and using considerable amounts of information. When the focus is on the child as an active memorizer, however, the picture that emerges is very different. Age differences, across this same age range, have been found to be the rule rather than the exception when the task demands that information beyond the subject’s immediate capacity must be acquired and later recalled. That young children do not attempt initially to acquire information that is presented to them for later recall is now well-established. as was argued in Section 111, B, 1. The use of mnemonic strategies emerges over a period of years. Often younger children are able to use cues or particular mnemonic strategies when they are provided to improve recall, although the facilitation is typically transitory and does not generalize to later situations. By 10 to 11 years the child appears to have a working, flexible repertoire of these strategies from which he can draw when the situation demands. Intrinsic properties to the stimuli can be used as well as imposed devices such as rehearsing or grouping into idiosyncratic categories. The child’s increased knowledge of linguistic properties and conceptual relations can and will be used if appropriate to the task at hand. These developmental differences are evident for situations involving both acquisition of new information and retrieval of already stored information, as shown in Section 111, B, 2. The recent studies of the child’s awareness of himself as a memorizer, reviewed in Section 111, C, provide correlational evidence for the relation between the child’s self-awareness and his performance in memory tasks, and also more direct evidence that the young child is not capable of distinguishing features in a task that suggest a particular acquisition strategy. Just why the child must be well into the grade-school years before he becomes proficient in these skills is not at all evident at this time. It does seem obvious, though, that these limitations in the child are not due to the incomplete development of the structural components involved in memorizing and retrieving. Rather, the locus of age differences appears to be in the control processes used by subjects that are under the child’s active direction. The importance of control processes is underscored by findings that developmental differences in memory performance can often be eliminated

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if young children are instructed in the use of strategies, or if the use of strategies by older children is prevented. Since memory is a very complex phenomenon, it is not surprising that a developmental “shift” in memory processes at a particular age level has not been identified. The shift in cognitite performance occurring at ages 5 to 7 identified by White (1965) is too narrow to encompass the changes in memory development. Instead of a well-defined shift, changes in memory between the ages 5 through 11 are a consequence of the child’s gradual acquisition and mastery of sophisticated mnemonic strategies. Changes in memory performance with age reflect the development of an ever-expanding repertoire of strategies rather than a shift in the fundamental bases of cognition. Memory is an integral component of cognition. Consequently, in some situations where a child appears to have a cognitive deficiency, the problem may lie more precisely in the child’s memory processes. This point has been documented recently (Bryant & Trabasso, 1971; Riley & Trabasso, 1974). Children at the preschool age were tested in Piaget’s transitive inference task, and as expected they were unable to make correct inferences when the standard testing procedures were used. However, in another condition, children were trained to criterion on the individual inequalities. The majority of these children were then able to make the correct inference, In a study of the use of hypotheses to solve a discrimination learning task, Eimas (1970) found that $7-year-old children were allowed to have access to their responses on previous trials, they could eliminate systematically incorrect hypotheses as effectively as adults. In these two studies, the young child’s lack of memory for important information seemed to be responsible for his deficient performance rather than an inability to perform the task per se . The major theme in our review has been that as the child develops, he is increasingly active in his efforts to remember. The information-processing approach, with its emphasis on processes that transform and manipulate information, has proved extremely useful in identifying different components of the memorial process in children. Furthermore, the memory model of Craik and Lockhart (1972), described in Section 11, B, does provide a framework into which much of the developmental research can be placed. Incoming information is processed at a number of levels, and the degree of retention depends on the depth of analysis the information receives. The subject plays an increasingly active role as “deeper” levels of analysis are reached. With development these deeper levels are more often employed in order to increase the probability of retention. In addition, the semantic network in which children encode information becomes richer. As the information-processing approach continues to be applied to different age groups and other situations, there will undoubtedly be better understanding of the ways in which memory develops. Because memory plays a key role in

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most aspects of cognition, the study of the processes underlying memory development should provide important insights to the basic properties of cognitive development.

REFERENCES Anastasi, A. Psychological resting. New York: Macmillan, 1968. Appel, L. F., Cooper, R. G., McCarrell, N., Sims-Knight, J., Yussen, S. R., & Flavell, J. H. The development of the distinction between perceiving and memorizing. ChiM Development, 1972, 43, 1365-1381. Atkinson, R. C., Hansen, D. N., & Bernbach, H. A. Short-term memory with young children. Psychonomic Science, 1964, 1, 255-256. Atkinson, R. C., & Shiffrin, R. M. Human memory: A proposed system and its control processes. In K. W. Spence & J. T. Spence (Eds.), The psychology of learning and motivation, Vol. 2. New York: Academic Press, 1968. Bach, M. J., & Underwood, B. J. Developmental changes in memory attributes. Journal of Educational Psychology, 1970, 61, 292-296. Barclay, J. R., & Reid, M. Semantic integration in children’s recall of discourse. Developmental Psychology, 1974, 10, 277-281. Belmont, J. M., & Butterfield, E. C. The relations of short-term memory to development and intelligence. In L. P. Lipsett & H. W. Reese (Eds.), Advances in child development and behavior, Vol. 4. New York: Academic Press, 1969. Belmont, J. M., & Butterfield, E. C. Learning strategies as determinants of memory deficiencies. Cognitive Psychology, 1971, 2, 41 1-420. (a) Belmont, 1. M., & Butterfield, E. C. What the development of short-term memory is. Human Development, 1971, 14, 236-249. (b) Benton, A. L. Revised Visual Retention Test: Manual. New York: Psychological Corporation, 1%3. Bjork, R. A. Short-term storage: The ordered output of a central processor. Paper presented at the Indiana Theoretical and Cognitive Psychology Conferences, Bloomington, Indiana, April 1974. Boring, E. G. A history of experimental psychology. New York: Appleton, 1950. Bousfield, W. A. The occurrence of clustering in the recall of randomly arranged sequences. Journal of General Psychology, 1953, 49, 229-240. Bousfield, W. A., Cohen, B. H.,& Whitmarsh, G. A. Associative clustering in the recall of words of different taxonomic frequencies of occurrence. Psychological Reports, 1958, 4, 39-44. Bower, G. H. A multi-component theory of the memory trace. In K. W. Spence & J. T. Spence (Eds.), The psychology of learning and motivation, Vol. 1. New York: Academic Press, 1967. Bransford, J. D., & Franks, J. J. Abstraction of linguistic ideas. Cognitive Psychology, 1971, 2, 33 1-350.

Broadbent, D. E. Perception and communication. Oxford Pergamon, 1958. Brown, A. L. Judgments of recency for long sequences of pictures: The absence of a developmental trend. Journal of Experimental Child Psychology, 1973, 15, 473-480. Brown, A. L. The role of strategic behavior in retardate memory. In N. R. Ellis (Ed.), fnrernational review of research in mental retardation. Vol. 7. New York: Academic Press, 1974. Brown, A. L., Campione, J. C., & Gilliard, D. M. Recency judgments in children: A production deficiency in the use of redundant background cues. Developmental Psychology, 1974,10,303. Brown, A. L., & Scott, M. S. Recognition memory for pictures in preschool children. Journal of Experimental Child Psychology, 1971, 11, 401-412. Bruner, 1. S. The course of cognitive growth. American Psychologist, 1964, 19, 1-15.

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Bryant, P. E., & Trabasso, T. Transitive inferences and memory in young children. Nature (London), 1971, 232,456-458. Buehler, C., & Hetzer, H. Testing children’s developmentfrom birth to school age. (Trans]. by H. Beaumont) New York: Rinehart, 1935. Cermak, L. S., Sagotsky, G., & Moshier, C. Development of the ability to encode within evaluative dimensions. Journal of Experimental Child Psychology, 1972, 13, 210-219. Cohen, B. H. Some-or-none characteristics of coding behavior. Journal of Verbal Learning and Verbal Behavior, 1966, 5 , 182-187. Cole, M.. Frankel, F., & Sharp, D. Development of free recall learning in children. Developmental PSychology, 1971, 4, 109-123. Corsini, D. A. Developmental changes in the effect of nonverbal cues on retention. Developmental Psychology, 1969, 1,425-435. (a) Corsini, D. A. The effect of nonverbal cues on the retention of kindergarten children. Child Development, 1969, 40, 599-607. (b) Corsini, D. A., Jacobus, K. A., & Leonard, S. D. Recognition memory of preschool children for pictures and words. Psychonomic Science, 1969, 16, 192-193. Craik, F. I. M., & Lockhart, R. S. Levels of processing: A framework for memory research. Journal of Verbal Learning and Verbal Behavior, 1972, 11, 671 -684. Cramer, P. A developmental study of errors in memory. Developmental Psychology, 1972, 7, 204-209.

DiVesta, F. J. A developmental study of the semantic structures of children. Journal of Verbal Learning and Verbal Behavior, 1966, 5 , 249-259. Eimas, P. D. Effects of memory aids on hypothesis behavior and focusing in young children and adults. Journal of Experimental Child Psychology, 1970, 10, 3 19-336. Felzen, E., & Anisfeld, M. Semantic and phonetic relations in the false recognition of words by third and sixth grade chiIdren. Developmental Psychology, 1970, 3, 163- 168. Fiavell, J. H. Developmental studies of mediated memory. In H. W. Reese & L. P. Lipsitt (Eds.), Advances in child development and behavior, Vol. 5 . New York: Academic Press, 1970. Flavell, J. H., Beach, D. R., & Chinsky, J. M. Spontaneous verbal rehearsal in a memory task as a function of age. Child Development, 1966, 37, 283-299. Flavell, J. H., Friedrichs, A. G., & Hoyt, 1. D. Developmental changes in memorization processes. Cognitive Psychology, 1970, 1, 324-340. Freund, J. S., & Johnson, J. W. Changes in memory attribute dominance as a function of age. Journal of Educational Psychology, 1972, 63, 386-389. Goggin, J., & Wickens, D. D. Proactive interference and language change in short-term memory. Journal of Verbal Learning and Verbal Behavior, 1971, 10, 453-458. Hagen, J. W. Some thoughts on how children learn to remember. Human Developmenr, 1971. 14, 262-27 1.

Hagen, J . W. Strategies for remembering. In S . Farnham-Diggory (Ed.), Information processing in children. New York Academic Press, 1972. Hagen, J. W., Hargrave, S., & Ross, W. Prompting and rehearsal in short-term memory. Child Development, 1973,44, 201-204. Hagen, J. W., & Kail, R. V. Facilitation and distraction in short-term memory. Child Development, 1973, 44, 831-836. Hagen, J. W., & Kingsley, P. R. Labeling effects in short-term memory. Child Development, 1968, 39, 113-121.

Hagen, J . W., Meacham, J. A., & Mesibov, G. Verbal labeling, rehearsal, and short-term memory. Cognitive Psychology, 1970, 1, 47-58. Hall, J. W., & Halperin, M. S. The development of memory-encoding processes in young children. Developmental Psychology, 1912,6, 18 1.

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Halperin, M. S. Developmental changes in the recall and recognition of categorized word lists. Child Development, 1974, 45, 144- 15 1. Harlow. H. F., Uhling, H., & Maslow, A . H. Comparative behavior of primates. 1. Delayed reaction tests on primates from the lemur to the orangutan. Journal of Comparative Psychology, 1932, 13, 313-344. Hunter, W . S. The delayed reaction in animals and children. BehaviorMonographs. 1913, 2, No. I , 1-86, Hunter, W . S. The delayed reaction in a child. Psvchologiral Review. 1917, 24, 74-87. Jablonski, E. M. Free recall in children, Psychological Bulletin. 1974. 81, 522 -539. James, W . The principles of p ~ y c h o l o g y .New York: Holt, 1890. (Reprinted: New York, Dover, 1950.) Kail. R . V., & Levine, L. Encoding processes and sex-role preferences. Developmental Reports Series, No. 48, University of Michigan, 1974. Kail, R . V . , & Schroll, J . T. Evaluative and taxonomic encoding in children's memory. Journal of Experimental Child Psychology, 1974, 18, 426 4 3 7 . Keeney. T. J . , Cannizzo. S. R.. & Flavell, J. H. Spontaneous and induced verbal rehearsal in a recall task. Child Development, 1967, 38, 953-966. Keppel, G., & Underwood, B. J . Proactive inhibition in short-term retention of single items. Journal of Verbal Learning and Verbal Behavior, 1962, 1, 153- 161. Kingsley, P. R., & Hagen, 1. W . Induced versus spontaneous rehearsal in short-term memory in nursery school children. Developmental Psychology. 1969. 1, 40-46. Kintsch. W. Models for free recall and recognition. In D. A. Norman (Ed.), Models of human memory. New York: Academic Press, 1970. Kobasigawa, A. Utilization of retrieval cues by children in recall. Child Development, 1974, 45, 127- 134. Kobasigawa, A,. & Middleton. D. B. Free recall of categorized items by children at three grade levels. Child Developmenr. 1972, 43, 1067-1072. Kreutzer. M. A.. Leonard, C.. & Flavell, J. H. An interview study of children's knowledge about memory. Monographs of rhe Sociefy f o r Research i n Child Development, in press. Kroes, W . H. Conceptual encoding by sense impression. Perceptual and Moror Skills, 1973, 37, 432. Lange, G. W . The development of conceptual and rote recall skills among school age children. Journal of E.rperimenta1 Child Psychology. 1973, 15, 394-406. Lange, G . W . , & Hultsch, D. F. The development of free classification and free recall in children. Drvrlopmental Ps,vchology, 1970, 3, 408. Laurence, M. W. Age differences in performance and subjective organization in free-recall learning of pictorial material. Canudian Journal of Psvchology, 1966, 20, 388-399. Libby, W . L.. & Kroes, W. H. Conceptual encoding and concept recall-recovery in children. Child Developmenr. I97 I , 42, 2089-2093. Liberty, C., & Ornstein, P. A. Age differences in organization and recall: The effects of training in categorization. Journal ofE.rperimenta1 Child Psychology, 1973, 15, 169- 186. Locke, J. L., & Fehr, F. S. Young children's use of the speech code in a recall task. Journal .f E.rperimenta1 Child Psychology, 1970. 10, 367-373. Mandler. G. Organization and memory. In K. W. Spence & J . T. Spence (Eds.), The psychology of /earning and motivation. Vol. I. New York: Academic Press. 1967. Mandler, G . Consciousness: Respectable, useful, and probably necessary. Report No. 41, Center for Human Information Processing, University of California, San Diego, 1974. (a) Mandler, G. Memory storage and retrieval: Some limits on the reach of attention and consciousness. In P. M. A. Rabbitt & S. Dornic (Eds.), Attention and Perfimnance V . London: Academic Press. 1974. (b)

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Mandler, G., & Stephens, D. The development of free and constrained conceptualization and subsequent verbal memory. Journal of Experimental Child Psychology, 1%7, 5, 86-93. Masur, E. F., McIntyre, C. W., & Flavell, J. H. Developmental changes in apportionment of study time among items in a multitrial free recall task. Journal of Experimental Child Psychology, 1973, 15, 237-246. Moely, B. E., & Jeffrey, W. E. The effect of organization training on children’s free recall of category items. Child Development, 1974, 45, 135-143. Moely, B. E., Olson, F. A., Halwes, T. G., & Flavell, J. H. Production deficiency in young children’s clustered recall. Developmental Psychology, 1969, 1, 26-34. Moynahan, E. D. The development of knowledge concerning the effect of categorization upon free recall. Child Development, 1973, 44, 238-246. Nadelman, L. Sex identity in American children: Memory, knowledge, and preference tests. Developmental Psychology, 1974, 10, 413-417. Neimark, E., Slotnick, N. S., & Ulrich, T. Development of memorization strategies. Developmental Psychology, 1971, 5,427-432. Osgood, C. E., Suci, G. J., & Tannenbaum, P. H. The measurement of meaning. Urbana: University of Illinois Press, 1957. Paris, S. G. Children’s constructive memory. Paper presented at the biennial meeting of the Society for Research in Child Development, Philadelphia, March, 1973. Paris, S. G., & Carter, A. Y. Semantic and constructive aspects of sentence memory in children. Developmental Psychology, 1973, 9, 109-113. Pender, N. J. A developmental study of conceptual, semantic differential, and acoustical dimensions as encoding categories in short-term memory. Unpublished doctoral dissertation, Northwestern University, 1969. Reese, H. W. Verbal mediation as a function of age level. Psychological Bulletin, 1962, 59, 502-509.

Reese, H. W. Models of memory and models of development. Human Development, 1973, 16, 397-416.

Riley, C. A,, & Trabasso, T. Comparatives, logical structures, and encoding in a transitive inference task. Journal of Experimental Child Psychology, 1974, 17, 187-203. Ritter, K., Kaprove, B. H., Fitch, J. P., & Flavell, J. H. The development of retrieval strategies in young children. Cognitive Psychology, 1973, 5 , 310-321. Rosner, S. R. The effects of rehearsal and chunking instructions on children’s multitrial free recall. Journal of Experimental Child Psychology, 1971, 11, 93-105. Rossi, E. L., & Rossi, S. I. Conceptualization, serial order and recall in nursery school children. Child Development, 1965,36, 771-778. Rossi, S. I., & Wittrock, M. C. Developmental shifts in verbal recall between mental ages 2 and 5. Child Development, 1971,42, 333-338. Rubin, S. M. Proactive and retroactive inhibition in short-tern memory as a function of sensory modality. Unpublished manuscript, Human Performance Center, University of Michigan, 1967. Scribner, S., & Cole, M. Effects of constrained recall training on children’s performance in a verbal memory task. Child Development, 1972, 43, 845-857. Shapiro, S. I.. & Moely, B. E. Free recall, subjective organization, and learning to learn at 3 age levels. Psychonomic Science, 1971, 23, 189-191. Sperling, G. A. The information available in brief visual presentation. Psychological Monographs, 1960, 74 (11, Whole No. 498). Sperling, 0.A. A model for visual memory tasks. Human Factors, 1963, 5, 19-31. Sperling, G. A. Successiveapproximationstoamodel forshort-termmemory.ActaPsychologica,1967, 27, 285 -292.

Spiker, C. C. Verbal factors in the discrimination learning of children. Monographs ofrhe Sociery for Research in Child Development, 1963, 28 (2, Whole No. 86), 53-68.

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Stevenson, H. W. Children’s learning. New York: Appleton, 1972. Tenney, Y. H. The child’s conception of organization and recall: The development of cognitive seategies. Unpublished doctoral dissertation, Cornell University, 1973. Terman, L. M. The measurement of intelligence. Boston: Houghton, 1916. Thurstone, L. L. Primary mental abilities. Psychomefric Monographs, 1938, No. 1. Tinklepaugh, 0. L. An experimental study of representative factors in monkeys. Journal of Comparative Psychology, 1928, 8, 197-236. Tulving, E. Subjective organization in free recall of unrelated words. Psychological Review. 1%2, 69, 344-354. Tulving, E.. & Pearlstone, Z. Availability versus accessibility of information in memory for words. Journal of Verbal Learning and Verbal Behavior, 1966, 5 , 381-391. Tumolo, P. J . , Mason, P. L., & Kobasigawa, A. Presenting category size information to facilitate children’s recall. Paper presented at the meeting of the Canadian Psychological Association, Windsor, Ontario, June, 1974. Underwood, B. J. Attributes of memory. Psychological Review, 1969, 76, 559-577. Underwood, B. J. Are we overloading memory? In A. W. Melton & E. Martin (Eds.), Coding processes in human memory. Washington, D. C.: Winston, 1972. Vaughan, M. E. Clustering, age, and incidental learning. Journal ofExperimental ChildPsychology, 1968, 6, 323-334. Wagner, J. F. A developmental study of categorical organization in short-term memory. Unpublished doctoral dissertation, University of Connecticut, 1970. Waugh, N. C., & Norman, D. A. Primary memory. Psychological Review, 1965, 72, 89-104. White, S. Evidence for a hierarchical arrangement of learning processes. In L. P. Lipsitt & C. C. Spiker (Eds.), Advances in child development and behavior, Vol. 2. New York: Academic Press, 1965. Wickens, D. D. Encoding categories of words: An empirical approach to meaning. Psychological Review, 1970, 77, 1-15. Wickens, D. D. Characteristics of word encoding. In A. W. Melton & E. Martin (Eds.), Coding processes in human memory. Washington, D. C.: Winston, 1972. Wickens, D. D. Some characteristics of word encoding. Memory & Cognition. 1973, 1, 485 4 9 0 . Wittlinger, R. P. Phasic arousal in short-term memory. Unpublished doctoral dissertation, Ohio State University, 1967. Yoshimura, E. K., Moely, B.E., & Shapiro, S . I. The influence of age and presentation order upon children’s free recall and learning to learn. Psychonomic Science, 1971, 23, 261 -263.

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THE DEVELOPMENT OF MEMORY: KNOWING, KNOWING ABOUT KNOWING; AND KNOWING HOW TO KNOW'

Ann L . Brown UNIVERSITY OF ILLINOIS

I. INTRODUCTION. .......................................... A. BACKGROUND: WHAT IS MEMORY?. .................... B. ORGANIZATIONAL SCHEME ............................ 11.

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A TAXONOMY OF MEMORY TASKS AND PROCESSES . . . . . . . A. DELIBERATE vs. INVOLUNTARY REMEMBERING . . . . . . . . . B. MEMORY AS A MEANS OR AN END ..................... C. REPRODUCTIVE vs. RECONSTRUCTIVE PROCESSES . . . . . . . D. COMPREHENSION, RETENTION, AND INTENTION . . . . . . . . E. EPISODIC AND SEMANTIC MEMORY ....................

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A. DELIBERATE SKILLS FOR REMEMBERING ............... B. INVOLUNTARY FORMS OF REMEMBERING . . . . . . . . . . . . . . C. DELIBERATE vs. INVOLUNTARY MEMORY: CONFLICT OR COMPLEMENT .........................................

IV.

V.

A MODEL OF DEVELOPMENTAL CHANGES IN MEMORY..

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A.INTRODUCTION ........................................ B.TERMINOLOGY ........................................ C.THEMODEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. THE UTILITY OF THE MODEL ...........................

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REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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SUMMARY

'This research was supported by Grants HD 06864 and HD 0595 1 from the National Institute of Child Health and Human Development. The author would like to express her appreciation to Joseph C. Campione and Martin D. Murphy for their continued advice and support and careful reading of the manuscript. Special thanks are also expressed to John H. Flavell, Scott G. Paris, and Hayne W. Reese for their invaluable comments on an earlier version of this paper. 103

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I. Introduction A. BACKGROUND: WHATIS MEMORY? An adequate definition of the term memory is a logical prerequisite for the task of tracing the ontogenesis of memorial processes.2 The problem of defining memory, however, has an honorable history considerably predating the inception of psychology as a science. It can be considered part of the more general question of the separability/inseparability of all the higher mental processes. William James (1890) believed that there is nothing unique about what we call memory, no special “faculty” involved and nothing to distinguish it from perception, imagination, or reasoning except the belief that we are reconstructing the past. The fundamental inseparability of memory from other higher mental processes has been periodically endorsed (Bartlett, 1932; Gomulicki, 1956) and is being reaffirmed today (Brewer, 1974a; Jenkins, 1973; Neisser, 1967; Norman, 1973; Piaget & Inhelder, 1973). For example, Bartlett’s view that it is impossible to understand any higher level mental process if it is simply studied “by and for itself” (Bartlett, 1932) is restated for present day psychology by Reitman (1970) “memory behavior does not depend solely upon a memory subsystem, it reflects the activity of the human cognitive system as a whole [p. 49oj ,” Jenkins (1973) contended that psychologists have avoided this issue, at least in part because such a view is “unsettling” or even “threatening,” for it appears to demand a concurrent understanding and consideration of all the higher mental processes. For the developmental psychologist, such a view would inevitably mean that it is impossible to understand memory development in isolation from cognitive development in general. According to this position, attempts to study the development of memory without reference to the development of perception, comprehension, inference, language, problem solving skills, etc., would be.of limited value at best, but to study such processes concurrently would seem to be an impossible task. Jenkins ( 1973) answered this conundrum by suggesting a “contextualist” approach to the study of the higher mental processes, whereby specific tasks are selected for study within a broad context because of their ecological validity or relevance to problems of everyday life. Such a view places heavy emphasis on defining the problem of interest, on selecting and formulating the questions carefully. It also demands that the particular type of memory be defined, thus, leading back to the *Although this paper bears the title of the development of memory, it should be pointed out that only a limited developmental spectrum will be considered, i.e., from approximately 3 years to maturity. No attempt to deal with memory in the infant (Cohen IQ Gelber, in press) or in the aged will be made. This limited spectrum, while reflecting the current state of developmental psychology, is to be regretted.

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central question: What is memory? Although no attempt will be made to answer the question in this paper, it will be argued that keeping such a question continually active will greatly affect the type of studies undertaken and the problems admitted to the domain of the developmental psychologist. Three forms of knowledge which have been studied under the general rubric of “memory phenomena” and which have been studied developmentally will be considered in this paper. The first is referred to in the title as “knowing.” Under this heading, an attempt will be made to deal with the development of the dynamic knowledge system, semantic memory, which underlies all cognitive activity. The problem of the inseparability of memory in this sense from intelligence in general will be considered. The second form of knowledge, “knowing about knowing,” refers to metamemorial processes (Flavell, 1971) or our introspective knowledge of the functioning of our own memory systems. The final type of knowledge to be considered, “knowing how to know,” refers to the repertoire of strategies and skills we possess for deliberate memorization activities. A major contention in this paper is that all three forms of memorial knowledge undergo qualitative changes in the course of human development, and the nature and extent of developmentally related differences will be determined by the extent to which any specific task or situation is dependent on any or all of these major knowledge systems.

B . ORGANIZATIONAL SCHEME First a basic taxonomy of memory processes will be given in order to provide a consistent terminology for use throughout the paper. This will be followed by a selected overview of the developmental literature. It should be noted that this paper is intended as a complement to previous reviews of the development of strategic skills (A. L. Brown, 1974, Flavell, 1970; Meacham, 1972) and metamemorial processes (Kreutzer, Leonard, & Flavell, in press) and, therefore the prime focus of attention in the literature review will be on semantic memory, an area which has received comparatively little attention. Following the review, a basic model for predicting the extent and nature of developmental changes will be presented. Finally, the implications of this model for future research will be examined.

11.

A Taxonomy of Memory Tasks and Processes

In order to describe developmental processes affecting memory, we need a clear statement of the various types of memory and the various types of processes. In this section an attempt will be made to provide some distinctions. These distinctions often take the form of dichotomies which by their nature lead to an

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oversimplification of a complex problem. However, it is accepted that these distinctions are artificial and oversimplified; they are introduced merely to provide a structure or framework within which to discuss developmental changes in memory.

A. DELIBERATE VS. INVOLUNTARY REMEMBERING The first basic distinction is between memory which is the product of deliberate attempts to remember and memory or knowledge which is the incidental result of interaction with a relatively meaningful environment. Developmental psychologists have concentrated almost exclusively on the child’s performance in laboratory or school situations where he is instructed to memorize deliberately with the goal of subsequent reproduction. In order to deal effectively with such situations, the mature memorizer adopts strategies or skills which increasingly involve attempts to render the material more meaningful, thus manageable. This is not the only form of memory, however, for a large part of what we remember or know was acquired, not through deliberate attempts at remembering, but as the involuntary result of our intelligent interaction with a meaningful environment. The very fact that we comprehend meaning and relations enables us to reconstruct meaning and relations at a later date.

B. MEMORYAS A MEANSOR AN END Soviet psychologists (Smirnov & Zinchenko, 1969; Yendovitskaya, 1971) have distinguished between memory as a goal in itself and memory subordinated to the fulfillment of a meaninful activity. Remembering, even deliberately, in the context of an ongoing activity, is a less demanding situation for the young child. Indeed, it is in the context of meaningful activities that deliberate attempts to remember first emerge (Smirnov & Zinchenko, 1969). Conversely, situations which demand exact reproduction of information as a goal in itself are, to some extent, artificial situations. The mature information processor has learned to recognize these atypical situations and to appreciate that in order to meet their demand characteristics, he must employ mnemonic skills of one form or another. Understanding the essential features of the material will not suffice, so deliberate attempts to memorize must be initiated. Such deliberate memorization skills, however, are not necessary when the task is to reconstruct the plot of an interesting novel or play, or, indeed, the gist of any meaningful series of events. Distinguishing between situations which demand deliberate memorization skills and situations where memory will be more or less automatic is a particularly difficult task for the young child (Yendovitskaya, 1971). Similarly, spontaneous initiation of deliberate tactics of memorization, as a goal in itself, is atypical of the developmentally young.

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C. REPRODUCTIVE VS. RECONSTRUCTIVE PROCESSES Key words in the preceding sections are reproduction and reconstruction, for these are fundamentally different types of regeneration. The child in the laboratory, under instruction to memorize deliberately, is often required to reproduce the to-be-remembered material, i.e., to provide an exact copy. Similarly the child in school is faced routinely with the task of reproducing, verbatim, material which is relatively meaningless to him. In contrast, memory which is the spontaneous result of intelligent activity is rarely an exact reproduction of the past experience but an imaginative recanstruction of the ideas (Bartlett, 1932; Binet & Henri, 1894), the meaning (Brewer, 1974b), or the gist (Fillenbaum, 1966) of the original input. We can reconstruct ideas and meaningful situations we have experienced in the past because they were meaningful and thus became part of our knowledge system. We readily regenerate the meaning even though the actual input from which we abstracted that meaning cannot always be reproduced.

D.

COMPREHENSION, RETENTION,AND INTENTION

Although a central theme of this paper is the intimate relationship between comprehension and retention of meaningful events, the terms should not be regarded as synonymous. Confusion has arisen due to the widespread use of comprehension tests to measure memory and memory tests to measure comprehension. Indeed, when an immediate appraisal is made of information gleaned from an event, comprehension and memory are inseparably linked. The same problem exists when attempting to separate the terms learning and memory. Although there may be distinct differences between the comprehension and retention of linguistic materials (Carroll, 1972; Fillenbaum, 1970; Scriven, 1972), these distinctions will not be addressed in this paper. Separation of comprehension and memory will be made only in t e n s of the temporal constraints on memory, for it is clear that we forget what we once understood. Furthermore, the passage of time affects the balance between the contribution of a weakening memory of an event and the active constructive processes used to reconstruct the experience (Neisser, 1967; Sulin & Dooling, 1974). Therefore, whereas comprehending or processing material at a deep semantic level (Craik & Lockhart, 1972) will lead to retention of the essential ideas without a deliberate attempt to remember, regeneration of that information at a subsequent date often depends on adequate retrieval operations or a favorable environmental reinstatement. Even the most meaningful events can become inaccessible after time. Thus, for brevity, reference is made to memory as the automatic or involuntary product of comprehension. This does not mean, however, that events are never forgotten, only that with an optimal retrieval environment the essential substance

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may be reconstructed even when no conscious attempts to remember had been evoked initially. One can deliberately attempt to retrieve information that was never consciously stored. The words involuntary and automatic are used throughout to refer to memory for meaningful events in the absence of a positive intent to remember. This is not intended to exclude the possibility that conscious, planful strategies may be involved in the comprehension and retention of meaningful events, only that the essential ideas can be retained in the absence of such deliberate acts. Strategies may enhance comprehension and retention of meaning but they are not an essential prerequisite for these processes to occur. Furthermore, comprehension should not be regarded as all or none, but as a process that can occur at different depths or levels depending on task demands. The depth of comprehension can range from a mere “awareness of the potential for interpretation” (Deese, 1969) to a full interpretation involving consideration of ambiguities, inferential steps, nuances of meaning, etc. (Mistler-Lachman, 1972). It seems reasonable to posit depth of comprehension as a prime cause of the richness of subsequent retention (Craik & Lockhart, 1972). Depth of Comprehension need not be the result of a deliberate intent to understand and remember, although such an intent might be expected to enhance performance. One largely ignored determinant of deep comprehension, which does not rely on deliberate intent, is the interest level or payoff value of the subject matter. Events that attract our interest will result in deeper levels of analysis. It is perfectly possible to comprehend a routine political speech, but to fail either to notice subtleties or to retain the message for long periods. By contrast, if the speech contains information of vital consequence to our lives, not only will nuances of meaning, whether real or imaginary, be perceived, but the essential message will be retained for long periods, perhaps indefinitely.

A. EPISODIC AND SEMANTIC MEMORY The final distinction which recurs throughout the paper is that between episodic and semantic memory (Tulving, 1972), a distinction which is roughly equivalent to Piaget’s separation of memory in the strict sense and memory in the broad sense (Piaget & Inhelder, 1973). Briefly, episodic memory is concerned with storage and retrieval of temporally dated, spatially located, and personally experienced events or episodes. A copy of events is required, i.e., reproductive memory of actually experienced but not necessarily meaningful events, such as whether a word occurred in an experimental list, its position in the list, the exact spelling of the word, etc. Similarly, for Piaget, memory in the strict sense is concerned with personally experienced events, localized in the past, involving single objects or instances, not necessarily meaningful or generalizable. In order to regenerate episodic information accurately the child must engage in intelligent retrieval strategies. If warned that such information will be required, he will benefit from intelligent use of acquisition strategies.

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Semantic memory, in contrast, is independent of specific episodic information. It is the system concerned with storage and utilization of knowledge or meaning about words, concepts, etc. Whereas episodic information refers to when, where, and how an item occurred, semantic information about an event is independent of that event’s actual Occurrence in a particular situation or its temporal co-occurrence with other events. Similarly, Piaget talks of memory in the wider sense, which involves the conservation of logical schemata or rules, by reason of their inherent logic or meaning. It refers to a “mode of knowledge” not bound up with specific data. Semantic memory is the organized knowledge a person possesses about words, meanings, relations, concepts, symbols, rules, etc. Inputs into the semantic memory system are referred to and absorbed within preexisting cognitive If memory in this wider sense involves an “imaginative reconstrucstruct~res.~ tion or construction” built on extant knowledge rather than the “re-excitation of fixed lifeless fragmentary traces” (Bartlett, 1932), then the developmental level of the child will have a profound influence on his memory processes. There is obviously an interdependence between what a child can understand and do and what he can reconstruct. Thus, we would expect “the qualitative content of memory to be transformed with age” and experience as the child’s “interest in and general understanding of his world changes [Piaget & Inhelder, 1973, p. 3791 .” In summary, the memorial processes of the developing child would be expected to undergo changes of two fundamental kinds. Gradually, as the child matures, his repertoire of specific skills for coping with episodic, reproductive memory demands expands. Maturation would also result in gradual changes and modification of his knowledge system or semantic memory, changes which would profoundly affect his reconstructions, “for the memory code itself depends on the subject’s operations and, therefore, this code is modified during development and depends at any given moment on the subject’s operational level [Piaget, 1968, p. 3.”

30ne glaring omission from this paper is any mention of developmental changes in the mode (Bruner, Greenfield, & Olver, 1966; Piaget & Inhelder, 1973) or organization (J. R. Anderson & Bower, 1973; Collins & Quillian, 1972; Loftus, 1973) of semantic memory. This question is of obvious importance for developmental psychologists, for it is essential that at least the organizational structure, if not the mode of representation, be understood before it is possible to tailor material to be congruent with the analyzing shuctures of the child. Influenced by current controversies surrounding the topics of language and thought, imagery and memory, and comprehension and meaning (Atteneave, 1974;Bransford& McCarrell, 1974; Brewer, IY74b). theauthorhasbeenpurposely neutral as to what the nature of the internal representation is. Rather what is “in the head” has been considered as “non-linguistic, imageless thought,” equivalent to Miller, Galanter, and Pribham (1960) concept of the Image, “The image is all the accumulated, organized knowledge that the organism has about itself and its world.” The issue of the form of mental representation was avoided in this paper.

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111. An Overview of the Developmental Literature A. DELIBERATE SKILLS FOR REMEMBERING 1. Memorial Strategies and Plans: Knowing How to Know Mnemonic strategies can be broadly defined as courses of action which are deliberately instigated for the purpose of remembering. By means of various mnemonic schemes, material is organized, transformed, or maintained at a given level of processing (Craik & Lockhart, 1972) in such a way that a more efficient use of a limited capacity memory system is ensured. Thus, the main feature of a mnemonic strategy is that it is not essential for task performance but is a voluntary plan adopted by subjects for cognitive economy, a plan which is subordinated to the goal of remembering (Meacham, 1972). Developmental psychologists have focused on the development of strategies of deliberate remembering to the virtual exclusion of other forms of memory. The simplest statement is one made by Flavell(1970), that if a mnemonic strategy is required for efficient performance on a task, developmental differences will be obtained. A. L. Brown (1973a, 1974) added the corollary that when no such strategy is required, the task will be relatively insensitive to developmental trends. Prior reviews of the literature have amply documented that the deliberate control of what to remember and what to forget, together with the strategic use of various tactics to aid these processes, is inadequate in the developmentally young (Brown, 1974; Flavell, 1970; Meacham, 1972); therefore, a further detailed review of this large and expanding literature will not be included here. In summary, there seems a general consensus that the degree to which a deliberate mnemonic strategy is required will determine the extent to which developmentally related differences in performance will occur. Thus, the use of cumulative rehearsal (Belmont & Butterfield, 1971; A. L. Brown, Campione, Bray, & Wilcox, 1973; Flavell, 1970), organizational (Tenney, 1973), and elaborative (A. L. Brown, 1973b; Reese, 1972; Rohwer, 1973) strategies, and the intentional nonprocessing of irrelevant material (Bray, 1973; Hagen, 1972) are all strategic behaviors under the control of the subject. As the child matures, he gradually acquires a basic repertoire of these skills, first as isolated taskdependent actions, but gradually these evolve into flexible, generalizableskills (A. L. Brown, 1974; Meacham, 1972; Smirnov & Zinchenko, 1969). With extensive use, strategic intervention may become so dominant that it takes on many of the characteristics of automatic and unconscious processing, in that only intensive introspective questioning can reveal the operations of the strategic device even to the operator. Not only are strategies for acquisition of information inadequate in the developmentally young but so also are retrieval strategies (for an excellent review of retrieval strategies, see Kreutzer et a l . , in press). Thus, developmental dif-

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ferences would be expected to the extent that any task demands either acquisition or retrieval strategies, or both. Piaget (1968) has proposed a developmental progression in memorial efficiency depending on the extent to which stimulus support is provided in the memory probe. The progression is from recognition, through reconstruction, to evocation (recall). Recognition memory can depend only on sensorimotor schemata and does not necessarily demand that an internal representation be constructed. It is a primitive process which occurs in the presence of the object and “consists of perceiving the latter as something known.’’ Reconstruction is a form of recall but occurs earlier in the developmental sequence because it involves recall by “actions instead of images. Whereas reconstruction restores “the supposed genetic order of the formation of memories (actions +schemata +memory images), simple recall reverses the order by starting from the images [Piaget & Inhelder, 1973, p. 3911.” Thus, recall is the most difficult process, as it demands regeneration in the absence of the stimulus, whereas reconstruction and recognition take place in the presence of the actual stimulus or its disarranged elements. Little attention has been paid to either the use of retrieval cues in general or reconstructive memory processes in children. However, one would predict developmental differences to the extent that any one task demands active retrieval strategies (Kobasigawa, 1974; Ritter, Kaprove, Pitch, & Flavell, 1973) and as a function of the degree of stimulus support provided in the memory probe (Blackstock & King, 1973; A. L. Brown, 1975b; K. E. Nelson, 1971). Under instructions to remember, the mature memorizer employs a variety of acquisition and retrieval strategies which are not available to the developmentally less mature individual. There is also an implicit assumption that there exists a hierarchy of strategies from simple processes like labeling and rote rehearsal, to elaborate attempts to extract or impose meaning and organization on the to-beremembered material. Indeed, as Reitman (1970) has pointed out, the outstanding feature of the mature memorizer is the amazing array of complex transformations he will bring to even the simplest laboratory task. Thus, the extent of developmental differences will be determined by the degree to which increasingly complex strategic skills can be applied. Finally, whereas it may be possible to distinguish certain basic skills the child must acquire, once he has mastered these it is no longer possible to define an optimal task strategy, for the optimal strategy for any one subject will depend on his success or failure with previous strategies, his estimation of his own capabilities, his creativity, certain personality variables, in fact, his personal cognitive style. ”

2 . Metamemorial Knowledge and Plans: Knowing About Knowing Although considerable attention has been paid to the ontogenesis of deliberate means of remembering, it is only recently that the intention to be strategic (A. L. Brown, 1974) or the plan to form a plan (Miller et a l . , 1960) have been examined. But the general factors of planfulness (Flavell, 1970) must

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underlie all intelligent application of strategic behaviors. Both the limitations and richness of the young child’s knowledge concerning the state and functioning of his own memory have been examined extensively by Flavell and his associates (Kreutzeret al., in press) and a detailed review will not be included here. Briefly however, recent studies have shown that such metamemorial (Flavell, 1971) processes as knowing how many items one can recall or accurately predicting one’s recall readiness (Flavell, Friedrichs, & Hoyt, 1970; Markman, 1973), are not well developed in young children. In addition, the very distinction between a set to memorize deliberatelyor just to look at items may be beyond the metamemorial functioning of very young children (Appel, Cooper, McCarrell, SimsKnight, Yussen, & Flavell, 1972; Shif, 1969). A form of “secondary ignorance” (Sieber, 1968) appears to be operating, for besides not knowing how to memorize efficiently, the young child does not seem to realize that he needs to memorize. He appears oblivious to the limitations of his memory capacity for reproductive tasks, and unaware that he can make more efficient use of his limited capacity by strategic intervention. Such a state of ignorance should not seem surprising in light of the ecological validity of strategic exercises in the life of the preschool child. The young child is seldom, if ever, required to reproduce exact information or to rote learn.“ Prior to the school years, the child has existed without the need to employ deliberate strategies of remembering. He has managed to acquire a language; he can comprehend an impressive set of conceptual relations; he can recognize familiar places and people and reconstruct meaningful events without the need to employ strategies. His emergent knowledge system is such that he can reconstruct the essential features of his past and deal intelligently with his present. It is only when he encounters material which is not inherently meaningful or must be reproduced exactly that deliberate memorial skills become’necessary. It takes time for him to recognize that these, in some sense artificial, situations exist and demand that he respond with something more than has been required in the past. He must, in fact, recognize that because of the nature of the material and the need for exact reproduction, he must apply a deliberate strategy or he will fail to retain the material. He can reconstruct what happened on his last birthday without such skills, but he cannot reproduce his phone number without them. Thus, along with the gradual emergence and refinement of specific memorial strategies, the child’s metamnemonic skills also develop as he is faced in‘This observation is, of course, culturally biased. It is the author’s impression that there is more stress on deliberate remembering in American compared with European nursery schools, and this may reflect different cultural emphasis. An interesting exception to the rule is that rhymes, accompanied by music, are readily acquired and can be reproduced exactly even by quite young children and relatively severely retarded individuals. The efficiency of using musical rhymes as information sources, while extensively used by media advertising aimed at children, and prograps like Sesame Street, has not been studied by developmental psychologists.

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creasingly with more demanding situations requiring reproductive recall. He learns to evaluate realistically the task demands (Moynahan, 1973), his memory ability (Flavell et al., 1970) and the interaction of his abilities and the task (Masur, McIntyre, & Flavell, 1973; Tenney, 1973). The development of knowledge about memory, memory monitoring (Flavell, I97 1), executive control of mnemonic activities (Butterfield, Wambold, & Belmont, 1973), and strategy transfer (A. L. Brown, 1974; Campione & Brown, 1974) have only recently received attention. However, such knowledge and beliefs concerning one’s own memory processes must play a vital role in determining if strategies and plans will be adopted and if appropriate plans will be used. Without such introspective knowledge, it would be difficult, if not impossible, to select an appropriate strategy at the onset of a task and to change or modify that strategy in the face of its success or failure. Indeed, a case could be made that it is the intention to use an appropriate strategy subordinated to the goal of remembering which is deficient in the developmentally young, not necessarily any specific memorial skill per se. Furthermore, as the failure to use strategies effectively is transsituational, attempts to train a specific memorial skill, without regard to metamemorial functioning, might be of limited value. Concentrating training efforts on metamemorial awareness and control (Butterfield et al., 1973) might be more productive in improving the cognitive functioning of the developmentally young. Considering the importance of metamnemonic knowledge for intelligent use of strategic behavior, the paucity of good research on the topic must be regretted.

B.

INVOLUNTARY

FORMSOF REMEMBERING

1. Memory and Intelligence As stated earlier, reproductive memory facilitated by strategic intervention is not the only form of memory. The vast majority of what we retain of our past experience, our semantic memory, our knowledge of the world, is the involuntary product of our continuous interactions with a relatively meaningful environment. This form of memory consists of our comprehension of rules and relationships involved in events, a comprehension which permits us to regenerate past experience in a suitable form for the needs of the moment. If we can extract meaning from a task or situation, we will “automatically get remembering” (Jenkins, 1971). The meaning is absorbed within and recreated from our existing operational schemata and, as such, it is difficult to separate memory in the broad sense from intelligence. Piaget and Inhelder (1973), also distinguished between the development of deliberate attempts at reproduction and the development of the operational schemata themselves, for memory development involves “not only quantitative changes in the acquisition, retention, and loss of (specific) data, or the capacity

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for immediate or deferred recognition and recall . . . but also the fundamental qualitative factor, namely, (changes in) the organization of the memory [Piaget & Inhelder, 1973, p. 3791 .” The development of memory is seen as the gradual organization and reorganization of past experience, an organizational process which is closely dependent on the structuring activities of intelligence in general. “The schemata used by the memory are borrowed from the intelligence, and this explains why they follow one another in stages corresponding to the subject’s operational level [Piaget & Inhelder, 1973, p. 3821.” The schemata of intelligence which intervene in the organization, interpretation, and reconstruction of memory are active in all phases of the memorial process, “during retention and recall no less than during the fixation of memories [Piaget & Inhelder, 1973, p. 3831.” Thus, the basic schemata of the intelligence do not merely intervene to determine how we perceive material or events initially but are continuously active in organizing and reorganizing material during retention up to and including the time when those events are reconstructed. This Piagetian view of memory in the broad sense is expressed most eloquently by Piaget himself. The memory is a store of information that has been encoded by way of a process of perceptive and conceptual assimilation. The information itself, however, depends in part on the code. . . . Memory changes in the course of a subject’s development do not simply reflect the level of his encoding and decoding powers [i.e., strategies]: the code itself is susceptible to change during the conshvction of operational schemata. This explains why the level of memory organization differs with age, reflecting not only the coding level of the subject, but also the transformation of the code in the course of retaining the memory [Piaget & Inhelder, 1973, p. 261.

For Piaget as for Bartlett (1932), memory is not a copy of events but a reflection of the subject’s current assimilation schemata. This view of memory as a continuously changing constructive process led Piaget to predict not only distortions and omissions but also “qualitative mnemonic improvement” with time. Here Piaget gave the example of memory for a long passage or lecture. It is quite possible that memory for the information (gist) contained in that lecture would be better after a period of time if during the interim the subject has gained relevant experience which produced better reorganization of the defective memory. In effect, the subject can reconstruct certain connections or central points “not merely forgotten but unnoticed in the first place [Piaget & Inhelder, 1973, p. 3841 .” Piaget and Inhelder (1973) devoted their entire recent work to mapping the correspondence of the subject’s operational level to his memory for logical, causal, and spatial structures, both at the time of acquisition and during subsequent retrieval. Qualitative improvement in the child’s performance follows the pattern of improvement in his general operational level. Thus, memory in the wider sense and intelligence are difficult to separate according to the Piagetian position. Again, a quotation from Piaget illustrates the point excellently.

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Once we realize that in order to discover an organization we must either construct it or at least reconstmct it . . . and once we consider the memory adequate to this construction or reconstruction, we must also grant that it has an inner capacity for organization or reorganization, isomorphous with that of the intelligence. But, in that case, there is no reason for separating the two, rather must we consider the memory as part of the intelligence, though differentiated and specialized to perform a precise task, namely, the structuring of the past [Raget & Inhelder, 1973, pp. 400-401].

For Piaget, understanding, knowing, and remembering are inseparable facets of the intelligence-a point of view with obvious developmental implications. As the general operational level of the child undergoes changes with maturation and experience, so would we expect qualitative differences in his ability not only to perceive but to remember orderly relationships and meaningful events. 2. Memory and Meaning The Piagetian position described above has obvious similarities with the assimilation theory of language comprehension proposed by Bransford and Franks (1971) and Barclay (1973). Arguing against the assumption that meaning is conveyed by the linguistic structure of sentences, Bransford, Barclay, and Franks (1972) adopted the position that meaning is in the head of the listener and not in the sentence. “People carry meanings, and linguistic inputs merely act as cues which people can use to recreate and modify their previous knowledge of the world. What is comprehended depends on the individual’s general knowledge of his environment [Bransford et al., 1972, p. 2071 .” Similarly, Crothers (1972) asserts that the “proper unit of analysis both in memory and in discourse is . , . the overall knowledge structure and not a set of independent sentences [p. 2471. ” The constructive approach to comprehension and memory suggests that both involve an active process which uses the entire knowledge system of the subject; indeed, even machines need a knowledge system in order to comprehend (see also Winograd, 1972). The depth of understanding and strength of subsequent retention must be intimately related to what is already known. Knowledge (and interest) determines what is perceived and what is retained. Striking examples of the interplay between interest, knowledge, and memory are provided by observations of memory feats determined by cultural relevance (Colby & Cole, 1973). Bartlett (1932) recounted the story of a Swazi cowherd able to recall identifying marks and prices of hundreds of traded animals long after the complex transactions had occurred. Even within our culture the phenomenon can be observed. For example, chess players have their own knowledge system which determines what they perceive and remember (Binet, 1894). Master chess players and amateurs differ in their ability to reconstruct, e.g., a middle position from a chess game consisting of 24 pieces (Chase & Simon, 1973; DeGroot, 1966). If the position is a legitimate one, i.e., could occur in a game, the masters are able to reconstruct the position of most of the 24 pieces from memory. Even experienced amateurs

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can reconstruct only about eight pieces. If, however, the position is illegitimate, i.e., with the pieces placed randomly, there are no differences between Masters and weaker players. As Jenkins (1971) has pointed out “the head remembers what it does” or, as illustrated by the preceding example, what it is capable of doing. If memory and meaning depend on the subject’s knowledge of the world, then again, the developmental implications are obvious; for there must be an intimate relationship between what the child can do or construct at a particular stage in his development and what he can remember or reconstruct. If the to-be-remembered material is meaningful, and is congruent with the analyzing structures of the child, then comprehension of and subsequent memory for the essential features of that material will occur readily. With the exception of Piaget, however, developmental psychologists have concentrated almost exclusively on the child’s memory performance with meaningless materials. While the skills employed to deal with such situations are of obvious developmental importance and deserve attention, it is also reasonable to study the child’s performance in natural situations which have meaning for him. Jenkins made this point clear. “If we give (the head) higher order things to do, it retains the analysis of the higher order relations it extracts and uses these relations to generate products related to the initial activity. It seems to function very efficiently in pursuing such tasks. If, on the other hand, we give the head stupid things to do by ‘brute force’ it can only do relatively stupid things with the task and in the normal case it functions relatively inefficiently [Jenkins, 1971, p. 2851 .” If this is a fair characterization of the adult “head,” how much more descriptive it should be of the young “head” which is not yet equipped with a battery of skills for coping with situations divorced from the usual operations of intelligence. Piaget and Inkelder (1973) suggest that the fact that children forget so much of what they learn in school “clearly shows what happens to the memory once it becomes divorced from the exercise of the corresponding schemata (and this is a polite way of putting it), since the absurdity of a number of school practices is precisely that they divorce the memory of spontaneous activities from the intelligence and its operational schemata [p. 3961.” Insert the words “laboratory task” for the words “school practices” and we have a reasonable statement concerning the tasks studied by many developmental psychologists. Although there is a great deal of evidence of the young child’s difficulty with tasks focused on the goal of remembering in and for itself, there is little information on whether the child has the means of remembering in situations where memory is subordinated to a meaningful activity (Smirnov & Zinchenko, 1969; Yendovitskaya, 1971). In Jenkins’ terms, if given higher-order things to do, can the young child perform efficiently? a. Memory for ideas: An early study. One of the earliest psychological ex-

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periments with children as subjects focused on memory for meaningful material. Binet and Henri5 (1894) studied memory for sentences and prose passages using protocols of children of between 8 and 13 years. They isolated two kinds of memory: verbal memory and memory for ideas. If asked to recall short phrases, the child uses his verbal memory (memory for surface structure) to give back verbatim recall of the actual words presented. When faced with the task of recalling lengthy passages of meaningful prose, the child remembers the underlying meaning and reconstructs a new (idiosyncratic) surface structure. Binet and Henri referred to this process as “verbal assimilation, i.e., when reconstructing a new surface structure in which to clothe the retained meaning, children tend to replace the original surface structure with syntactic constructions more characteristic of their own speech. In recalling long passages, the child retains only the underlying ideas and reconstructs these ideas in a syntactic and lexical form more appropriate to his linguistic level. ”

b. Semantic integration. Binet and Henri regarded the process underlying recon-

struction of prose passages as one of assimilation. Similarly, the contextual approach to meaning, exemplified by the work of Jenkins (1973), emphasizes the active construction and integration of semantic relations within existing cognitive structures. Indeed, Barclay (1973) labeled the contextualist approach to sentence comprehension as an “assimilation theory.” A series of studies concerned with semantic integration illustrates this point. In a recognition memory task requiring identificationof sentences previously seen in paragraphs, both adults (Bransford et a l . , 1972) and children (Paris & Carter, 1973) confuse original and new sentences which preserve the same semantic relationships, but readily discriminate new sentences which violate these relationships. Apparently, when faced with the task of comprehending and remembering paragraphs, both adults and grade-school children integrate the meaning and relationships perceived in the individual sentences into holistic situational descriptions and forget syntactic information, such as which felations occurred in which specific sentences. By the process of semantic integration, the listener improves comprehension and memory for the ideas being communicated by storing a holistic unit rather than several fragmentary ones. However, in the process, memory in the strict sense of exact recall of specific sentences may be impaired. Thus, comprehension of linguistic material involves the spontaneous construction and integration of semantic relationships, both explicit and implicit. sI would like to thank Dr. Joan W. Reeves of the University of London for bringing the Binet and Henri paper to my attention in 1964. Unfortunately, due to my extant cognitive structures at that time, I failed to appreciate its significance. I would like to thank Dr. William F. Brewer of the University of Illinois for bringing the Binet and Henri paper to my attention in 1974. At this stage, it was entirely congruent with my current knowledge system and became an integral part of this paper. Thanks are also due to Tom Thieman at Illinois for his translation of crucial parts of the manuscript.

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Children, as well as adults, make spontaneous assumptions when comprehending or reconstructing meaningful events and frequently fail to differentiate the information generated from such assumptions from information they actually saw or heard. An excellent discussion of the semantic integration phenomena in children exists elsewhere (Paris, in press) and, therefore, only a brief review of the literature will be included here. Paris and his associates (Paris & Carter, 1973; Paris & Mahoney, 1974; Paris, Mahoney, & Buckhalt, 1974) have documented the semantic integration phenomena in retarded children and normal children of between second and fifth grade. The phenomenon was found reliable when either pictures or sentences served as stimulus materials and when a variety of locative relationships were involved. Children do not store pictures or sentences as static copies of the originals, but incorporate the sequential relationships into unified representation or holistic units. Of interest is whether semantic integration ability improves with age. Paris (in press) has suggested that it may not be possibie to answer this question using a recognition memory paradigm, for such a task may prove insensitive to developmental changes in semantic integration. The older children in his studies committed fewer errors than the younger subjects. As the index of integration is the ratio of false alarm errors to true inferences (also technically recognition errors), this overall decline in error rate is a problem. As the older children make fewer errors, because of increased memory span, facility with strategies of remembering, etc., there is a strong possibility that any developmental effects would be masked in this paradigm. For these reasons, Paris and his associates (Paris, in press) have turned to a task where comprehension and memory for narratives are measured by free recall and a question-asking task. c. Memoryfor narratives. Considering the ecological validity of the narrative as an information source for young children and other preliterate peoples (Colby & Cole, 1973), methods of constructing and conveying meaning from this source are of particular interest. In his pioneering studies of memory for stories, Bartlett (1932) demonstrated that transmission of the gist of a narrative involves contortions and embellishments, presuppositions and contextual inferences, that reflect the interests and biases of the purveyors. Rarely is there accurate recall of the exact input, or, indeed, any attempt at verbatim recall unless a particular piece of information is sufficiently bizarre, or crucial to the main theme, to warrant exact reproduction. Both the interest of the material, or notoriety in the case of rumor spreading (Hunter, 1957; Sulin & Dooling, 1974), and the exact form of questioning (Loftus & Zanni, 1973) all influence subsequent reconstruction of both the main theme and specific details. The need to study cognitive development in situations of cultural relevance has lead anthropologists to consider memory for narratives because they play an important part in the maintenance and transmission of tradition in preliterate societies (Werner, 1966). Colby and Cole (1973) reviewed studies by Pany and

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Lord on narrative recall involved in South Slavic epic songs. The themes (ideas) and structures of the songs are traditionally determined and of great significance to the people. The singers perform great feats of memory, delivering different songs throughout the forty nights of Ramadan. Although the singers report that they sing the songs exactly as they have heard them from other singers, in actuality, the songs are greatly modieed by each individual singer and reflect his personality, individual creativity, and even the mood of the audience. The singer lacks the concept of a “fixed and sacred original version” of the song which requires exact reproduction. Rather, his idea of the stability of the song “does not include the wording, which to him has never been fixed, nor the unessential parts of the story. He builds his performance, or song in our sense, on the stable skeleton of narrative, which is the song in his sense [from Lord, 1965; quoted by Colby & Cole, 1973, p. 861.” By retaining the central ideas of the stories and learning certain stable “melodic, metric, syntactic and acoustic patterns,” the singer is able to retain many hundreds of such tales (tales which may last throughout the entire night), a feat which would be impossible if word-forword rote memorization were required. By learning the rules of structure and retaining the gist or central ideas, the singer is freed from the necessity of learning many stories verbatim and can concentrate on recurrent themes and patterns which can be changed and substituted for one another. It stories and songs are a major source of cultural information in preliterate societies, can a parallel be drawn with the preliterate child in Western cultures? The analogy may be weak, but stories do appear to play an important role in the early socialization of the child. Yet, psychologists have rarely considered how children extract meaning from stones. The Soviet investigator, Korman (quoted by Yendovitskya, 1971) found that preschool children behave in a manner comparable to adults. Required to reproduce fairy tales, they do not reproduce the material mechanically, rather, they omit minor nonessential happenings and concentrate on the central ideas, which they emphasize and embellish. Experimental studies on story comprehension have been sadly lacking in America; however, some recent studies with young children have been reported (Barclay & Reed, 1974; A. L. Brown, 1975b; A. L. Brown & Murphy, 1975; Paris, in press). Primarily due to previously mentioned problems with the recognition paradigm, Paris (in press, Paris & Upton, 1974) has turned to a memory-for-stories approach to the study of semantic integration and inference in children. Kindergarten through fifth-grade subjects listened to stories, followed immediately by a question-asking task where comprehension and memory of both contextual inferences (presupposition and inferred consequences) and lexical inferences (semantic entailment and implied instruments) were examined. Memory for both explicit (verbatim) and implicit (inference) information improved with age, as illustrated in Fig. 1 , even when a correction for differential response bias (d’) was introduced. In order to determine whether the enhanced ability to deal with

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GRADE

Fig. I . A group showing d 's for verbatim and inferential questions as a function of grade level. (From Paris, in press.) Contort Inferanca 0 LaaIcaI Inferanca

I0

w

a a

0 0

I

I

1

1

,

1

K

1

2

3

4

5

GRADE

Fig. 2. Adjusted mean percent correct responses for inferential questions. Solid circle, contexi inference; open circle, lexical inference. (From Paris, in press.)

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inferences was dependent upon increases in capacity or span, per se, the effects of verbatim items were partialled out. These data are illustrated in Fig. 2, where it can be seen that there still remained a reliable improvement in inferential operations even when developmental differences in capacity or memory span for explicit information were taken into consideration, These data were replicated in a second study that also included a delayed free-recall attempt. Kindergarten children recalled 1.9 semantic units (ideas) per story compared with 4.4 and 9.3 for second and fourth graders. Within each grade level the best predictor (from the question-asking test) of subsequent free recall was the ability to make correct contextual inferences. Thus, spontaneously inferring consequences and making presuppositions may be an important contributor to the facility with which a child can both comprehend and retain the meaning of stories. These studies by Paris and his associates are extremely important as they illustrate that the child’s understanding and retention of implicit information does improve with age, a finding which was not readily apparent within the confines of the recognition memory studies of semantic integration (Paris & Carter, 1973). Furthermore, Paris has demonstrated that improvement in inferential reasoning is not simply due to increased memory capacity for the premise information (Bryant & Trabasso, 1971). As the child’s tendency to make inferences develops, his ability to understand and retain prose passages also improves (Paris, in press). Barclay and Reed (1974) failed to find evidence of an improvement in semantic integration beyond 5 or 6 years of age as kindergarten, first, third, and fifth graders were statistically indistinguishable in their recall of sentences containing either full passives or truncated passives as target sentences. When opportunities for semantic integration were not optimal (when the truncated passive was not followed by the nomination of a potential actor), the children recalled the sentences verbatim, a finding congruent with the adult literature (Slobin, 1968). When opportunities for semantic integration were established by introducing previously unmentioned actors elsewhere in the passage, the tendency to recall truncated passives verbatim decreased significantly, replicating the results of Bransford and Franks (1971). However, it should be noted that the truncated passive occurs in first-grade reading texts and, therefore, comprehension may involve a relatively simple form of semantic integration. When more complex inferential reasoning is required the ability to go beyond the information given improves with age (Paris, in press). An interesting finding in the Paris and Upton (1974) study is the low level of recall of the kindergarten children. If stories play an important part in the ecology of young children, then the poor recall scores are somewhat surprising. One might expect adequate retention of the essential ideas, even if many exact details have faded. Piaget (1969) and Fraisse (1963) believe that the poor recall of stories shown by preoperational children is a result of their failure to understand the concept of temporal sequence. The regeneration of a narrative relies on the

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ability to reproduce the order of events, each event thus serving as a prompt, or retrieval cue, for the next event in the sequence. By maintaining the order, it becomes possible to capitalize upon causal or logical inferences to reproduce the story in the original sequence. The difficulty with the concept of temporal sequence is regarded by Piaget as the primary determinant of young children’s poor recall of narrative sequences. Before 7-8 years, children’s narratives remain “purely egocentric, i.e., events are linked together on the basis of personal interest and not on the real order of time [Piaget, 1969, p. 2721.” Similarly, Fraisse points out that children’s memories of stories are “completely jumbled up, for they have not learned to reconstruct their past; this is shown by the haphazard way in which they retell stories, for the order of events depends more on their interests or on incidental associations than on reality [Fraisse, 1963, p. 2541.’’ Shif (1969) reports the work of Zankov, who found that similar confusion existed in the recall of stories attempted by retarded children. These children tended to recall only scattered portions of the story, not the main events, with these portions ordered haphazardly. Anecdotally, however, children appear to be able to retell stories, or reenact the plot of television cartoons, before 5 years of age, particularly if allowance is made for their focus of interest. Korman (quoted by Yendovitskaya, 1971) reported frequent departures from the original sequences of events, but these departures were accompanied by logically defensible “jumps.” The integrity of the main theme was maintained. An interesting question, then, is whether the failure to retell a story in order is due to the young child’s lack of expository skills or whether it reflects a true failure to comprehend and hence reproduce ordered sequences imbedded in narratives. A series of studies from our laboratory examined children’s memory for the order of events in a story using three response modes, recognition, reconstruction, and recall (A. L. Brown, 1975b). In the Piagetian task, subjects were required to verbally retell the story-a recall task. However, Piaget himself (Piaget, 1968; Piaget & Inhelder, 1973) has demonstrated the developmental progression in the young child’s ability to regenerate past experience, with recognition easier than reconstruction which in turn produces better performance than recall. If the child experiences difficulty in his verbal recounting of a story because he generally has problems with recall tasks, then it is conceivable that he would be able to regenerate the information by means of reconstruction or recognition. If, however, the child fails to recall events in order because he has difficulty with the concept of order, per se, then the use of a developmentallyless mature response mode should not enhance his regeneration of order information. Kindgergarten and second-grade children were asked to listen to, or make up, five separate stories, each involving an actor and three distinct items. When a story was provided, the interactions of the actor with each of the three items

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could either be unconnected events (Random) or form part of the unfolding of a story or logical sequence (Ordered). Retention of the stories was measured by means of a free-recall or nonverbal reconstruction task, where the subject was required to arrange pictures of the items in the order they occupied in the story. The mean number of correctly ordered stories is illustrated in Fig. 3, where it can be seen that older children can regenerate the stories both by verbal recall and nonverbal reconstruction. In contrast, kindergarten children experience difficulty recalling the stories but are quite capable of reconstructing the sequence of events by nonverbal means. In a subsequent series of studies recognition of the correct order was also found to be far superior to recall, if care was taken in the choice of the distractor items (A. L. Brown, 1975b). a Second Grad. 0

OR0

Kindargarien

RAN

--

O.S.

RECONSTRUCTION

ORD

RAN

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FREE RECALL

Fig. 3. The mean number of torally correct orders (out of jive) as a function of age, story condition, and response mode. ORD, ordered sequences; RAN, random sequences; 0 .S., own story. (From A . L . Brown, 19756.)

A reliable finding, recurrent throughout a series of similar studies, is that logical sequences, whether self-produced or imposed, are regenerated far better than arbitrary series of events (A. L. Brown, 1975 a & b; A. L. Brown & Murphy, 1975). As an example (A. L. Brown & Murphy, 1975), four-year-old children were given sets of four pictures which depicted either logical narrative sequences, or random series of events. In addition, the logical sets were presented in their correct order (Ordered) or jumbled (Scrambled). The proportions of completely correct reconstructions, after lags of between 0 and 5 intervening sets, are illustrated in Fig. 4. Consider first the Ordered vs. Random sets. Performance remained accurate over lags in the Ordered condition, but there was

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a decline in accuracy as a function of increasing lag for the Random sets. A reasonable explanation of these findings is that when dealing with orderable material, subjects rely heavily on the inferential reasoning capacity of their semantic memory systems to construct or reconstruct logical orderings, whereas when dealing with random material, memory is basically episodic. Thus, the normal episodic memory pattern is found in the Random condition, high initial accuracy followed by a decline in performance with increasing lag. In the Ordered condition, subjects make use of meaningful relations to reconstruct the logical orderings. With increasing lag, specific episodic features tend to dissipate, whereas features essential to the meaning of the event or story are relatively resistant to decay (Brockway, Chemielewski, & Cofer, 1974; Tulving, 1972). ’*0°

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An intriguing pattern of errors was found with the Scrambled sets. In this condition, subjects were required to disregard the inherent order of a set and reproduce the actually experienced order. Accuracy levels were always lower on Scrambled compared with Random sets, suggesting that disregarding an inherent order is a difficult task. If this-were the case, one might predict that errors on the Scrambled sets would be nonrandom. Of the 143 error trials, 51 (36%) were “correct11reconstructions in the sense of reproducing the logical rather than the viewed order. When the lag 5 error trials (67) were considered, 37 (55%) of the

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reconstructions followed the “correct order. ” Both values are significantly greater than the chance probability of .04.In his effort after meaning (Bartlett, 1932; Piaget & Inhelder, 1973) the child reconstructed a better order than the one he viewed initially. One problem with these studies was that the correct order of logical sets could be produced without experiencing a prior viewing trial, thus, it is difficult to separate reconstructive and constructive processes. To correct this problem the studies were replicated using pictures of isolated items as stimuli (A. L. Brown & Murphy, 1975). Logical or narrative sequences were imposed by providing a meaningful connective narrative linking the items. All subjects saw the same sets of pictures, sets which could not be ordered correctly without the viewing trial, however, half the subjects heard a connective narrative while the remainder did not. The results of the replication are presented in Fig. 5 , where the superiority of Ordered vs. Random sets is again apparent. 1.ooc

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Taken together the data support the hypothesis that in reconstructing sequences young children benefit from the presence of a unifying connective logic. Children, like adults, behave differently when required to reproduce arbitrary events in isolation from a larger context than when required to reconstruct meaningful unitized events (Horowitz, Lampel, & Takanishi, 1969; Jenkins, 1973). Arbitrary sequences are processed by the episodic system and acquisition and

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Ann L. Brown

retrieval from episodic memory demand deliberate strategies and skills beyond the problem-solving capacity of the young child (A. L. Brown, 1974; Flavell, 1970). Logical sequences, however, are processed predominantly by the semantic memory system. When faced with the task of reconstructing a meaningful series of events, the preoperational child is capable of using logical connections to construct a holistic unit, i.e., to use the inferential reasoning capacity of semantic memory. In summary, narrative prose passages and songs are a powerful medium for the transmission of information for both preliterate societies (Colby & Cole, 1973) and young children. Preschool children can reconstruct meaningful sequences even when considerable intervening material is interprosed (A. L. Brown & Murphy, 1975). They spontaneously concentrate on central themes when reconstructing the gist of stories (Yendovitskaya, 1971) but experience difficulty recounting the sequence of events because of their immature expository powers (A. L. Brown, 1975b). As children mature, they become increasingly more efficient at recounting stories and more capable of deriving inferential relationships essential to the meaning of the story (Paris, in press). Increasingly, the maturing child capitalizes upon causal and logical inference founded on probability (Fraisse, 1963; Paris, in press) to reconstruct both the explicit and implicit meaning, to seek and produce the most probable order of events. d. Memory for meaningful activity. i. Incidental learning and the activity of the subject. If a child engages in a meaningful activity (Meacham, 1972) or experiences a meaningful event (Jenkins, 19731, he will retain the essential features of that activity whether or not a deliberate intention to remember has been evoked. Soviet psychologists have described this phenomena as “involuntary memory” which is largely the result of the incidental learning that accompanies the child’s active exploration of his environment (Smirnov & Zinchenko, 1969). The general thesis is that memory depends on the “structure and contents of actions” and is a “permanent component of all behavior patterns, no matter whether remembrance be involuntary or intentional [Zinchenko & Smimov, 1966, p. 61.’’ Studies of incidental learning in children have focused predominantly on what Postman (1964) refers to as Type II paradigms. Here the subject is given a specific learning task during which he is also exposed to material which is irrelevant to the task as specified by the learning instructions. Hagen and his associates (Hagen, 1972) have documented the development of the child’s ability to ignore irrelevancies and to concentrate exclusively on relevant information during the course of a deliberate memorization task. Little attention has been paid to Postman’s Type I paradigm of incidental learning, where the subject is exposed to the stimulus materials but given no explicit instructions to learn. The degree of interaction between the subject and the material is determined by the

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nature of the orienting instructions. In a series of Type I incidental learning studies with adults, Jenkins and his associates (Hyde & Jenkins, 1969; Jenkins, 1971; Johnston & Jenkins, 1971) distinguished between comprehensionorienting instructions, which required the subject to understand the meaning of words, and formal-orienting instructions, which involved treating words structurally (checking the number of vowels, etc.). Comprehension tasks reliably resulted in free-recall and organization scores equivalent to those found under deliberate instructions to learn, whereas formal tasks produced significantly inferior performance. In general, the adult literature on Type I tasks supports Postman’s (1964) contention that intent to learn, per se, has no significant effects on learning. Instructions to learn facilitate performance only to the extent that they induce the subject to process the material in an appropriate manner, i.e., to process at a deep semantic level (Craik & Lockhart, 1972) or the level of associative meaning (Paivio, 1971). That it is the acfivily of the subject, rather than the intent to learn, that is important is of great interest to those concerned with memory in the young child (Meacham, 1972; Yendovitskaya, 1971). Rarely do preschool children adopt appropriate activities in responses to explicit instructions to learn (A. L. Brown, 1974; Flavell, 1971). Adults, who spontaneously adopt appropriate strategies when instructed to learn, perform equally well in incidental and intentional situations when both induce the appropriate activity. Children, however, fail to produce appropriate activities in response to explicit instructions to learn and, as such, should perform better in incidental situations which induce task, to analyze relevant activities. It is the execution of the plan (Miller et ~ l . 1960) at a semantic level (Craik & Lockhart, 1972) which leads to efficient learning, not the intention to learn in itself. Incidental learning in children, in the sense of executing a plan without intent to memorize, has rarely been studied by American psychologists, although the Soviet psychologist, Zinchenko (quoted in Smirnov & Zinchenko, 1969; Yendovitskaya, 1971), conducted a relevant study. Preschool children performed equally well when asked to classify pictures, with or without instructions to remember. Both groups remembered more items than subjects instructed to remember by any means that might occur to them. A series of studies which combine the features of the Russian work with children and Jenkins’ studies with adults have recently been completed in our laboratory (Murphy & Brown, 1975). Preschool children were given two 16-item lists, one list under open-ended instructions ‘‘to remember” and the other under incidental orienting instructions. In the incidental phase of the experiment, the subjects were divided into five groups: a control group told to classify in order to remember, and four incidental learning groups not warned that item recall would be required. The four sets of incidental orienting instructions consisted of two sets of comprehension activities and two formal orienting tasks. The two comprehension tasks were designed to

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induce categorization. The first involved categorization in the context of a meaningful activity of buying items at a store, If, as suggested by Soviet psychologists (Yendovitskaya, 1971), memory is most efficient when subordinated to a meaningful activity, this task should produce superior recall than the activity of categorization in and for itself (comprehension task 2). The two formal tasks were also intended to vary in the degree of semantic analysis they would induce. The first required the subject to name the items and then say their first sound, while the second did not demand labeling but merely identification of the dominant colors. According to Paivio’s (1971) model, labeling should induce processing at least to the level of representational meaning, whereas in the absence of labeling, items could be processed in terms of their physical features without reference to their meaning. The recall and clustering scores, illustrated in the top half of Fig. 6, show the same pattern. No differences in recall or clustering were found between the baseline free-recall session and incidental-learning session involving formal orienting tasks (color and sound). In contrast, performance under comprehension incidental tasks was significantly better than performance in free-recall situations. Comprehension tasks produced better recall and clustering than formal tasks in preschool children as they do in adults (Hyde & Jenkins, 1969; Tresselt & Mayzner, 1960). Contrary to predictions, the incidental tasks did not form a continuum in the extent to which they influenced learning. Categorization, whether accompanied by explicit instructions to recall or occurring in the context of a meaningful activity, was no more efficient than categorization in and for itself. That categorization was equally efficient with or without intentional learning instructions confirms the finding of Mandler (1967) with adults and Zinchenko (Smirnov & Zinchenko, 1969) with preschool children. The two formal tasks also did not differ. However, as the majority of children labeled spontaneously in both the sound and color conditions, differences in terms of levels of processing could not be assessed. One problem with interpreting the results of this experiment is that the comprehension tasks all involved the activity of taxonomic categorization, the appropriate strategy for memorizing an organized list. In this sense, the notion of “comprehension tasks” and that of ‘‘appropriate strategy” were confounded. However, the effectiveness of comprehension-orienting tasks with adults is not limited to those which produce the response of taxonomic categorization. The task most commonly used by Jenkins and his associates is rating the words as pleasant or unpleasant, while Tresselt and Mayzner (1960) required subjects to judge the degree to which words were instances of the concept “economic.” Furthermore, the Craik and Lockhart model cites, as the major determinant of learning, the degree to which the subject processes the material at a deep semantic level, i.e., understand the meaning of the words. Therefore, it was not

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Fig. 6 . The proportion of items correctly recalled and the degree of clustering as a function of experimental condition in both Experiments I and 2. Cat., categorization; S. Cat., categorization in the storefront activity; Cat. R.. categorization in ord$r to remember; N. N.,nice-nasty instructions; Cat., S. Car., and N. N.are comprehension tasks: Sound and color are formal tasks. (From Murphy and Brown, 1975.)

possible to determine, from this experiment, whether the comprehensionorienting tasks succeeded because they forced the children to adopt the most appropriate task relevant strategy, categorization, or because they induced the subjects to consider the meaning of the words. In order to clarify this point, the study was replicated using as comprehension tasks, the Jenkins' orientation of rating items pleasant or unpleasant, together with the categorization and the color tasks of the first experiment. The recall and clustering data from the second experiment are presented in the bottom half of Fig. 6, where it can be seen that the data replicate the original

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study. Comprehension tasks, whether they induce taxonomic categorization or not, produce better performance than both open-ended ‘‘remember” instructions (baseline) and formal orienting activities. These findings provide strong support for the hypothesis that intent to learn has no significant effect on memory (Craik & Lockhart, 1972; Jenkins, 19’3; Postman, 1964). Instructions to learn or to remember enhance performance only to the degree that they induce an appropriate activity. Thus, the pattern for preschool children is different from that found with adults. For adults, instructions to remember elicit an appropriate plan of action (Mandler, 1967) while this is not the case with children (Appel et al., 1972). As preschool children do not spontaneously introduce appropriate activities when asked to remember, incidental situations which induce meaningful activities result in superior recall and clustering than situations involving openended instructions to learn deliberately.6 ii. Memory for some purpose. Consideration of these data reawakens the question of the “ecological validity” (Jenkins, 1971) of instructions “to remember” for the preschool child who has rarely been required to memorize deliberately and consequently has not developed a systematic series of strategic operations to deal with such eventualities. Apparently, the child is capable of remembering, even reproducing exactly, material with which he has interacted in a meaningful way (Murphy & Brown, 1975). Soviet psychologists (Smirnov & Zinchenko, 1969; Yendovitskaya, 1971; Zinchenko & Smirnov, 1966) have argued at length that it is in the context of meaningful activity that memory is most efficient. Remembering as a goal in itself is not a meaningful aim for the preschool child (or very often for adults?). Memory as a means of obtaining a meaningful goal, however, can be understood by even very young children. For example, Istomina

TABLE I MEAN NUMBER OF WORDS RECALLED (OUT OF FIVE) AS A FUNCTION OF THE PURPOSE OF REMEMBERINGa Age Purpose

4-5

5-6

6-1

0.6

15

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2.3

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3.8 4.4

Conditions

3-4

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Laboratory task

Memory as means

Play activity Practical activity

aFrorn Yendovitskaya (1971), p. 94. 6 A similar set of studies (Yussen, Levin, DeRose, & Ghatala, 1974) was brought to my attention after the completion of this chapter. In a Type i incidental learning situation, first- and second-grade children recalled and clustered more when they processed items semantically rather than physically. This held true when the type of processins was self-selected or imposed by the experimenter.

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(quoted by Yendovitskaya, 1971) investigated retention of a list of five words when the task was a means of achieving a meaningful goal, or when memory of the list was the goal itself (as in laboratory tasks). The results are reproduced in Table I. Memory, in and for itself, is much less efficient than memory which is directed at some meaningful goal or purpose. “Only the presence of definite motives makes the mnemonic goal meaningful for the child [ Yendovitskaya, 1971, p. 931 .” The interaction of both deliberate and involuntary memory and meaningful activity in children deserves further attention.

c. DELIBERATEvs. INVOLUNTARY MEMORY: CONFLICT OR COMPLEMENT

The distinction has been made between deliberate strategies for remembering and memory which is the involuntary product of meaningful activity, with or without prior warning of impending recall. Here the interaction between the two forms of memory will be considered. First, consider the case that deliberate and involuntary forms of remembering are complementary. It is assumed within the levels of analysis model (Craik & Lockhart, 1972) that the degree to which the material is compatible with existing cognitive structures is a major determinant of the depth of processing. Similarly, it is also assumed that this compatibility interacts with deliberate attempts to analyze material to a deeper level. Two examples will be given here of enhanced memory in a deliberate paradigm when the material is tailored to fit the child’s current cognitive status. The first is the release from proactive interference paradigm. The second is the associative clustering, free-recall situation. In a release from proactive interference study, subjects are given several trials in which they observe a short list of stimuli (usually three or four words), engage in an overtly interfering task for about 30 seconds, and then attempt serial recall of the stimulus list. On each trial the stimulus list in drawn from words containing some features in common. Recall is quite accurate on the first trial but drops rapidly providing that the successive trials present words from the same category. On the release trial the stimulus category is changed (e.g., from animals to foods). Typically, performance returns to its original high level (release from proactive interference) but deteriorates again if trials are continued with the new stimulus class. The phenomenon is viewed as a sensitive measure of determining the categories that a subject actually uses, deliberately or involuntary, in encoding words. Several studies with children (Cermak, Sagotsky, & Moshier, 1972; McBane & Zeaman, 1970; Pender, 1969; Wagner, 1970) have shown the release phenomenon in children with some dimensions but not with others. Failure to obtain the phenomenon along a dimension presumably means that the dimension is not used for encoding at that stage of development. Of particular interest here is the

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fact that both. adults (Reutener, 1972; Wickens, 1972) and children (Pender, 1969; Wagner, 1970) show reliable release along categories, the criteria of which they are subsequently unable to identify. The suggestion is that the underlying semantic organization of the subject influences the manner in which he encodes stimuli, but that differential encoding is not necessarily the result of a deliberate strategy on the part of the subject (Posner & Warren, 1972; Wickens, 1972). As such, the release from proactive interference paradigm could provide a sensitive measure of developmental differences in semantic constructs, relatively uncontaminated by strategic transformations, as young and retarded children appear to differ from adults on the type of categories along which they show release but not in the release phenomenon itself. Whether the release is the result of automatic or deliberate differential encoding, it provides an example (in a deliberate memory paradigm) of enhanced memory if the material is tailored to fit the child’s head. Another example of a deliberate memorization paradigm where some consideration has been given to head fitting is that of free recall of organized lists. Although the developmentally young show relatively limited tendencies to cluster during free recall, there is some suggestion that young children may prefer different organizational structures from those used by adults. If this were true, providing an organization congruent with the child’s own should enhance the probability that he will use that structure in the process of remembering. Denney (1974) has reviewed the considerable literature which suggests that young children prefer organization based on thematic rather than taxonomic relations in free association tasks (R. Brown & Berko, 1960; Entwisle, Forsyth, & Muus, 1964; Riegal, Riegal, Quarterman, & Smith, 1968), free classification tasks (Annett, 1959; Inhelder & Raget, 1964), and matching tasks (A. L. Brown, Smiley, Murphy, & Overcast, 1974c; Kagan, Moss, & Sigel, 1963). Considering the pervasiveness of this organizational preference, Denney and Ziobrowski (1972) looked at clustering in free-recall tasks when the material was thematically or taxonomically related. They compared the performance of six-year-olds (when thematic relations predominate) and college students and found that six-year-olds clustered more on the thematic lists, while college students clustered more on the taxonomic lists. Thus, providing structure which is congruent with the child’s preferred organizational schemes enhances the possibility that he will spontaneously or deliberately note that structure and thereby enhance the probability of organized recall. Attempts to fit material to the “head” have not always been successful in improving recall. Both K. J. Nelson (1969) and Tenney (1973) addressed the head fitting problem, head-on as it were, by asking young children to provide their own material for subsequent recall. Nelson compared recall of a standard list (with a category structure based on adult norms) with recall of a categorized list containing the child’s own categories and examplars. No differences between

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self-produced and traditional categorized lists were reported. Similarly Tenney (1973) studied children’s recall of self-produced lists. Kindergarten, third-, and sixth-grade children were asked to make up lists that would be easy for them to recall. College students faced with such a task tended to behave in a systematic manner, generating lists with clear categorical structures (e.g., the numbers 1-50, the 50 states, instances from taxonomic categories and cities along a familar highway). When grade school children were asked to produce easy lists for recall, even the youngest showed some appreciation of the problem and named friends, family pets, numbers, or days of the week. However, although the young children did not differ from adults in the type of material generated, they did differ markedly in their degree of organization. They tended to jump back and forth between topics and to generate many miscellaneous words often neglecting to take advantage of the preordered nature of the materials they had selected. As with the Nelson study, Tenney found that providing self-produced material did not aid recall in the younger children. On the contrary, experimenterprescribed taxonomic structures were far more useful for younger children than any structure they devised themselves. Older children, in contrast, benefited from the inclusion of their own materal for recall. As older children almost exclusively generated lists that followed a category structure and younger children did not, this comparison is confounded. Young children failed to produce organized lists as they have little insight into the workings of their own memory. Although they took advantage of a category structure when it was presented, they did not foresee its usefulness. Consequently, they did not think of building structure into their self-generated recall lists. Due to deficiencies in his metamemorial functioning, it is not an easy task to induce the young child to help in the head fitting business-he doesn’t appreciate the limitations of his head. Next, consider the case for a conflict between deliberate and spontaneous remembering. Although there is some experimental evidence that the deliberate use of a specific strategy, particularly labeling and rehearsing, can interfere with more mature strategies (Flavell et a l . , 1970; Hagen, Meacham, & Mesibov, 1970), situations where use of a deliberate strategy could interfere with the ability to abstract meaning from the material, and, therefore, to remember it spontaneously, have not been examined. But it is conceivable that the rigid use of a dominant strategy may blind the child to a higher-level interaction with the material. For example, if a child is trained to rote rehearse series of digits such as 4 9 2 6 1 8 , 9 1 7 3 4 2, he may attempt to rehearse the set 1 2 3 4 5 6 embedded within such a series, failing to realize that rehearsal is not needed for such a meaningful set. The analogy here is to problem-solving tasks such as the Luchins’ water jar problem (Luchins, 1942) where facility with a successful complex solution, applied over a series of problems, leads the subject to adopt the complex rule even when a far simpler solution could be used. Thus, subjects

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trained to rote rehearse may also be less likely to notice and use redundancies (Spitz, 1973) in digit sets (such as 425, 425) than subjects not pretrained in the rehearsal strategy. The interplay between deliberate and involuntary forms of memory has received little attention to date; however, it would appear to be an interesting avenue for future research.

IV. A Model of Developmental Changes in Memory A. INTRODUCTION In this section, a guideline or organization scheme for studying developmental changes in memory will be presented. The scheme, like all simplified models, is at best a crude indicator of where to look for developmental differences and what kind of change one would expect to find. The intention is to provide a structure or organization to guide research rather than to suggest that the model reflects the ‘‘real world.” In the developmental literature, three main themes can be seen running throughout. The themes often take the form of dichotomies. For the purpose of the model, these dichotomies will be adopted, although the distinctions are better thought of as representing continua rather than dichotomous divisions. The three major dichotomies are, (a) between tasks which do or do not require strategies for their efficient execution; (b) between production and mediation deficiencies in the use of memorial and metamemorial skills; and (c) between episodic and semantic memory systems.

B . TERMINOLOGY 1. The Strategy-No Strategy Distinction

The first assumption of the model is that tasks will be developmentally sensitive to the degree that they demand strategic transformations for their efficient execution (A. L. Brown, 1974; Flavell, 1970). Note that the assumption includes the word degree for clearly there exists a hierarchy of tasks varying in the degree to which strategic intervention can be fruitfully applied. At the simplest level are those situations where efficient performance relies little upon active acquisition or retrieval strategies, or a working knowledge of one’s own strategic capabilities. At the highest levels are those tasks which require complex strategic intervention involving the flexible application, monitoring, and control of a variety of complex cognitive operations. Developmental differences will be found to the extent that such operations are demanded for efficiency because the developmentally immature do not spontaneously adopt appropriate plans

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(A. L. Brown, 1974; Flavell, 1970), nor do they possess the requisite insight into the workings of their own memory (Flavell et a l . , 1970) to appreciate this fact.

2. Mediation and Production Dejiciencies A further distinction which will form an essential feature of the model is that between mediational and production deficiencies in the use of both memorial and metamemorial skills. Again, the distinction has been amply discussed and documented in previous review papers (Flavell, 1970; Meacham, 1972), so only a brief statement will be included here. A mediation deficiency is said to be in effect when the subject is unable to use a potential mediator (strategy) efficiently even when he is specifically instructed and trained to do so. A production deficiency is implicated when the subject can be induced (e.g., through training or simple instructions) to use a mediator which he did not produce spontaneously. As with all three of the dichotomies, the mediation-production deficiency distinction is best seen as a continuum with children differing in the degree to which they display a deficiency. For example, Flavell and his co-workers have made the distinction between production deficiencies and production inefficiencies (Corsini, Pick, & Flavell, 1968). A production inefficiency refers to the stage where the child attempts to apply a potential mediator but does so ineptly due to some developmentally related limitation in his facility with that strategy. So once again, a continuum of ability is implied rather than a strict dichotomy. 3 . Episodic and Semantic Memory Systems The final distinction which will form part of the model is that between the semantic memory system and episodic memory, “the other kind of memory, the one that semantic memory is not [Tulving, 1972, p. 3841 .” An outline of the major differences between episodic and semantic memory is provided in Table 11. The episodic system invoIves the type of memory usually studied in the laboratory, i.e., the system, concerned as it is with the reproduction of directly perceived instances’ in isolation, involves retrieval of information that has been directly entered into the store on an earlier occasion. Criteria of success are

’Unfortunately the terms “events” and “episode” have been used by Tulving (1972) and Jenkins (1973) to refer to incompatible ideas. Tulving uses the term “event” as a “loose synonym of occurrence.” Events refer to instances which are distinctive and separate although part of a larger series. Thus, for Tulving, an event is a perceptible discrete unit or instance. Jenkins (1973) uses the term ”event” to refer to the holistic unit, consisting of the total meaning of an experience in context. To avoid confusion between these two incompatible usages of the word “event,” the term “instance” will be used herc for Tulving’s “events,” and “holistic units” to refer to Jenkins’ “events.”

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TABLE I1 MAJOR DISTINCTION BETWEEN EPISODIC AND SEMANTIC MEMORY SYSTEM Episodic 1. Memory for directly experienced in-

stances 2 . Concerned with temporal-spatial re-

lations of experienced instances

3. Memory for discrete perceptual in-

Semantic Not necessarily dependent on personal experiences Only concerned with temporal-spatial relations if they form an integral part of the meaning of the holistic unit Memory for holistic units in context

stances that are distinct and separable from the larger unit in which they occur 4. Memory for relatively meaningless items, i.e., instances in isolation

Memory for meaningful systems, i.e., units in context

5 . Memory for actual input, usually reproductive

Memory for gist, usually reconstructive

6 . Criteria concern “correctness” or accuracy of response compared with input

Divergence from input as interesting as “correct” responses

I. Does not include the capability of infer-

Includes the capability for inferential reasoning, generalization, application of rules, etc.

ential reasoning or generalization

usually measured against the accuracy of the reproduction compared with the input. Finally, the system does not include the “capabilities of inferential reasoning or generalization.’ ’ The semantic memory system is concerned with memory for meaningful holistic units experienced in context. Semantic memory does not register perceptual properties of inputs except to the extent that they permit “unequivocal identification of semantic referents of the event [Tulving, 1972, p. 2881 .” As a result, identical changes in semantic memory can result from a whole variety of different inputs. As the system does not rely on actual input, or personally experienced instances, it is possible to retrieve information from semantic memory which was never directly experienced. Retrieval from the system includes imaginative reconstruction of the meaning or ideas fundamental to the information and involves the total knowledge system of the individual. As a result, there are no “errors” in retrieval (other than omissions, or failure to retrieve) as all responses reflect the semantic memory system. Measures of interest become such things as false alarm recognition scores (Cramer, 1972, 1973) and synonym substitutions (Binet & Henri, 1894; Brewer, 1974a; E. V. Clark, 1972), technically errors but actually the data of principal interest. As the input conditions responsible for the existing semantic structure are seldom

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known, experimenters are relatively freed from the preoccupation with measuring exact input-output correspondences. Finally, since retrieval from the system is by means of active constructive processes, important methods of using information stored in semantic memory are inferential reasoning, generalization, application of rules and formulas, etc., methods which involve the total dynamic knowledge system of the individual. While these distinctions are relatively clear, identifying various tasks as either episodic or semantic may not only be difficult but not particularly informative due to the essential interdependenceof the two systems. The assignment of tasks to either category is one of degree and depends in part upon the kind of question or requirement addressed to the memorizer. For the purposes of the model, the episodic-semantic distinction has been adopted with the understanding that assignment to either end of the continuum is somewhat arbitrary.

C. THEMODEL 1. The Ideal Model Two major types of developmentaI effects will be discussed, level differences and pattern differences. The analogy is from an analysis of variance model. A level difference would be a main effect of developmental stage, while a pattern difference would be reflected in interactions between developmental stage and task variables. As a concrete example, consider studies of free recall of categorized lists. Performance improves with age (amount of clustering), a level difference. In addition, interactions between developmental level and the type of categorization (e.g., taxonomic vs. thematic) are frequently obtained, a pattern difference. Serial position curves also show level and pattern differences. Again amount of recall increases with age, a level difference, and there are interactions between developmental level and the shape of the curve (elevated primacy and recency for older subjects, only recency for younger subjects), a pattern difference. The major distinctions made thus far, between strategic and nonstrategic tasks and between episodic and semantic memory, are seen as jointly determining both when developmental differences will occur and, if they occur, what type(s) of differences, level or pattern, would be expected to emerge. The basic idea is illustrated in Fig. 7. Memory tasks are divided roughly into those which do and those which do not demand mnemonic strategies for their efficient execution. If mnemonic strategies are required, the developmentally young should perform poorly compared with more mature subjects, for they fail to employ mnemonic strategieseffectively (A. L. Brown, 1974; Flavell, 1970).Further, there would be differences in both overall levels of performance and patterns of performance. If, however, mnemonic strategies are not required, then developmental differences would be expected only to the extent that the task taps the semantic basis of

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Fig. 7 . The memory model: The strategy-no strategy distinction.

memory. If the task is entirely episodic in nature with no extra-episodic reference, then the task should be relatively insensitive to developmental stage. If, however, the task does tap semantic features, then developmental differences would be expected in the pattern but not necessarily the level of performance. The inclusion of the production vs. mediation deficiency distinction is necessary for the next stage of the model, as the interrelation of production and mediational deficiencies with the processes already described yields the more complex model schematized in Fig. 8. Thus, when a task requires mnemonic strategies, the subject can spontaneously adopt the required strategy. In this case, he will perform efficiently, and developmental differences would be expected only to the extent that the task is semantic in nature or the strategy is performed inefficiently. If the subject does not spontaneously produce the strategy, the question is, can it be induced with suitable intervention? If it cannot, a mediational deficiency is said to be operating, and the developmentally young should perform poorly. If, however, the appropriate strategy can be induced, the original deficiency is one of production. Developmental differences following successful remediation of a production deficiency would again be expected only to the extent that the task taps the semantic basis of memory, or the strategy is used inefficiently by the subject. At this point, the basic taxonomy is completed. Thus, memory tasks would be expected to differ in the degree to which they are developmentally sensitive. Tasks which do not demand strategic intervention and are primarily episodic in nature will be the least sensitive to developmental factors. Tasks which do not demand mnemonic strategies but are sensitive to changes in the underlying

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Fig. 8 . The memoty model, including the three continua-strategy-no tic, and production and mediation deficiencies.

strategy, episodic-seman-

semantic structure of memory will show developmental differences in the pattern of performance (types of false recognitions, quality and nature of clustering, etc.) but not necessarily in the level of performance. Tasks which do require mnemonic strategies yield more possibilities regarding developmental differences. If the strategy is not produced and cannot be induced, differences would be expected in terms of both patterns and levels. If the strategy can be induced, the prediction is determined by the nature of the task, episodic or semantic. If it is primarily episodic, the prediction is for different levels if the strategy is not used efficiently, although the patterns should be similar. If the task is semantic, primarily pattern differences would be predicted.

2. The Four Ideal Tasks As mentioned earlier, the model is an ideal representation of the nature of memory tasks. The value of any such model is the extent to which it leads to differential predictions and clarifies rather than confuses. In this section, the possibility of providing concrete examples of the idealized distinctions contained within the model will be examined, beginning with examples of the four types of tasks resulting from the factorial combination of episodic-semantic and strategic-nonstrategic. a. Nonstrategic-episodic. An ideal nonstrategic-episodic task is one that does not demand any obvious strategy for efficient performance and is episodic in

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nature, i.e., completely independent of the semahtic memory system. Such an ideal task does not have a strict counterpart in reality, as all tasks are to some extent susceptible to strategic transformation, and all tasks involve to some extent the semantic memory system. The information in the semantic memory system is obviously involved in the identification and encoding of events even when the main requirements of the task are episodic in nature. Therefore, this cell will include tasks which are the least likely to demand active retrieval or acquisition strategies and the ability to monitor them, and the least dependent on the semantic system. It would follow from the model that such tasks should be the least sensitive to developmental trends. The first contender for inclusion in this cell is recognition memory for unrelated pictures, for the task does not require active plans for acquisition and is relatively independent of retrieval strategies. Although the semantic system is involved in identifying the items, the task is predominantly episodic as it involves a decision as to where and when an isolated item occurred in our personally experienced past, What empirical evidence exists would support the contention that the task is relatively insensitive to developmental trends. The ability of three- to five-year-old children to recognize repeating pictures approximates that of adults (A. L. Brown & Campione, 1972; A. L. Brown & Scott, 1971; Corsini, Jacobus, & Leonard, 1969). K. E. Nelson (1971) found equivalent retention in picture recognition across the age range from 7-13 years. Similarly, mildly retarded children show excellent levels of recognition memory for pictures (A. L. Brown, 1972, 1973c; Martin, 1970). The problem with interpreting the data from picture recognition tasks is that such interpretations are contaminated by the ceiling effect, so far found for all ages, which could mask any developmental trends. To overcome this problem, an episodic task is required where adults’ performance is good but not perfect and no obvious mnemonic is required for efficient performance. A suitable candidate appears to be the discrimination of relative recency tasks (Yntema & Trask, 1963), for adults’ performance is not on the ceiling and the ability to process and retrieve this form of temporal information does not necessarily rely on the use of a deliberate strategy (Hintzman & Block, 1971; Underwood, 1969; Zimmerman & Underwood, 1968). Therefore, if storing of the relative temporal position of an item is not necessarily under the subject’s control, no deliberate mnemonic would appear to be a prerequisite for accurate performance. Furthermore, coding an isolated item in terms of its temporal-spatial relations with other isolated instances is an archetypical episodic task. If developmental effects are found only in relation to the appropriate use of mnemonics, or on tasks which rely on semantic memory, the ability to discriminate relative recency should be developmentally insensitive. Evidence from our laboratory essentailly supports this prediction, In a series of studies on relative recency judgments in children (A. L. Brown, 1973a, 1973b; A. L. Brown, Campione, & Gilliard, 1974), no

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developmental effects were reported when the judgments of recency were required for isolated items, with no additional spatial or contextual cues to serve as anchors. Children of 7 years performed on a par with 8- and 10-year-olds and with college students. There are three sets of apparently disconfirming evidence. The disconfirming evidence from our laboratory concerns the performance of children under 7 years of age. It proved impossible to gain relative recency judgment information in the continuous paradigm of Yntema and Trask (1963) and A. L. Brown (1973a), as the younger children refused to cooperate. When simpler tasks were introduced, a developmental trend between 4 and 7 years became apparent in the ability to recall order information. In the Yntema and Trask task, the subject is presented two items he has seen before and is required to state which occurred more recently-in essence, this is a recall task as information concerning order is not contained in the stimulus item. In a series of studies (A. L. Brown, 1975b; A. L. Brown & Murphy, 1975) recognition and reconstruction of orders or sequences was found to be extremely efficient in young children (4 years old) and no developmental trends were apparent. However, children above 7 years were more efficient in recalling order information (see Section 111, A, 1 for a discussion of Piaget’s developmental progression from recognition, to reconstruction, to recall, and Section III, B, 2 on memory for narratives in children). The other disconfirming data concern children in the age range (7- 18) of the original paper (A. L.Brown, 1973a). Whereas Brown reported no developmental trend on the Yntema and Trask (1963) continuous recency task,von Wright (1973) did find differences between 8 -13 years of age. Close inspection of these data reveals that the main differences occurred when the test item immediately followed exposure of the most recent inspection item (0 lag condition). The older children were virtually errorless on such problems while the younger children were not. In the A. L. Brown (1973a) study, pretraining ensured virtually errorless performance on these 0 lag problems. On problems with larger lags, the levels of performance in the von Wright study were essentially similar to those reported by A. L. Brown (1973a). Mathews and Fozard (1970) also reported developmental differences in a recency judgment task with children of above 7 years; however, they used short sequences of 7- 12 items compared with the 120-item sequence used by Brown. The use of short lists may have encouraged the older subjects to rehearse, organize, or number the items. An attempt to rehearse a seven-item list would not seem unreasonable. The developmental trend, therefore, represents an increased use of mnemonics by the older subjects. Indeed Mathews and Fozard reported that not only did the deliberate use of such strategies increase with age but it was related to superior performance. Although rehearsal may be an appropriate strategy to employ in recency tasks using short sequences, it may be inappropriate for long sequences. In support of

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this is the fact that only 22%of college students (A. L. Brown, 1973a) reported any rehearsal attempt or the application of a deliberate strategy and half of these abandoned the effort. The use of a deliberate mnemonic appears inappropriate for long lists and is unrelated to efficient performance. Thus, the judgment of recency task is one which can be either strategic or nonstrategic depending upon the way the question is formulated. The provision of short lists in the Mathews and Fozard study encouraged active rehearsal strategies and, therefore, the task no longer fits the episodic-nonstrategic cell. In summary, prime candidates for inclusion in the first cell are recognition memory and relative recency judgments for series of unrelated items. Taken as a whole, the data support the contention that these primarily episodic tasks require little strategic intervention and are, as a consequence, relatively insensitive to developmental trends. b. Strategic-episodic. The vast majority of laboratory tasks conducted with children would be included in the strategic-episodic cell. Required to rote learn sequences of isolated instances for subsequent reproduction, the mature memorizer employs an amazing array of skills to make the most efficient use of his limited memory capacity for such information. In contrast, the young child fails to harness such strategies, not only because of a limited (or nonexistent) repertoire, but also because he fails to realize that such skills are required. Extensive documentation of the young child’s production deficiency with both mnemonic and metamnemonic plans and tactics predicate this chapter (A. L. Brown, 1974; Flavell, 1970; Kreutzer et al., in press; Meacham, 1972), so concrete examples will not be provided here. So far, this cell not only seems easy to fill with supporting empirical data but seems simple conceptually as well. Nothing is ever this simple. The deceptive simplicity stems from the use of dichotomous divisions rather than continua. Tulving included in his definition of episodic tasks, situations which vary widely in the degree to which they tap the semantic memory system. For example, episodic information concerning meaningful or related words would rely more heavily on semantic information than would episodic tasks with unrelated words or nonsense syllables. In recognition of this fact, Tulving singled out studies of associative clustering and organization as exceptions to the usual practice of scoring only “correctness” of responding in episodic tasks. Obviously, the knowledge structure of the individual must come into play when he is faced with recall of related words. Thus, the degree to which the semantic system can be referred to in a strategic-episodic task will determine the type of developmental difference found. If semantic memory plays a large role then the developmental difference will be in both levels of performance (better performance with the use of strategies) and patterns (reflecting the influence of the semantic memory system). If the semantic system is relatively uninvolved, the developmental differences will be primarily in levels.

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Another complication becomes apparent when we consider the impact of an efficient strategy on an episodic task. A rough characterization of a good strategy is that by using it, the memorizer attempts to impose meaning on a relatively meaningless input. He attempts to embed the material within a context or to provide it with the characteristics of a holistic unit by means of elaborative techniques such as the method of loci (Yates, 1966) or by providing a miniature world or context such as a connective story. To the extent that such mature strategies are successful, the artificial dichotomy between episodic and semantic systems becomes even more artificial. And to the extent that the mature memorizer can successfully impose meaning, developmental differences should occur not only in levels but also in patterns of performance. Thus, on episodic tasks that require strategies, developmental differences in terms of overall efficiency would be predicted, as suggested in the model. However, whether or not pattern differences, reflecting the underlying semantic structure, will be found depends on the extent to which the episodic task taps the semantic system or can be made to tap this system by means of the strategy adopted to impose meaning on the input. c. Nonstrategic-semantic. The type of task which would fit the nonstrategic-semantic cell is one where the automatic result of meaningful activity is retention, at least to the extent that the gist can be reconstructed at a subsequent date. If the material is meaningful and the child interacts with it in an interesting activity, &liberate mnemonic strategies should not be required for retention of at least the gist, and sometimes even exact input (Murphy & Brown, 1975, Yendovitskaya, 1971). The child can reconstruct the essential features of a prior experience because of his interest in and comprehension of that experience, not because he intended to remember. Developmental differences on such tasks would reflect changes in semantic memory, relatively uncontaminated by strategic intervention. The developmental trends should reflect the close correspondence between the operational level of the child and his involuntary memory for meaningful events. If material fits the head, memory for the substance of that material will be involuntary. If the material does not fit the head, the task will be essentially meaningless (if too difficult) or uninteresting (if too easy). Thus, the child’s level of intellectual development interacts with the material to determine what falls within the domain of semantic memory. If the material is congruent with the child’s operational level, it will be perceived and retained as meaningful, i.e., the task is semantic. If, however, the child is insufficiently mature to perceive a logical or meaningful structure in the material, he will treat it as a meaningless situation and retention will demand the application of deliberate memorial skills. Our current picture of the young child’s memorial poverty has been generated largely by his performance on tasks requiring deliberate strategies where the primary goal is to remember, rather than situations where memory serves as a

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mans of achieving an interesting end product (Smirnov & Zinchenko, 1969). We have, as yet, little information concerning the young child’s memory for information gleaned from culturally relevant situations; information which is both compatible with the child’s extant analyzing structures and interesting in terms of the ecology of young children. Therefore, an interesting avenue for future developmental research would seem to be the nonstrategic- semantic tasks which may prove fruitful in revealing the richness rather than the poverty of memory in early childhood. d. Strategic-semantic. As mentioned earlier (Section 11, D), even though semantic memory may be largely the result of nonstrategic processes, this does not exclude the possibility that deliberate strategies may be used to enhance comprehension and subsequent retention of meaningful events. It certainly seems reasonable to propose that the mature information processor is capable of enriching his comprehension of events by deliberate means. What these means may be can only be surmised at this stage, but deep levels of comprehension may be achieved by consciously expanding, elaborating, paraphrasing, and editing as the material dictates. Deliberate attempts to focus on the central theme, to observe inferences and nuances of meaning, and to capitalize on logical and causal relationships may all be initiated in the effort to comprehend. Such strategies of comprehension, although purposeful acts, may be qualitatively different from those skills evoked to deal with episodic reproductive tasks, but would still be forms of strategic interventions. Studies of reading comprehension in adults have shown that alerting subjects to important content areas by (a) providing thematically relevant titles (Dooling & Lachman, 1971), (b) asking subjects to perform specific search tasks with the text materials (Frase, 1972), or (c) requiring the application of principles to new examples (Watts & Anderson, 1970), all improve performance. Even presuppositions concerning the text context affect subsequent comprehension and retention (Dawes, 1964, 1966). Rothkopf‘s (1972) concept of a general group of “mathemagenic activities” includes those activities which result in a heightening, expansion, or focusing of the observational powers of the reader. If such deliberate attempts to glean the gist of a written passage exist, then presumably comparable strategies for extracting meaning from other sources also form part of the cognitive repertoire of the developmentally mature individual. If there are deliberate strategies for enriching semantic memory then developmental differences in the ability to comprehend and retain meaningful material would be expected. But separating out the effects of deliberate intervention from effects due to general cognitive maturation may prove to be a difficult task for the developmental psychologist. For example, the ability to make contextual inferences improves during the early grade school years, and this ability is related to enhanced memory for the idea units of the material (Paris, in press). But is this the automatic result of maturation of the judgment and

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reasoning capacity of the child, e.g., his ability to make inferences, to comprehend cause and effect relationships, etc. (Piaget, 1928), or is it the result of an increasingly deliberate foray after meaning? This and many more questions need to be addressed. Thus, an examination of the processes involved in the construction and reconstruction of meaning, whether spontaneous or deliberate, would seem to be an exciting area of future research, particularly for the developmental psychologist, and considering the importance of head-fitting (Jenkins, 1971), both educationally and theoretically, the vacuum in the cells concerned with semantic memory is regrettable.

D. THEUTILITY OF THE MODEL In order to develop a simple predictive model of developmental memory phenomena, four cells were constructed to represent ideal situations. From this practice, one thing at least has become clear; developmental psychologists in the past have been concerned primarily with two of the cells, those concerned with episodic memory situations. Indeed, as a result of the preoccupation with strategic skills of remembering isolated materials, the vast majority of data can be included in only one cell, the strategic-episodic cell. If the present exercise has any value, it may be in highlighting this preoccupation and in suggesting new questions for developmental research. The second, less positive, result of this exercise is that the difficulty of dividing memorial situations into simple dichotomies is amply documented. Not only are the dichotomies themselves inadequate, but the interaction between them is a complex multidimensional one rather than the relatively simple model provided here. Yet, the very simplicity of the model may increase its predictive power. The utility of the model lies not in its exact correpondence with real situations, but in its function in raising questions concerning why we predict developmental differences and what the nature of those differences should be.

V. Summary As the title would suggest, the focus of this paper has been three main aspects of memory and their ontogenesis. The first, “knowing,” refers to the developing knowledge of the world, or semantic memory, which the child brings to all memorial situations be they deliberate or involuntary. A relative lack of prior interest dictated the concentration of effort given to this topic and the attendant literature review. The two other aspects mentioned in the title, “knowing about knowing” and “knowing how to know” have received more prior attention and, therefore, were treated superficially in this paper. While it is true that the lion’s share of attention was focused on the semantic system, no attempt to belittle the importance of memorial or metamemorial skills

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was intended. Both the acquisition of mnemonic strategies and the ability to monitor and control them effectively are esential skills which must be mastered by an efficient information processor. Only when the child has mastered such skills can he begin to deal efficiently with an increasingly complex environment. Rather, this paper was seen as a complement to existing reviews of strategy development (A. L. Brown, 1974; Flavell, 1970; Meacham, 1972) and metamemorid awareness (Kreutzer et al., in press), designed to draw attention to a neglected area of developmental research. Finally, the original question raised in this paper was “What is memory?” Whereas it may be impossible to provide a definitive answer to such a global question, it is possible to specify the type of memory involved in any one task and how this is related to memorial processes in the broader sense. By providing a rubric, a model of developmental changes, a series of questions have been raised which can be used when deciding “what memory is” within the confines of laboratory tasks. Furthermore, the model suggests not only where or when developmental trends should be manifested but what type of developmental effects one would predict.

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Flavell. J. H., Friedrichs, A. G . , & Hoyt. J. D. Developmental changes in memorization processes. c0gtfJtil.C fSyChO/(Jgy. 1970, 1, 324 -340. Fraisse, P. The psychology OffrhIe. New York: Harper, 1963. Frase. L. T. Maintenance and control in the acquisition of knowledge from written materials. In J . B. Carroll & R. 0. Freedle (Eds.), Lcinguuge comprehension rind the ocyuisition of knowlerlge. Washington. D. C.: Winston, 1972. Pp, 337-360. Gomulicki. B. R. Recall as an abstraction process. A m Psychologicvr. 1956, 12, 77 -94. Hagen, J. W. Strategies for remembering. In S. Farnham-Diggory (Ed.), Information processing in children. New York: Academic Press, 1972. Pp. 66-78. Hagen. J. W . , Meacham. J. A , , & Mesibov. G. Verbal labelling, rehearsal, and short-term memory. Cognitive Psychology. 1970, 1, 4 7 -58. Hintzman, D. L., & Block, R. A. Repetition and memory: Evidence for a multiple-trace hypothesis. Jouriml of Experimenttrl Psychology. I97 1 , 88, 297 -306. Horowitz, L. M . , Lampel. A . K., & Takanishi. R . N. The child’s memory for unitized scenes. Journcrl of E.rpt~rirnetitu1Child Psychology. 1969. 8, 375 -388. Hunter, I. M. L. Memory; Facts undfu[lucy. Middlesex, Engl.: Harmondsworth, 1957. Hyde, T . S . , & Jenkins. J. J. Differential effects of incidental tasks on the organization of recall of a list of highly associated words. Journul of Experimenttrl Psychology. 1969, 82, 4 7 2 4 8 1 . Inhelder, B., & Piaget, J. The early growth oflogic in the child. London: Routledge & Kegan Paul, 1964. James, W . The principles of psychology. Vol. I . New York: Holt, 1890. Jenkins. J . J. Second discussant’s comments: What’s left to say? Huinrrn Development. 1971, 14, 279 -286. Jenkins, J. J. Remember that old theory of memory? Well, forget it. Paper presented at the meeting of the American Psychological Association, Montreal, September, 1973 (Presidential Address, Division 3 ) . Johnston, C. D.. & Jenkins. J. J. Two more incidental tasks that differentially affect associative clustering in recall. Journal of E.rperitwntul Psychology. 197 I . 89, 92 -95. Kagan. J.. Moss, H . A , , & Sigel, 1. E. Psychological significance of styles of conceptualization. Monogruphs of the S o c i r t y f i ~ rResetrrch in Child Development. 1963, 28 (2. Whole No. 86), 73 -I 12. Kobasigawa, A. Utilization of retrieval cues by children in recall. Child Development, 1974, 45, I27 - 134. Kreutzer, M . A., Leonard, C., & Flavell, J. H. An interview study of children‘s knowledge about memory Monogruphs of the Society f o r Resecrrrh in Child Development, in press. Loftus, E. F. How to catch a zebra in semantic memory. Paper presented at the Minnesota Conference on Cognition, Minneapolis. June 1973. Loftus, E. F.. & Zanni. G . Eyewitness identification: Linguistically caused misreflections. Paper presented at the meeting of the Psychonomic Society, St. Louis. November 1973. Lord. A. B. The singer of tales. Atheneum: New York. 1965. Luchina, A. S. Mechanization in problem-solving. Psychologicul Monogruphs. 1942, 54, No. 6 . Mandler, G . Organization and memory. ln K. W . Spence & J . T. Spence (Eds.), Psycholog! of leurning oncl motivation. Vol. 1 . New York: Academic Press, 1967. Markman, E. M. Factors effecting the young child’s ability to monitor his memory. Unpublished doctoral dissertation, University of Pennsylvania, 1973. Martin, A. L. The effect of the novelty-familiarity dimensions on discrimination learning by mental retardates. Unpublished doctoral dissertation, University of Connecticut, 1970. Masur. E. F., Mclntyre, C . W . , & Flavell, J. H. Developmental changes in apportionment of study 1973, time among items in amultitrial free recall task.Jouri~crlofE.rperimentcrlChildPsychology. 15, 237 -246. Mathews, M. E., & Fozard, J. L. Age differences in judgments of recency. Developinmtul Psychohgy. 1970, 3, 208-217.

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Mistler-Lachman, J. L. Levels of comprehension in processing of normal and ambiguous sentences. Journal of Verbal Learning and Verbal Behavior, 1972, 11, 614623. Moynahan, E. D. The development of knowledge concerning the effect of categorization upon free recall. Child Development, 1973, 44, 238 -246. Murphy, M. D., & Brown, A. L. Incidental learning in preschool children as a function of level of cognitive analysis. Journal of Experimental Child Psychology, 1975, 19, 32 4 7 . Neisser, U. Cognitive psychology. New York: Appleton, 1967. Nelson, K. E. Memory development in children: Evidence from nonverbal tasks. Psychonomic Science, 1971, 25, 346-348. Nelson, K. J. The organization of free recall by young children. Journal of Experimental Child Psychology, 1969, 8, 284 -295. Norman, D . A. Memory, knowledge, and the answering of questions. In R. L. Solso (Ed.), Contemporary issues in cognitive psychology: The Loyola symposium. Washington, D. C . :Winston, 1973. Paivio, A. Imagery and verbal processes. New York: Holt, 1971. Paris, S . G. Integration and inference in children's comprehension and memory. In F. Restle, R. Shiffron, J. Castellan, H. Lindman, & D. Pisoni (Eds.), Cognitive theory. Vol. 1. Potomac, Md.: Erlbaum & Associates, in press. Paris, S . G., & Carter, A. Y. Semantic and constmctive aspects of sentence memory in children. Developmental Psychology, 1973, 9, 109-1 13. Paris, S . G., & Mahoney, G. J. Cognitive integration in children's memory for sentences and pictures. Child DeveloDmenr, 1974, 45, 633 -642. Paris, S. G., Mahoney, G. J., & Buckhalt, J. A. Facilitation of semantic integration in sentence memory of retarded children. American Journal of Mental Dejiciency, 1974, 78, 714-720. Paris, S . G., & Upton, L. R. The construction and retention of linguistic inferences in children. Paper presented at the meeting of the Western Psychological Association, San Francisco, April 1974. Pender, N. J. A development study of conceptual, semantic, differential, and acoustical dimensions as encoding categories in short-term memory. Final Report, hoject No. 9-E-070, U.S. Department of Health, Education and Welfare, Northwestern University, 1969. Piaget, J. Judgment and reasoning in the child. New York Harcourt, 1928. Piaget, J. On the development of memory and identity. Worchester. Mass.: Clark University Press and Barre, 1968. Piaget, J. The child's conception of time. London: Routledge & Kegan Paul, 1969. Piaget, J., & Inhelder, B. Memory and intelligence. New York: Basic Books, 1973. Posner, M. I., & Warren, R. E. Traces, concepts and conscious constructions. In A. W. Melton & E. Martin (Eds.), Coding processes in human memory. New York: Winston, 1972. Pp. 25 4 4 . Postman, L. Short-term memory and incidental learning. In A. W. Melton (Ed.), Categories of human learning. New York: Academic Press, 1964. Pp. 145-201. Reese, H. W. Imagery and multiple-list paired-associates learning in young children. Journal of Experimental Child Psychology, 1972, 13, 3 10-323. Reitman, W. What does it take to remember? In D. A. Norman (Ed.), Models of human memory. New York: Academic Press, 1970. Pp.470-509. Reutener, D. B. Class shift, symbolic shift and background shift in short-term memory. Journal of Experimental Psychology, 1972, 93, 90-94.

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Riegal, K. F., Riegal, R. M., Quarterman, C. J., & Smith, H. K. Developmental differences in word meaning and semantic structure. Human Development, 1968, 11, 92-106. Ritter, K., Kaprove, B. H., Fitch, J. P., & Flavell, J. H. The development of retrieval strategies in young children. Cognitive Psychology, 1973, 5 , 310-321. Rohwer. W. D., Jr. Elaboration and learning in childhood and adolescence. In H.W. Reese (Ed.), Advances in child development and behavior. Vol. 8. New York: Academic Press, 1973. Rothkopf, E. Z. Structural text features and the control of processes in learning from written materials. In J. B. Carroll & R. 0. Freedle (Eds.), Language comprehension and the acquisition of knowledge. Washington, D. C.: Winston, 1972. Pp. 315-336. Scriven, M. The concept of comprehension: From semantics to software. In J. B. Carroll & R. 0. Freedle (Eds.), Language comprehension and the acquisition of knowledge. Washington, D. C.: Winston, 1972. Pp. 31 40. Shif, Z. I. Development of children in schools for the mentally retarded. In M. Cole & I. Maltzman (Eds.), A handbook of contemporary Soviet psychology. New York: Basic Books, 1969. Pp. 326 -353. Sieber, J. Secondary Ignorance. Paper presented at the UNESCO International Conference on Learning and the Education Processes, Stockholm, August, 1968. Slobin, D. I. Recall of full and truncated passive sentences in connected discourse. Journal of Verbal Learning and Verbal Behavior, 1968, I, 876-881. Smirnov, A. A., & Zinchenko, P. I. Problems in the psychology of memory. In M. Cole & I. Maltzman (Eds.), A handbook of contemporary Soviet psychology. New York: Basic Books, 1969. 4.452-502. Spitz, H. H. Consolidating facts into the schematized learning and memory system of educable retardates. In N. R. Ellis (Ed.), International review of research in mental retardation. Vol. 6. New York: Academic Press, 1973. Pp. 149-166. Sulin, R. A., & h l i n g , D. J. Intrusion of a thematic idea in retention of prose. Journal of Experimental Psychology, 1974, 103, 255 -262. Tenney. Y. H. The child’s conception of organization and recall: The development of cognitive strategies. Unpublished doctoral dissertation, Cornell University, 1973. Tresselt, M. E., & Mayzner. M. S. A study of incidental learning. Journalof Psychology, 1960, SO, 339 -347. Tulving, E. Episodic and semantic memory. In E. Tulving & W. Donaldson (Eds.), Organization of memory. New York: Academic Press, 1972. Pp. 381 4 3 . Underwood, B. J. Attributes of memory. Psychological Review, 1969, 76, 559-573. von Wright, J. M. Judgment of relative recency: Developmental trends. Journal of Psychology, 1973, 84, 3-12. Wagner, J. F. A developmental study of categorical organization in short-term memory. Unpublished doctoral dissertation, University of Connecticut, 1970. Watts, G. H., & Anderson, R. C. Effects of three types of inserted questions on learning from prose. Unpublished manuscript, University of Illinois, 1970. Werner. 0. Pragmatics and ethnoscience. Anthropological Linguistics, 1966, 8, 42-65. Wickens, D. D. Characteristics of word encoding. In A. W. Melton & E. Martin (Eds.), Coding processes in human memory. New York: Winston, 1972. Pp. 191 -216. Winograd, T. Understanding natural language. Cognitive Psychology, 1972, 3, I -191. Yates, F. A. The art ofmemory. London: Routledge & Kegan Paul, 1966. Yendovitskaya, T. V. Development of memory. In A. V. Zaporozhets & D. B. Elkonin (Eds.), The psychology ofpreschool children. Cambridge, Massachusetts: MIT Press, 197 I. Pp. 89-1 10. Yntema, D. G., & Trask, F. P. Recall as a search process. Journal of Verbal Learning and Verbal Behavior, 1963, 2 , 65-74. Yussen, S . R., Levin, J. R., DeRose, T. M., & Ghatala, E. S. Semantic versus physical processing in children’s recall and clustering of pictures. Unpublished manuscript, University of Wiscon-

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DEVELOPMENTAL TRENDS IN VISUAL SCANNING

Mary Carol Day1 HARVARD UNIVERSITY

I. 11.

INTRODUCTION .........................................

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DEMONSTRATION OF A SYSTEMATIC STRATEGY FOR THE ACQUISITION OF VISUAL INFORMATION . . . . . . . . . . . . . . . . . . .

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111. MAINTENANCE OF A STRATEGY ACROSS VARIATIONS IN THE CONTENT AND ARRANGEMENT OF STIMULI . . . . . . . . . . . . . . . A. THE EFFECT OF STIMULUS STRUCTURE AND STIMULUS ATTRIBUTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. CONTEXT SUPPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. CONTEXT INTERFERENCE . . . . . . . . . . . . . . . . . . . . . , . . . . . . . .

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IV . FOCUS ON ASPECTS OF THE VISUAL STIMULI MOST INFORMATIVE FOR THE SPECIFIC TASK . . . . . . . . . . . . . . . . . . . . . . A. FOCUS ON THE INFORMATIVE PORTIONS OF A DISPLAY . B. THE VIEWER'S QUESTIONS DURING VISUAL SCANNING..

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EXHAUSTIVENESS AND EFFICIENCY OF VISUAL SCANNING . A. COMPARISON AND MATCHING-TO-STANDARD TASKS. . . . B. OUTLINED SHAPES AND REALISTIC VISUAL SCENES . . . . .

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VI . SPEED OF VISUAL SCANNING VII . FIELD OF VIEW

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VIII. SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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'Present address: The Learning Research and Development Center, University of Pittsburgh, Pittsburgh, Pennsylvania. 153

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I. Introduction In the visual environment a tremendous amount of varied information is potentially available to the perceiver. Although our field of vision spans about 210”, sharp and detailed vision is possible only within the small foveal region of the retina, which covers approximately 2”. Thus detailed perception requires movement of the eyes and successive fixations about the visual field. Visual scanning is the process by which the individual actively, selectively, and sequentially acquires information from the visual environment. While the term visual scanning most frequently refers to the sequential allocation of attention by successive eye movements, attention can also be selectively directed within a fixation (e.g., see Engel, 1971; Sperling, 1960). In this paper overt visual scanning will receive primary emphasis, although the direction of attention to certain areas within a fixation will be discussed where relevant. Visual scanning can be viewed as a “perceptual-motor” process, but it can also be viewed as a cognitively-mediatedprocess which reflects the individual’s interests, his expectations about the visual environment, and his strategies for acquiring visual information. Thus visual scanning patterns (the duration, location, and sequence of fixations), considered as overt behavioral correlates of some ir ternal mental processes, offer another window through which to view the changes which occur with development. The purpose of this paper is to provide a review of the developmental literature on visual scanning, identifying some general changes in scanning which occur during the preschool and elementary years. Data from numerous studies have demonstrated age differences in performance on tasks which require scanning. Eye movement data, both independently and in conjunction with other dependent variables, provide the most precise information on visual scanning. However, data on developmental changes in eye movement patterns are still quite limited, perhaps because of the difficult and restricting nature of eye movement recording and the time-consuming analyses required of these records. Therefore studies in which a variety of dependent variables and experimental tasks was used contributed to the attempt to identify developmental trends. One additional point should be made before proceeding further. Age, like socioeconomic status or sex, is a “package” variable. Pointing out that a particular behavior changes with age serves only as a description, and does not indicate the cause of the change nor specify the mechanism of the change. Wohlwill (1970) has argued that although cross-sectional research contrasting the performance of different age groups tends to make age an independent variable, the interest of the developmentalist is not in age per se, but is in the behavior changes that occur over an age span. The data from many of the studies reviewed here only described age differences in behavior within the experimental context. The relationship between characteristics of the age changes and independent

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variables has not been extensively probed, nor has attention been focused on explaining the age differences. In this paper the phrase “age differences” will be used with reference to the performance differences found at various ages in the primarily cross-sectional studies. This phrase is not meant to imply that the behavior is a function of age in a causative sense. In a number of studies, the greater familiarity of older children and adults with the stimulus materials and the task requirements may constitute a particularly important factor in the changes found over age. Furthermore, the research is too spotty to allow plotting trends precisely across ages or locating specific transition points, if they do exist. Six developmental trends can be identified in the literature on visual scanning. The trends will be stated in general terms here, and their scope and exceptions will be discussed. Comparing data from a variety of experimental contexts serves to highlight the importance of the relationships among the child’s knowledge and strategies, the specific stimulus materials, and the difficulty of the experimental tasks. In general, with age there is: 1‘. Increased demonstration of a systematic plan or strategy for the acquisition of visual information. 2. Increased maintenance of a strategy across variations in the context and arrangement of stimuli. 3. More focus on aspects of the visual stimuli most informative for the specific task. 4. Increased exhaustiveness and efficiency of visual scanning. 5 . Increased speed of visual scanning. 6. And, perhaps, an enlarged field of view. Each of the trends will be discussed in turn, commencing with a definition of the trend and a review of the evidence supporting that trend. A discussion of the main issues raised by the data and some possible interpretations will follow.

11. Demonstration of a Systematic Strategy for the Acquisition of Visual Information Since only limited information is obtained in each visual fixation, numerous fixations are typically required to scan a visual array. Many researchers have reported age differences in the extent to which the child’s sequential exploration is “systematic” or “nonsystematic.” These terms are generally defined operationally within the context of particular experiments, but a broader interpretation of them leads to several useful distinctions. “Nonsystematic” exploration by the child typically means that adults who are observing his successive encounters with the visual field do not see a task-appropriate pattern in the responses. However, a “nonsystematic” series of responses

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may nevertheless be rule-governed. The child may be following rules, but rules which the adult considers inadequate for the task. For example, in order to determine if two houses with six windows each are identical, adults will compare the windows in the corresponding locations on the two houses. A young child, when asked if the houses are the same, might search for a symmetrical window in each of the houses. This child would be following a rule, but it would not succeed by adult criteria. In general, a sequence of responses is termed “systematic” (or organized or patterned) if consistent, task-appropriaterelationship can be seen among the separate responses of the sequence. In comparison to a nonsystematic strategy, a systematic strategy is more likely to be exhaustive (i.e., to cover all of the visual array) although it could be applied to only a portion of an array. Enough responses must be made, however, for a pattern to be identified. Also, systematic responses are typically nonredundant, usually being spatially adjacent or alternating between each item in one display and the spatially corresponding item in another. A further differentiation can be made within the category of “systematic performance.” A child may either use a perceptually-given pattern or impose a pattern of his own on the array. A perceptual array may itself be sufficiently patterned that the child only needs to choose a starting point and a direction, and then use a relatively simple systematic strategy of following the clear contour of the array. If the child’s performance is systematic on patterned arrays (e.g., on linear arrays or arrays which form a circle or triangle), we cannot conclude that the child is imposing the pattern on the array. Rather, he may be simply following the pattern provided by the array. When, however, the child exhibits systematic performance on an array with no simple contours (i.e., when the child scans from left to right starting at the top and proceeding through each successive row of a 5 X 5 matrix array), the child must then make a series of decisions at choice points. Here we can assume that the child is imposing the pattern on the array. Two types of tasks have shown an increase with age in children’s use of a systematic scanning strategy. One type simply requires the subject to name all of the pictures in an array. The other one requires the subject to compare two displays or forms in order to make a “same” or “different” judgment. In the first case the systematicity of visual scanning is inferred from the pattern of naming. However, research is needed where eye movements are recorded simultaneously with naming responses in order to verify the correspondence of scanning and naming patterns, for the two might be different. All of the studies in which children have been asked to name the items in arrays of different configurations have clearly revealed an increase in systematic scanning and a decrease in errors of omission and commission between approximately 3 and 11 years of age (Dorman, 1971; Elkind & Weiss, 1967; Gottschalk, Bryden, & Rabinovitch, 1964; Hansley & Busse, 1969; Kugelmass

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& Lieblich, 1970; Matheny, 1972; Teegarden, 1933). In most of these tasks systematic scanning patterns consisted of adjacent responses which mirrored contours or formed consistent horizontal and/or vertical patterns. In addition to an overall increase in systematic scanning with age, an interaction between age and stimulus configuration was found in the naming studies. Young children exhibited a more systematic pattern of exploration on simply patterned arrays than they did on matrix arrays or random arrays (i.e., arrays with pictures positioned to suggest no pattern). [In most of these studies the number of pictures was not held constant across stimulus arrangements; the random and matrix arrangements included more pictures than the arrangements which formed simple outlined figures. Dorman’s (1971) study was the notable exception, and her results were similar to those of the confounded studies.] Elkind and Weiss (1967) found that all of their 5-year-olds were systematic in naming the pictures in a triangular array whereas only half were systematic in exploring a random array. Other studies have shown that children are more systematic when pictures are arranged in the form of a T, a circle, vertically, or in a square than when they are arranged either randomly or in a matrix (Dorman, 1971; Kugelmass & Lieblich, 1970; Matheny, 1972). In addition, Dorman (1971) showed that providing structure by giving explicit instructions, as well as by presenting a simply patterned array, increased the organization of young children’s responses. In Dorman’s study, 3-year-olds performed least systematically when the stimuli were arranged randomly and when instructions were least explicit (i.e., “pick up some marbles” rather than “find a raisin hidden under one marble” or “pick up each marble once”). It thus appears that systematic exploration is a joint function of age and stimulus configuration. The child can respond systematicallyon a naming task by using a perceptually-given pattern at a younger age than he can impose a pattern which is not perceptually given. As discussed previously, systematic performance on the patterned array requires fewer decisions and a less complex strategy. More precise assessments of visual scanning made by photographing the eye movements of children during comparison tasks have also indicated an increase in systematic scanning with age (Nodine & Evans, 1969; Nodine & Lang, 1971; Nodine & Steuerle, 1973). For example, Nodine and Lang (1971) asked children to compare four-letter pseudowords in order to make a “same” or “different” judgment. In this task the appropriate systematic strategy is to make paired comparisons, i.e., to compare the letters in the same relative positions of the two words. Third graders made more paired comparisons than kindergarten children. Indeed, the kindergarten children tended to scan sequentially the letters within words more frequently than those between words. Differences were also found in the manner in which kindergarten, first grade, and third grade children compared graphemes which were enlarged to require fixations on different letter features

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(Nodine & Steuerle, 1973). The fixation patterns of the first and third graders were simpler and less redundant than those of kindergarten children. In a study conducted by Vurpillot (1968), similar age differences were found in the comparison of component parts of a visual stimulus. Vurpillot recorded the eye movements of children (3.9 to 8.8 years) as they compared pairs of houses, each house having six windows, in order to make a judgment of “same” or “different.” The youngest group of children appeared to scan the windows of the houses nonsystematically, making few paired comparisons between the corresponding windows of the two houses. The number of children making paired comparisons increased with age, and by 8.8 years 18 of 20 subjects made paired comparisons. All of these studies indicated an increase in task-appropriate, systematic scanning with age. The young child, especially the child younger than 5 years of age, is less likely than the older child to partition a display into a series of systematic encounters unless the display itself provides a concrete guide in the form of a simple perceptual pattern. When the child does not exhibit a systematic pattern of exploration, however, the reasons are not apparent. Perhaps the child does not understand what is expected of him; he may not understand the requirements of the task. Alternatively, the child may simply not produce a strategy that specifies more than a starting point and an initial direction; formulating a more extensive strategy may not occur to the child or he may be unable to formulate a more extensive strategy. Finally, the child may formulate a strategy but may be unable to use it for extended exploration, perhaps because he forgets the strategy or because he is distracted from his strategy by the stimulus content. These alternative explanations have not been researched extensively in visual scanning, although in other contexts they have been labeled comprehension, production, and mediation “deficiencies,” respectively (Bem, 1970; Flavell, 1970; Flavell, Beach, & Chinsky, 1966; Moely, Olson, Halwes, & Flavell, 1969). Data relevant to someofthesepossible explanationswill be discussedin SectionsIIIandIV.

111. Maintenance of a Strategy across Variations in the Content and Arrangement of Stimuli Young children’s performance on a visual scanning task is affected by characteristics of the visual stimuli to a greater extent than is the performance of older children and adults. The performances (or dependent variables) which have been assessed as a function of stimulus variation include the pattern of exploration, the accuracy of recognition or matching, and response latency. Three main types of variation in stimuli have been studied: the configuration or arrangement of a number of stimuli; the presence of visual noise (ix., visual information un-

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necessary for the task); and the structure or attributes of the individual stimulus (e.g., symmetry or complexity). These variations may either support or interfere with performance, depending upon the task requirements and, probably, the subject’s strategy. Stimulus variations which serve to improve performance on the dependent measure being used are said to offer context support, while those which disrupt performance are said to provide context interference. On the types of visual stimuli and tasks used in most visual scanning studies, young children appear to be more susceptible to both context support and context interference than older children and adults. With increasing age the child generally shows an increasing independence of the particularities of the visual field, which results in a greater consistency of performance across stimulus variation (cf. Gollin, 1968; Wohlwill, 1962).

A. THEEFFECTOF STIMULUS STRUCTURE AND STIMULUS ATTRIBUTES Younger children appear to be more affected than older children by the particular attributes of the stimuli used in the experimental task. The symmetry of shapes, the “complexity” of shapes (generally defined by number of angles), and the location of the focal point of a figure are all stimulus variations which have been used in the studies which demonstrate this trend. The results of two studies using matching-to-standard tasks indicated that the search time of children varied more as a function of stimulus characteristics than did the search time of adults. Forsman (1967) found that both asymmetry and complexity of form slowed the search time of third graders more than that of sixth graders and adults. H. A. Spitz (1969) found that fourth graders’ search time was slowed more than seventh graders’ by lowering the “information value” of the standard to be located, where information value was defined either by number of angles or by independent raters’ judgments. A substantial amount of research has been focused on how the location of a focal point affects the recognition of tachistoscopically presented forms. For simple stimuli a focal point is defined as “the one differentiating feature in an otherwise homogeneous figure or card,” such as an acute angle or a convex portion. “By extension, the focal feature for complex figures can be defined functionally-behaviorally-as whatever kind of feature the young child prefers at the top [Braine, 1972, p. 1831.” Ghent (1961) found that young children best recognized a briefly-presented form when the focal feature was at the top. She hypothesized that children younger than 5 years of age begin scanning a form at its focal point and proceed in a downward direction, whereas older children start at the top of a form regardless of the location of its focal point. A substantial body of research has been generated in support of this hypothesis (Antonovsky & Ghent, 1964; Braine, 1965, 1968, 1972; Ghent, 1961; Ghent & Bernstein, 1961;

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Harris & Schaller, 1971; Strang, 1967). Thus processing proceeds in a downward vertical direction (on forms with a vertical main axis) at all of the ages studied, but the starting position, or the “phenomenal top,” changes at around 4 or 5 years of age. One characteristic of the stimuluDits focal point-determines the starting position of the scan for children under 5 , whereas children over 5 years of age appear consistently to impose a starting point at the top of the stimulus.

B . CONTEXTSUPPORT Context support for systematic scanning has been reported on naming tasks, on a comparison task, and on a matching-to-standard task. All of these studies suggest that young children can scan systematically with context support before they can without it. In the naming tasks previously described, the interaction between age and stimulus configuration offered evidence for the importance of context support for young children (Dorman, 1971; Kugelmass & Lieblich, 1970; Matheny, 1972). Children systematically named pictures arranged linearly or as a simple outlined form at a younger age than they systematically named pictures in a matrix or random array. The value of context support for systematic comparison was demonstrated in a study by Day and Bissell (in preparation). The Vurpillot (1968) comparison task, requiring paired comparisons of windows in the corresponding locations of two houses, was administered to 4-year-olds who were asked to justify their judgments verbally or by pointing to the windows of the houses. The justifications used by the children were categorized. Twenty-five percent of the 32 children used a paired comparison strategy on houses which were the pame but nor on houses which were different. When the houses were identical, the children used the identical windows to aid their comparisons. Given some notion that windows in the same relative location of each house should be compared, and given some perceptual help in the form of identical windows in the corresponding locations, children performed as would adults. On pairs of houses which were different from one another, however, children could not maintain the paired comparisons without the perceptual support provided by the identical windows, and they resorted to other inappropriate strategies. A similar finding was reported by Venger (1971), who asked children to find a match for a black strip of a specified length among 20 other strips of varying length. He found that 3- to 5-year-olds conducted a systematic search of a linearly-arranged array only when they depressed keys beneath the strips, thereby making a record of past guesses. Their search became disorganized, however, if the keys indicating their guesses did not remain depressed. Children of 5.5 to 7 years of age, in contrast, were able to maintain a systematic search without a concrete record of their past guesses.

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These studies suggest that an increase in systematic performance occurs at certain ages as a partial function of the availability of supportive perceptual information. Although longitudinal research is needed, these studies suggest the following developmental sequence in visual scanning: First, subjects are not able to explore an array systematically, regardless of characteristics of the array; second, subjects can conduct a systematic exploration by following a given perceptual pattern; and finally, subjects can impose a pattern that is not directly given by the perceptual array.

C. CONTEXTINTERFERENCE In some cases particular stimulus arrangements or visual noise result in the disruption of performance, or context interference. While the value of context support for the systematicity of visual scanning was discussed above, the disruptive influence of stimulus characteristics is revealed by other dependent measures-the accuracy of form recognition and response latency. One type of context interference may be created by the arrangement of stimuli. The positive effect of a patterned array was previously discussed, but on some tasks a clearly patterned array may not improve performance, as was found by Rand and Wapner (1969). Rand and Wapner presented 8- to 18-year-oldswith a “segment identification test” which required the subjects to match a simple isolated figure with 1 of 16 figures in an array. In one condition the figures of the array formed a contour; in the other condition the figures of the array were arranged randomly. Although the time required for a match decreased wiEh age, the primary finding was a significant interaction between age and configuration. The younger children had significantly longer search times on the patterned array than on the random array, while the configuration of the array had little effect on the search times of adults. Thus the arrangement of stimulus elements in a pattern positively influenced performance (by increasing its systematicity) on naming tasks but negatively influenced performance (by lengthening search time) on the segment identification task. Although the dependent variables were different, the studies do suggest, at a gross level, opposite effects of a patterned array. The studies differed, however, in the “tightness” of the contour formed by the distinct elements. In the naming tasks the pictures comprising the contour were quite clearly distinct from each other, but in the Rand and Wapner task the figures were pushed together to form a contour and were Jess distinct as independent units. Thus the parts had to be separated from the whole in order to identify the matching figure. Although Rand and Wapner did not describe the adults’ strategies, they may well have used the contour as a guide for the direction of the scan while also segmenting the contour to view the individual elements, thereby dealing with the parts and the whole simultaneously. Several studies have dem-

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onstrated that children have trouble dealing simultaneously with the parts and the whole of a visual form (Elkind, Koegler, & Go, 1964; Meili, 1931). Thus context interference may have been produced by adding to the task a requirement which is especially difficult for young children. Another type of context interference can occur when visual noise (irrelevant visual information) is added to a stimulus display. There is limited evidence that with increasing age the performance of children is less influenced by the presence of irrelevant information. Munsinger and Gummerman (1967) varied the type (random or systematic) and amount (low or high density) of background noise against which second grade, fifth grade, and college students tried to identify forms presented tachistoscopically. They found that children were much more adversely affected by the noise than were the adults. In a similar study, but one requiring tactual form discrimination, Gollin (1960, 1961) found that tactual noise (irrelevant tacks scattered around a shape formed by larger tacks) was more disruptive for the recognition performance of younger children than for older children and adults. The significance of the subject’s strategy in determining the effect of visual noise was demonstrated in a study reported by Hochberg (1970). Hochberg, Levin, and Frail presented two versions of short stories to first and second graders. In the unfilled version normal spaces were left between words, but in the filled version meaningless symbols were placed between words. When the 8 slowest and 8 fastest readers (of 24) on the unfilled version were compared with respect to their reading speed on the filled version, it was found that the faster readers, but not the slower readers, decreased in reading speed. The slower readers, who were still scanning letter by letter, would normally make little use of the blank spaces between words for directing their next eye movements. The faster readers, who do not scan letter by letter, might normally use these peripheral cues to guide subsequent fixations. When the cues are no longer available, their performance suffers. On a form recognition task it also seems likely that the subject’s strategy in interaction with the stimulus display would determine the effect of noise. If the child attends to relevant and irrelevant stimuli indiscriminately, we might expect noise to be more disruptive than if the child were to selectively attend to relevant stimuli while ignoring irrelevant stimuli. There is substantial common belief that with age children attend more selectively. However, surprisingly little concrete evidence exists for age changes in visual selective attention although there is evidence for age changes in auditory selective attention (e.g., see Doyle, 1973; Maccoby, 1969). In addition to the studies just described, incidental learning tasks provide some indirect evidence about selective attention to visual stimuli. In incidental learning tasks children are exposed to stimuli which are not referred to in the task instructions but which are included in subsequent tests of retention. These tasks have typically indicated that the retention of task-irrele-

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vant information remains constant across age or increases between the ages of approximately 7 and 1 1 years and then decreases between 11 and 13 years. Simultaneously, intentional learning increases consistently between 7 and 13 years (Druker & Hagen, 1969; Hagen, 1967; Maccoby & Hagen, 1965; Siege1& Stevenson, 1966; Steveson, 1972). The increase with age in the ratio of central to incidental learning has been interpreted as indicating developmental changes in selective attention to stimulus features critical for the task. The absence of a consistently positive relationship between central and incidental learning in younger Ss and of a consistently negative relationship between them in older Ss suggests that such incidental learning tasks are not maximully sensitive to the assessment of age changes in selective attention. Furthermore, the relationship between age and selective attention is undoubtedly more complex than this paradigm indicates. For example, age differences in incidental learning are somewhat dependent upon properties of the stimulus. If incidental and central components are integrated in a colored shape, for instance, incidental learning increases with age (Druker & Hagen, 1969; Hale & Piper, 1973). Furthermore, one study has indicated that in a task where no one stimulus attribute is designated as relevant, 8-year-olds attended more to a redundant stimulus attribute than did Cyear-olds (Hale & Morgan, 1973). In general, these studies suggest that children become more flexible in their allocation of attention with age and become more capable of differentiating between situations in which selective attention to a limited amount of the available information will and will not be useful. In sum, with age children are better able to maintain a strategy over variations in stimulus arrangement and stimulus attributes. The child’s performance reveals “a decreasing dependence of behavior on information in the immediate stimulus field [Wohlwill, 1962, p. 731.” This does not necessarily mean that the child comes to use perceptual information less, however. Rather such information comes to have less of a determining influence on his behavior as the child begins to use it more selectively. While the first developmental trend focuses simply on the increase with age in children’s demonstration of a systematic scanning strategy, this second developmental trend points to the decreasing influence of stimulus materials on the child’s demonstration of a systematic strategy.

IV. Focus on Aspects of the Visual Stimuli Most Informative for the Specific Task With age and with familiarity children reveal an increasing tendency to focus on the portions of visual stimuli which are most informative for the task at hand. Familiarity is considered jointly with age here because it appears to exert a

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critical independent inkence on the demonstration of this &end, and in many experiments age and familiarity are confomckd. The “informative” portions of stimdi 8ce those which provide information necessary for the assigned task. Thus the informative portions are not fixed an8 constant properties of stimuli. Different segments of a scene or figure are informative in responee to different questions. Yarbus (1967) has demonstrated convincingly tkat tke portions of a pichue fixated by adults are a function of the questions they have been asked about the pictwt, i.e., by “the problem facing the observer at the moment of perception [p. 1961.’’ The perceiver is engaged in a p p s i v e search for information; he is seeking answers for questions cw testing hylpotheses when he samples the v i s d world (Green & Courtis, 1966; k h b e r g , 1%8, 1970,1972). Since children do not focus as exclusively as adults on PoptiORs of a display which. are most iREormative for the specific task, children and dd?s may be asking different questions or testing diffcmtt hypotheses-a p d d l c y that will be explored later in this section.

A. FOCUS ON THE INFORMATIVE PoRT’fONS OF A &PLAY Within Eleanor Gibson’s (1969) theory of perceptual learning, this one trend is considered to be the essence of all perceptud learning: “The criterion of perce-1 karning is thus an increase in specificity. What is hmed can be described as detection of properties, patterns, and distinctive featmes [p. 771.” Gibson’s research supporting the notion of increasing diffeteatiatioR among stisnuli with experience has primarily used outlined forms or line &signs, suck as Roman capital letters or “scribbles,” which differ in number of distinctive features of in specific transformations. For exawnpie, in m e&y study Gibson and Gibson (1955) asked subjects of three ages (6-8 years, 8-5-11 years, and adults) to identify a standard, four-coil scribble when it ap)eYed in a pack of carcts containing replicas of the standed a d mnerous variants. OR the first trial the younger children made more incorrect identity judgments thrrn did the oider children or adults. With uncorrected practice all subjects improved in performance, but the younger children improved less than the d d r r subjects. Furt h e m r e , the number of errors increased as the number of stimulus features by which an item difired from the stanchi decreased. In a comparable study, Gibson, Gibson, Pick, and Osser (1962) asked 4- to 8-year-olds to match standard letterlike forms with identical figures displayed among 12 transformations of the standard figure. The total number of confusion errors decreased with age, although the specific transformations varied in difficulty. The increasingly more accurate discrimination among these figures and among letters of the alphabet occurs, according to Gibson, because distinctive features-those features which discriminate among figures-are learned through experience. More precise data on age changes in fmus on informative portions of stimuli come from a series of studies by Nodine and his collaborators (Nodine & Evans,

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1969; Nodine & Lang, 1971; Nodine & Steuerle, 1973), who recorded the eye movements of children comparing pairs of words or graphemes. The data from these studies indicate that with age and with experience with letters and words, children focus more often on their distinctive features. For example, in the study by Nodine and Steuerle (1973) mentioned above, kindergarten, first grade, and third grade children compared letters which were enlarged to necessitate overt eye movements. They found an increase in focus on distinctive features (as defined by Gibson) with age, although only 29% of all fixations fell on distinctive features. Perhaps some of the most provocative research on the eye movements of children during visual scanning was conducted by the Soviet psychologists Zinchenko (Zinchenko, 1965; Zinchenko, Chzhi-tsin, & Tarakonov, 1963) and Pushkina (1971). Both reported differences in the locations of fixations as a function of age (especially during the initial inspection of a figure) and as a function of familiarity with the particular figures and/or the task. Zinchenko el al. (1963) photographed the eye movements of children while they were initially viewing an irregular shape in order to identify it later. The eye movements of a second group of children were photographed during the recognition phase. From 3 to 6 years of age the number of eye movements made during the initial inspection phase increased, and the location of the fixations changed as well. While the 3-year-olds fixated primarily on the camera lens at the center of the figure, the 6-year-olds fixated almost exclusively along the contours of the figure. The older children thus obtained information about shape which was important for later recognition. Interestingly, during the recognition phase the eye movements of the second group of 3-year-olds were similar to the eye movements made by the 6-year-olds during the initial inspection phase. Even though the use of different groups of children for eye movement recording during the inspection and recognition phases weakens the methodology of the study, the data suggest that with familiarity the younger child begins to scan in a manner comparable to the older Ghild. From these results Zinchenko et al. (1963) concluded that “the development of perceptual acts follows the line of identifying specific sensory content, increasingly adequate to the material presented and to the task facing the subject [p. 61 .” The problem for the young child is that he does not know which stimulus attributes are relevant for the task. Zinchenko’s group postulated two stages of perceptual activity. During the first stage of perception the subject must determine what content is significant. If the material is familiar or if the subject is informed of the significant content, then this phase may not be apparent. During the second phase the subject focuses solely on the information relevant to the task. Pushkina’s (1971) data and analyses are quite congruent with those of Zinchenko. In a study of the transposition of size relations, Pushkina found that subjects made more eye movements while comparing stimuli during their first

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trials than during their later trials. Over trials their eye movements became simpler and linear, appropriate and efficient for the required task of discerning the size of the forms. Pushkina also reported that older children were more likely than younger children to show the decrease in eye movements as they mastered the &imposition of relations. The onenting-investigatory activity of a child passed through three stages in its development with transposition of relations: The first stage (children up to and including the age of 3) was characterized by expanded orienting activity during transposition, with a relatively small number of correct answers. For the second stage (4- and 5-year-olds), orientation was more restricted, but it expanded when new shapes were presented in control trials. The third stage (6-year-olds) was distinguished by a restricted orientation with error-free estimation of size relations (Pushkina, 1971, p. 231).

Pushkina’s results thus suggest that children under 6 are less likely to make eye movements which gather only the information needed for the task than are children 6 years of age and older. These data are consistent with the previously noted changes over age in selective attention to only task-relevant information. Zinchenko’s group would expect adults, in their first encounter with unfamiliar visual material such as aerial photographs or topographical maps, to go through the phases most typically seen in children. What Zinchenko and his co-workers did not point out, though, is that children and adults may well use different strategies when they first encounter unfamiliar or unrecognizable perceptual displays. Although the irregular figures were unfamiliar to the older children, they may have had a different notion of how to scan and of what content might be relevant. Indeed, the results of a study by Mackworth and Bruner (1970) indicate that the fixations of children and adults differed most on blurred photographs of unknown content. Mackworth and Bruner recorded the eye movements of 6-year-old children and adults while they were viewing colored photographs. One group of subjects viewed a sharp photograph, followed by viewings of the same photograph in a blurred condition and then in a very blurred condition (the “inspection series”). Another group of subjects viewed the photographs in the opposite order and attempted to identify the object in the photograph (the “recognition series”). Based on adult ratings of “informativeness” (i.e., ratings of the extent to which the segment could be recognized on a second occasion), an “informative index” was calculated for each subject’s fixations. On the sharp pictures in the inspection series the fixations of the children were as informative as those of adults, whereas in the recognition series adults made more informative fixations on the blurred photographs. These data point to an increasing focus with age and familiarity on stimulus features informative for a specific task. Several underlying factors are probably important for these age-related changes in attention to task-relevant information,

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including: comprehension of the task requirements and of what constitutes appropriate performance in a task; knowledge of the visual world (expectancies about regularities of the visual environment and knowledge of culturally-used differentiating features of stimuli); strategies for internally encoding (representing) that knowledge; the cognitive capability required for handling the conceptual distinctions necessary for the task; and the ability to attend selectively to informative aspects of stimuli when those aspects are known. If visual scanning is considered to be a purposive search for information to answer questions or to confirm hypotheses, then the first four factors would be expected to influence the types of questions asked by the subject and thereby influence his visual scanning. The fifth factor (which was discussed briefly in Section 111) would influence the extent to which he can ignore information which is irrelevant to his questions.

A. THE VIEWER’S QUESTIONS DURING VISUAL SCANNING Consider the Vurpillot (1968) task, where the subject was asked if pictures of two houses were the same. Although the question most adults would attempt to answer is “Are all pairs of windows in corresponding locations on the two houses identical?,” 4-year-olds may ask “Are any of the windows on the two houses the same?” or “Have I seen any windows like these on previous pairs of houses?” Although Vurpillot (1968) inferred the questions asked by subjects from records of their eye movements and subsequent judgments, Day and Bissell (in preparation) questioned children after each comparison to determine the reasons for their judgments. They found that the subject’s search was, in most cases, directed by such as his conception of the task and by the questions he was asking-uestions those suggested above. A necessary prerequisite for an adultlike search is posing the question as an adult would; herein may lie many of the differences in adult and child scanning patterns. In a similar vein, Daehler (1970) has proposed that before subjects can make “investigatory responses” to ascertain the “real” characteristics of illusory or ambiguous stimuli, they must conceptually differentiate the real from the phenomenal. Eye movement records of children participating in a conservation task also indicated that eye movements reflect the children’s conceptions of the task requirements and their questions about the stimuli (Boersma, O’Bryan, & Ryan, 1970; O’Bryan & Boersma, 1971). Perceptual activity was least in nonconservers, somewhat variable in transitionals, and greatest in conservers. The conservers demonstrated more couplings (shifts of fixation from one element to another) and covered more of the informative aspects (e.g., length and width of a container) of the stimulus elements than nonconservers. Also, while the nonconservers fixated significantly more on the element chosen as “greater than,” the conservers fixated approximately equally on transformed and nontransformed elements.

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None of these studies, however, attempted to manipulate the questions asked by the child in the experimental situation to determine whether the change in questions would be reflected in eye movements. In a more recent study, Boersma and Wilton (1974) reported that nonconservers with conservation training demonstrated more visual activity and less centration than nonconservers without training. In addition, the eye movement patterns of the trained conservers were quite comparable to those of the untrained conservers in the previous studies. This study suggests that direct comparison of the scanning patterns of the trained conservers before and after training would have revealed changes as a function of the child’s cognitive approach to the task. Olson (1970), also, has argued that eye movement patterns vary as a function of the viewer’s questions and assumptions. In one study Olson asked children to determine whether each of four variants differed from a “standard” house. On the initial trials Olson found that 6- and 7-year-olds made correct judgments much more frequently than did 4- and 5-year-olds. Eye movement records indicated that the older children focused more frequently than the younger children on all four of the significant features (e.g., door, chimney), possibly because they knew what features were likely to be important whereas the older children did not. Results consistent with this interpretation were found when children were presented with a diagonal comprised of checkers and then were asked to recognize it among several alternatives. The older children were again more accurate than the younger children were. But when the children viewed the alternatives and then looked again at the diagonal, both younger and older children were 100% correct. Using these and other data, Olson posited that visual search is a function of the child’s assumptions of what to look for in the specific task, i.e., of the child’s notions of the alternatives among which he must choose. The findings of Olson, Zinchenko et al., and Gibson all indicate‘that young children increase the appropriateness of their scanning and the accuracy of their discrimination with practice and with exposure to the stimuli among which they must discriminate. These results suggest that younger and older children have different conceptions about what features are important for the task; they initially ask different questions. Older and younger children may also differ in their typical manner of encoding visual stimuli, i.e., in the manner they store or remember stimuli. Performance on matching tasks suggests that young children may attempt to encode stimuli wholistically, without analyzing and then resynthesizing their components. Rand and Wapner ( 1969) investigated developmental differences in encoding by comparing the speed of 9- to 17-year-olds on an embedded figures task with either simultaneous or successive presentation of the simple figure and the complex figure in which it was embedded. Differences in speed within age groups for these two modes of presentation were smaller for the 9- and 10-year-olds than for

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the 12-, 13-, 15-, and 17-year-olds. If the younger children first formed a general impression of the simple figure, its lack of availability for detailed comparisons would have little effect on performance, as was found. However, if subjects successively compared certain distinctive features across all of the components, the absence of the simple figure throughout the search would affect performance more adversely, which it did for the older subjects. Similarly, on a Matching Familiar Figures test, Drake (1970) found that adults made more comparisons of specific features across the different figures than children did. It must be noted, though, that differences in manner of comparison across figures have been found within as well as behveen age groups, with such cognitive style characteristics as reflectivity-impulsivity influencing performance (Drake, 1970; Siegelman, 1969; Zelniker, Jeffrey, Ault, & Parsons, 1972). A distinction can be made on these types of tasks between two primary types of encoding: naturalistic-encoding a figure by its similarity to the form or to a specific feature of a familiar object or figure, e.g., noting that an unfamiliar figure looks something like a dog; and conceptual-analytic-encoding a figure as the intersection of several classes or of several values within one class, e.g., noting that a figure is red and is comprised of both straight and curved lines (Rand & Wapner, 1969). The first type appears to be favored by young children, whereas adults can probably use each type as it is appropriate. The Soviet psychologist Venger ( 197 1) has offered a parallel interpretation of scanning changes during the preschool years. He posits a move from the use of “objectoriented templates” to the use of “standard or criteria] models.” Object-oriented templates “globally reflect the objective properties of objects [p. 561 while standard or criteria] models “can represent the separate properties of objects in their objective and mutual interconnections and relations [p. 541 .” Developmental changes in the manner of encoding visual characteristics are closely tied to general cognitive development. For example, a conceptual analysis on the basis of several dimensions requires the ability to abstract and remember the specific dimensional characteristics. The general literature on cognitive development (Case, 1972; Pascual-Leone, 1970) and the more specific literature on multiple classification (Inhelder & Piaget, 1964; Kofsky, 1966; Parker & Day, 1971) suggest that before 5 to 7 years of age the child has difficulty considering two or more attributes simultaneously. Similarly, a detailed analysis of a form requires a consideration of the components of the form and its gestalt simultaneously. These abilities, typically considered to be cognitive, are clearly reflected in the child’s visual scanning. In summary, with age the child reveals an increasing focus on portions of visual stimuli which are most informative for the specific task. Visual scanning can be viewed as a purposive search for information, and the information the subject seeks is influenced by a number of factors. Among them are comprehension of the task requirements, knowledge of the visual world, manner of

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encoding that knowledge, and the cognitive ability necessary for handling the demands imposed by the task.

V . Exhaustiveness and Efficiency of Visual Scanning The fourth developmental trend concerns the scope of visual scanning. With age it appears that there is an increase in both the exhaustiveness and efficiency of visual scanning. “Exhaustiveness” increases as the proportion of the total visual scene covered increases. “Efficiency” is essentially an exhaustiveness which is limited to relevant aspects of the visual stimulus. Optimal performance on some tasks does not require exhaustive scanning. For example, on comparison tasks requiring “same” or “different” judgments, it is appropriate to scan only until a difference is found. When only task-relevant aspects of the visual field are scanned and task-irrelevant aspects are ignored, the visual scan is termed efficient. If a visual scene is only partially covered and some task-relevant aspects are omitted, the scan is termed partial rather than efficient. On comparison or matching-to-standard tasks where a certain number of elements or aspects of stimuli must be compared, labeling performance as partial, exhaustive, or efficient is relatively clear-cut. On some of these tasks age-related increases in exhaustiveness and efficiency appear together, as if both can be attributed to- greater comprehension of the task requirements and the ability to handle them adequately. On other such tasks, there appear to be three stepspartial scanning, exhaustive scanning, and then efficient scanning. These changes in the scope of scanning are often functionally related to the use of a more systematic scanning strategy, although the use of a strategy and the scope of its application are conceptually separable. In the inspection and recognition of outlined figures or realistic visual scenes, exhaustiveness refers simply to the proportion of the total visual scene scanned. But efficiency in these cases (and in certain matching tasks) is a somewhat looser concept referring to adequate performance with minimal visual information. Here partial and efficient scanning cannot always be distinguished simply by observing eye movement records. Labeling a nonexhaustive scan efficient or partial would require knowledgeof the adequacy or inadequacy of the subject’stask performance. Familiarity with the stimulus seems to play a major role in the exhaustiveness and efficiency of scanning figures or scenes. Much research has documented consistent relations between looking time and such variables as novelty and complexity (see Nunnally & Lemond, 1973, for a comprehensive review), but researchers have not yet adequately studied eye movement patterns as a function of age and familiarity, and their interaction. The generalizations made here must therefore be regarded as tentative. In general, it appears that similar progressions in scanning patterns are found with increasing age and with increasing familiari-

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ty. With age the initial exploration of unfamiliar scenes becomes more exhaustive. Within any one age group, exhaustiveness first increases and then decreases with familiarity. The scanning variations associated with familiarity appear to be related to the formation and use of an internal schema or image of the visual stimulus. Age differences in the inspection of unfamiliar stimuli may similarly be related to changes in the repertoire of internal representations to which unfamiliar stimuli can be assimilated.

A. COMPARISON AND MATCHING-TO-STANDARD TASKS The developmental trend toward more exhaustive scanning constitutes a major feature of Piaget’s (1969) conception of perceptual development, and much of his work on age changes in perception has used comparison and matching-tostandard tasks. Piaget distinguishes between centration and perceptual activity. Centration, the allocation of attention within a fixation, produces “field effects” which result from the “quasi-simultaneous interaction of elements perceived together in one single field of centration without the invoIvement of a displacement of fixation [Piaget, 1969, p. 31.’’ The elements centrated tend to be overestimated while the more peripheral elements are underestimated. With age the child begins to decentrate; he makes more fixations and centrations while looking at a visual display. These perceptual activities are associated with an increase in the integration of the individual centrations and their effects across spatial and temporal intervals. Piaget posited the increase of a variety of perceptual activities with age-exploration (moving from one point to another on the same element), transportation (moving from one visual object to another), spatiotemporal or temporal transposition (a collection of transportations involving relations between objects), referral (to perceptual coordinates), and schematization (formation of a generalization based on common structures or schemas of sensorimotor activities). He considered exploratory activity, in general, to be “the activity which directs eye movements and determines pauses or centrations during the examination of a figure [Piaget, 1969, p. 137.’’ On Vurpillot’s (1968) task requiring the comparison of the six windows of two houses, the eye movements of the children revealed both increasing exhaustiveness and efficiency with age. The 4- and 5-year-old children fixated about six or seven windows on each pair of houses, while children over 6 years of age tended to fixate the number necessary for an accurate judgment. On the identical houses the older children tended to be exhaustive; they fixated about 10 to 12 windows. On the different houses they tended to look until they found a pair of different windows. Because they did not continue looking after finding a difference, their performance was efficient. Three matching-to-standard tasks have indicated an increase with age in the exhaustiveness of scanning (Drake, 1970; Forsman, 1967; Venger, 197 1). The study by Venger provides an excellent example of the difference between partial

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and efficient scanning and indicates a progression from partial, to exhaustive, and then to efficient scanning with age. Venger recorded children’s eye movements while they attempted to match a standard strip of a certain Iength to one of 11 strips which were arranged in order of increasing length. The 3- to 4-year-olds typically examined only a small group of two to four elements, and the next group of elements they searched was not necessarily closer to the match. The 4to 5-year-olds typically examined eight to ten of the strips during their search and thus were exhaustive. The 5.5- to 7-year-olds, in contrast, examined fewer elements within a narrow search zone. They used their understanding of the serial order of the strips in the array to shorten their search to the group of strips most likely to contain a match to the standard. For older children the decreased exhaustiveness was highly appropriate and efficient, whereas for the 3- to 4-year-olds the focus on a small number of elements simply represented partial scanning. Finally, Pushkina (197 1) found a greater efficiency of scanning in 6-year-olds than in younger subjects. In the study described previously (see Section IV), Pushkina found that 6-year-olds gathered only information relevant t0 their judgments on a size transposition task, whereas the scanning of 3- to 5-year-olds was less restricted. In both Venger’s and Pushkina’s tasks the child’s visual scanning probably reflected the manner in which he was encoding the stimuli. Venger noted tbat in his task Ss were not able to use the serial order of the strips to shorten their s e m h until they understood the relationships of transitivity and relativity of size existing among the strips, i.e., until they could encode the relations among the elements. Similarly, efficient performance on Pushkina’s task required abstracting one specific attribute (size) and constructing relationships between objects with respect to only this attribute.

B. OUTLINED SHAPES AND REALISTICVISUAL SCENES There is limited evidence that in simple inspection tasks the exhaustiveness of

the initial scan increases with age. Mackworth and Bruner (1970) found that the amount of picture covered (i.e., the total distance moved by an individual gaze) was less for the children than for the adults (with time held constant). Zinchenko et al. (1963) also found that with age children made more eye movements when initially inspecting an irregular shape. As described earlier, the 3-year-olds made few eye movements. The 4- and 5-year-olds made twice as many eye movements as the 3-year-olds, but their fixations were clustered at distinctive portions of the figere. By 6 years of age the eye movements were still more numerous, and they traced more of the figure’s contour. However, the familiarity of a visual stimulus seems crucial in determining the scope of visual scanning, In general, eye movements appear first to increase and then to decrease with successive presentations of a visual scene or shape. Zin-

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chenko’s group found that with relatively familiar pictures, 3- to 6-year-olds did not scan differently. The number of eye movements made by 3-year-olds was greater after familiarization; indeed, their eye movements were approximately equal in number to those made by the 6-year-olds during initial inspection. Furthermore, 3- to 6-year-olds did not differ in eye movement trajectories when viewing illustrations from children’s storybooks. Unfortunately, the authors did not mention how equivalent familiarity for all age groups with the storybook illustrations was established. As familiarity continues to increase, eye movements begin to decrease in number and viewers may again fixate only a few details of a visual stimulus. Zinchenko and his co-workers found that a group of 6-year-olds made more eye movements during initial inspection than did another group of 6-year-olds during a recognition phase after initial familiarization. Additionally, Zinchenko (1965) has found, using several other types of tasks with adults, that increasing familiarity is accompanied by a decrease in the frequency of eye movements and an increase in their stereotypy. With sufficient familiarity it appears that only a few key features are sufficient for recognition. Given the brevity of report in the translated Soviet articles, it is fortunate that other researchers have reported related data in more detail. Noton and Stark (1971a, 1971b, 1971~;cf. Spitz, 1971) presented line drawings to subjects under conditions of marginal visibility so that direct fixation on features was required. During an initial 20-second inspection period, eye movement records indicated that some Ss intermittently followed a fixed path characteristic of that particulars viewing that specific pattern. During subsequent recognition, in 65% of the cases the first few fixations and saccades were spent traversing the same “scanpath” used in initial inspection, but fewer fixations were made along the scanpath. Additional data come from Furst (1971), who was interested in the automatizing of visual attention, i.e., “a stereotyping in sampling of sensory information together with an attendant decrease in the rate of sampling of that information [p. 651.” In this study adults viewed color photographs for 5 seconds on each of 5 separate trials. Furst found clear evidence of automatizing, both within each trial and across trials. The average fixation rate decreased from more than 13 fixations per trial to 9.5 fixations per trial, and there was a decrease in the exhaustiveness of scanning on each successive trial. Furthermore, the redundancy of information sampling increased over trials. The data from another study with adults offer a parallel to the Zinchenko et al. (1963) finding that 4- and 5-year-olds fixated primarily the distinctive features of irregular figures. When adults were asked to inspect nonrepresentational polygons, Zusne and Michels (1964) found that they tended to fixate the intricate portions of complex polygons most frequently, while they scanned the outlines of simpler polygons. Perhaps with more familiarity the adults would have more

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completely scanned the contours of the complex polygons. Thus adults, as well as children, may initially exhibit a partial scan, fixating primarily the distinctive features of unfamiliar stimuli which cannot be encoded readily and completely or which cannot be assimilated easily to a similar image in the Ss’s repertoire. In summary, over the course of familiarization with visual stimuli viewers may first focus only on salient features, then scan more broadly to include more aspects of the visual stimulus, and finally rely again on a few specific features. According to numerous theoretical accounts (Hebb, 1949; Jeffrey, 1968; Venger, 1971; Zaporozhets, 1965; Zinchenko, 1965), as eye movements are made an internal model, image, or schema of the visual stimulus is being formed. As the image becomes increasingly complete, more eye movements are made. After an adequate image has been formed, however, fixations on a few significant features of the visual stimulus are sufficient for recognition. In addition to reducing the number of fixations, representations of the visual world and expectancies about visual events function to integrate numerous fixations over time by providing a framework into which the fixations can be placed. Jeffrey (1968) has offered an explanation for the increasing exhaustiveness of scanning in terms of the progressive construction of a schema, and Hochberg (1968, 1972) has offered a congruent conception of the role of the schema in the integration of numerous fixations. Jeffrey posited that the mechanism of serial habituation may account for the gradually increasing exhaustiveness of scanning. The subject orients to a particular cue, but with repeated stimulation the orienting response to that cue habituates and the subject shifts his attention to another cue. Gradually, a chain of responses is established in which the subject orients and habituates to a series of cues. Once a schema has been formed, little scanning is required for the recognition of a familiar visual stimulus (cf. Hebb, 1949). Soviet psychologists (Yendovitskaya, Zinchenko, & Ruzskaya, 1971) have explained the decreased need for exhaustive scanning with familiarity in the following manner: During the last stages in the formation of the perceptual process, for example, after the child has had a long training in recognition and differentiation of a given type of figure, the exploratory eye movements are successively shortened and decreased, fixating on the distinct, most informative characteristic of the object. At this stage a higher internalization of the perceptive process is accomplished, when on the basis of the formerly obtained, external models (for example, formed with the help of the hand or eye movements), which have been frequently contrasted with the object and corrected in relation to its properties, an internal model-a constant and orthoscopic perceptual image-is finally formed. Now, without extensive exploratory actions a quick glance at an object directed to a particularcharacteristic aspect of the object can actualize the entire “internal” model in a child and, in such a way, lead to an instantaneous judgment of the qualities of the perceived object [pp. 55-56].

Internal representations of the visual world serve another function in addition to reducing the number of fixations required to recognize familiar objects. They

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provide a framework for integrating across successive fixations, for chunking individual fixations into larger units (Miller, 1956). Hochberg (1968, 1972) has pointed out that the successive glimpses of a visual stimulus which are obtained over time and space frequently exceed the number that could be held, unconnected, in short-term memory. It is by virtue of the perceiver’s “schematic map” that he is able to integrate a number of fixations. Hochberg (1968) defined a schematic map as “a program of possible samplings of an extended scene and of contingent expectancies of what will be seen as a result of these samplings [p. 3231.” Although Hochberg’s definition of a schematic map differs slightly from other definitions of schema, it is clear that the schematic map is a form of internal representation of the visual world. The subject does not “passively” take in information, but samples the visual world as if he were actively testing his expectancies and were placing successive fragments of visual information into schematic maps. Thus it seems that the initial perception of a form or scene too large to be seen in a single glance is built up over successive fixations. Hochberg (1968) has argued that is is by virtue of a schematic map that the mature perceiver integrates numerous fixations, and Jeffrey (1968) has offered a mechanism for the gradual construction of such schemata. This discussion, by focusing on the role of representations of the visual world, takes us once again to some of the issues discussed in the last section. Where the perceiver looks and how long he continues looking depend partially upon his current knowledge and representations of the visual world and upon his manner of encoding that knowledge.

VII. Speed of Visual Scanning An increase with age in the speed of visual scanning has been found with three types of measures. First, speed has been assessed globally as the time required to complete a search task or a comparison task. On these tasks, the increase in speed could be due to a host of factors, such as a decrease in redundant fixations, an increase in fixations on only the informative portions of stimuli, faster processing within each fixation, a wider field of view within each fixation, etc. Second, the average duration of fixations during visual scanning has been used as an index of speed. Fixation duration is assumed to represent the length of time it takes to process the information being fixated. Finally, the period of time necessary for form recognition between presentation of a visual stimulus and presentation of a mask (assumed to interrupt processing of the stimulus) provides a measure of the speed of visual information processing. The data base for each of the measures of visual scanning speed will be briefly reviewed. In research on the speed of visual search for somewhat familiar forms, letters and words have been used most frequently. Gibson and Yonas (1966a, 1966b) found a decrease from Grade 2 to college in the time required to find a

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target letter embedded in a matrix of letters. And Leslie and Calfee (1971) found a decrease from Grade 2 to college in the speed of visual search for words. The speed of scanning has also been assessed in comparison tasks using alphabetic material. Nodine and Steuerle (1973) and Nodine and Lmg (1971) recorded eye movements while children were comparing graphemes and four-letter pseudowords, respectively. They found a decreasing number of fixations and a decreasing mean fixation time for each letter or word pair with age. Similarly, in tasks where all children were previously unfamiliar with the meaningless figures used as stimuli, Forsman (1967) and Rand and Wapner (1969) found decreases in the time required to solve matching-to-standard tasks. Decreases with age in the mean duration of fixations also suggest an increase in the speed of scanning. Mackworth and Bruner (1970) found that, averaging across sharp, blurred, and very blurred photographs, the mean fixation duration of 6-year-olds was slightly longer than that of adults (adults = 360 msec; children = 373 msec). On the sharp photographs the difference was greater, with children averaging 375 msec and adults 348 msec per fixation. Similarly, but with different age groups, Zinchenko et al. (1963) found a decrease in the mean fixation duration from 3 to 6 years of age during the initial inspection of a form. However, the Zinchenko data again point to the importance of familiarity and task requirements, for the fixation durations increased for the 6-year-olds and decreased for the younger children when they attempted to recognize a previously viewed shape. Age differences in the mean duration of fixations on text have also been reported (Buswell, 1922; Taylor, 1965; Tinker, 1958). For example, Taylor ( 1965) found that mean fixation duration decreased from 330 msec at Grade 1 to 240 msec at college. This decrease is greater than that found for pictorial material and again emphasizes the importance of considering the subject’s experience with visual stimuli. The information-processingliterature offers more precise data on the speed of processing the visual information obtained in a single fixation. In a number of studies subjects have been asked to identify visual targets presented for very brief periods of time. The shorter the mean target duration required for correct identification, the faster the speed of processing the target is assumed to be. These studies (see Table I) have indicated a decrease with age in the mean target duration required for accurate identification of a form (Goyen & Lyle, 1971; Haith, Morrison, & Sheingold, 1970a; Munsinger, 1965). In addition, a series of studiesbyBraine(Braine, l968,1972;Ghent, 1960;Ghent &Bernstein, 1961)has indicated an inverse relationship between age and the tachistoscopic exposure duration required for 50% correct recognition (see Table II). However, because the initial internal representation of information provided by light hitting the retina can persist after termination of a brief exposure for between .300 and 1.5 sec (Mackworth, 1963; Posner, Boies, Eichelman, &

TABLE I STUDIES OF THE SPEED OF PROCESSING SINGLE STIMULI WITHOUT A MASK

Author (s)

Subjects

Stimuli and response

Goyen and Lyle (1971)

7.3-8.3 years; 8.5-9.5 years; normal and retarded readers at each age

Rectangular shapes resembling contours of 4-letter words; recognition by pointing

10 msec

4 years; 5 years; adults

Geometric forms; recognition by pointing

5,10,20, and 30 msec for adults; 10,20, and 30 msec for children

Target duration

Results The younger, retarded readers were less accurate than the other three groups of subjects

P 5

4

g k

Haith e l al. (1970a)

Munsinger (1965)

4.5-5.0 years

(n=4); adults

Random shapes of 5 or 20 independent turns; recognition by pointing

Varied durations

Adult performance was above 50% accuracy at 10 and more rnsec. The 5-year-olds were less accurate than adults at 10 msec, and the 4-year-olds were somewhat less accurate than adults at 10, 20, and 30 msec The exposure duration required for a recognition accuracy of 40-95% ranged from 5 to 18 msec for adults and from 80 to 400 msec for children

c1

1'

2 ! i rn

B

3. m

TABLE I1 TACHISTOSCOPIC EXPOSURE DURATIONS REQUIRED FOR 50%CORRECT rnCOGNITION ~~

~

Author (s)

Target

Ghent (1960)

Outlined realistic figures

Ghent and Bernstein (1961)

Geometric figures

Age or grade 3 years 4 years 5 years 6-7 years

3 years 4 years 5 years

Exposure duration in msec for each age group Median Range 100 20-500 20 10-200 5 5-40 5-40 5 100 20 5

10-500 3- 100 3-20

Braine (1968)

A:

Rectilinear figures

Grade 3 Grade 5 Grade 7 College

120 60 36 12

36- 120 12- 120 12- 120 12-24

B:

Binary patterns formed by a row of 8 circles with 2 or 3 circles blackened

Grade 5 Grade 7 College

120 60 24

24- 120 24- 120 24-24

Braine (1972) A: B:

Rectilinear figures Simpler rectilinear figures than in A

6.8 years 3.1-3.9 years 4.0-4.4 years 4.5-5.1 years

3.3- 100 msec 40-200 20-100 10-100

Developmental Trends in Visual Scanning

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F;z~;on

179

SUBJECT

REPORT

Interstimulus interval (ISI)

Stimulus onset asynchrony (SOA) : Equal to target duration t IS1

Fig. I . Sequence of events for a typical tachistoscopic task investigating speed of processing. The

IS1 (or SOA) is typically varied within the experiment to allow different time intervals for encoding the target(s).

Taylor, 1969; Sperling, 1960), an accurate assessment of processing speed requires that the duration of the initial representation (or “short-term visual store”) be controlled. A patterned mask, occurring at specified intervals after target presentation, has frequently been used to interrupt the processing of the stimulus (Haber & Standing, 1968; Kahneman, 1968; Liss, 1968). Figure 1 presents the sequence of events for a typical tachistoscopic study of information processing speed where a visual mask is used. In the “typical” experiment the subject is presented with a target for a certain period of time, and a mask is presented at various intervals after target presentation. The stimulus onset asynchrony (the interval of time between target onset and mask onset) appears to be the time interval of importance for identification accuracy, although a number of studies have reported data in terms of the interstimulus interval (the interval of time between target offset and mask onset). A direct comparison of the time intervals used in the various developmental studies is not feasible because of differences across studies in both experimental procedure (e.g., target duration, mask duration, stimulus onset asynchrony, target complexity) and dependent variables (e.g., threshold for incorrect identification, proportion of items correct at a specific interstimulus interval or stimulus onset asynchrony). In addition, several variables other than speed of processing, such as fatigue, the ability to construct a figure from partial information, and the ability to identify a figure in a noisy array, could influence results on these tasks. Fortunately, most of the studies tried to control for some of these possibly confounding variables. With these limitations in mind, an attempt has been made to identify the developmental trends within each study and then to assess their consistency across studies. Table I11 presents the details of the studies in which the speed of processing single forms was investigated using a mask to control the duration of the initial visual image.

TABLE I11 m D I E S OF THE S E E D OF PROCESSING A SINGLE nIMULUS WITH A MASK ~

Author (s)

~

~~

~~

~~

Stimuli and response

Subjects

Target duration; Stimulus Onset Asynchrony (SOA)

Results

Metacontrast and discrimination of succession Pollack (1965)

7 , 8 , 9 , and 10years

Thor (1970)

Normals: 7.0, 9.8, and 13.8 years; retardates: CA = 16 years, IQ = 62.3

~

Mid-gray disc and a white-ring mask presented successively; verbal report of target visibility

Targets for 12 msec; SOA’s from 12 to 262 msec

The mean stimulus onset asynchrony (SOA) required for target visibility decreased with age from 172 to 117 msec

Two black squares presented successively; verbal report of 1 or 2 squares

Targets for 10 or 30 msec; SOA’s varied using method of limits

The mean SOA required for discrimination of succession decreased with age. Retardates and 9.8-year-olds performed comparably

Target identification with mask Blake (1974)

4.8 and 8.5years, adults

Outlined forms; recognition by pointing

Targets for 30 msec for 4-yearolds and for 15 msec for 8-year-olds and adults

The mean number of correct responses increased with increases in the SOA up to 165 and 180 msec; no significant differences were found among age groups

Bosco (1972)

7 , 9 , and 12 years

Liss and Haith (1970)

4-5,9-10 years, adults

Geometric forms; not stated by author Horizontal and vertical lines; recognition by pointing

Target for 5 msec; SOA’s from 5 to 125 msec Target for 20 msec; SOA’s from 20 to 170 msec

The mean SOA required for target identification decreased with age With both forward and backward masking the mean SOA required for target identification decreased with age. The absence of an age

masking interaction indicated no age differences in speed of target identification X

Gummerman and Gray (1972)

Grades 2 , 4 , and 6, adults

Capital T rotated 90” to left or right; verbal report of left or right

Target for 80 msec; mask presented immediately on offset of target

Children in Grades 2 and 4 made fewer correct responses than Grade 6 children and adults

L. K. Miller

8 and 12 years, adults

Capital letters D, 0, and S; verbal report of letter

Target for 30 msec; SOA’s from 0 to 90 msec

Identification accuracy increased with age over all SOA’s. Although a nonmonotonic function relating performance and SOA was found for the two older groups, performance of the 8-year-olds was low at all SOA’s

Normals: 9.8 and 15.O years; retardates: CA= 16, IQ=63.8

Capital letters D and 0; verbal report of letter or “nothing”

Target for 10 msec; SOA’s from 10 to 80 msec

The 15-year-old normals made more correct responses than the other two groups. The percentage correct responses increased as a monotonic, negatively accelerated function of SOA

5 , 1 0 , and 16 years, adults

Capital letters E, H, K, and X;verbal report of target target

Target for 8 msec; SOA’s from 8 to 158 msec

All age groups increased in accuracy

(1972)

H. H. Spitz and Thor (1968)

Welsandt e t al. (1973)

c

m

with longer SOA’s, but age differences occurred at the longer SOA’s From 83 to 153 msec, 5-year-olds were least accurate From 8 3 to 133 msec, 10-yearolds were less accurate than 16-year-olds and adults

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The data from all but two of the studies reviewed indicated a decrease with age in the stimulus onset asynchrony required for recognition of a single target (Bosco, 1972; Gummerman & Gray, 1972; Miller, 1972; Pollack, 1965; H. H. Spitz & Thor, 1968; Thor, 1970; Welsandt, Zupnick, & Meyer, 1973). Blake (1974) found no age differences in the speed of processing a single shape, though the significance of a 15 msec longer presentation time for Blake’s youngest subjects is Lnclear. Liss and Haith (1970), who used the simplest stimuli-horizontal and vertical lines, also found no significant age differences. It is possible that children process very simple stimuli as rapidly as adults but process “complex” or “confusable” stimuli more slowly than adults. Further studies which vary target “complexity” or “confusability” in a within-subjects design are needed to test this hypothesis. The speed of processing multiple-form arrays has been investigated using tasks which require subjects to locate a particular target in a multiple item display. Miller (1971, 1973) and Liss and Haith (1970) found that older subjects were able to locate targets at shorter exposure durations than younger children. In addition, Blake (1974) and Haith et al. (1970) have investigated age differences in the time required for shape recognition in arrays of different sizes. They reported that, compared to older children and adults, 4- and 5-year-olds were progressively slower as array size increased. These data will be discussed in more detail in Section VII. Thus, in general, the information-processing literature suggests an increase with age in the speed of processing the information available within a single fixation. These small differences in speed could, when accumulated over numerous fixations, contribute to significant age differences in visual scanning speed, but it seems unlikely that they are totally responsible for speed differences on extended search tasks. Indeed, L. K. Miller (1973) attempted to relate performance in a single fixation to performance across multiple fixations and found, using two different models, “that the predicted rate of performance increase [with multiple fixations] is much faster than that actually found, the fit being especially poor for the youngest subjects [p. 2511.” Miller’s youngest subjects were in Grade 1. Therefore, it seems that additional factors come into play on multiple-fixation tasks when peripheral information may be used for directing the next saccade and when information may be integrated across glances.

VII.

Field of View

Data on developmental changes in the field of view and in the use of peripheral information are ambiguous, but the significanceof such changes, if they do exist, warrants their discussion. The useful field of view has been defined as “the area around the fixation point from which information is being temporarily stored and

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then processed during a visual task [Mackworth & Bruner, 1970, p. 1581.” The field of view is influenced by two primary factors. Although these factors can be considered separately, they are often functionally related in visual scanning. One factor is the “amount” of visual information present in a field of a specified visual angle, where “amount” may depend upon both number of items and characteristics of items (e.g., complexity, confusability). For example, Mackworth (1965) found that the addition of extra letters to a stimulus display seriously impaired the ability of adults to accurately compare three letters; he concluded that “visual noise causes tunnel vision.” The other factor is the retinal location of the visual information. The fovea of the retina, which covers approximately 2” of visual angle, enables the resolution of fine detail. Visual acuity drops off rapidly and continuously in the area outside of the fovea, the peripheral retina or periphery (Kerr, 1971; Riggs, 1965). During visual scanning the eyes move in fast jumps called saccades, with fixations being directed toward “informative” portions of the visual display (Gould & Dill, 1969; Mackwolth & Morandi, 1967) so that these portions fall upon the fovea. The nonrandom placement of the fixations indicates that the periphery provides information which is used to guide subsequent eye movements. Furthermore, it has been shown that peripheral processing reduces the time required for foveal processing after an eye movement (Sanders, 1963). Both of these factors-the amount and the location of visual information-play a role in visual information processing and visual scanning. Mackworth and Bruner (1970) presented data on the scanning patterns of 6-year-olds and adults which suggested that children have smaller useful fields of view than adults. They found that, while inspecting photographs, children made considerably more shorter steps (eye movements of .5 to lo) than adults. The number of short steps and the number of longer saccades made by the children did not change as a function of the sharpness of the pictures, whereas the number of short steps made by adults increased and the number of longer saccades decreased on the blurred pictures. Thus the adults appeared to use peripheral visual information to direct their saccades more frequently and more flexibly than children. Mackworth and Bruner noted that the children seemed unable to ‘‘examine details centrally and simultaneously monitor their peripheral fields for stimuli which might be candidates for closer inspection [p. 1721.” Mackworth and Bruner offered several possible reasons for these differences, but the one they favored was that “children have greater difficulty than adults processing the visual data” and thus have a smaller useful field of view. But they did not spell out the mechanism mediating the child’s smaller field of view, although they implied a limited-capacity visual processing system. With an overload of information, the field constricts to allow processing of those items nearer the fovea. The constriction of the field of view would result in shorter interfixation distances.

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Other data are consistent with the notion that less information is required to “overload” children than to “overload” adults. Haith et af. (1970b) and Blake (1974) reported age changes in short-term memory for several shapes presented tachistoscopically. Four- and 5-year-olds were able to report accurately no more than two shapes whether two, three, or four were presented, whereas the number of shapes accurately reported by adults increased as the array size increased to four. Furthermore, Blake found that Cyear-olds took longer to process two items in a four-item array than in a two-item array, and the performance of 4-year-olds was quite adversely affected when selective processing was required, i.e., when they were asked to report the items in two specificlocations of the four-item array. Holmes (1972), also, has provided some evidence that children may be less able than adults to simultaneously process a foveal and a peripheral shape, although her data were somewhat equivocal. Possible explanations for these findings may be that, compared to the adult, the child has less total processing capacity, or that more of the child’s total capacity is required for processing each item, or that the child is less able to process shapes in parallel (for discussions of processing models, cf. Blake, 1974; Haber, 1969; Norman & Rummelhart, 1970). Apparent constriction in the field of view is an important issue in visual scanning because such “tunnel vision” would limit the extent to which eye movements could be guided by the peripheral location and the initial processing of stimuli on the retina’s periphery. Sanders (1963) has suggested that the complexity of a perceptual task may have a determining influence on the visual angle at which that task can be performed. Sanders distinguished among three levels of the functional visual field: the stationary field, where competent performance is achieved by peripheral viewing; the eyefield, where eye movements are necessary to supplement peripheral vision; and the headfield, where head movements are also required. Such factors as discriminability of signal and number of signals presented simultaneously affect the display angle at which adults changed their selective strategy from one field to another. Sanders suggested that the visual field transitions, especially the eyefield-headfield transition, may provide a criterion of “perceptual load,” meaning the “difficulty of a largely mental task [p. 1681.” Sanders’ analysis is consistent with the interpretation that children have restricted fields of view in that the same material may present a processing load which is relatively greater for children than for adults. The other factor, retinal location of the presented information, is definitely important for the acuteness of vision, and the finding of smaller useful fields of view in children may be based partially on age differences in peripheral acuity. In two studies with adults (Erickson, 1964; Johnston, 1965) a positive relation between peripheral acuity and the speed of visual search was found. To the extent that the peripheral acuity of children is less than that of adults, we might expect shorter interfixation distances and longer over-all search times. Research on the adult peripheral visual system is limited, but research on age changes in peripheral functioning is almost nonexistent. Lakowski and Aspinall

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(1969) found that the retinal sensitivity of children between 6 and 11 years of age (with n at each age ranging from 1 to 3) increased, with the most dramatic increase found in peripheral sensitivity. However, the few Ss and the problems involved in using standard techniques of visual perimetry with young children (Harrington, 1964) make these findings inconclusive. Holmes (1972), presenting outlined shapes at 1, 2, 4, and 6” of visual angle, found that adults outperformed 5-year-oh and that recognition accuracy decreased as visual angle increased. However, no interaction between age and distance was found except under conditions of weak illumination and little practice. Miller (1969) investigated age differences in peripheral functioning by recording the latency of saccadic eye movements to peripherally-presentedtargets. He found that the latency was greater for 8-year-olds than for 20-year-olds. Furthermore, for children but not for adults, eye movement latencies increased as the target light moved farther into the periphery. The only researcher to use a visual search task to assess age changes in the field of view was Miller (1971, 1973). In his first study, Miller (1971) asked 8-, 1 I-, and 2Gyear-olds to search an array of letters for a target letter located at various distances from the fovea. While the accuracy of target location increased with age and decreased with target distance, Miller found no interaction between age and target distance. In a second study Miller (1973) used a larger display, which subtended 20” of visual angle and which required eye movements for a thorough scan. Exposure duration was varied from 250 to 2000 msec. Once again Miller found little indication of an interaction between age and target distance. He interpreted his data as evidence for age differences in the speed of information processing. However, the tasks Miller and Holmes used to investigate tunnel vision are qtite different from Mackworth and Bmner’s (1970) picture inspection task on which chiidren had shorter interfixation distances than adults. The former tasks do not embody the types of regularities normally encountered in the visud world. It may be primarily in situations where expectancies about the visua1 world can influence performance that the greatest difference exists between the child’s and the. adult’s fields of view. In these more realistic situations the adult may be able to infer more from less perceptual information than can the child as a function of the richer development of the adult’s representations and expectancies concerning the visual world (cf. Wohlwill, 1962). Indeed, Hochberg (1968) has argued that “the effects of perceptual learning consist of changes in where you look, and of how you remember what you saw, but not of changes in what you see in any momentary glance [p. 3261.” Morrison’s (1971) and Sheingold’s (1973) findings that children differed from adults not in the amount of information initially represented in the short-term visual store but in the subsequent encoding and rehearsal processes, are consistent with this position. Virtually no systematic research has been directly focused on the use of peripheral information for the direction of subsequent eye movements. The

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normal visual environment, and printed text, present certain regularities which a viewer may detect peripherally and use to govern his eye movements. As Hochberg (1972) has noted:

. . . the content of each glance is always, in a sense, an answer to a question about what will be seen if some specific part of the peripherally-viewed scene is brought to the fovea. In viewing a normal world, the subject has two sources of expectations: (i) he has learned something about what shapes he should expect to meet with in the world and about their regularities; and (ii) the wide periphery of the retina, which is low in acuity and therefore in the detail that it can pick up, nevertheless provides an intimation of what will meet his glance when the observer moves his eyes to some region of the visual field [p. 651. Research is needed which assesses the child’s use of the periphery with realistic scenes as well as with other types of stimuli, and in situations where the child’s knowledge of what peripheral information is significant is controlled or systematically varied. Mackworth and Bruner (1970) found that children’s long saccades sometimes ended on areas of high contrast, whereas adults’ saccades did not land on high-contrast areas unless they were also informative. Also in contrast to adults, children did not vary their number of saccades as a function of the sharpness of the photographs. Thus there do appear to be differences either in the flexibility with which children use peripheral information or in the actual peripheral information they use.

VIII. Summary Visual scanning, the process by which information is sequentially acquired from the visual environment, reveals several functionally interrelated changes during childhood. These age-related trends in visual scanning provide evidence concerning changes in the child’s expectations about what aspects of the visual environment are important and in his strategies for acquiring visual information. Although the trends discussed here were drawn from the literature on visual scanning, it is significant that the first five of the developmental trends which were discussed can also be induced from the literature on haptic exploration. The parallels in the visual and haptic modalities support the position that central, cognitive processes play a directive role in the acquisition of perceptual information. The six developmental trends which were identified are recapitulated below. With age children demonstrate more systematic, task-appropriate strategies for acquiring visual information. Sequential encounters with visual stimuli are termed systematic when a consistent, task-appropriate relationship can be seen among the individual responses of the sequence. Tasks on which children are asked to name the items in an array and comparison tasks indicate that children can perform systematicallyon simply patterned arrays before they can on random or matrix arrays. Thus children are able to use the contour of an array to guide

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systematic performance before they are able to impose a pattern on an array. Only in the latter case can it be inferred that an internally-generated strategy is primarily responsible for systematic performance. With age children show an increasing ability to maintain optimal performance across variations in the content and arrangement of stimuli. Younger children, relative to older children and adults, have more need of context support for systematic scanning, and their scanning is more vulnerable to context interference, i.e., to disruption by particular stimulus attributes or task-irrelevant visual information. With age children’s visual scanning becomes more exhaustive and more efficient. On comparison and matching-to-standard tasks the scope of children’s scanning becomes more task-appropriate; it becomes more exhaustive or more efficient as required to meet task demands. Also, the initial inspection of outlined figures or visual scenes becomes more exhaustive with age. With age there is an increasing focus on the portions of visual stimuli which are most informative for the specific task. If visual scanning is viewed as a purposive search for information, it is obvious that the subject must know what information is significant for a specific task before he can focus on the “informative” aspects of stimuli. The information a subject seeks is probably a function of a number of factors, including his comprehension of the task requirements, his knowledge of the visual environment, his strategies for encoding that knowledge, and his more general cognitive ability. Another factor-the ability to attend selectively to the informative aspects of stimuli when those aspects are known-also appears to be important. With age there is an increase in the speed of completion of visual search and visual comparison tasks. Data on fixation duration and the identification of tachistoscopically-presented stimuli suggest that with age the child can more rapidly encode the information present within each fixation. Nevertheless, it is likely that additional factors, such as the ability to integrate information rapidly across glances or to pick up information farther into the periphery, affect speed on tasks requiring multiple fixations. The sixth trend is more ambiguous than the preceding ones, but some data suggest that with age the size of the useful “field of view” increases. Three factors may possibly contribute to the apparent expansion of the field of view. The child’s smaller field of view may be based partially on a constriction in the field with an “overload” of information and the same information may represent a greater processing load for children than for adults. The role of peripheral acuity and peripheral processing, independent of processing load, is currently unclear. The child’s lesser-developed ability to sample wisely and to infer from limited perceptual information may also contribute to age changes in the field of view. Throughout this review the significanceof familiarity with the stimuli has been evident. With increasing familiarity subjects learn which stimulus features are likely to be informative or distinctive for particular purposes. Furthermore, with

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increasing familarity it appears that subjects form an internal model (an image, a schema) of the visual stimulus, which then influences subsequent visual scanning. With an unfamiliar stimulus which cannot be readily assimilated to an existing schema, there is a sequence from only a few fixations on salient details, to more exhaustive scanning of the visual stimulus, and then again to fixations on only a few details. The “microgenetic” sequence from limited to more exhaustive scanning of an unfamiliar visual stimulus roughly parallels the ontogenetic sequence typically found in the initial scanning patterns of children and adults confronted with a visual stimulus. These six main trends point to two major dimensions on which age changes occur. One dimension refers to the systematicity of the acquisition of visual information-to the how or the form of information acquisition. With age, the child appears increasingly able to conduct a task-appropriate, systematic, and exhaustive scan which is less vulnerable to disruption by irrelevant particularities of the visual field. The second dimension refers to the child’s growing knowledge about the “informative” aspects of the visual stimuli he encounters and his increasing focus on these aspects of the visual environment. This dimension refers to the what or the content of information acquisition. The research on changes in the scope and locus of fixations with familiarity and age and on the apparent increase in the field of view point to the importance of the child’s representations of and expectancies concerning the visual world. Both of these dimensions-form and content-reflect the child’s cognitive capacities and his representations of significant regularities in the visual environment.

ACKNOWLEDGMENTS The author would like to thank Joan S. Bissell, Karen M. Cohen, Deborah K. Walker, and Sheldon H. White for their encouragement and for their constructive comments on several previous versions of this paper.

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THE DEVELOPMENT OF SELECTIVE ATTENTION: FROM PERCEPTUAL EXPLORATION TO LOGICAL SEARCH'

John C . Wright UNIVERSITY OF KANSAS

and Alice G . Vlietstr-a UNIVERSITY OF MISSOURI. ST. LOUIS

I . INTRODUCTION ...........................................

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I1. DEVELOPMENT OF ORGANIZED OBSERVING BEHAVIORS: EXPLORATION vs . SEARCH ................................ A . PROPOSED DISTINCTION ............................... B . DEVELOPMENTAL HYPOTHESIS .........................

111. EXPERIMENTAL EVIDENCE

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A.OVERVIEW ............................................ B . FREE EXPLORATION TASKS ............................ C . HABITUATION AND NOVELTY TASKS . . . . . . . . . . . . . . . . . . . D . POINTING AND NAMING TASKS ......................... E . CUE AND DIMENSIONAL PREFERENCE TASKS . . . . . . . . . . . F . DISCRIMINATION AND MATCHING TASKS . . . . . . . . . . . . . . . G . MEMORY AND RECALL TASKS .......................... H . TASKS INVOLVING FORMALIZED SEARCH STRATEGIES . .

IV . SUMMARY AND CONCLUSIONS REFERENCES

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'The authors acknowledge the support of this work by the Kansas Center for Research in Early Childhood Education. underacontract with the National Institute of Education.The opinionsexpressed are those of the authors and do not necessarily coincide with those of the sponsoring agencies . 195

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I. Introduction It is the thesis of this paper that there is a major developmental shift in the nature of the stimulus variables that control attending behavior. This shift is proposed as an important contributor to the development of systematic information processing in children. We propose a distinction between exploration and search as distinctive modes of information-getting behavior. These two patterns are discriminable in their own right in terms of measurable response properties; they are further discriminable in terms of the stimulus and task features which control them; and they are observed to have a different course of development and period of acquisition. It is argued that exploration is a simpler process, that it develops earlier than search, that it is maintained by different types of motivation, and that it provides the germinal perceptual experiences out of which logical, systematic search can evolve when the appropriate cognitive structures for its organization become available. ParalIel with the developmental evolution of exploratory schemas into search routines, the evidence reviewed suggests a shift from the control of attention by salient features of stimuli toward its control by logical features of the task, and a shift from passively tracked to actively sequenced attending. Moreover, this developmental change appears to be marked by a transitional period in which the intentional and goal-directed aspects of deliberate search are fairly well developed, and the capacity of salient features to capture attention is no longer particularly helpful, even when such features are informative, but is still a major source of interference when they are distracting or irrelevant. Cognitive style or conceptual tempo as a characteristic of individuals is related to the development of selective attention. In tasks where speed and accuracy are negatively related, reflectives are defined as slow, but accurate responders, while impulsives are faster, but less accurate. Differences between impulsive and reflective children in the nature and patterning of information-processing have been well documented. Such differences imply differential determinants of attending for reflectives, as compared with impulsives. It is hypothesized that impulsive responding characterizes information-getting performances where the salience of environmental cues and automated responses to them predominate. Impulsive responding in that sense is associated with exploratory attending patterns. Conversely, reflective styles of response not only characterize older children and involve more systematic and logical patterns of search behavior, but also, like effective search, require more task than stimulus orientation and more fully developed schemas for performing cognitive operations. In capsule form, it is suggested that impulsive responding, like exploration, is perceptually organized and predominates in less familiar tasks and situations, whereas reflective responding, like search, is cognitively organized on the basis of established operative concepts.

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11. Development of Organized Observing Behaviors: Exploration vs. Search A. PROPOSED DISTINCTION In this section we are concerned with two modes of organizing sequences of selective observing behaviors: exploration and search. The distinction between exploration and search is approximately the same one made by Berlyne (1960) between diversive and explicit exploration, respectively. In a somewhat different context Hun (1970) has made an analogous distinction between play (exploration in our terms) and exploration (which we call search). Both exploratory and search behavior deal with the child’s acquisition of information obtained from the environment. The information obtained from the environment in turn represents the child’s organization of the environment, store of knowledge, and potential for logical decision-making. The study of exploration and search must be concerned with the stimuli in the external environment as well as the child’s perception of them. Central to this process are the organism’s decisions as to what sources of stimulation are interesting or relevant or informative (the question of selective attention). Exploratory and search behaviors differ in that exploratory behavior is more spontaneous and less systematic than search behavior. Exploratory behavior occurs in shorter sequences; shows less continuity from one sequence to another; is more divergent; and is more determined by external stimuli. For example, a young child in a store may look at and pick up various toys, one and then another, turning them over in his hands, and putting them down, depending on which stimulus attributes attract his attention. The child’s behavior appears to correspond to specific stiinulus events in the environment in a nonsystematic, unorganized fashion. The exploration is at an overt level, and the objects of the child’s attention and his observing responses to them are directly observable. This process has been well described by Nunnally and Lemond (1973). It is playful in nature, instigated by curiosity or boredom, and consummatory rather than instrumental with respect to the infomation it generates. Search behavior, however, appears more systematic and planned. The child’s intentions are not directly observable, but may be inferred from the increased continuity of his behavior. Search behavior is more task- and goal-oriented. It is thus more convergent than exploratory behavior. Since the continuities in the behavior are directed toward a common goal, search often has some type of systematic plan. For example, the same child in a toy store may peruse different toys, but perhaps only a selected few and with repeated comparisons. If the child were later asked what he was doing, he might say something to indicate that he had a definite goal in mind, such as finding a birthday present for his sister. Indeed, it is not uncommon to observe a child whose intent may be to search for an appropriate object, and whose observing behavior indicates an organized,

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goal-directed search, but who gets seduced away from his programmatic routine by particularly salient stimuli, and who thus lapses back into exploration, leading him perhaps to buy a present more appropriate for himself than his sister. Still more formal and elaborate algorithms for search are observable in older children and adults (G. A. Miller, Galanter, & Pribram, 1960), but we are concerned here primarily with the emergence of active exploration and the development of its offshoot, systematic search, in young children. Search behavior is usually perceived as work. That is, it is instrumental to the acquisition of information that will be used subsequently to organize and direct a goal-oriented behavior sequence. The information is valuable for its contribution to ongoing decision processes, and not so much for its inherent interest. Two types of search behavior are mentioned in this paper. One type of search is referred to as perceptual search, because it appears to occur on a perceptual level of response. The other type of search is referred to as logical search and occurs on a more cognitive level. Perceptual and logical search are alike in that they both are convergent and have some definite goal. Perceptual search, however, has some specifiable sequence of stimulus events to which the S responds. An example of perceptual search is an individual’s looking for a number in a phone book and running his finger down the list of names until he finds the desired name and phone number. Perceptual search is terminated by some stimulus event in the environment and is directly observable in the form of attending and observing behaviors. Logical search occurs at the cognitive level. One cannot readily observe the actual search process. Instead of being terminated by a physical stimulus event, it is terminated by an internal logical constraint. The individual does not deal directly with overt stimuli, but with logical alternatives. Forexample, little of the behavior of a chess-player between moves is likely to reveal the sequence of alternatives considered, plans and contingencies developed, and decisions reached.

B. DEVELOPMENTAL HYPOTHESIS 1 . Exploration vs. Search Processes The major thesis of this section is that exploratory behavior is a necessary precursor to, and stimulator of, systematic search behavior. Rather than a simple stage model, what is being proposed is a lag model in which each advance in the child’s understanding of how his environment is organized enables him to structure a greater portion of his exploratory response repertoire into the format of systematic search. Put another way, there are forms of exploration observable from birth onward throughout life-exploration is never renounced, and serves important functions in adults, but beginning with the child’s acquisition of the concept of object permanence at 18 to 24 months of age, there is an increasing

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capacity and tendency to organize and systematize search behavior in logically effective and goal-directed patterns. Accompanying the development of each new form of deliberate search there is a somewhat delayed but inevitable decline in the potency of salient stimulus features to control attention in that situation and a corresponding increase in the probability that a child will adopt a logically based attentional strategy for identifying and isolating relevant informative cues, regardless of their inherent attention-getting features. Thus, we contend that in terms of developing intellectual competence of the child, the shift from predominance of exploration to predominance of search is indeed a developmental change in the child’s typical approach to an uncertain environment. But within particular task domains there is a microgenetic shift from exploration to search that is based simply on familiarity. By the age of 2 years a familiar object, however completely hidden, is sought more or less effectively by a young child, provided that the potential hiding places, as well as the object itself, are assimilable to schemas of familiar objects and events. But aside from such well-established routines, the child’s attending behavior is mostly controlled by the curiosity-producing features of his environment, such as intensity, contrast, change, incongruity, novelty, complexity, and surprise (Berlyne, 1960). As Jeffrey (1968) has suggested, the growth of familiarity presumes the formation of schemas, which may initially consist of repeated patterns of habituation of attention. Thus, until the advent of concrete operational thought, effective verbally mediated concepts, and logically based strategies at perhaps age 5 to 7 years, the child observes and explores the environment playfully, attends successively to various salient features of repeatedly experienced stimuli, comes to know them in terms of how he habitually explores them and by the critical features they possess. In the process, those acts of exploration that have produced noncritical or redundant feedback, even though initially directed to perceptually salient features, are habituated and become less capable of being excited by such features, however salient. Correspondingly, the child’s attention to more critical features, loci, or sources of stimulation do not undergo habituation, but are strengthened because as a class they serve to disambiguate the environment in ways that lead to reinforcement. For example, a 4-year-old has a well-established routine for asking “why” questions, but he asks them randomly and disconnectedly, without an apparent plan or strategy. Analogously, he explores novel environments erratically and discontinuously, fixating or manipulating in random sequence those aspects of the environment that catch his attention. In more familiar settings his information-getting behavior is probably better organized, but inflexible and stylized, and easily subject to disruption by unexpected outcomes. He can logically search in one or two likely places where he has found his toothbrush or his shoes in the past, but is distracted if he does not find them in the usual place, or when there are no usual places because he is away from home. When such a logically based search routine is disrupted, the child’s control over selective

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attention is lost, and search is immediately replaced by exploration. He is once again vulnerable to being hooked by salience. There is no overriding logical search plan, nor even an effective routine for generating new places to look, and consequently his distractability increases. By age 6 or 7, a child still explores novel environments erratically and still executes highly familiar search routines rigidly on many occasions, but he begins to demonstrate a sharper discrimination between occasions for playful exercise of curiosity through exploration and those in which organized search will achieve a more or less recognizable goal. He begins to appreciate the advantages of keeping track of where he has looked and where he has not. He begins to exhaust the logical possibilities by looking everywhere once before he looks anywhere twice. He is at first inept in inventing search routines and applying them to new situations, but in a variety to tasks he seems much more organized and much less distractable. There can be no doubt that decentration in the Piagetian sense is involved in these changes, for the ability to entertain simultaneously more than one hypothesis is critical to the sequential organization of search behavior. Moreover, there is considerable evidence that the ability to imagine a discrepancy between what is apparently true and what is demonstrably true is involved in both concrete operational thought and selective attention. Finally, it must be noted that by this age the verbal organization of memory and reasoning offers a powerful new aid to the organization and sequencing of selective attention. Not only do words help keep track of where one has been and where one is going, but they also facilitate the selective and appropriate generalization of scanning routines and search strategies to stimuli or tasks quite different from those for which they were originally developed. Information-getting skills are thus seen as the culmination of a developmental hierarchy which begins with perceptual familiarization and simple learning processes. Throughout early childhood they benefit from each cognitive advance the child makes. Exploration at first resembles, and could be merely, a manifestation of idle curiosity. Although it is clearly disorganized and playful in nature, it may well be a necessary precursor to systematic inquiry through organized search. If so, study of the former may well facilitate effective development of the latter.

2 . Associative vs. Cognitive Processes: White's Model Sheldon White (1965, 1966) has developed a model for a hierarchical arrangement of learning processes. While the idea for a hierarchical model came largely from developmental changes found in learning experiments, they parallel a number of other shifts which involve perceptual, emotional, and intellectual facets of behavior. For this reason, White's model for learning processes may be applied to the developmental changes that occur in exploratory and search behavior. White (1965, 1966) has argued that these changes may be characterized

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as representing a shift from an “associative” level of response to a “cognitive” level of response. This shift occurs in children primarily between 5 and 7 years. According to White (1965) the preshift mode of behavior characteristically is laid down early in development. Typically, this earlier behavior is fast-acting and involuntary, and follows conventional associative stimulus-response principles; that is, the stimulus, as a whole, is associated directly with the response. This associative level of response does not disappear with age. It still exists in adults, but only as a potential determinant of behavior and then only in relatively simple situations, where a routinized response is appropriate. In nonroutinized situations the associative level of response is later superseded by a cognitive and more abstract level of response. At this level, the previously automatic response may be inhibited so that a more complex decision process can determine behavior. According to White (1966) the stimulus at the cognitive level is “interpreted, that is, coded and linked with other coded models of stimuli which may be quite distant in time and space, or differ in discernible features quite markedly [pp. 119-120~.” Behavior at the cognitive level of response appears more systematic and planned. It constitutes what White (1966) calls a longer-latency, “reflective system” of response, while the preshift behavior constitutes a shorter-latency, ‘‘impulsive system” of behavior. One correlated change that may be related to the same developmental process is a shift from passive control of attentional behaviors by stimulus properties (as in exploration) to active direction of attention by the child toward appropriate information sources (as in systematic search). Thus, our main thesis that exploration “teaches” search is not incompatible with models such as White’s (1965). In fact, a “shift toward planning [p. 2071” was explicitly mentioned by White (1969, although he did not specifically apply it to search behavior. Moreover, accompanying the shift from an associative to a cognitive level of functioning are a number of changes in the kinds of stimuli which appear to be most salient for children or to which they readily attend. One such change is a proximo-distal shift from early tactual, kinesthetic, proprioceptive, and viseral sensitivity, toward a progressively greater concern with visual and auditory cues. In problem-solving and discrimination-learning tasks it appears as a shift from position-guided responding in young children to cue-guided responding in older children. The latter is also taken as evidence for the occurrence of hypothesis testing behavior (Eimas, 1969; Gholson, Levine, & Phillips, 1972), which is another form of search. Another change mentioned by White (1965) is the shift of selective attention from color to form in vision. An analogous shift is from texture to shape in haptic touch (Gliner, Pick, Pick, & Hales, 1969). These changes in what is attended to may be functionally related to a shift from exploration to search. One problem that arises in the adoption of a hierarchical model such as White’s is contained in its developmental assumptions. Because one type of

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response or one modality is used more frequently at a later stage of development, there is an underlying assumption that it is a better mode of response than that which occurs most frequently at an earlier stage of development. Whether or not it is indeed better, however, may depend on other factors such as the nature of the task. For example, it would be inappropriate to assume that a cognitive level of response in adults is better than an assxiative level for a routinized task like typing. A strict hierarchical approach may overlook the nature of the judgmental demands of the task and whether the child’s method of exploration and search is appropriate for the task. Other variables neglected by such a position include the ease with which individuals can change their method of exploration and search when needed and the extent to which individuals differ in their repertoire of exploratory and search behaviors (Goodnow, 1971). Individual differences that reflect only a differential rate of development probably need to be distinguished from more lasting qualitative differences in information processing. The status of conceptual tempo in this regard is still in doubt. In summary, our developmental hypothesis is that exploration is motivated by curiosity and guided by stimulus salience, that it is natural and dominant in young children. With development and growing familiarity of a wider range of situations, exploration becomes less dominant and is more restricted to playful situations and novel environments. With experience and maturation, there evolves a goal-oriented search mode of attending that is more deliberate and purposeful, more organized and systematic, and more based on relevance and informativeness of cues. Perceptually based information processing as seen in iconic representation (Bruner, Olver, & Greenfield, 1966) and eidetic imagery (Haber & Haber, 1964), both of which occur more frequently in children than in adults and which exemplify the exploratory mode, are replaced by linearly organized, verbally guided, and logically programmed routines (G. A. Miller et al., 1960). In the sections to follow, the experimental evidence bearing upon the developmental progression from exploration to search is reviewed. The discussion is organized by types of tasks in which exploration can be distinguished from search. Following a brief overview defining the domain to be surveyed, free exploration is discussed in visual and haptic tasks which place few or no constraints on the child, but simply record his natural exploratory behavior. Habituation is then discussed as a basic process which both defines the familiar and underlies a preference for gradually increasing discrepancies from what is familiar (i.e., moderately novel). Next, perceptual search is examined in three kinds of tasks requiring more than inspection or examination of stimuli: pointing and naming, cue and dimensional preferences, and discrimination and matching tasks. A brief discussion of attentional effects on memory and recall follows. Finally, the emergence of logical search is traced in a variety of more complex tasks, such as probability learning and strategic concept formation.

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ZIT. Experimental Evidence A. OVERVIEW A wide variety of arousal indices may be termed attentional behaviors and may serve to increase the organism’s receptivity to those stimuli that elicit them. Visual and tactual orienting behaviors have, in addition, the capacity to select specific environmental inputs for sampling or scrutiny. That is, visual and tactual observing responses are not only elicited more strongly by stimuli in which the organism is momentarily interested than by familiar, habituated, uninteresting, or background cues. Unlike such passive indicators of interest as the heart rate or GSR,visual and tactual observing behaviors also involve selective control by the organism of what sources of stimulus information in the environment will be attended to and processed. In other modalities, such as taste and smell, only the general sensitivity to all inputs can be voluntarily changed, for example, by savoring or sniffing. In passive touch and audition there can be deliberate selection of inputs, but it is accomplished within the central nervous system (as in selective dichotic listening) rather than by receptor orienting as in the case of vision and active touch. Thus, only vision and touch require continual decision making by the organism as to what to sample next, and also offer the observer a chance to record directly the nature and sequence of those decisions. Therefore, visual fixation and haptic touch are the sensory modalities to be discussed. According to Jeffrey’s ( 1968) serial habituation hypothesis, familiarity and perceptual recognition are indications of the existence in the infant of schemas formed to represent the known visual world. He proposed that the earliest schemas are derived from the process of habituation of attention to repeated stimuli, and that their organization results from the fact that the most perceptually salient features of repeated stimuli are fixated until attention to them habituates, followed by the next most salient features, etc. Familiar stimuli are recognized by these constituent features to which attention has habituated, and the cognitive structure or schema representing that familiarity is organized on the basis of the sequence in which features were initially attended to and habituated. The strong implication of this model is that the relative perceptual salience of features controls the order of habituation of attention to those features. In an ingenious experiment D. J. Miller (1972) began by measuring the salience of three components of a standard stimulus by the general magnitude of orienting response they elicited when presented separately to 4-month-old infants. Then the compound stimulus was presented repeatedly, following which the cue components were again tested separately. She found that habituation of visual attending had indeed been occurring for each component during presentation of the compound stimulus in proportion to its initial salience.

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Age changes in the development of hierarchies of dimensional salience have been tracked by Odom and Guzman (1972). They found not only that salience hierarchies can be derived and change with age, but also that the relative salience of a dimension is positively associated with speed and accuracy of response when that dimension is relevant in an identity task. Again, it appears that selective attention begins with determination by salience and proceeds towards information processing based on the dimensions or features attended to initially. In Cyear-olds perceptual training or “cue training” which requires the child to match stimuli on the subsequent relevant dimension, prior to a discrimination and reversal task, facilitated reversal shifting, though not as much as did verbal pretraining (Kendler, Glasman, Kz Ward, 1972). Cue training was not markedly superior to no pretraining in a subsequent study where the dimensions could not be differentiated by distinctive observing responses (Kendler & Ward, 1972). These data are at least consistent with the hypothesis that prior to the development of verbal control over multidimensional information processing, experience with differential attending to features that can be made discriminable by selective observing responses does serve to organize search behavior. In a study of cue-selection employing compound stimuli, Hale and Morgan (1973) found that Cyear-olds attended more to single features than did 8-yearolds, as Piaget would have predicted. However, in a subsequent task where one stimulus dimension was made relevant and the dimensions were no longer redundant, the older children were better able to select the relevant cue and stay with it to solution. The interpretation of interest here is that younger children center on one focal feature, apparently on the basis of cue or dimension salience, and that while older children’s attention is decentered and encompasses multiple cues, they can more flexibly select one dimension on which to “recenter” when the task logic demands it, than can younger children. That is the essence of the developmental distinction between exploration and search.

B. FREEEXPLORATION TASKS Mackwoxth and Bruner (1970) recorded the spontaneous eye movements of 6-year-olds and adults as they explored, without instructions, a slide presented at three levels of optical resolution. They assumed that the task was defined by the subjects as one of visual comprehension under blurred conditions, or as a casual inspection period if the stimulus was sharply focused. In the sharp condition, children fixated longer than adults and made twice as many very short-distance shifts between successive fixations. When shown very blurred stimuli, however, the children showed twice as many large shifts of fixation during the first second of exposure, while the adults spent more time fixating informative details. The children in general did not show as much early concentration on details as adults, and when they did engage in concentrated attention, it was less frequently de-

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voted to the informative regions. The contours, bright and dark elements, and points of high brightness contrast were frequently fixated by children, but not by adults, unless they were also rated as informative. The same pattern of results was obtained in a subsequent study by Mackworth and Bagshaw (1970). In our terminology, the children explored the stimuli on the basis of interest, while the adults tended to search them for information. Zinchenko, Van Chizhi-tsin, and Tarakanov (1963) recorded the eye movements of children between the ages of 4 and 6, first while inspecting or exploring a sample object and later while recognizing the object. The authors distinguished between two types of exploratory activity that took place. The first was called an “act of perception,” consisting of those exploratory activities involving the formation of an image or a model (obruz) of the object displayed. The second type of exploratory activity was referred to as an “act of identification” or “recognition,” in which the child compared the object in front of him with the model already stored in memory. Zinchenko’s group found an increasing difference between the act of perception and the act of recognition with age. Young children showed many eye movements in both the original inspection and later recognition of the figure. Older children investigated the figure more thoroughly in the initial presentation, but inspected only the critical points in the recognition task. Recognition errors decreased with age. It was noted with surprise that younger children fixated within the figure more than older children during both familiarization and recognition. However, this fixation pattern may be attributed to the fact that the lens of the camera was located in the center of the figure and was clearly visible to the subjects. It is possible that the younger children were attracted to the unexplained camera lens more than older children, This age difference may further indicate a developmental decrease in the effect of novel, salient stimuli on the fixation patterns of children, at least when a decision is required. In summary, there was more tracing of the outline of the figure in older children, and generally increased and more-systematic scanning during familiarization. In the sense that the older children were tracing the contour, where the informative features of shape were located, they were also taking into account the demands of the task of form recognition. Their subsequent inspection of only the critical points during recognition further indicates the emergence of a task logic that can override stimulus salience as a determinant of selective attention. Next we consider studies of free exploration in the haptic modality (active touch). Most of the research on haptic exploratory behavior has been done with matching tasks. A developmental progression from passive, partial, and unsystematic exploration to active, exhaustive, and organized examination in children has been fairly well documented (Abravanel, 1968; Piaget & Inhelder, 1956; Zaporozhets (1965). Zaporozhets (1965) reported an experiment by

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Ginevskaya where children were asked to acquaint themselves with an object only by closing their eyes and touching it. The exploratory behavior of 3- and 4-year-olds was described as consisting primarily of “executive” movements, such as those used in controlling and manipulating an object, rather than in exploring it. For example, the children would try to roll, push, or knock with the object rather than explore it. Later, the palping actions of the hands were separated from their practical executive actions, but the palping actions were reported to be mainly of a holding character and not exploratory. Children 6 to 7 years of age used some holding movements, but also used more fine exploratory movements such as tracing the object, palping it to find out how solid it was, and examining its texture. Zinchenko, Ruzskaya, and others as summarized by Zaporozhets (1965) collected data on children’s exploratory movements while the children were familiarizing themselves with a large, flat, irregular form for 60-second intervals. Again the movements of 3-year-olds were mostly of the holding type. The investigators reported that small children often played with the figure instead of examining it. The 4- and 5-year-olds exhibited holding movements, but also started examining the figures more actively by using the palms and the tips of their fingers. Children 5 years of age explored the figure with the hands moving toward each other in opposite directions, carefully examining specific features of the figure, but without relating them or their position to the whole figure. Sixyear-olds were observed to trace systematically the whole outline of the figure with their fingertips. Abravanel ( 1968) observed similar trends in children’s exploratory behavior while they were comparing lengths of various stimuli to be identified visually later. The children ranged in age from 3 to 14 years. The haptic activity of the children was classified according to the type of activity involved, the sections of the stimuli that were explored, and the parts of the hand that were used for exploration. The most frequent activity of 3- and Cyear-olds was that of clutching the stimulus bars as if they were trying to determine their shape rather than their length. Another frequently observed activity among 3- to 5-year-olds was holding the ends of the bar passively between the palms, with the fingers cupped loosely aroung the sides. By 5 , the children were focused on length. This trend was more predominant by 7 and 8 years. The 7- and 8-year-olds more frequently held and actively pressed the ends of the bar, spanned the entire bar with one hand, or slid their fingers from the ends to the center of the bar, examining the parts as well as the whole. Few new techniques appeared after age 7 or 8. In addition to the changes in exploratory activity described above, Abravanel found that the degree of exploration carried out with the fingertips increased with age. Young children typically used the entire hand, relying on the palmar function for perception and estimation. Ss 9 years and older rarely used the palms for haptic exploration, but relied almost exclusively on finger activity. During the

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middle childhood years, exploration both with fingers alone and with palms and fingers jointly often occurred within a single trial. Klein (1963) also found a progression from passive to more active exploratory activity, using a matching task, corroborating the stages of haptic exploration described by Zaporozhets (1965) and Abravanel ( 1968). Hence, there appears to be a progression in the haptic modality from passive touching to unsystematic exploration, followed by outline tracing and more systematic search. This trend is also correlated with a change from matching on the basis on texture, which requires only passive touching, to matching on the basis of form, which requires active exploration or search involving more precise localization.

c. HABITUATION AND NOVELTY TASKS There is a generalized two-stage model (Hunt, 1961) for explaining the apparent shift from preference for familiar stimuli to preference for novel ones in infancy which is consistent both with Piaget’s sensorimotor stages and with Berlyne’s ( 1960) diversive exploration theory, as well as with general discrepancy theory (Kagan, 1970a, 1970b). It is consonant with the hypothesis that for the young infant, apparently familiar stimuli still possess moderate novelty and are hence more interesting than completely novel stimuli. The argument (Finley, Kagan, & Layne, 1972) is that the young infant lacks the cognitive structures necessary either to thoroughly familiarize himself with recurrent stimuli or to process novel ones. Later, objectively familiar stimuli are truly (i.e., subjectively) familiar, and response decrement occurs with their repetition, while previously uninterpretable (excessively novel) stimuli become interesting because they are now interpretable and yet still moderately novel. Wetherford and Cohen ( 1973) have recently confirmed these predictions, demonstrating that in infants 10 to 12 weeks old habituation of attention to familiar, repeated stimuli occurs more often than at 6 to 8 weeks. In general, the older infants preferred novel stimuli, while the younger ones preferred familiar ones. Of course, analogous results have been found by many other investigators, but these are distinguished by the fact that the data were collected both longitudinally and crosssectionally. At between 4 and 5 years of age there is evidence for a shift away from preference for novel stimuli, which might appear to contradict the general developmental hypothesis. But this phenomenon, called the Moss-Harlow effect (Grabbe & Campione, 1969), while clearly involving both novelty preference and reinforcement (Fisher, Sperber, & Zeaman, 1973), has been demonstrated only in discrimination tasks where discriminative responses are differentially reinforced. Thus, rather than demonstrating a return to familiarity preference, the data on the Moss-Harlow phenomenon indicate to us the ability of the older

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child to reclaim control of attention from such exploration determinants as novelty, when and if the task logic requires him to do so. By age 5 search behavior takes over in such tasks and outweighs the inherent salience produced by novelty. That salience-governed attention proceeds, over time, toward informationoriented scanning may be seen in minature in an experiment by Cohen (1972). Four-month-old infants in that study fixated checkerboards initially more on the basis of their size (i.e., retinal angle) than on the basis of the number of squares they contained. However, duration of fixation was more governed by number of squares than by size. Though not providing direct confirmation, these data are consistent both with Jeffrey’s serial habituation hypothesis and with our notion that exploration “teaches” search. The infants in Cohen’s experiment explored the environment until their attention was attracted by the salient feature of size, but it may be that they maintained attention as a function of how long it took to scan the stimulus for its internal information content. At least it is clear from the range of ages discussed so far that the transition from exploration to search as a predominant strategy cannot be said to occur all at once. Rather, it appears to occur in restricted situations at almost any age with increasing shortand medium-term familiarity. The long-term change reflects a gross summation of more and more situations in which short-term shifting toward search has occurred. WhiIe the very extensive literature on habituation cannot be fully reviewed here, the general model of response decrement and recovery (Lewis & Goldberg, 1969) has been widely used, not only to demonstrate habituation and dishabituation at various ages, but also indirectly to test for the presence of perceptually based schemas for organizing experience. The study by Miller cited above followed this paradigm. Again, using 4-month-old infants, Cornell and Strauss (1973) habituated attention to simple stimuli and then presented the habituated elements in a compound or a compound made of novel elements. Males, but not females, showed habituation of visual attention to the elements over presentations, generalization of habituation to the compounds made of habituated elements, and recovery (dishabituation) of attention to novel compounds. If we assume that habituation indicates completion of the initial exploration of a stimulus, we would interpret the results for males as indicating more complete familiarization, leading to low salience (and correspondingly low recovery of looking) when the familiar elements were presented in a compound, but high salience and recovery when novel compounds were presented. The females, who did not show habituation in the number of presentations offered, possibly explored the elements more thoroughly, therefore requiring more exposure than was available in order to complete exploration and thus to habituate. Alterna-

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tively, females may simply explore and habituate more slowly than males. Without a complete habituation procedure for females, one cannot choose between the two interpretations, but analogous sex differences have been found by a number of other investigators (e.g., Cohen, Gelber, & Lazar, 1971; Pancratz & Cohen, 1970). Regardless of the reason for the lower habituation rate than for males, the females explored the compounds of familiar elements more than the elements themselves, while the males showed generalized decrement to the familiar compounds, and both sexes showed increased attention to novel compounds. The exploration-familiarity interpretation would be that females gained less familiarity with the elements during habituation and therefore found permutations more subjectively novel than did the males. If habituation indicates completed exploration, familiarity, and the formation of a schema for the habituated stimuli, it could be argued that generalization of habituation to related test stimuli would serve to indicate the scope and boundaries of schemas formed in this manner. Faulkender, Wright, and Waldron (1974) used this logic with older Ss (29 to 44 months) and found a similar indication of schema formation, but with sex differences just the opposite of those found by Cornell and Strauss. Females at this age, habituated to criterion on a set of six conceptually related stimuli (e.g., fruits), showed generalization of habituation to new stimuli in the habituated category, but not to test stimuli from a novel category (e.g., animals). Males, similarly habituated, showed equally strong recovery of looking to new members of the habituated category and members of the novel category. It was concluded that either the females had developed more stable and generalizable concepts than the males, or the males were more sensitive to literal novelty than the females. Either way the females were responding in a more mature fashion. Apparently the males were engaged in exploration, the less mature attentional pattern, where visual fixation was under the control of salience variables, like absolute novelty. The looking behavior of females, however, more nearly resembled search in that their attention was devoted to conceptually novel stimuli, rather than literally novel stimuli, despite the absence of instructions or task requirements.

D. POINTING AND NAMINGTASKS Elkind and Weiss (1967) investigated the development of children’s spontaneous exploratory behavior by the use of a naming response. They presented children 5 through 8 years of age an “unstructured” or a “structured” m a y of familiar figures and asked them to name them (or, if they could not name some figures, to point to them). The “structured” array consisted of figures arranged

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in the form of a triangle so that they exhibited gestalt properties of continuity and closure in contrast with a randomized placement of the figures in the “unstructured” array. It was hypothesized that the gestalt properties of the structured array would lead to more systematic exploration, especially among the young children. They found that exploration of the unstructured array became more systematic and more complex with increasing age. In addition, the number of children who made at least one error in naming the items of the unstructured array decreased significantly with age. Exploration of the structured array was systematic at all age levels. However, the form of exploration did not always follow the triangular form of the stimulus. Many kindergartners and third graders and some second graders “read” the array according to the triangular pattern imposed by the picture. However, about half of the first graders “read” the pictures from top to bottom and from left to right. Elkind and Weiss interpreted this finding to mean that the first graders were spontaneously practicing the top-to-bottom and leftto-right scanning pattern required by reading. The findings were thought to reflect the development of motor skills acquired as a result both of maturation and practice. Matheny (1972) also found beneficial effects of perceptual organization of the array and generally more systematic and accurate scanning as a function of age. Kugelmass and Liebich ( 1970) further investigated this top-to-bottom left-toright pattern of responding by giving the same stimulus array to Israeli children. Israeli children learn to read Hebrew, which is printed from right-to-left. Hence, if the pattern of responding in the Elkind and Weiss study was due to motor skills required by reading, they would appear in the opposite direction. Kugelmass and Liebich found that with increasing age the patterns of exploration became more complex and systematic and that the number of errors decreased. Children in the early school grades showed more right-to-left patterns than triangular patterns to the structured array, as well as a left-to-right patterns of response. Both right-toleft and left-to-right patterns decreased with age and were weak in college students. Perhaps these results reflect a tendency for scanning rules acquired in the learning of reading to generalize to pictorial scanning, but only during the period of their acquisition. Before a child learns to read, no such effect is observed. After he has become proficient, the requisite scanning routines are automated and no longer generalize as readily to other tasks. Hansley and Busse (1969) extended the Elkind and Weiss (1967) study to poverty children. They confirmed the general increase of systematic responding with age. However, the distribution of the types of systematic response across age was different. The triangular and complex patterns of response occurred irregularly across age levels and the number of left-to-right patterns of response increased with age.

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E. CUE AND DIMENSIONAL PREFERENCE TASKS Color vs. form in vision, and texture vs. shape in haptic touch have been used in a variety of studies with children designed to assess developmental changes in preference, selective attention, or dominance; to illustrate the favorable effects of such biases when they direct attention to critical or relevant features of a task; and to substantiate the view that well before multidimensional problem solving comes under the control of verbal processes, it is organized by selective attention. Just as the organization of perceptual search depends on familiarity established by exploration, so the rudiments of logical search that will be required for more structured multidimensional tasks may first appear in the form of perceptual search in simpler tasks. Dimensional preference tasks are of this kind. The most common type of task that has been used to measure preferences among stimulus dimensions is a matching task. The child is presented three stimuli, a standard and two comparison stimuli, which vary simultaneously in at least two dimensions. For example, in vision, the child may be presented three colored forms. One of the comparison stimuli is like the standard in color but not in form. The other comparison stimulus is like the standard in form but not in color. The child is asked to select the comparison stimulus that is most like the standard. Consistent choices of the comparison stimuli along one dimension (color or form) are taken to indicate a preference for that dimension. For the texture-shape experiments in the haptic modality, the three stimuli vary simultaneously in texture and shape, with one comparison stimulus like the standard in texture, but not in shape, and the other comparison stimulus like the standard in shape, but not in texture. The haptic stimuli, of course, are presented out of the S's sight. Again, consistent choices to one of the dimensions of the comparison stimuli is taken to imply a preference for that dimension. 1. Vision: Color vs. Form In vision, an increase of selective attention to form over color with age is well documented, the preference for form manifesting itself most clearly after 5 years of age. Before this age the data are less conclusive. But most research shows that 3- and 4-year-old children are color-dominant (Brian & Goodenough, 1929; Colby & Robertson, 1942; Corah, 1964; Suchman & Trabasso, 1966a, 1966b). One question that has arisen in the literature is to what extent attention to color or form is a function of stage, set, or dimensional salience. The stage hypothesis is that if selective attention to color or form is a function of development stage, it is not a fully reversible phenomenon. If selective attention to color or form is a function of salience or induced set, it should be manipulable in a predictable fashion by conditions which emphasize color or form. Gaines (1970) investigated stage vs. set by screening Ss for color or form dominance and then by training them on a dimension different from their dominant dimension. Another

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group of Ss was trained on the dominant dimension, and a third was given no training. Training was on easy or hard oddity problems (in terms of the discriminability of the stimuli) and was given over a 5-week period. The subjects ranged in age from 4 to 7 years. In a retest of preference, Gaines found significant changes in selective attention for the group of Ss given training on their nondominant dimension, but only among the Ss given difficult training discrimination. For those given easier training there was a change for color-dominantSs to form and a nonsignificant trend for form-dominant Ss to change to color. The subjects trained on their dominant dimension showed no significant changes in dimensional preference, and neither did controls who received no training at all. Other investigators (Galloway & Petre, 1968; Tiffany, 1967) have not found that color and form preferences change with training. However, these studies involved less extensive and definitive training procedures. One implication of the fact that Gaines WE.S able to obtain significant changes in selective attention as a result of training is that preference is not merely a function of developmental stage. That it can be affected by training experiences supports Gaines’ contention that setting experiences and expectations of what will be relevant can strongly influence dimensional preferences. The implication is that the observed developmental shift merely reflects an increasing actuarial estimate on the part of the child that form is likely to be important. It is only an assumption, however, that older children systematically experience more form-setting situations and fewer color-setting ones than younger children. Our hypothesis of a developmental shift from exploration to search is consistent with the results of a number of studies, including Gaines (1970), many of which have stressed attentional phenomena, rather than training and reinforcement, as causes of the developmental shift from color to form. Such studies include those by Colby and Robertson (1942), Corah (1964, 1966) Corah and Gospodinoff (1966), and Katz (1971). We contend that the shift in attentional patterns from exploration to search is manifested in a shift from control by salient features to control by logical requirements. This change is analogous to Piaget’s concept of decentration. According to Piaget (1961), the young child’s attention is centered at any one time on the dominant characteristic of a stimulus configuration at the expense of the other features. With development, the child’s perception and judgment become increasingly decentered, and he attends selectively to a variety of specific characteristics of the stimulus configuration. In color-form experiments where the stimuli consist of solid colors, color inheres in every part of the stimulus and in this sense is a dominant characteristic of the stimulus. Any random or exploratory visual fixation to the colored stimulus will provide adequate cues for color and may thus account for the younger child’s selective attention to color. Form perception, however, requires the child to search for and to visually fixate specific loci, usually on the perimeter of the stimulus, where informative features for form discrimination (such as

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angles and curves) are located. The decentration of attention with increasing age does not imply a diffusion or random dispersal of attention. Rather, it becomes focused on a set of discrete loci that have been informative or relevant for various decision processes. Thus, the decentration of attention with increasing age should weaken immediate response to color and increase the likelihood of somewhat delayed responses to form cues by older children and adults. Corah and Gospodinoff (1966) attempted to elicit in adult Ss responses analogous to the centered response of younger children by experimentally limiting the amount of time the adult Ss could attend to the stimuli. They presented the standard stimulus tachistopically to an experimental group of adult Ss, and for 1 second to a control group of adults, as well as to preschoolers and third graders. They found that adults in the brief exposure group gave more color responses than the control adults, and that younger children gave more color responses than older children. These results support the hypothesis that dimensional dominance is in part a function of the distribution of looking behavior, and that color preferences in young children result in part from centration of attention on the initially most salient cues. Moreover, these results confirm the expectation that multiple fixations characteristic of older children and unhurried adults are necessary for form discrimination. Other studies have been concerned with the effect of stimulus characteristics on color-form preferences. Corah (1966) investigated the effect of complexity and the effect of using forms with colored outlines vs. solid-colored forms on color-form preferences in preschool and third grade children. He found that both the amount of color in the stimuli and the complexity of the stimulus forms were positively related to the number of color responses, but only in preschool children. There were more color responses to the solidly colored forms than to the forms with colored outlines and more color responses to the complex forms than to the simple stimuli. All of the studies discussed so far have dealt with only two stimulus dimensions at a time. Hence, a response to one stimulus dimension automatically implies that the child is not responding to the other stimulus dimension. One way to achieve more independent selection of stimulus dimensions is to include a third dimension. Two studies have incorporated such a procedure. Siege1 and Vance (1969) investigated visual preferences for color, form, and size, as well as haptic preferences for texture, shape, and size in preschoolers, kindergartners, and first and third graders. The results showed that, in general, selective attention to form increased with age more than color decreased with age, while size remained roughly constant at a low level. Similar preferences for color over size and for form over size were found in preschoolers and third graders, respectively by Kagan and Lemkin (1961), although they did not find an increase in form responding by older boys. They suggested that this difference was due to the greater use of verbal labels by older girls.

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Based on the assumptions that (1) the perceptual salience of color vs. form, (2) a set or expectation as to which might be the relevant basis for response, and (3) age may each contribute separately to the developmental color-form shift, Wright, Embry, Klein, Tresch, and Vlietstra (1974) devised six series of color-form matching stimuli differing in salience and distribution of color vs. form cues. The strongest color-dominant series contained stimuli of bright and contrasting colors, with complex forms which differed only slightly. Successive series progressed through the standard “neutral” stimuli used by other investigators to a strongly form-dominant series. In the strongest form-dominant series the form contours were repeated concentrically five times within each figure, while color cues were located only in the outer perimeter and only at the apices, where a colored line segment replaced the otherwise black contour line. With 4and 5-year-old children there were strong effects of color-form salience generating a range of from 10% to 90% form-responding, depending upon stimulus series. The authors also varied order of presentation in order to assess the effects of set or expectation. Some children received all 10 problems from the formdominant series first, then the next strongest form-dominant series, and so on until the last series, which was the strongest color-dominant. Other children received the series in the reverse order: color-dominant first and form-dominant last. Controls received the 60 items in random order regardless of series. Compared to control Ss, the experimental Ss exhibited color or form dominance after the first few items depending upon whether they were programmed to proceed from color-dominant to form-dominant stimuli or from form-dominant to colordominant stimuli, respectively. The initial salience-biased responses generalized to the rest of the items, presumably by creating a set or expectancy, and this effect held more for 4-year-olds than for 5-year-olds. Among the control Ss there was still a significantly greater preference for form among the older than among the younger subjects, so the results support the attention, expectancy, and stage theories, contradicting none of them. Katz (197 I) also found that salience of cues influenced color-form matching preferences. She further demonstrated that children classified as reflective on the Matching Familiar Figures Test of conceptual tempo preferred form, while impulsive children more often preferred color. Four statements can be made concerning the results of the studies reviewed. First, the increase in response to form represents a change in selective attention rather than a mere preference (Gaines, 1970) and is explained in part by Piaget’s theory of decentration (Corah, 1964; Corah & Gospodinoff, 1966). Second, it is possible to change an initial preference for color to a preference for form, either by varying the stimuli in the experiment (Corah, 1966; Katz, 1971; Wrightet a l . , 1974), or by employing training (Gaines, 1970), or by inducing a set through varying order of presentation of color vs. form salient items (Wright et a l . , 1974). Younger children may be more susceptible to such sequence effects than

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older children within the preschool range (Wright et al., 1974). It is more difficult to change a preference from form to color than the reverse, at least by means of training experiences (Gaines, 1970). Third, there appear to be individual differences in color-form preferences beyond those associated with age. Sex differences in color-form preferences have been found: older girls prefer form more than older boys (Kagan & Lemkin, 1961). Reflective children prefer form more than impulsive children (Katz, 1971). In both cases the presumably more-mature subjects show stronger form preferences. Finally, form responding is more pronounced, even at younger ages, when a third stimulus dimension (size) is added. Nevertheless, the relative decline of color and increase of form preferences with age are still obtained under these conditions. It appears that such changes may be reliably observed because they are over-determined, but in any case the shift with age from exploration of what is salient to search for what is informative is again implicated.

2 . Haptic Touch: Texture vs. Shape Just as color ordinarily inheres in the whole stimulus, while form cues are located in restricted loci, so in haptic (active) touch, texture cues are ordinarily located on all surfaces, while shape cues are located only at comers and edges. Thus, a developmental shift from texture to shape preferences in haptic touch would also be predicted as a part of the exploration-to-search evolution of attention. The data on selective attention to texture vs. shape have shown an early preference for texture (the haptic analog of color in vision) followed by a shift to a preference for shape (the haptic analog of form in vision). The study by Siege1 and Vance (1969) cited above experimentally confirmed the analogy in the sense that the hierarchy of dimensional preference was the same in haptic touch as in vision. That is, form and shape were the most preferred, followed by color and texture, and finally size. The correlations between the visual and haptic scores forform/shape, color/texture, and size were .40,.25, and .37, respectively. Thus, beyond the overall age changes, there was some tendency for individuals who had made the transition in one modality to have made it in the other. Klein (1963) investigated selective attention to texture vs. shape in a matching task where either texture or shape could be used as a basis for matching. The stimuli, constructed from %-inch posterboard with a texture glued to the top surface, were explored with one hand and could not be grasped because they were relatively thin and fastened to a table top. In one experiment, Klein used these solid two-dimensional forms and found equivalence matches primarily by texture among children 8 to 12 years of age. In another experiment, Klein employed raised outline figures. Under these conditions, form dominance occurred at all of the grade levels tested (Grades 1 through 6). Other investigators, using solid geometric forms, have demonstrated selective attention to shape among children younger than those studied by Klein. Gliner et

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al. (1969) investigated visual and haptic preferences for texture and shape in a discrimination-learning task with stimuli of approximately the same thickness and mounting as Klein’s solid ones. The subjects were kindergartners and third graders. In the haptic discrimination experiment, 64% of the kindergartners used texture as the basis for discrimination, while 67% of the third graders used shape as a basis for discrimination. The subjects in this study may have shown selective attention to shape earlier than the subjects in Klein’s study because a forcedchoice discrimination learning task with reinforcement contingencies was used instead of a matching task with no reinforcement contingencies. Abravanel(l970) investigated haptic shape and texture matching at ages 4-6. He had the subjects actively explore three-dimensional shapes using both hands to clutch and grasp the stimuli rather than restricting exploration to one hand as had been done in the Gliner et al. and Klein studies. Under these conditions, Abravanel found that 62% of the younger (4-5 years) children’s matches were on the basis of shape, whereas about 79% of the older (5-6 years) children’s matches were on the basis of shape. These results suggest that shape preferences are related to the use of three-dimensional stimuli and/or active methods of exploring the stimuli available to the subjects. Abravanel(l970) interpreted his findings as resulting from the “compatibility between the young child’s preferred modes of perceptual exploration and the properties of the object [p. 5311.” In other words, the three-dimensional stimuli were compatible with the grasping and clutching methods of exploration of the young child. Thus, the use of three-dimensional stimuli boosted the level of shape preferences among younger children more than it did among older children, but not enough to completely close the age gap. Gliner et al. (1969) confirmed the finding that kindergarten children tend to discriminate on the basis of texture and that third graders’ discriminate on the basis of shape when both stimuli are made readily discriminable by use of distinctive values. Attempts were made to reverse this age difference by making texture cues less distinctive for kindergartners, and shape cues less distinctive for third graders. Both attempts had effects in the predicted directions, but only the shift to shape by kindergartners was significant. The finding is analogous to the differential effects obtained in the visual modality by Gaines (1970). In summary, there appears to be an age shift from some texture preference to strong shape responding in haptic touch that is parallel to the shift from color to form preferences in vision. The results of the study by Gliner’s group with two-dimensional stimuli in a discrimination learning task demonstrated a shift to shape somewhere between 5 and 8 years of age. The results of the Klein study, using less forced presentation conditions, indicated the transition, but at a later age. Investigators of haptic touch who have used three-dimensional shapes (Abravanel, 1970; Siegel C Vance, 1969), raised outline figures (Klein, 19631, and/or more active methods of exploration (Abravanel, 1970; Siegel & Vance,

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1969) have found shape preferences at an earlier age. This finding suggests that early preferences for shape may also be accounted for by the decentration hypothesis. Shape preferences occur in younger children when the stimuli are so constructed as to make shape more salient. They also occur if the task is designed to encourage more active forms of exploration characteristic of the shapedominant older child. The experimental attempts by manipulation of distinctiveness to change shape preference to texture preferences among older children have not been as successful as attempts to change texture preferences to shape preferences in younger ones (Gliner et a l . , 1969). This difference would be predicted by the exploration-search hypothesis on the grounds that it is the younger subjects whose attention is most influenced by salience, and that intradimensional distinctiveness is a component of dimensional salience. No such asymmetry would be predicted by our model for direct logical training in a task where the nonprefemed dimension was relevant, for older children should find it easier to override the pull of salience on the basis of search logic that should younger ones.

F. DISCRIMINATION AND MATCHING TASKS As one begins to consider more complex discrimination, matching, and transfer tasks, where logical relevance begins to come into conflict with perceptual salience, the advantages of older children’s perceptual search behavior over younger children’s exploration becomes increasingly apparent. Elements of logical search begin to be required for optimal performance on discrimination and matching tasks, but perceptual factors still govern attending behavior to a large extent. There is an abundant literature on this point, and only representative examples are discussed in which specific observing behaviors have been assessed. 1. Spontaneous Attending Patterns Vurpillot ( 1968) investigated sequential visual fixations of children between 3 and 9 years of age during a complex same-different discrimination task. The stimuli were six different drawings of pairs of house fronts containing windows. In three pairs, the corresponding windows of the two house fronts were identical. In the remaining pairs, the corresponding windows of the two house fronts differed in one, three, or five locations (i.e., windows). The children were asked to determine whether the two houses presented on a given trial were the same or different. Children under age 6 scanned only a limited part of each house and judged the two houses as identical or different on the basis of insufficient information. A method of systematic scanning, consisting of making comparisons (successive fixations) of windows in corresponding locations on the two houses (homologous comparisons) first appeared in children at age 5 and was adopted by

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the majority of the children over 6. Erron correspondingly decreased with age. When age was held constant, Ss who made more homologous comparisons also ma& more correct responses. Clearly the development of systematic perceptual search facilitated the occurrence of the necessary logical search (has a homologous difference been found?). Other studies have investigated individual differences in cognitive style as determinants of scanning behavior. These studies have usually employed the Matching Familiar Figures test, a complex matching task in which the child has to find which of a number of likely alternatives exactly matches a standard. Drake (1970), using Mackworth’s (1967) method, recorded the visual fixations of impulsive and reflective third graders and college students while they performed a modified Matching Familiar Figures test. During the first 6 seconds of performance on the test items, reflective children and impulsive adults allocated to the standard a significantly larger portion of their fixations and looking times than did the other two groups (i.e., impulsive children and reflective adults). Younger impulsives failed to appreciate the logical centrality of the standard, while adult reflectives systematically scanned the array to isolate variable features which could then be checked easily in the homologous part of the standard. In terms of response time, the reflective subjects looked at a larger portion of all stimuh s figures and in more detail than did the impulsive subjects. Reflectives also made about twice as many homologous comparisons (successive fixations of corresponding parts of different figures) as did impulsives. Consonant with previous research on reflection-impulsivity , adults appeared more reflective than did the children. In particular, it is noteworthy that adults compared across figures a larger number of design features and repeated these comparisons more than children. In other words, they were more systematic and exhaustive in their scanning. Siegelman (1969) investigated reflective and impulsive observing behavior in fourth grade boys using a button-pushing response. The Matching Familiar Figures test was presented in an apparatus constructed so that the child had to push a button in order to make each figure come into focus. Reflective children looked more frequently and spent more time looking at both the standard and alternative stimuli than did impulsive children. Impulsive children spent proportionately more time looking at the standard stimulus, the eventually chosen alternative, and the longest observed stimulus than did the reflectives. In other words, impulsives were more biased. They tended to favor a few alternatives and chose between them, whereas they reflectives observed more of the alternatives and distributed their attention among them in a more homogeneous and systematic fashion. Siegelman hypothesized that there was a broad difference in the search strategy for these two types of Ss. She suggested that the reflectivesdifferentiated the properties of the array by comparing the alternatives for explicit differences

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and consulting the standard for confirmation, selection, or elimination. This strategy of perceptual search facilitated efficient logical search in this task. Siegelman (1969) further noted that “impulsives . . . appear more likely to compare the standard globally with one alternative at a time, interpreting the task as a series of up to six binary decisions (‘same’ or ‘different’). As soon as they fail to find a difference between an alternative and a globally memorized standard, . . . they choose that alternative [p. 11201.” Again the impulsive 9-yearold child appeared to behave like the younger child in terms of his inability to develop a systematic strategy for effective search. Wright (1971) confirmed the prediction that among younger children (4-and 5-year-olds) reflectives looked more at the standard stimulus while impulsives failed to show any recurrent scanning strategy. He used the Kansas Reflection Impulsivity Scale for Preschoolers, a simpler form of the Matching Familiar Figures for younger children. Like Siegelman, Wright found that impulsives ignored more alternatives and displayed more evidence of preference or bias in their attention to alternatives than did reflectives. Ault, Crawford, and Jeffrey (1972) confirmed most of these findings as well. McCluskey and Wright (1973) recorded the visual fixations of 3- and 5-yearolds on a task where the child was instructed to point to the location of the difference between two similar stimuli. The stimuli were so constructed that in each pair there were three corresponding loci to be compared: “head,” “middle,’’ and “tail.” Successive fixations of corresponding parts of the two figures in a pair were scored as homologous comparisons. No differences were ever provided in the middle position, so that informative homologous comparisons (head with head and tail with tail) could be recorded separately from uninformative homologous comparisons (middle with middle). Sex differences and cognitive style differences between reflectives and impulsives on the Kansas Reflection-Impulsivity Scale for Preschoolers were also analyzed. Not only did 5-year-olds make fewer errors than 3-year-olds on the location-of-differences task, but the older children made more total fixations; took more time to respond; and made more comparisons, more homologous comparisons, and more informative homologous comparisons than did the younger ones. Reflectives at both ages showed more effective and systematic scanning than did impulsives, and on most measures females were more systematic scanners than males. Since the middle position had been shown to be the most fixated by children of this age in previous studies, it can be argued that salience and preference exerted stronger effects on younger, impulsive, and male subjects, resulting in poorer perceptual search for them and in poorer logical decisions (more errors). Conversely, the presumably more mature reflective, female, and older Ss showed effective perceptual search in their higher rates of homologous comparisons, better logical search in their inattention to the salient but uninformative middle locus, and consequently higher rates of correct response.

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In summary, the age change from partial, passive, and erroneous scanning in young children to more exhaustive, active, and systematic search strategies in older children is paralleled in the differences between the scanning strategies of impulsive and reflective children at a single age level. White and Plum (1964) investigated the eye movements of 3- to 5-year-old children as they solved a discrimination learning-set problem. White and Plum observed that on the first one or two trials of a new discrimination problem the number of eye movements was high. There followed a relatively inactive period with one or two visual fixations per trial. This presolution stage was marked by visual and choice position biases. During this period the learning curve was flat, but eye movements increased as the subjects approached the onset of the criterion run. After an asymptotic level of performance had been obtained, the number of eye movements per trial decreased. Hence, the children’s rate of eye movements appeared to be related to their performance on the learning task. White and Plum argued that the eye-movement change reflected a change in attention to the stimulus dimensions of the task. They noted that the only discernible regularity in young children’s responses at the beginning of the task was attention to the position of the stimuli. Only later, when position responses were extinguished, did they attend to the stimuli themselves. This change of attention from positions to stimuli appeared in the form of increased fixations of the stimuli at the onset of problem solution.

2. Induction of Selective Attention by Stimulus Manipulation In a subsequent experiment, White (1966) attempted to disrupt children’s early position responses by varying the position of the cue so that position would be totally irrelevant. Instead of presenting the two-choice discrimination in two stimulus windows, he used three stimulus windows in a triangular arrangement. Stimuli on any trial were presented in two of the three stimulus windows with the six possible arrangements of stimuli varied across trials. Hence, any attempt to follow a position-guided responses would be frustrated by the fact that on a random third of the trials, any given locus would be dark and not available for choice. In a control condition, the two stimuli were placed side by side in the traditional array with position randomized over trials. The triangular array facilitated the performance of the second and third graders, to whom position is presumably a salient cue. In other words, varying the positions helped older children ignore them by logically demonstrating their irrelevance. The same manipulation with younger children enhanced the salience of position cues, and since their attention is more stimulus-controlled, the treatment enhanced their attention to and reliance on positional cues, to the detriment of correct responding. In a third experiment, White (1966) investigated the effects of a novel vs. repeated stimulus in a standard two-choice discrimination task. In varying posi-

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tive and varying negative conditions, subjects were faced with a constant (familiar) stimulus from trial to trial which varied in position between the right and the left stimulus windows. The other window was occupied by a continually varying (novel) picture. In the varying positive condition the subjects had to learn to choose the novel picture. In the varying negative condition, the subjects had to ignore the novel picture and respond to the familiar one. Subjects in a control condition were repeatedly presented the same two pictures with the right or left position of the pictures varying across trials. They had to learn to continuously choose one figure and ignore the other figure. The subjects were drawn from the nursery school, kindergarten, first and second, and fourth and fifth grades. The results indicated interference by the varying position condition, relative to controls, at the kindergarten level, and no difference from control at other ages. The varying negative condition produced interference for most younger children, but not for fourth and fifth graders. White (1966) concluded that normally, young children find extraneous cue variation an interfering factor in learning and that between the ages of 5 and 7 at least some kinds of extraneous variation become neutral or even beneficial for learning. We might add to that conclusion that salience interferes with logical information processing if the subject is in the exploratory mode, even when that salience is made a marker of relevance to the task. As the child becomes more able to overcome salience (moving toward a search mode) such salience effects weaken, but the child would still be vulnerable if salience were systematically correlated with an irrelevant cue, like position. Only with full development of the search mode should salience cease either to help or to hurt the process of selective attention to relevant cues or dimensions. In a haptic discrimination study, Brown, Scott, and Urbano (1972) identified three exploratory strategies (we would call them search strategies) differing in efficiency of information gained per observing response. Analysis of the conditional probabilities of correct response, given the strategy used on that trial, indicated a performance benefit associated with strategy efficiency. When irrelevant cues were variable, as opposed to constant, children were less able to inhibit attention to them, and their performance suffered accordingly. Only preschoolers were used, and thus the question of individual strategic differences other than those attributable directly to developmental stage is again raised. If the relevant dimension is a subtle one, well down the child’s hierarchy of things to explore, young children may still be able to use it if nothing more salient is available on which to base discriminative responding. For example, McGurk (1972) taught preschoolers a discrimination between stimuli differing only in orientation. The discrimination was readily acquired when no other cues were present. When color or size was also varied, the same discrimination proved to be very difficult. Koenigsberg (1973), moreover, has shown that orientation can be made salient and effective for preschoolers by using and demonstrating a rotating standard stimulus. Analogously, Maccoby and Konrad

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(1966, 1967) have shown that older, but not younger, children benefit from high sequential probability of words in the target messages in a dichotic listening task. In general, it appears that the youngest explorers are helped or hurt, depending upon the relevance of salient cues. The beginning of a transition to search is marked by interference when salient cues are irrelevant, but no strong facilitation when they are relevant. The use of well-developed search routines is not directly influenced by salience of cues, but if the logic itself is somehow made salient, selection of an appropriate perceptual search strategy may be facilitated. However, it should be noted that Yussen (1972) failed to find that visual highlighting of various dimensions had any effect on discrimination learning, reversal, or generalization and transfer performance of preschoolers or second graders. While direct training of relevant search behavior clearly should and does improve discrimination, a number of investigators have examined initial bias and training with one dimension relevant as they affect transfer of training involving a reversal or an extradimensional shift. Smiley and Weir (1966) first assessed color-form preferences in kindergartners, and then trained them in a two-choice discriminationin which each pair of stimuli differed in both color and form, with one dimension relevant. As expected, there is an advantage in discrimination when the S’s preferred dimension is the relevant one. Utilizing the optional shift procedure, the authors further noted that those trained with their preferred dimension relevant chose to stick with that dimension in transfer, while those trained on their nondominant dimension reverted to their originally dominant dimension when forced to choose in transfer. In a subsequent series of studies, Smiley (1972a, 1972b. 1973) used intradimensional distinctiveness of cues to manipulate dimensional dominance. Again, the present authors would include this variable as a manipulation of salience. Regardless of what it is called, this manipulation facilitated initial discrimination when values on the relevant dimension were relatively distinctive and interfered when the relevant dimension contained cues of high relative similarity. This result was obtained for kindergartners and third graders, but no significant effects of intradimensional distinctiveness were obtained for sixth graders or college students. In the subsequent optional shift task the Ss trained with the salient dimension relevant made more intradimensional shifts, while those trained with the salient dimension irrelevant made more nonreversal (extradimensional) shifts. Once again, the difference was obtained with kindergarten and third-grade Ss, but not with sixth graders or college students. Other studies have attempted to induce more efficient scanning strategies by changing the stimulus materials. Zelniker, Jeffrey, Ault, and Parsons (1972) gave impulsive and reflective children a match-to-sample task where five of the alternatives were identical to the standard and only one differed. This is different from the usual Matching Familiar Figures task where the alternatives differ and

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only one is identical to the sample. After 10 differentiation items, impulsive Ss made significantly fewer errors on an immediate Matching Familiar Figures retest. The procedure had no effect on latency of response.

3. Induction of Selective Attention by Training or Instruction Using a multidimensional same-different task, Pick and her associates (Pick, Christy, & Frankel, 1972; Pick & Frankel, 1973) have found an age difference between second and sixth graders in the ability to sample selected cues from an array at a perceptual level. The experimental manipulation was whether Ss were informed before or after a presentation which aspect (color vs. shape or size vs. shape) was relevant for comparison. In both studies not only did the older children respond faster, but the advantage of being preinformed about the relevant cue was consistently greater for older children. The authors interpreted the results as indicating that what improves with age is attentional selectivity (in our terms, systematic perceptual search), rather than general efficiency in processing both relevant and irrelevant information. Lehman ( 1972) investigated scanning strategies of children in kindergarten and Grades 2, 4, and 6 on haptic matching tasks involving task-relevant and either task-irrelevant or redundant information. In three experiments, children matched textured objects on shape or texture or matched symmetrical crossshaped stimuli on size. The textured objects were two-dimensional shapes with circular patches glued to the center. Hand movements in exploring the objects were recorded on videotape. The three experiments varied in the extent to which attention was directly manipulated. In Experiment I, the children were told the relevant dimension, and the major search strategy at all grade levels was to explore that dimension. Preference affected the search strategy of kindergartners. More one-dimensional search occurred when the preferred dimension was relevant than when it was irrelevant. It is also of interest that on the few trials where both the relevant and irrelevant dimensions were explored, older children searched more systematically than younger children, first searching the relevant dimension, them making a match on the relevant dimension, and finally feeling the irrelevant dimension. In Experiment 11, the irrelevant dimension was made invariant. For half of the Ss, the textured patches in a stimulus set were the same, while the shape of the comparison stimuli varied. For them, the match had to be made on the basis of shape. For the other half of the Ss, shape was invariant and texture relevant. No children were told the relevant dimension. In this experiment, very few children appeared to discover the invariance of the irrelevant dimension and then to disregard it. Not until fourth grade did any meaningful increase in the use of one-dimensional selective strategy occur across trials. There was also a greater effect of preference on dimensional search than had been evident in Experiment I. For kindergartners and second graders, as in Experiment I, more one-

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dimensional search occurred when the preferred dimension was relevant than when it was irrelevant. In the few cases where the irrelevant dimension alone was touched, it tended to be the preferred dimension. This trend was particularly pronounced in kindergartners. In other words, the younger children’s observing behavior was more determined by salient stimuli and preferences than was that of the older children. In Experiment 111, the children were asked to match crosses for size by haptic touch. The crosses were as long on one axis as on the other. Hence only one axis needed to be felt in order to locate a match. This intrastimulus redundancy was explained to half of the children and not explained to the remaining half. Search was reduced more at all grade levels in the directive condition than in the nondirective condition. Within each condition, older children searched more economically than younger children and also showed more improvement across trials. Apparently, older children were more able to isolate the relevant dimensions of the task and to limit their observing behavior to the minimum necessary to provide adequate cues for matching. Almost compulsive exploration of demonstrably irrelevant cues, when they vary, is a frequently observed characteristic of younger children’s discrimination performances. Wright and Gliner (1968) investigated the effect of training dimensionally selective observing responses in the haptic modality on subsequent discrimination learning. The discrimination learning task consisted of a simultaneous discrimination between two objects differing in both shape and texture, with texture, the generally nonpreferred dimension, always relevant. The Ss were fourth and fifth graders. The stimuli were constructed with different loci for the shape and texture cues (i.e., large geometric shapes cut from %-inch plywood with smaller texture patches glued to the center of the top surface), so that a child’s hand movements could serve as an indication of the dimension being explored. Subjects in three experimental conditions were pretrained, using a shaping technique with auditory feedback, to explore actively either texture only, shape only, or both shape and texture equally in alternation. Subjects in a fourth (control) condition were given no pretraining. Half of the subjects learned the subsequent texture discrimination problem with easily discriminable texture differences between the correct and incorrect stimuli, and the other half had nondistinctive (barely discriminable) differences between the two texture stimuli. In the texture discrimination task which followed pretraining, the expected main effect favoring relevant (texture) pretraining over irrelevant (shape) pretraining was obtained. Ss in the control (no pretraining) group learned about as fast as those who were trained to alternate observing responses to texture and shape. Learning was easier for Ss who had the more distinctive texture stimuli regardless of pretraining. Thus, an experimentally induced bias for exploring one stimulus dimension or another has the same effect as an initial dimensional preference on discrimination learning (Smiley & Weir, 1966). Distinctiveness of

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the texture stimuli did not enhance selective attention to texture, perhaps because distinctiveness was not varied enough to produce a salience difference favoring texture, or because the children were too old (8-9 years) or too thoroughly pretrained to remain in the exploratory mode.

G. MEMORY AND RECALLTASKS There is a current wave of published research on children’s mnemonic skills, a considerable portion of which makes reference to attentional variables. It will be useful simply to assume that attentional processes are important in memory at least viewed superficially. If attention governs information input, then the computer operator’s adage would be appropriate: “Garbage in, garbage out.” In particular, it is the thesis of this section that the improvement of mnemonic performances among younger children results from the growth of systematic attending during initial presentation of materials. Many studies have demonstrated that mature logical search, often dependent on verbal processes or imagery, contributes to effective rehearsal and retrieval. Improvements in memory among younger children, however may result primarily from the increasing selectivity and systematicity of observing behavior found in the development of perceptual search. The raw mnemonic capacities of children as young as 4 years are startlingly good. Kagan (1970a) reported that children of that age can flip through 50 pictures in 3 minutes and then recognize on the average 45 of them when paired with new ones. Entwisle and Huggins (1973) demonstrated better than chance recognition of 40 unfamiliar landscapes and cityscapes either 2% hours later or one week later by about 90% on the first and second graders tested. Clearly, given a nonverbal recognition and pointing task to assess recall, young children do very well. In the section that follows only a few studies, selected for their relevance to exploration and search, are discussed. 1. Stimulus Manipulations Haith, Momson, Sheingold, and Mindes (1970) presented one- to four-picture arrays tachistoscopically followed by a 10-item array containing the displayed item(@and others. The child was asked to point to the picture(s) he had just seen. Exposure durations were too brief for voluntary scanning movements to occur during the exposure. When only one item was shown, 5-year-olds performed as well as adults. But when more than one stimulus was shown, 5-year-olds were significantly inferior, despite the elimination of scanning strategy differences, and the mimimization of difference attributable to verbal encoding, rehearsal, and retrieval strategies. Apparently, the young children could not handle multiple simultaneousinputs without some additional help in deciding which to attend to.

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Sheingold (197 1) used the Sperling procedure to determine whether children could profit from a cue as to which item in a seven-item array to attend to. The circular arrays were presented at subscan durations tachistoscopically, followed by a blank interval of from zero to 1000 msec, after which a position pointer was presented (like a clock hand) indicating one of the seven position. The subject then tried to name the stimulus &at had occupied that position. Recall was an irregularly decreasing function of the time interval between presentation of the array and presentation of the position indicator, but up to 150 msec, the 5-yearolds were as good as the adults. Thereafter adults leveled off, while 5-year-olds continued to decline, with intermediate ages falling in between. These and other results reviewed by Haith (1971) suggest to us that children are basically as good as adults at very short-term iconic storage, provided either that only one item is presented, or that a nearly simultaneous indicator is provided to make one element salient. Once again, it is the lack of organization of attention to multiple cues that sets limits to the younger child’s information processing. Odom (1972) investigated recall in kindergartners, third graders, and sixth graders using the Odom-Guzman ( m o m t Guzman, 1972) stimuli. The children were presented an array of cards, each card containing different values on each of four dimensions that had previously been assessed for salience. The children were told to recall the values of a single dimension by designating their locations following repeated array exposure. Salience of the relevant dimension was varied. Fewer recall errors were made when the relevant dimension was relatively high in salience that when it was relatively low. Fewer recall errors were made by older than by younger children, in general. But kindergarten children made many more errors than did the third graders when a nonsalient value was relevant. In a second task, the Ss were probed on the recall of values from the three incidental dimensions. Older children made fewer errors in recalling the incidental information than the younger children and fewer errors were made when the incidental dimension was highly salient than when it was less salient. In a subsequent study Odom and Corbin (1973) gave 6-year-old and 9-year-old children recall tasks which required processing of one stimulus dimension or of two stimulus dimensions simultaneously for solution. More errors were made by both first and fourth graders when the task required attention to two dimensions than when only one dimension was needed. The relative difficulty of the twodimensional task as compared to the one-dimensional task was greater for the first graders than the fourth graders. In addition, fourth graders did better when, in the two-dimensional task, the two dimensions to be processed were both high in salience than when one dimension was high and the other low. The salience studies by Odom and his colleagues in general strengthen the hypothesis that salience is a major determinant of both deliberate and incidental recall. They do not, however, provide strong support for our hypothesis that

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salience effects decline with age or that such a decline, accompanied by increasing use of relevance-oriented attentional strategies, account for the age effects that are obtained. However, the data presented do not contradict this hypothesis. One possibility is that underlying the age-related improvements found in these studies may be an increase in the flexibility with which subjects can adopt differing strategies for attending as a function of the task demands, regardless of initial salience hierarchies. Evidence on this point is contained in the results of the Hale and Morgan (1973) study cited earlier. When two redundant cues served to identify the positon of a card in an array, older children (8-year-olds) could identify the position from memory on the basis of either the dominant or the nondominant cue, while Cyear-olds could do so only on the basis of the dominant cue. When either the original array or instructions indicated that only one cue was relevant, the age difference was eliminated. These results indicate a developmental increase of both judgment and flexibility in distinguishing between conditions under which attention to redundant stimulus information is or is not effective. The development of systematic perceptual search appears to precede flexible and appropriate application of that mode to certain complex tasks. The latter may require an element of logical search as well.

2. Instructions, Modeling, and Training Manipufations Vlietstra (1973) investigated the relationship between observing strategies and short-term recognition performance of preschoolers in a delayed match-tosample task. During a training task, Ss received either strategy training in selective and systematic search of relevant cues, or repetition of the same problems without strategy training to the same performance criterion. Control Ss, of course, took much longer to complete that training. Then all Ss received new problems of the same format in a transfer task. In each condition the training and transfer stimuli were modified for one-third of the Ss so that the relevant cues were made perceptually salient. For another third irrelevant cues were made salient, and for the rest no portions of the stimuli were made salient. In general, the results showed that strategy training facilitated both effective search behavior and recognition performance in both training and transfer. Four conclusions were drawn from Vlietstra’s results: 1. Salience effects when present tended to influence younger preschoolers’ observing behavior and memory, but not that of older preschoolers. 2. Logical relevance overcame the influence of salience when a systematic strategy for exclusive and exhaustive attention to relevant cues was experimentally provided. Some control Ss also eventually evolved a relatively effective scanning strategy without specific training, but only over several extended sessions. When they did, it also facilitated scanning and memory in transfer. 3. Salience affected observing behavior more on the early portion of each trail during initial inspection than later during recognition.

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4. For control Ss, who lacked a trained strategy, salient irrelevant cues interfered

with search and recognition, but salient relevant cues did not facilitate performance. This effect was more pronounced on early trials where stimuli were less familiar and where a search routine had not yet developed. Recall that Yussen (1972) failed to find beneficial effects of visual highlighting of relevant cues. It is our hypothesis that this asymmetrical effect of salience characterizes the developmental transition from exploration to search. Put another way, young children can acquire, either by training or by arduous experience, a search routine which obviates any benefits which may accrue from the perceptual salience of relevant cues. But such search routines are at first fragile and susceptible to disruption by salient sources of irrelevant information. Only later when they are well established and generalize on logical grounds do such scanning strategies become so stable that they make the child relatively impervious to distraction. Yussen (1974) investigated the effects of instructions to remember the performance of a model on preschoolers’ and second graders’ abilities to recall the choices made by the model, in a distracting situation, Half the children at each age were instructed in advance to remember which of three toys the model chose. During the model’s performance distracting, irrelevant stimuli were displayed so that they could be seen only by looking away from the model. The older children attended more to the model than the younger ones, and those instructed to remember attended to the model more than those not so instructed. Moreover, instructions enhanced the older children’s attention to the model more than that of the younger children. Attention to the model was correlated with recall accuracy, as expected. It is interesting, in the light of the exploration-search hypothesis, that the previous studies of this type yielded little or no effect of such instructions, apparently because no salient distracting stimulus was present. Clearly, the age and strategy effects obtained by Yussen depended in part upon the presence of salient distractors. Although the evidence reviewed here on attentional strategies and salience effects as determinants of memory is neither comprehensive nor entirely coherent, it appears that improved memory performance is associated with moresystematic patterns of attending. Such patterns occur more frequently in older than in younger children, more frequently after a task has become familiar than before, and more frequently following instructions or training in relevant and organized search than without such treatments. Stimulus salience may facilitate memory when it calls attention to relevant cues, but has stronger effects when it interferes with memory by enhancing attention to irrelevant cues. When a logical search strategy is available, it tends to override any effects of salience of irrelevance or incidental cues, presumably because it is more efficient and generalizable as a means of problem solving. In general, the distracting effects of salient but irrelevant cues appear to decline with age, and eventually children are able in

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most situations to invent or adopt an appropriate search strategy strong enough to overcome ordinary distractors, even without specific training or instructions.

SEARCHSTRATEGIES H. TASKSINVOLVING FORMALIZED We turn next to tasks in which logical search, rather than perceptual search, is required for effective information processing. The developmental trend from exploration to perceptual search has been demonstrated in simple tasks benefiting from systematic observing behaviors at the level of looking and touching. In this section we are concerned with tasks requiring explicit strategic decisions which logically determine the information available to the child over a longer and more complex sequence of events. In 1964, Weir first demonstrated that choice of the only reinforced response in a probability learning task is a nonmonotonic function of age. In a three-button, discrete-trials procedure, one button was reinforced either 33 or 67% of the time, and the other two were never reinforced. At asymptote, 3- and 5-year-olds exhibited a preference for the reinforced button, which Weir attributed to simple reinforcement effects, analogous to the associative responding described by White (1965). The 7- and 13-year-oldsdid not show this response, but instead engaged in patterned responding (such as right, middle, left sequences) which Weir interpreted as hypothesis-testing behavior. Even at asymptote, however, these poorly reinforced patterns continued to dominate the behavior of the “middleaged” children, indicating perhaps that rather than being hypotheses as to the nature of the solution in the process of being evaluated, the patterns might have been search routines designed to generate orderly data about the solution. Older subjects (14 to 18 years) entered the task with more complex response patterns than the preschoolers, but eventually converged on a maximization-of-reward solution similar to that of the youngest subjects. Odom and Coon (1966) used a variant of the Weir task with 6-, 11-, and 19-year-olds. They confirmed that simple response patterns would occur, especially in the middle-age and older children, and would stabilize to the extent that they were reinforced. This finding, however, does not rule out the possibility that simple patterns of response are initially used more to keep track of complex information and to organize search than as intuitive hypotheses regarding a game solution. Perhaps in such uncertain situations younger subjects do indeed operate at a level of random exploration of single responses, finally settling mostly on the one that pays off. If we are correct that the middle-age children begin to develop search routines that are distinguishable from simple sequential hypotheses, they could still convert such patterns to hypotheses (or simply continue them) if they produced consistent reinforcement. The position taken here is that in addition to the fact that older children can develop more complex hypotheses to test and retain if reinforced, they can also

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develop orderly routines in trial and error settings with uncertain outcomes which are more information-oriented than reinforcement-oriented. There is more direct evidence bearing upon this point in two studies by Wright (1962, 1963) on the effects of varied probabilities of noncontingent reinforcement on response patterning in 10-year-olds, 13-year-olds, and adults. The apparatus consisted of a circular array of buttons which, when pressed one at a time, sometimes produced a reinforcing event, according to a randomized schedule that was completely independent of which button was pressed. The resulting patterns of response were thus entirely subject-generated (and perhaps could be termed superstitious). That is, no matter what a subject did, the exact same preprogrammed sequence of reinforcements and nonreinforcements was delivered following any press of any button. Citing G. A. Miller et al. (1960) analysis of heuristic versus algorithmic plans, Wright characterized as heuristic those response patterns which the Ss used as intuitive hypotheses, retaining only those subsequences that happened to result in reinforcement. He identified as algorithmic those patterns which were used primarily under conditions of low frequency of reinforcement, and were apparrently more designed to produce systematic information than to maximize reinforcement directly. Patterns labeled button-repetition and constant-interval rotation around the array occurred more often than chance at all age levels studied. Increased patterning at high densities of noncontingent reinforcement was obtained as expected at all ages. This finding was interpreted as an indication of hypothesis testing: simple patterns were retained primarily because they appeared to succeed in generating reinforcement. They were more likely to be repeated following a reinforcement than following nonreinforcement, an indication that the Ss were testing hypotheses, to be repeated if they worked. At 50% reinforcement, hypotheses were still being tested on a win-stay, lose-shift basis, but they were more complex than simple repetition and rotation. However, as the density of the reinforcement declined below 25%, instead of testing newer and still more complex hypotheses, Ss began again to increase in the consistency with which they used simple patterns. This upturn in patterning at low probabilities of reinforcement appeared to be an algorithmic routine, used to generate information and to keep track of what had been tried. Such patterns were more likely to be repeated following nonreinforcement than following reinforcement. Adults, for example, used one-step rotation patterns only so long as they continued to get no reinforcements, but repeated those buttons that were reinforced. This kind of patterned search is like mathematical algorithm in that it promises to find a solution if one exists, but is not itself the solution. It is, in short, a search routine. In Wright’s (1963) study, the use of algorithmic search patterns increased for adults as the probability of reward approached zero. A somewhat weaker effect

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of the same kind was observed in 13-year-olds, who did more hypothesis testing than algorithmic search. The 10-year-olds showed no such effect. For them the probability of repeating any pattern was directly related to the probability of reinforcement, and did not show an upturn when rewards became sparse. That older children and adults use more systematic and logical strategies has also been demonstrated in an experiment by Neimark and Lewis (1967). The subjects were 9 through 16 years of age. They had a complex task that could be solved by using a logical strategy (analogous to Wright’s algorithmic search) which eliminated alternatives or by a gambling strategy (analogous to Wright’s heuristic trial and error). The younger subjects made more noninformative first moves, while the older subjects displayed a more logical strategy in their first moves. Moreover, random behavior decreased with age. In other words, the older children appeared to plan and think out each move before making it to a greater degree than the younger children. A year after their first study, Neimark and Lewis (1968) retested the 9- through 11-year-olds on the same task and again rated the Ss problem-solving for informative and logical strategies. They found that, in general, more logical information gathering strategies were displayed on the second-year administration than a year previously. Consistent individual differences were also found: the secondyear performance of individuals could be predicted from their first-year performance, both in terms of their latency to respond and in terms of the type of strategy employed. In a concept identification task Nuessle (1972) recorded the use of efficient focusing strategies and latency of response following feedback among reflective and impulsive fifth and ninth graders. Longer latencies were associated with more proficient focusing, and both were more characteristic of older and reflective children than of younger and impulsive children. Here, then, is a more direct confirmation that reflection is not only characteristic of mature search, but that older children and reflectives devote time to decision processes involved in logical search, rather than merely seeking to maximize reinforcement. Analogous results have been reported by McKinney (1973). Olson (1966) investigated search behavior in children 3, 5, 7, and 9 years of age. The children were presented two, three, or more printed model patterns in matrices, one of which (the “correct” one) was wired into a matrix of light bulbs of the “push-to-test” variety. The child had to find the correct pattern by pressing bulbs on the bulb board matrix. If the bulb pressed was part of the prearranged correct pattern of displayed bulbs, it would light up when pressed and go off again when released. If it was not part of the prearranged correct pattern it would not light up when pressed. Half of theSs were given an unrestricted choice of bulbs in solving the problem (the “free” condition). The other half of the Ss had a “constrained” choice of bulbs in that they were allowed to press only one

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bulb at a time and were instructed each time to press the bulb that would tell which pattern was correct. After each response the experimenter asked whether or not the S knew which diagram of the displayed bulbs was correct. The results showed that the 3-year-olds tended to search the board for the bulbs that would light up (on-pattern) independently of the diagrams in front of them in both the free and constrained conditions. The 5-year-olds tested each pattern separately, independently of what bulbs had been tried previously. They largely concentrated on the on-pattern bulbs, redundant and informative alike, although more informative on-pattern bulbs tended to be pressed in the constrained than in the free condition. The 7-year-olds pressed more informative on-pattern bulbs than did the 5-year-olds. This effect was especially pronounced in the constrained condition. The children at this age appeared to be internalizing informational constraints. By age 9, the subjects pressed mainly informative on-pattern bulbs, regardless of the presence of constraint instructions. The authors also analyzed latencies in the free and constrained conditions. The latencies when plotted took the form of an inverted U function with the 3- and 9-year-olds differing little in latency between the two conditions and the 5- and 7-year-olds taking more time in the constrained condition. This result might be interpreted to indicate (cf. Weir, 1964) that 3-year-olds cannot comprehend the constraint instructions and thus do not respond differentially to them, while 9-year-olds constrain themselves regardless of the instructions. Thus, only the 5through 7-year-olds could benefit by the organization inherent in the constraint instructions. The young children’s short latency responses were in White’s (1965) “zone of automation.” The middle-aged children’s longer latency responses were more characteristic of White’s (1965) “zone of decision.” The shorter latencies of the oldest children, however, could be interpreted to represent the capacity for logical search based on efficient decision-making. The above results are also consistent with the developmental change in reflection-impulsivity showing increasing reflectivity with age. The younger children were more fast-acting and incorrect (impulsive) while the older children were more slow and correct, except for the oldest Ss for whom the task was so routinized that it was no longer ambiguous or uncertain. These results illustrate the more frequent appearance of strategies that produce information relevant to the task at hand among older than among younger children. Younger children’s strategies appear to be more determined by salient characteristics of the stimulus array or by a direct attempt to maximize reinforcement, a logically salient feature of such tasks. Although we have not considered any studies of verbal question-asking, and other more abstract, symbolic forms of information-getting, there is abundant evidence of increasing logical control of such behaviors with age. The decreasing impact of concrete and salient features as determinants of logical search has been documented in this domain as

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well (Mosher & Hornsby, 1966). The strategic superiority of reflective subjects over impulsive ones has also been demonstrated (Ault, 1973; Denney, 1973).

IV. Summary and Conclusions Three major points have emerged from the discussion. First, we shall summarize the four major distinctions between the exploration and search modes of information acquisition. Second, we shall try to specify the nature of the microgenetic changes underlying cumulative development of information-getting behaviors. Finally, we shall underscore the importance of effective information acquisition skills to the development of cognitive competence in general. Four kinds of distinctions can be made between exploration and search behavior. At the behavioral level, exploration is playful and open-ended by nature. It involves automated, rapid, and often impulsive responding of a simple associative kind. Search, however, is task-oriented and focused on a more or less well specified goal. It involves slower and more reflective decision-making processes. At the causal level, exploration appears to be controlled primarily by salient, dominant, or reinforcement-correlated features of the stimulus environment. Search, by contrast, is controlled by task-defined informational needs and logical constraints. There is a middle ground wherein stimulus saliency competes for control of attention with relevance and informativeness of cues. Here the salience of irrelevant cues appear to interfere with logical search more than the salience of relevant cues facilitates it. At the tusk level, there are structural differences between tasks for which exploration or search is the more appropriate form of information-getting behavior. When the job to be done consists of familiarizing oneself with a variety of features of a novel stimulus environment and when no active demands or constraints are placed upon the child, exploration is the appropriately dominant form of attentional activity. Beyond simple familiarization, any tasks requiring imaginative and divergent thinking may also be of this type, as perhaps are projective techniques and tasks requiring expression of feelings. However, when convergence on a correct solution to a logical problem is required, or when an optimal sequence or strategy of information acquisition for achieving a solution can be specified, then presumably search, rather than exploration, is the appropriate mode. The latter statement holds whether the task requires specific perceptual search of particular cues and dimensions or whether it requires purely logical search among symbolic alternatives at a covert level. At the temporal level, exploration occurs earlier than perceptual and logical search and usually facilitates their development. Logical search represents an elaboration of perceptual search, and usually follows it developmentally. The proposed developmental trend is microgenetic, in that it represents the history of

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the child’s growing familiarity and competence with specific situations over relatively short time periods. It is also macrogenetic, in that it represents a basic change in his generalized competence to acquire useful and orderly information from his environment. In any recurrent behavioral setting, exploration leads to habituation of attention to various features of the environment in decreasing order of their salience. This mechanism underlies the process of familiarization and schema formation and must occur at any developmental level before the individual can exert logical control over selective attention. That is, one must know where most of the landmarks are before he can make a reasoned decision to attend to particular ones. In this sense the developmental progression from some form of exploration to some form of search can be seen at almost any age in situations undergoing familiarization. The major long-term developmental trend represents in part a summation of short-term familiarization processes with increasing generalization. In this sense it is analogous to “learning to learn.” But the long-term trend also represents an ability and a choice. With age there is a gradual change in the relative frequency of use of the two modes. Not only does the child increasingly contact reinforcement because the search mode is more appropriate for god-directed information-processing, but he also acquires better means of ordering and sequencing what he knows. This advance, in turn, makes more critical each decision as to what information is needed next. Parallel improvements in memory organization enhance the need for orderly information, and the increasing number and diversity of available responses and imaginable hypotheses further compound the need to keep track of where one is in a network of possibilities. It appears that exploration-to-searchis not a model for a single major developmental reorganization of attention or a theory of discrete stages. gather these changes occur continuously in a manner that both depends an and facilitates cognitive development. Furthermore, it may be in part a matter of preference as to how much structure and organization one wishes typically to apply to the task of acquiring information. Reflective children seem to delay until at least a rough plan or algorithm is developed for sampling the information available. Impulsives, often of equal intellectual ability, nevertheless tend to approach such tasks in a less organized fashion. All of these developmental changes begin early, and play their major developmental role prior to the remarkable improvements in thinking and reasoning manifested in concrete operational thought and symbolic verbal representation. These abilities in turn require increasingly selected and refined information to process, and must depend on correspondingly improved information-acquisition skills. It appears that beginning with the earliest attentionally based schemas, children’s early intellectual competence depends to a great degree on the libera-

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tion of attentional processes from the control of stimulus salience. In its place there must be increasingly selective and logical control by considerations of informativenessand relevance. The gradual replacement of exploration by search in various tasks gives the child greater control over his environment; improves the signal-to-noise ratio in his information processing; and enhances the flexibility with which he can call upon various logical devices to cope with complexity and uncertainty. In summary, each major advance in cognitive development necessarily depends upon the availability of appropriate and orderly information. The availability of such information to the child in the last analysis depends on his growing ability to engage in selective and appropriate information-getting transactions with his environment. ACKNOWLEDGMENTS We wish to thank Ann Branden and Melody Campbell for their continuing assistance in preparing this paper. Reprints of many of the unpublished papers cited are available from the Kansas Center for Research in Early Childhood Education, Department of Human Development, University of Kansas, at cost.

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Kagan, J. Attention and psychological change in the young child. Science, 1970,170,826-832. (a) Kagan, J. The determinants of attention in infants. American Scientist, 1970, 58, 298-306. (b) Kagan, J., & Lemkin, J. Form, color and size in children’s conceptual behavior. Child Development. 1961, 32, 25-28.

Katz, J. M. Reflection-impulsivity and color-form sorting. Child Development, 197 1,42,745-754. Kendler, H. H., Glasman, L. D., & Ward, J. W. Verbal-labeling and cue-training in reversal-shift behavior. Journal of Experimental Child Psychology. 1972, 13, 195-209. Kendler, H. H., & Ward, J. W. Reversal learning: The effects of conceptual and perceptual training in the absence of differential observing responses. Psychonomic Science, 1972, 28, 346-347. Klein, S. D. A developmental study of tactual perception. Unpublished doctoral dissertation, Clark University, 1%3. Koenigsberg, R. S. An evaluation of visual versus sensorimotor methods for improving orientation discrimination of letter reversals by preschool children. Child Development, 1973, 44, 764-769.

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Lehman, E. B. Selective strategies in children’s attention to task-relevant information. Child Development, 1972, 43, 197-210. Lewis, M., & Goldberg, W. The acquisition and violation of expectancy: An experimental paradigm. Journal of Experimental Child Psychology, 1969, 7 , 70-80. Maccoby, E. E . , & Konrad, K. W. Age trends in selective listening. Journal of Experimental Child Psychology, 1966, 3, 113-122. Maccoby, E . E . , & Konrad, K. W. The effect of preparatory set on selective listening: Developmental trends. Monographs of the Society for Research in Child Development, 1967, 32(4, Whole No. 112). Mackworth, N. H. A stand camera for the line-of-sight recording. Perception & Psychophysics, 1967. 2, 119-127.

Mackworth, N. H., & Bagshaw, M. H. Eye catching in adults, children, and monkeys: Some experiments on orienting and observing responses. Research Publication of the Association for Research in Nervous and Mental Disease, 1970, 48, 201-2 13. Mackworth, N. H., & Bruner, J . S. How adults and children search and recognize pictures. Human Development, 1970. 13, 149-177. Matheny, A. P. Perceptual exploration in twins. Journal of Experimental Child Psychology. 1972, 14, 108-116.

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McKinney, J. D. Problem-solving strategies in impulsive and reflective second graders. Developmental Psychology. 1973, 8, 145. Miller, D. J. Visual habituation in the human infant. Child Development, 1972, 43, 481-493. Miller, G. A., Galanter, E., & Ribram, K. H. Plans and the strucrure of behavior. New York: Holt-Dryden, 1960. Mosher, F. S., & Hornsby, J. R. On asking questions. In J . S. Bruner, R. Olver, & P. Greenfield

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Author Index Numbers in italics refer to the pages on which the complete references are listed. A Abravanel, E., 205, 206, 207, 216,235 Anastasi, A., 58, 59,97 Anderson, J.R., 109,146 Anderson, R.C.,144,152 Anisfeld, M., 69, 98 Annett, M., 132, 146 Antonovsky, H.F., 159,188 Appel, L.F., 91,97, 112, 130,146 Appleyard, D., 21, 22, 23, 25, 26,48 Arrigoni, G., 19,48 Aspinall, P., 184,191 Assal, S.A., 19, 50 Asso, E., 39,48 Atkinson, R.C., 61, 62, 76, 97 Atteneave, F., 109,146 Auk, R.L., 169,193, 219,222,233,235,239

B Babich, J.M., 39, 53 Bach, M.J., 69, 97 Bagshaw, M.H., 205,237 Baker, A.H., 13, 42,54 B ~ Q , J.R., 7 ~ 9 7 115, , 117,119, 121,ilis Bartlett, F.C., 104, 107, 109, 114, 115, 118, 125,146 Beach, D.R., 74, 98, 158,189 Belmont, J.M., 59, 73,97, 110, 113,146,148 Bem, S., 158, 188 Benton, A.L., 19,48, 59,97 Berger, P.L., 16,48 Bergson, H., 12,48 Berko, J., 132,147 Berlyne, D.E., 197, 199,207,235 Bernbach, H.A., 75,97 Bernstein, L., 159, 176, 177, 189

Bertrand, C., 19, 50 Binet, A., 107, 115, 117, 136,146 Bjork, A.L., 63,97 Blackstock, E.G., 38,48, 111, 146 Blake, J., 180, 182, 184, 188 Blaut, A.S., 22,48 Blaut, J.M., 22,48, 54 Block, R.A., 140,149 Boersma, F.J., 167, 168,188, 192 Boies, S.J., 176, 192 Boring, R.A., 59,97 Bosco, J., 180, 182,188 Boulding, K.E., 21, 22,48 Bousfield, W.A., 81,97 Bower, G.H.,64,68,97, 109,146 Brain, W.R., 19,49 Braine, L.G., 159, 176, 177,189 Bransford, J.D., 70, 71, 97, 109, 115, 117, 121,146,147 Bray, N.W., 110,147 Brewer, W.F., 104, 107, 109, 136,147 Brian, C.R., 211,235 Broadbent, D., 61,97 Brockway, J., 124,147 Brown, A.L., 59,90,97, 105, 110, 111, 113, 119, 122, 123, 124, 125, 126, 127, 128, 130, 132, 134, 136, 137, 140, 141, 142, 143, 146, 147, 148, 150, 221,235 Brown, R., 132, 147 Bruner, J.S., 37, 49, 63, 97, 109, 147, 166, 172, 176, 183, 185, 186,191, 202, 204, 235,237

Bruyn, G.W., 19,54 Bryant, P.E., 96,98, 121,147 Bryden, M.P., 156,190 Buckhalt, 118, 150 Budin, W.A., 33, 50 Buehler. C., 58. 98 Busse, T.V.,156,190, 210, 236

24 I

242

Author Index

Buswell, G.T., 176,189 Butteffield, E.C., 59,73,97,110,113,146, 148

Crawford, D.E., 219,235 Critchley, M., 18, 19,25, 33,49 Crothers, E.J., 115,148

C

D Calfee, R.C., 176,191 Campione, J.C., 90,97, 110, 113, 140,147, 148, 207,236 Cannizzo, S.R., 74, 77,99 Carey, R.N., 43,52 Carr, S.,22 26,49 Carroll, J.B., 107,148 Carter, A.Y., 71,72,100,117,118,121,150 Case, R., 169,189 Cassirer, E., 12,32,49 Cermak, L.S.,66,98, 131,148 Chambers, R.A., 33,@ Chase, W.G., 115,148 Chemielewski, D., 124,147 Cheng, M.F., 33,49,54 Chinsky, J.M., 74,98,158,189 Christy, M.D., 223,238 Chzhi-tsin, B., 165, 172, 173, 176,193 Cirillo, L., 13,42,54 Clark, E.V., 136,148 Cofer, C.N., 124, 147,148 Coghill, G.E., 31,49 Cohen, B.H., 81, 84,98 Cohen, L.B., 104,148,207, 208,209,235, 238, 2.99 Coie, J.D., 43,49 Colby, B., 115, 118, 119, 126,148 Colby, M., 211, 212,235 Cole, M., 83,84,98,100,115,118,119,126, 148

Collins, A.M., 109,148 Colonna, A., 19,49 Coon, R.C., 229,238 Cooper, R.G., 91,97,112, 130,146 C o d , N.L., 211,212,213, 214,236 Corbin, D.W., 226,238 Cornell, E.H.,208,236 Corsini, D.A., 64, 90,98,135, 140,148 Costanzo, P.R., 43,49 Courtis, M.C., 164,190 Craik, F.I.M.,62,63, 96,98,107,108,110, 127, 130, 131,148 Craik, K.M.,22,49 Cramer, P.A., 69,98, 136,248

Daehler, M.W., 167,189 Dawes, R.M., 144,148 Day, M.C., 40,49,169,192 Deese, J., 108,148 DeGroot, A.D., 115,148 Deiktnan, A.J., 18,49 Denney, D.R., 233,236 Denney, N.W., 132,148 Denny-Brown, D.,33,49 DeRenzi, E., 19,48,40 DeRose, T.M., 130,152 Dill, A.B., 183,190 DiVesta, F.J., 66,98 Dooling, D.J., 107, 118, 144,148, 151 Dorman, C., 156, 157, 160,189 Downs, R.M., 11, 21, 22,123,26,49,54 Doyle, A.B., 162,189 Draguns, J.A., 32, 33,50 Drake, D.M., 169, 171,189,218,236 Druker, J.F., 163,189 Duncan, B., 42,49 Durford, M., 19,/9 E Eichelman, W.H., 176,192 Eimas, P.D., 96,98, 201,236 Eliot, J., 42,49 Elkind, D., 156, 157,162,189,209, 210,236 Embry, L.,214,215,239 Engel, F.L., 164,189 Entwisle, D.R., 132,148,225,236 Erickson, R.A., 184,189 Ettlinger, G., 19,34,/9,55 Evans,J.D., 157,192

F Faglioni, P., 19,49 Farnill, D., 43,49 Faulkender, P., 209,236

Author Index

Fehr, F.S., 78,99 Feinberg, L.D., 33,50 Felzen, E., 69,98 Fillenbaum, S.,107,149 Finley, G.E., 207,236 Fischer, K.W., 35, 36,50 Fishbein, H.D., 42,50 Fisher, M.A., 207,236 Fitch, J.P., 87,100,111, 151 Flavell, J.H., 32, 33,50, 73, 74,77, 78,79, 80,81, 87, 91,92, 93,97,98,99,100, 105, 110,111, 112, 113, 126, 127, 130, 133, 134, 135, 137, 142,146,146,148, 149, 150,151, 158,189,191 Fogel, M.L., 19,& Forsman, R., 159,171, 176,189 Forsyth, D.F., 132,148 Fozard, J.L., 141,150 Fraisse, P., 121, 122,126,149 Frankel, F., 83,98 Frankel, G.W., 223,238 Franks, J.J., 70, 71,97, 115, 117, 121,146 Frase, L.T., 144,149 Freedman, J., 24,50 Freeman, F.N., 41,50 Freund, J.H., 69,98 Friedrichs, A.G., 78, 92,98, 112, 113,133, 135,149 Furst, C.J., 173,189

243

Goldberg, W., 208,237 G o b , E.S., 159, 162, 190 Gomulicki, B.R., 104,149 Goodenough, F.L.,211,235 Goodnow, J.J., 202,236 Goodovitch, E.,22, 50 Gospodinoff, E.J., 212, 213, 214,236 Gottschalk, J., 156,190 Gould, J.D., 183,190 Goyen, J.D., 176, 177,190 Grabbe, W., 207,236 Gray, C.R., 181, 182,190 Green, R.T., 164,190 Greenfield, P.M., 109,147,202,235 Grinder, R.,31,50 Gummerman, K., 162, 181, 182,190,191 Guzman, R.D., 204,226,238

H

Haber, R.B., 202,256 Haber, R.N., 24,37,50,177, 184,190,202, 236 Hagen, J.W., 73, 75, 76, 77,78,91,98,99, 110, 126, 133,149,163,189,190, 191 Haith, M.M., 176, 177, 180, 182,184,190, 191, 225, 226,236 Hale, G.A., 163,190 Hale, G.H., 204, 227,296 Hales, J.J., 201, 216, 217, 236 G Hall, J.W., 69,98 Hall, R.J., 18,50 Gaines, R., 211,212,214, 215,216,236 Galanter, E., 109, 111, 127,150,198,202, Halperin, M.S.,69,84,98,99 Halwes, T.G., 81,91,100,158,191 230,297 Hansen, D.N., 75, 97 Galloway, C., 212,236 Gelber, E.R., 104,148,209,255 Hansley, C., 156,190,210,296 Ghatala, E.S., 130,152 Hargrave, S.,77,98 Ghent, L., 19,53,54,159, 176,178,188,189 Harlow, H. F., 68,99 Gholson, B.,201,236 Harrington, D.O., 185,190 Gibson, E.J., 39,50, 164, 175,189,190 Harris, L.J., 13, 19, 43, 50, 160,190 Gibson, J.J., 39,50, 189,190 Hart, R.A., 13,22,50 Gilliard, D.M., 90,97,140,147 Hebb, D.O., 174,190 Gladwin, T., 10,23, 26,29, 30,50 Hecaen, H., 19,50 Glasman, L.D., 204,237 Henri, V., 107,117, 137,146 Gliner, C.M., 201, 215, 216,217,224,236, Herrick, C.J., 15, 31,50 299 Herrick, C.L.,31,50 Gloning, K., 18,50 Hershenson, M.,24,37,50 Go, E., 162,189 Hetzer, H., 58,98 Goggin, J., 68,98 Hintzman, D.L., 140,149

244

Author Index

Hochberg, J., 162, 164, 174, 175,185, 186, 190 Hoff, H., 18,50 Holmes, D,L., 184, 185,190 Horowitz, L.M., 125,149 Hornsby, J.R., 233,237,238 Howard, I.P.,13,50 Hoyt, J.D., 78, 92,98, 112,113, 133, 135, 149 Huggins, W.H., 225,236 Hultsch, D.F., 86,99 Hunt, J. McV., 207,236 Hunter, I.M.L., 118,149 Hunter, W.S., 67,58,99 Hutt, C., 197,237 Huttenlocher, J., 37, 42,47,50,51 Hyde, T.S.,127, 128,149 I Inhelder, B., 13,25, 32, 37, 40,41, 43,52, 104, 108,109, 111, 113,114, 116, 116, 122, 126, 132,149,150, 169,190,205, 238 J

Jablonski, E.M.,81,99 Jackson, J.H., 13, 14, 18,51 Jacobus, K.A., 90,98,140,148 Jambor, K., 33, 34,55 James, M., 19,25, 54 James, W., 61,99,149 Jeffrey, W.E., 81,100,169, 174,176,191, 193, 199,203,219,222,235,237,239 Jenkins, J.J., 104, 113, 116, 117, 125, 126, 127, 128, 130, 135, 145,149 Johnston, C.D., 127,149 Johnston, D.M., 184,191 Johnston, J.W., 69,98

Kaplan, Bernard, 17,36,51, 55 Kaplan, Bert, 17,51 Kaplan, S.,21,22, 51 Kaprove, B.H., 87,100, 111,151 Katz, J.M., 212, 214,215,237 Keeney, T.J., 74,77, 99 Keiffer, K., 42,50 Kendler, H.H., 204,237 Keogh, B.K., 38,51 Keogh, J., 38,51 Keppel, G.,64,99 Kerr, J.L., 183,191 Kershner, J.R., 42,51 Kimura, D.,19,49 King, W.L., 38,48,111,146 Kingsley, P.R., 75, 76, 77, 91,98,99 Kintach, W., 84, 90,99 Kirasic, K.C., 39,53 Klein, K., 207, 215,239 Klein, S.D.,214, 215, 216,237 Kluver, H., 37,51 Kobaaigawa, A.,83,88,89,99,101, 111,149 Koegler, R., 162,189 Koenigsberg, R.S., 221,287 Kofsky, E., 169,191 Konrad, K.W., 221,237 Kreutzer, M.A., 91,92,93,99, 105, 110, 112,142, 146,149 Kroes, W.H., 66, 67,99 Krueger, F.,32,51 Kugelmass, S.,156, 157, 160,191,210,237

L

Lackman, R., 144,148 Ladd, F.C., 21,22,26, 38,51 Lakowski, R., 184,191 Lampel, A.K., 125,149 Lang, N.J., 157, 165, 176,192 Lange, G.W.,82, 83,86,99 Lashley, K.S., 36,51 Laurence, M.W., 86,99 Laurendeau, M., 13,51 Layne, D., 207,236 Lazar, M.A., 209,235 K Lee, T.R., 21, 22, 26,51 Kagan, J., 132,149,207,213,216,225,236, Lehman, E.B., 223,237 Lemkin, J., 213, 215,237 237 Lemond, L.C., 170,192,197,238 Kahneman, D., 177,191 Leonard, C., 90, 91, 92, 93,99, 105, 110, Kail, R.V., 66,67,78,98,99 112, 142, 146,149 Kant, I., 12,51

Auihor Index

Leonard, D.S., 140,148 Leonard, S.D., 90,98 Leslie, R., 176,191 Levin, J.R., 130,152 Levine, L., 67,99 Levine, M., 201,236 Levy, J., 19,51 Lewis, M., 208, 231,237 Lewis, N., 231,238 Lewis, S., 42,50 Libby, W.L., 66,99 Liberty, C., 86,99 Lieblich, A., 157, 160,191,210,237 Lhs, P., 177, 180, 182,192 Livingston, R.B., 27, 46,51,52 Locke, J.L., 78,99 107,108,110, Lockhart, R.S., 62,63,96,98, 127,130,131,148 Lofius, E.F., 109, 118,149,150 Lord, A.B., 119,150 Lowenthal, D., 22,52 Lowrey, R.A., 22,52 Luchins, A.S., 133,150 Luckmann, T., 16,48 Luria, A.R., 19,25, 33, 47,52 Lyle, J.G., 176, 177,190 Lynch, K., 16,21,22, 24, 26,30,39,49,52

M Maceoby, E.E., 162, 163,191,221,237 Mackworth, J.F. 166, 176,191 Mackworth, N.H., 172, 176, 183, 185, 186, 191,204, 205,218,287 Mahoney, G.J., 118,150 Malmo, R., 19,50 Mandler, G., 35,52,63,86,87,99,100, 128, 150 Markman, E.M., 112,150 Matheny, A.P., 210,287 Matheny, A.P., Jr., 167, 160,191 Martin, A.L., 140,150 Maslow, A.H., 58, 99 Mason, P.L., 89,101 Masur, E.F., 79,100,113,150 Mathews, M.E., 141,150 Mayner, M A , 128,151 McBane, B.M., 131,150 McCarrell, N.S., 91,97,109,112, 130,146, 147 McCandless, B.R., 8

245

McCleary, G.S., 22,48 McCluskey, K.A., 219,237 McFie, J., 19,52 McGurk, H., 221,237 McIntyre,~C.W.,79,100, 113,150 McKinney, J.D., 231,287 Meacham, J.A., 77,98, 105, 110,126, 127, 133, 135,142, 144,150 Meili, R., 162,191 Meisbov, G., 77,98, 133,149 Menzell, E.W., 22,52 Meyer, P.A., 181, 182,198 Michels, K.M., 173,193 Middleton, D.B., 83, 99 Miller, D.J., 203,237 Miller, G.A., 109, 111, 127,150, 175,191, 198,202, 230,287 Miller, L.K., 181, 182, 185,191 Milner, E., 33,512 Mindes, P., 182,184,190,225,236 Minnigerode, F.A., 43,52 Mistler-Lachman, J.L., 108,150 Moely, B.E., 79,81,83, 86, 91,100,101, 158,191 Moore, G.T., 13,22,50 Monty, R.A., 18,50 Morandi, A.J., 183,191 Morgan, J.S., 163,190,204, 227,286 Morrison, F.J., 176, 177, 182, 184,185,190, 191, 225,236 Mosher, F.S., 233,237 Moshier, C., 66,98, 131,148 Moss, H.A., 132,149 Mountcastle, V.B., 19,52 Moynahan, E.D., 92,100,113,150 Munroe, R.H., 37,52 Munroe, R.L., 37,52 Munsinger, H., 162, 176,177,191 Murphy, M.D., 119,123,124,125, 126, 127, 128, 130, 132, 141, 143,147,150 Muus, R., 132,148

N Nadelman, L., 67,100 Neimark, E.D., 80,100,231,238 Neisser, U.,104,107,150 Nelson, K.E., 140,150 Nelson, K.J., 111, 132,150 Nerlove, S.B., 37,52

Author Index

246

Newcombe, F., 19,52 Newcombe, G., 19,55 Nodine, C.F., 157, 158, 164, 165, 176,192 Norman, D.A., 61, 63,101,104,150,184, 192 Noton, D., 173,192 Novikoff, A.B., 31,52 Nuessle, W., 231,238 Nunnally, J.C., 170,192, 197,238 0

O'Bryan, K.G., 167,188,192 Odom, R.D., 204,226,229,238 Oliver, R.R., 109,147,202,235 Olson, D.R., 168,192,231,238 Olson, F.A., 79,81,91,100,158,191 Ornstein, P.A., 86,99 Osgood, C.E., 66,100 Osser, H.A., 39,50, 164,189 Overcast, T.D., 132,147 Overton, W.F., 20,52 P Paivio, A,, '127,128,150 Pancratz, C.N., 209,288 Paris, S.G., 71, 72,100,117, 118, 119, 120, 121, 126, 144,150 Parker, R.K., 169,192 Parsons, J., 169,193, 222,239 Pascual-Leone, J.A., 45,52, 169,192 Paterson, A., 19,25, 52 Pearlstone, Z.,84,101 Peiper, A., 33,52 Pender, N.J., 66,67,100, 131, 132,150 Penfield, W.,19,50 Petre, R.D., 212,236 Phillips, S., 201, 236 Piaget, J., 13,25,32,37,39,40,41,43,52, 104, 108, 109, 111, 113, 114, 115,116, 121,122, 126,132,145,119,151, 169, 171,190,192, 205,212,238 Pick, A.D., 13,39, 50, 136,148, 164,189, 201,216, 217,223,236,238 Pick, H.L., 41,53, 201, 216,217,236 Piercy, M.F., 19,52, 53 ' Pinard, A., 13,51 Piper, R.A., 163,190 Plum, G.E., 220,239 Pollack, R.H., 180,182,192

Posner, I.M., 176,192 Posner, M.I., 132,151 Postman, L., 126, 127, 130,151 Presson, C.C., 37,51 Pribram, K.H., 109,111,127,150,198,202, 230,237 Pushkina, A.G., 165,166, 172,192

Q Quaterman, C.J., 132,151 Quillian, M.R., 109,148

R Rabinovitch, M.S., 156,190 Rand, G., 22,53, 161,168, 169, 176,192 Reed, M., 119, 121,I46 Reese, H.W., 20,36,52,53,73,74,95,100, 110,151 Reid, M., 71,97 Reitan, R.M., 19,53 Reitman, W.,104, 111,151 Reutener, D.B., 132,151 Riegal, K.F., 132,151 Riegal, R.M., 132,151 Riggs, L.A., 183,192 Riley, C.A., 96,100 Ritter, K., 87, 100, 111, 151 Robertson, J., 211,212,235 Rochford, G., 33,53 Rohwer, W.D., 110,151 Rosenberger, M.A., 18,50 Rosner, S.R., 85,100 Ross, W., 77,98 Rossi, E.L., 77,82,100 Rossi, S.I.,82, 83,100 Rothkopf, E.Z., 144,151 Rozin, P., 33,49, 54 Rubin, S.M., 65,100 Rudel, R.G., 19,53 Rumelhart, D.E., 184,192 Ruzskaya, A.G., 174,193 Ryan, B.A., 167,188

S Sagotsky, G., 66,98,131,148 Sander, F., 32,53 Sanders, A., 183,184,192 Savoiardo, M., 19,/9 .

247

Author Index

Schadler, M., 21, 41, 42, 44, 53 Schaller, M.J.,160, 190 Schilder, P., 32, 39, 53 Schissler, D., 22, 26,49 Schneirla, T.C., 31,53 Schroll, J.T., 66, 99 Scott, A.L., 90,97 Scott, K.G., 221,235 Scott, M.S., 140, 147 Scotti, G., 19,49 Scribner, S., 84,100 Scriven, M., 107,151 Semmes, J., 19, 53, 54 Shantz, C.U., 37,53 Shapiro, S.I., 83, 85, 100, 101 Sharp, D., 83,98 Sheingold, K., 176, 177, 182, 184, 185,190, 192, 225, 226,236, 288 Shemyakin, F.N., 13, 21, 24, 25,32, 37, 38, 40, 42, 44, 45, 53 Sherrington, C.S., 14, 53 shif, Z.I., 112, 122,151 Shiffrin, R.M., 61, 62,97 Sieber, J., 112, 151 Siegel, A.W., 21, 39, 41, 42, 44, 53, 163, 192, 213, 215, 216, 2.98 Siegelman, E., 169,192, 218, 219,238 Sigel, I.E., 132, 149 Simon, H.A., 115,148 Sims-Knight, J., 91,97, 112, 130, 146 Slobin, D.I., 121, 151 Slotnick, N.S., 80, 100 Smdey, S.S., 132,147, 222, 224,238 Smirnov, A.A., 106,110, 116,126,127, 128, 130, 144, 151, 152 Smith, A., 45, 53 Smith, H.K., 132,151 Smith, J., 52 Smith, V., 19, 53 Smothergill, D.W., 38, 53 Spencer, H., 12, 53, 54 Sperber, R., 207,236 Sperling, G.A., 61,100, 154, 177,192 Spiker, C.C., 73,100 Spinnler, H., 19,49 Spitz, H.A., 154,192 Spitz, H.H., 134, 151, 173, 181, 182,192, 193 Standing, L., 177,190 Stark, L., 173, 192 Stea, D., 11, 21, 22, 23, 26,49, 54

Stephens, D., 86, 87,100 Steuerle, N.L., 157, 158, 165, 176,191 Stevenson, H.W., 73, 101, 163, 192, 193 Strang, H.R., 160,193 Strauss, M.S., 208, 236 Strommen, E., 43, 50 Suchman, R.G., 211,238 Suci, G.J., 66, I00 Sulin, R.A., 107, 118,151 Szeminska, A., 25, 40, 41, 43, 52

T Takanishi, R., 125,149 Tannenbaum, P.H., 66,100 Tarakanov, V.V., 165, 172, 173, 176,198, 205,239 Tarshes, E.L., 19,53 Taylor, A.M., 19, 5.4 Taylor, R.L., 179, 192 Taylor, S.E., 176, 193 Teegarden, L., 157, 198 Teitelbaum, P., 33,49, 54. Templeton, W.B., 13, 50 Tenney, Y.H., 93,101, 110, 113, 133,151 Teman, L.M., 58,101 Teuber, H.L., 19,53, 54 Thor, D.H., 180, 181, 182,198 Thurstone, L.L., 59, 101 Tiffany, P.G., 212,238 Tinker, M.A., 176,193 Tinklepaugh, O.L., 58,101 Tolman, E.C., 21, 26, 54 Trabasso, T., 96,98, 100, 121,147, 211,288 Trask, F.P., 140, 141,152 Tresch, M., 214,239 Tresselt, M.E., 128, 151 Trowbridge, C.C., 21,54 "ulving, E.,85,101, 108, 124, 136, 151 Tumolo, P.J., 89, 101

U Uhling, H., 58,99 Ulrich, T., 80, la, Underwood, B.J., 64,68, 69, 97, 99, 101, 140,151, 152 Upton, L.R., 119, 121, 150 Urbano, R.C., 221,235

Author Index

248

Y Vance, B.J., 213, 215, 215,288 Van Chzhi-tsin, 206,289 Vaughan, M.E., 82,83,101 Venger, L.A., 160, 169,171, 174,198 Vignolo, L.A., 19,49 Vinken, P.J., 19,54 Vlietstra, A.G., 214, 215,227, 289 von Bertalanffy, L., 35,54 von Uexkull, J., 39,54 von Wright, J.M., 141,151 Vurpillot, E., 158, 160, 167, 171,198, 217, 289

Wilcox, B.L., 110,147 Williams, M.,33,53,55 Wilton, K.M., 168,188 Winograd, T., 115,152 Wittlinger, R.P., 65,101 Wittrock, M.C., 82, 83,100 Wohlwill, J.F., 22,55, 154, 159, 163, 185, 192 Woodward, M., 33,55 Wright, J.C., 209, 214, 215,219, 224,230, 286, 237,289 Wyke, M., 34, 39,4.8,55

Y

W Wagner, J.F., 66,67,101, 131, 132,152 Waldron, A., 209,286 Wambold, C., 113,148 Wapner, S.,13,42,54,161, 168, 169,176, 192 Ward, J.W., 204,2897 Warren, H.C., 27,54 Warren, R.E., 132,151 Warrington, E.K., 19,25,54 Warrington, F., 19,49 Watson, J.S., 37,58 Watts, G.H., 144,152 Waugh, N.C., 61,63,101 Weinstein, s., 19,58, 54 Weir, M.W., 222, 224,229,232,238,239 Weiss, J., 156, 157,189, 209,286 Welsant, R.F., Jr., 181, 182,192 Werner, H.,13, 17,32,36, 37, 54, 55 Werner, O., 118,152 Wetherford, M.J., 207,289 White, S., 96,101 White, S.H.,200,201, 220, 221, 229,232, 289 Whitmarsh, G.A., 81,97 Whitty, C.W. M.,19,52,55 Wickens, D.D.,64,66,68,70,72,98,101, 132,152

Yarbus, A.L., 4Q,55,164,193 Yates, F.A., 143,152 Yendovitskaya, T.V., 106, 116, 119, 122, 126,127, 128, 130, 131, 143,152, 174, 198

Yntema, D.G., 140, 141,152 Yonas, A.,175,189 Yoshimura, E.K., 83,101 Yussen, S.R.,91,97, 112,130,146,152, 222,228,239

2

Zangwill, O.L., 19,25,49,52, 55 Zanni, G., 118,150 Zaporozhets, A.V., 24,40,55,174,198,205, 206,207,289 Zeaman, D.,131,150,207,286 Zelniker, T., 169,198, 222,289 Zimmerman, 111, 140 Zinchenko, P.I.,106, 110,116, 126, 127, 128,130, 144,151,152, 206, 206,259 Zinchenko, V.P., 165, 172,173,174, 176, 198

Ziobrowski, M., 132,148 Zupnick, J.J., 181,182,192 Zusne, L., 173,193

Subject Index

A

F

Activity, memory for, 126-131 Adults, formation of spatial representations by, 25-30 Acquisition strategies, in memory, 73-80 Associative processes, in selective attention, 200-202 Attention, see Selective attention Attributes, in encoding, 64-70

Form, see also Shape in selective attention, 211-215 Free recall, of categorizable stimuli, 81-84 H Habituation tasks, selective attention in, 207-209

C

Cognitive processes, in selective attention, 200-202 Color, in selective attention, 211-215 Comparison tasks, visual scanning and, 171-172 Comprehension, in memory, 107-108 Context interference, visual scanning and, 161-163 Context support, visual scanning and, 160-161 Cue preference tasks, selective attention in, 211-217 D Dimensional preference tasks, selective attention in, 211-217 Discrimination tasks, selective attention in, 217-225

I Ideas, memory for, 116-117 Instructions, selective attention and, 223-225, 227-229 Intelligence, memory and, 113-115 Intention, in memory, 107-108

J Journal acceptance rates, 2

K Knowledge, spatial, see Spatial representations

L

E Encoding, in memory, 63-72 Exploration, see under Selective attention

Labeling, in recall, 75-78 Learning mechanisms, for spatial representations, 2 6 3 0 Locomotion, in formation of spatial representations, 26

249

Subject Index

250

M Macrospace models, 21-22 elements of, 23-26 functions of, 22 Manuscripts, 1-8 classification of, 3-7 journal acceptance rates for, 2 Matching tasks selective attention in, 217-225 visual scanning and, 171-172 Meaning, memory and, 115-131 Mediation, 135 Memory, 57-101, 103-152 acquisition strategies in, 73-80 comprehension, retention and intention in, 107-108 definition of, 104-105 deliberate, 106, 131-134 skills for, 110-113 developmental model of, 134-145 encoding and representation in, 63-72 episodic and semantic, 108- 109,134-137, 139- 145 as goal, 106-131 historical perspective, 57-59 information processing approach to, 59- 60 involuntary, 106, 113-134 models of, 60-63 reproductive versus retonstructive, 107 retrieval strategies in, 80-90 selective attention in, 225-229 self-awareness in, 90-94 Modeling, selective attention and, 227-229

N Naming tasks, selective attention in, 209-210 Narratives, memory for, 119-126 Novelty tasks, selective attention in, 207-209

0 Organizational processes, in memory, 80-90 P Pointing tasks, selective attention in, 209-210

R Recall of categorizable stimuli, 81-84 selective attention in, 225-229 serial, 75-78 Reconstructive processes, 107 Rehearsal, in recall, 75-78 Representation, see also Spatial representations in memory, 63-72 Reproductive processes, 107 Retention, 107-108 Retrieval strategies, 80-90 S

Scanning, see Visual scanning Search, see under Selective attention Selective attention, 196-239 cue and dimensional preference tasks and, 211-217 discrimination and matching tasks and, 217-226 exploration versus search in development of, 198-202 distinction between, 197-198 formalized search strategies and, 229-233 free exploration tasks and, 204-207 habituation and novelty tasks and, 207-209 memory and recall tasks and, 225-229 pointing and naming tasks and, 209-210 Self-awareness, in memory skills, 90-94 Semantic integration encoding as, 70-72 in involuntary memory, 117-119 Shape, see also Form in selective attention, 215-217 Spatial representations, 9-55 adaption and, 30-31 developmental parallelisms and, 31-34 main sequence and, 3456 development of, 17 in adults, 25-30 in children, 3745 learning mechanisms in, 26-30 locomotion and, 26 dissolution of, 17-20 models of macrospace, 21-22 elements of, 23-25

Subject Index

functions of, 22 philosophical and neurological considerations, 11-16 symbolized space, 16-17 Stimuli categorizable, free recall of, 81 -84 visual scanning and, 158- 163 Stimulus manipulation, selective attention and, 220-223, 225-227

T Texture, in selective attention, 215-217 Training, selective attention and, 223-225, 227-229

25 1

v Verbal labeling, in recall, 75-78 Verbal mediation, in recall, 73-74 Visual scanning, 153- 193 exhaustiveness and efficiency of, 170- 175 field of view and, 182-186 focus on informative portions in, 163-167 speed of, 175-182 systematic strategy for, 156- 159 context interference and, 161-163 context support and, 160-161 stimulus structure and attributes and, 159-160 viewer's questions during, 167- 170

Contents of Previous Volumes Volume 1 Responses of Infants and Children to Complex and Novel Stimulation Gordon N. Cantor Word Associations and Children’s Verbal Behavior David S. Palermo Change in the Stature and Bod] Weight of North American Boys during the Last 80 Years Howard V. Meredith Discrimination Learning Set in Children Hayne W . Reese Learning in the First Year of Life Lewis P. Lipsitt Some Methodological Contributions from a Functional Analysis of Child Development Sidney W. Bijou and Donald M. Baer The Hypothesis of Stimulus Interaction and an Explanation of Stimulus Compounding Charles C.Spiker The Development of “Overconstancy” in Space Perception Joachim F. Wohlwill Miniature Experiments in the Discrimination Learning of Retardates Betty J . House and David Zeaman AUTHOR INDEX-SUBJECT INDEX

Volume 2 The Paired-Associates Method in the Study of Conflict Alfred Castaneda Transfer of Stimulus Retraining in Motor Paired-Associate and Discrimination Learning Tasks Joan H. Cantor The Role of the Distance Receptors in the Development of Social Responsiveness Richard H.Wahers and Ross D. Parke Social Reinforcement of Children’s Behavior Harold W. Stevenson Delayed Reinforcement Effects Glenn Terrell 252

A Developmental Approach to Learning and Cognition Eugene S. GoNin Evidence for a Hierarchial Arrangement of Learning Processes Sheldon H. White Selected Anatomic Variables Analyzed for Interage Relationships of the Size-Size, SizeGain, and Gain-Gain Varieties Howard V . Meredith AUTHOR INDEX-SUBJECT INDEX

Volume 3 Infant Sucking Behavior and Its Modification Herbert Kaye The Study of Brain Electrical Activity in Infants Robert I. Ellingson Selective Auditory Attention in Children Eleanor E. Maccoby Stimulus Definition and Choice Michael D. Zeiler Experimental Analysis of Inferential Behavior in Children Tracy S. Kendler and Howard H. Kendler Perceptual Integration in Children Herbert L. Pick, Jr., Anne D. Pick, and Robert E. Klein Component Process Latencies in Reaction Times of Children and Adults Raymond H. Hohle AUTHOR INDEX-SUBJECT INDEX

Volume 4 Developmental Studies of Figurative Perception David Elkind The Relations of Short-Term Memory to Development and Intelligence John M . Belmont and Earl C.Bunerfield Learning, Developmental Research, and Individual Differences Frances Degen Horowitz

Contents of Previous Volumes Psychophysiological Studies in Newborn Infants S.J. Hurt, H.G. Lenard, and H.F.R. Prechtl Development of the Sensory Analyzers during Infancy Yvonne Brackbill and Hiram E. Fitzgerald The Problem of Imitation Justin Aronfreed AUTHOR INDEX-SUBJECT INDEX

Volume 5 The Development of Human Fetal Activity and Its Relation to Postnatal Behavior Tryphena Humphrey Arousal Systems and Infant Heart Rate Responses Frances K. Graham and Jan C. Jackson Specific and Diversive Exploration Corinne Hun Developmental Studies of Mediated Memory John H.Flavell Development ~d Choice Behavior in Probabilistic and Problem-Solving Tasks L.R. Goulet and Kathryn S. Goodwin AUTHOR INDEX-SUBIECT INDEX

Volume 6 Incentives and Learning in Children Sam L. Witryol Habituation in the Human Infant Wendell E. Jeffrey and Leslie B. Cohen Application of Hull-Spence Theory to the Discrimination Learning of Children Charles C. Spiker Growth in Body Size: A Compendium of Findings on Contemporary Children Living in Different Parts of the World Howard V. Meredith Imitation and Language Development James A. Sherman Conditional Responding as a Paradigm for Observational, Imitative Learning and VicariousReinforcement Jacob L. Gewirtz AUTHOR INDEX-SUBJECT INDEX

253

Volume 7 Superstitious Behavior in Children: An Experimental Analysis Michael D. Zeiler Learning Strategies in Children from Different Socioeconomic Levels Jean L. Bresnahan and Martin M. Shapiro Time and Change in the Development of the Individual and Society Klaus F . Riegel The Nature and Development of Early Number Concepts Rochel Gelman Learning and Adaptation in Infancy: A Comparison of Models Arnold J . Sameroff AUTHOR INDEX-SUBJECT INDEX

Volume 8 Elaboration and Learning in Childhood and Adolescence William D. Rohwer, Jr. Exploratory Behavior and Human Development Jum C . Nunnally and L. Charles Lemond Operant Conditioning of Infant Behavior: A Review Robert C. Hulsebus Birth Order and Parental Experience in Monkeys and Man G . Mitchell and L. Schroers Fear of the Stranger: A Critical Examination Harriet L. Rheingold and Carol 0.Eckerman Applications of Hull-Spence Theory to the Transfer of Discrimination Learning in Children Charles C. Spiker and Joan H. Cantor AUTHOR INDEX-SUBJECT INDEX

Volume 9 Children’s Discrimination Learning Based on Identity or Difference Betty J . House, Ann L. Brown, and Marcia S. Scott

254

Contents of Previous Volumes

Two Aspects of Experience in Ontogeny: Development and Learning Hans G . Furth The Effects of Contextual Changes and &gee of Component Mastery on Transfer of Training Joseph C . Campione and Ann L. Brown

Psychophysiological Functioning, Arousal, Attention, and Learning During the First Year of Life Richard Hirschman and Edward S. Katkin Self-Reinforcement Processes in Children John C. Masters and Janice R. Mokros AUTHOR INDEX-SUBJECT INDEX

A 5 8 6

c 7

D B E 9 F O G 1

H 2 1 3 1 4