Direct Perception Claire F Michaels LAKE FOREST COLLEGE Claudia Carello UNIVERSITY OF CONNECTICUT PRENTICE-HALL, INC, Englewood Cliffs, New Jersey 07632 ii Library of Congress Cataloging in Publication Data Michaels, Claire F. (1948) Direct perception. (Century psychology series) Bibliography: p. Includes index. 1. Perception. 2. Environmental psychology. I. Carello, Claudia, joint author. 11. Title. BF311.M496 153.7 80-28572 ISBN 0-13-214791-2 Editorial production/supervision and interior design by Edith Riker Manufacturing buyer Edmund W. Leone In Memory of JAMES JEROME GIBSON (1904-1979) CENTURY PSYCHOLOGY SERIES James J. Jenkins Walter Mischel Willard W. Hartup Editors ©1981 by Prentice-Hall, Inc., Englewood Cliffs, N.J. 07632 Copyright tranferred to authors. All rights reserved. No part of this book may be reproduced in any form or by any means without permission in writing from the authors. Printed in the United States of America 10 9 8 7 6 5 4 3 2 1 Prentice-Hall International, Inc., London Prentice-Hall of Australia Pty. Limited, Sydney Prentice-Hall of Canada, Ltd., Toronto Prentice-Hall of India Private Limited, New Delhi Prentice-HaH of Japan, Inc., Tokyo Prentice-Hall of Southeast Asia Pte. Ltd., Singapore Whitehall Books Limited, Wellington, New Zealand iii Contents Credits vi Preface vii 1 CONTRASTING VIEWS OF PERCEPTION 1 Indirect Perception: The Theory of Impoverished Input, 2 Direct Perception: The Ecological View, 9 Additional Contrasts, 13 Summary, 16 Overview of the Book, 17 iv 2 INFORMATION AND THE ENVIRONMENT 19 Invariants, 19 Environment, Information, and Animals, 37 Summary, 39 3 3 INFORMATION AND THE ANIMAL 41 Affordances, 42 The Relation Between Perceiving and Acting, 47 Affordances in the Human-Made Environment, 54 Affordances and Constraints on Learning, 56 Summary, 58 4 DETECTION OF IN FORMATION 61 Biology of Knowing, 62 Attention: The Control of Detection, 69 Learning, 76 Summary, 82 5 PHILOSOPHICAL IMPLICATIONS OF ANIMAL-ENVIRONMENT SYNERGY 85 Realism, 86 Describing Reality and Describing Knowledge, 97 Evolutionism, 106 Summary, 111 v 6 APPLICATIONS 1 15 Binocular Stereopsis, 116 Perceiving the Age of a Face, 122 Action, 133 Summary, 152 7 SUMMARY AND CONCLUSIONS 155 The Ecological Approach: A Summary, 156 Direct and Indirect: A Reconciliation?, 164 The Future of the Ecological Approach, 165 APPENDIX: DISCUSSION AND DEBATE 171 REFERENCES 189 NAME INDEX 197 SUBJECT INDEX 199 vi Credits Figure 3-1. From Karl von Frisch Bees: Their Vision, Chemical Senses, and Lan­ guage. Copyright ©1971 by Cornell University. Used by permission of the publishers, Cornell University Press and Jonathan Cape Limited. Figure 3-2. From C. S. Holling. "The Analysis of Complex Population Processes." Canad. Ent. 1964, 96, 335-347, Figures 4 and 5. Reprinted with permis­ sion of the publisher and author. Page 88 and Appendix. We thank Herbert Kaufman for permitting us to quote the perception book he is writing. He also reviewed the first four chap­ ters and provided several questions in the Appendix. Figure 6-3. From R. E. Shaw, M. McIntyre, and W. Mace. "The Role of Symmetry in Event Perception," in R. MacLeod and H. Pick (Eds.): Perception: Es­ says in Honor of James J. Cibson. Ithaca, New York: Cornell University Press, 1974. Copyright ©1974 by Cornell University. Figure 6-4. From R. E. Shaw and J. B. Pittenger. "Perceiving the Face of Change in Changing Faces: Implications for a Theory of Object Perception," in R. E. Shaw and J. Bransford (Eds.): Perceiving, Acting, and Knowing. Hillsdale, New Jersey: Lawrence Erlbaum Associates, 1977. Figure 1. Figure 6-5. Courtesy of Leonard Mark and Jim Todd. Figure 6-6. From J. B. Pittenger and R. E. Shaw. "Aging Faces as Viscal Elastic Events: Implications for a Theory of Nonrigid Shape Perception." Journal of Experimental Psychology: Human Perception and Performance, 1975, 1, 374-382. Copyright (1975) by the American Psychological Association. Reprinted by permission. Figure 6-7. From J.B. Pittenger, R. E. Shaw, and L. S. Mark. "Perceptual Informa­ tion for the Age Level of Faces as a Higher-Order Invariant of Growth." Journal of Experimental Psychology: Human Perception and Performance, 1979, 5, 478-493. Copyright (1979) by the American Psychological As­ sociation. Reprinted by permission. Figure 6-8. From R. E. Shaw and J. B. Pittenger. "Perceiving the Face of Change in Changing Faces: Implications for a Theory of Object Perception," in R. E. Shaw and J. Bransford (Eds.): Perceiving, Acting, and Knowing. Hillsdale, New Jersey: Lawrence Erlbaum Associates, 1977, Figure 4. vii Preface There is a movement afoot in psychology. In its early days it was known as the theory of direct perception; it is now known more gener­ ally as the ecological approach. Its main assumption can be (over)simplified as follows: The phenomena of psychology reside i n animal-environment systems, not merely in animals. A seed of this thought was planted by J. J. Gibson in 1950 and carefully tended and nurtured by his further works in 1966 and 1979 and by the works of others. It has flourished; its roots are starting to crack some of the phi­ losophical bedrock under psychology and its branches are reaching out to influence the entire field. We believe that the ecological approach should be the wave of the future for psychology and we have tried to muster a cogent case for its serious consideration. The ecological position may appear at first glance to be unorthodox, but it is the inevitable consequence of phi­ losophical and scientific commitments that are themselves very diffi­ cult to undermine. This book explores those commitments and the ap­ proach to perception that they entail. Our central goal was to present these fundamentals in a clear way. We tried to be explicit about where we were going and why, where we arrived and how, often pausing along the way to take stock of our progress. We think that this, taken together with carefully cho­ sen examples and metaphors, makes the approach readily understand­ able. The style of presen­ viii tation makes the ecological approach accessible to students, but at the same time the book's content should stir even the most sophisticated professional. Even if the reader ultimately rejects the ecological approach, adopting it momentarily provides a unique perspective on the field of psychology. It brings into bold relief many of the tacit assumptions of traditional (non-ecological) psychology. Making these assumptions more visible permits their analysis, criticism, and defense. Whether or not the ecological movement holds sway in the decades to come, a se­ rious consideration of the approach and of the controversies it raises cannot fail, in the long run, to improve our science. Many individuals and institutions have helped us with the book. A Lake Forest College grant-in-aid and a University of Connecti­ cut Predoctoral Fellowship supported the early phases of our work. The following people provided various degrees of comment, criticism, en­ couragement, and manuscript preparation: Jean Cranston, Roger Faber, Linda Ferrell, Jean Hardisty, Petie Harlan, Herbert Kaufman, Robert Michaels, Katrina Young, and, of course, our parents. Special thanks go to Michael Turvey, William Mace, and Robert Shaw, who read many versions of the manuscript, fleshed out and in­ terpreted much of the theory explained here, and made every effort to insure that we have not misrepresented the ecological view. Our grati­ tude to Turvey and Shaw comes from far more than their inspirational and editorial efforts on this book, but we will forego the effusive praise they deserve—it would only make them uncomfortable—and thank them with a case of Guinness. Our Century Psychology Series sponsor and editor, James Jen­ kins, was a joy to work with. He was a thoughtful (though prompt) and thorough (though gentle) critic. We are also tempted to thank Jimmy Gibson here but, after all, this book is our thanks to him. C.F.M. and C. C. 1 Contrasting Views of Perception An animal’s most commonplace successes in behaving give witness to the vastness and accuracy of its perception of its environment. A hu­ man, for example, usually walks without stumbling, normally grasps an object without toppling it, and often recognizes a friend even after decades. Such behaviors all illustrate that perceivers know their envi­ ronments well. It is this fact that theories of perception, ultimately, should explain. The routes taken to explanation may be different, but the goal, we believe, is to account for the fact that animals perceive their surrounds sufficiently to guide discriminating actions (moving among surfaces without collision, catching prey, following verbal in­ structions, and so on). A theory of perceiving, then, is a theory of knowing the environment. While theories of perception can be sorted into categories accord­ ing to various criteria, one set of distinctions, central to this book, sets the theory of direct perception apart from the more conventional ap­ proaches to perception. In this chapter, we examine these distinctions and thereby provide a contrast between the two classes of theories, for the contrast itself reveals much about the theory of direct perception. James Gibson and those who follow his approach adopt an eco­ logical stance: they believe that perceiving is a process in an animal- environment system, not in an animal. Proponents of the ecological view argue that 2 perception is, quite simply, the detection of information. This approach is labeled direct because a perceiver is said to perceive its environment. Knowledge of the world is thought to be unaided by inference, memo­ ries, or representations. Conversely, a second family of theories con­ ceives of perception as mediated—or, to contrast it with Gibson’s the­ ory, indirect— and is so called because perception is thought to involve the intervention of memories and representations.