Theories of Visual Perception This thoroughly revised and expanded edition of Theories of Visual Perception contains critical accounts of the major approaches to the chal- lenge of explaining how we see the world. It explains why approaches to theories of visual perception differ so widely and places each theory into its historical and philosophical context. Theories of Visual Perception begins with a discussion of the hierarchical status of theories of perception and the impact of technological and meth- odological developments, giving the reader a clear understanding of the background to the subject. It provides accounts of the major theories of visual perception, ranging from early theories by some of the most influen- tial writers in perception, such as Helmholtz and the Gestalt School, to recent work involving computer models of vision and cognitive brain imaging. Chapters cover subjects including Brunswik’s probabilistic func- tionalism, Gibson’s theory of direct perception, neurophysiology and empiricism, providing an in-depth analysis and critical appraisal of each theory. This volume provides extensive coverage of the most significant theories of visual perception, along with a valuable insight into their historical back- grounds. It will be welcomed by students and researchers in the fields of psychology, physiology and neuroscience. Ian E. Gordon has taught and carried out research in universities in Australia, Canada, New Zealand and Tianjin (where he is visiting Profes- sor). He has published numerous articles on perception and has also written on psychology and art. Theories of Visual Perception Third edition Ian E. Gordon First published 2004 by Psychology Press 27 Church Road, Hove, East Sussex BN3 2FA Simultaneously published in the USA and Canada by Psychology Press 270 Madison Avenue, New York NY 10016 This edition published in the Taylor & Francis e-Library, 2005. “To purchase your own copy of this or any of Taylor & Francis or Routledge’s collection of thousands of eBooks please go to www.eBookstore.tandf.co.uk.” Psychology Press is part of the Taylor & Francis Group Copyright © 2004 Psychology Press All rights reserved. No part of this book may be reprinted or reproduced or utilized in any form or by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval system, without permission in writing from the publishers. This publication has been produced with paper manufactured to strict environmental standards and with pulp derived from sustainable forests. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging in Publication Data Gordon, Ian E. Theories of visual perception / Ian E. Gordon. p. cm. Includes bibliographical references and index. ISBN 1-84169-383-9 1. Visual perception. I. Title. BF241.G67 2004 152.14–dc22 2004006844 ISBN 0-203-50225-6 Master e-book ISBN ISBN 0-203-59534-3 (Adobe eReader Format) ISBN 1-84169-383-9 (Print Edition) For Ross Day, scholar and enthusiast Contents Preface to this third edition ix Acknowledgements xiii 1 Theory and method 1 The calibre of scientific theories 1 The importance of methods and measurement 3 2The Gestalt theory 7 Historical background 7 A general outline of the Gestalt approach 13 Köhler’s brain model 21 A preliminary assessment of the Gestalt theory 26 Subsequent research on some of the Gestalt principles 39 3 Brunswik’s probabilistic functionalism 55 Egon Brunswik 55 A general outline of Brunswik’s work 56 The terminology of probabilistic functionalism 57 Brunswik’s lens model 60 Brunswik’s empirical researches 61 An evaluation of probabilistic functionalism 65 Final remarks on Brunswik’s theory 67 A more recent development: the empirical theory of vision 69 4 The neurophysiological approach to visual perception 73 An outline of neural function 74 Three examples of the neurophysiological approach to perceptual theory 78 viii Contents Classical computer models vs. parallel distributed networks 97 Two more recent technical developments 108 Some problems with the neurophysiological approach to perception 111 5 Empiricism: perception as a constructive process 117 Historical background 120 Gregory’s theory: perceptions as hypotheses 127 An evaluation of Gregory’s theory 132 Final remarks on empiricism 138 6 Direct perception and ecological optics: the work of J. J. Gibson 143 J. J. Gibson 143 An outline of the theory of direct perception 145 An evaluation of the theory of direct perception 159 More recent research 165 Final remarks on direct perception 180 7 Marr’s computational approach to visual perception 183 David Marr 183 The background to the artificial intelligence (AI) approach 184 Marr’s theory of vision and his programme for research 188 Applying the theory 193 Further aspects of Marr’s work 204 An appraisal of the computational approach to vision 205 8 Some final remarks on theories of visual perception 213 Evaluation of approaches to theorizing in perception 213 Other aspects of visual perception 218 The challenge of vision 220 Some of the gains made during the search for general theories 221 Problems remaining 224 Theories and the future 230 References 235 Author index 247 Subject index 251 Preface to this third edition Responses to the first two editions of Theories of Visual Perception were generally very positive. Students in five countries told the author that the book helped them to grasp the essentials of some of the various theories of visual perception. Many lecturers have adopted the book. With two excep- tions, the book received favourable reviews. A number of young researchers in artificial intelligence have reported that Theories of Visual Perception was their entry point into vision. All this has been very gratifying. Any feelings of complacency were quickly checked by some general criti- cisms from the author’s own students at Exeter University. In the main, these focused on two chapters: that on psychophysics, and that on Brunswik’s theory. To argue that the essential nature of a sensory threshold has been a subject of theoretical debate for 100 years, and that a major branch of visual research had arisen because of this debate, did not convince these young readers. After much thought, the original chapter on psychophysics has been dropped from this volume. Brunswik’s probabilistic functionalism struck many students as a real oddity. They understood the chapter on his theory, but found his own writ- ings difficult in the extreme. The chapter has been retained in this second edition for two reasons: first, because of the present author’s hunch that Brunswik may have been right in his intuitions concerning the basic nature of perception; second, because of some recent publications concerning per- ception and the statistical nature of real world events. This new work has been described in the present chapter on Brunswik’s contribution. Since the second edition of this book appeared, there has been a torrent of recently published research findings concerning visual perception. At this point it must be stressed that Theories of Visual Perception is not a textbook on visual perception per se. Rather, the book is an attempt to describe how a number of general theories of visual perception developed: their back- grounds, their underlying assumptions, their strengths and weaknesses, and their current status. For those wishing to read fuller accounts of experi- mental findings in vision research, there exist a number of remarkably good textbooks, one example being Bruce, Green and Georgeson (1996), which is the present author’s favourite. Readers should also enter the Web x Preface to this third edition for up-to-date findings in particular areas – search engines, such as Google, can be invaluable. This is the place to say something about the style of Theories of Visual Perception. When acting as a book reviewer, the present author used to take a quick glance at the References section in his review copy. This gave him a feel for the likely coverage in the book and how up-to-date this was. Any- one reading the present volume who repeats the above tactic will be struck by the large number of references to work published around the middle of the last century – a lifetime ago. There are two reasons why this is the case. The first has to do with the present author’s teaching style. The second is historical. Different academics have different approaches to the challenge of teach- ing, and there seems to be no single best one. All agree, however, that good teaching should not comprise the stuffing of students’ heads with details. What is important is to give students a framework within which they can organize their studies. As a lecturer, the present author believed that by showing students the origins of a particular theory – its philosophical and historical background, its initial emergence and development, together with the first criticisms of the theory – students would gain an understanding that would enable them to grasp with ease subsequent developments or refinements of the theory. The second reason for including much material published in the middle of the twentieth century is simply this: as we shall see, this is the period during which many theories of perception began to take shape. At the same time, psychologists began to be much more self-conscious about theories per se. Terms such as ‘hypothetical construct’ and ‘intervening variable’ were appearing in the literature for the first time. Theorizing was being taken seriously and on a scale that included memory, learning, language and perception. The organization of this third edition will now be described. Chapter 1 is an introductory chapter and begins with a general discussion of the hierarchical status of scientific theories in general and theories of perception in particular.