The Psychology of Perception

A Philosophical Examination of Gestalt Theory and Derivative Theories of Perception

D. W. Hamlyn

• Publisher: Routledge
• Year: 2017
• Topic: Psychology
• eBook ISBN:
  9781315473277
• Subtopic: Cognitive Psychology & Cognition
• Index: Psychology

Originally published in 1957, the primary aim of this study was to shed light upon the logical character of the psychology of perception. D.W. Hamlyn begins by delimiting the field of psychological inquiry into perception, then gives a detailed account of the types of explanation appropriate in the field. He maintains that these explanations have certain important peculiarities which distinguish them from other scientific inquiries. In view of the central importance of Gestalt Theory in this field an account is given of its origins, and its main features are critically discussed. The work should still be of considerable interest to both philosophers and psychologists, as well as to all those interested in the relations between the two subjects.

Chapter One
Introduction

THE layman often receives the claim of the psychologist to be concerned with the subject of perception with surprise, if not with scepticism. This is partly, no doubt, due to the fact that he has in his mind certain stereotyped ideas about what the psychologist is and is not; there is a popular confusion, for example, between the psychologist and the psychotherapist. I suspect, however, that there are other grounds for the popular scepticism with regard to the psychologist and the subject of perception. Is not the psychologist concerned with the ways in which the mind works? And surely perception cannot be one of the ways in which the mind works? It is sometimes suggested that the investigation of the problems of perception is the province of the physiologist who is concerned with the workings of our sense-organs and their stimulation by stimuli from without. For the basic conditions under which perception takes place are that there should be sense-organs and that they should be stimulated. Philosophers down the ages, too, have been concerned with perception. Their theories have not appeared to be like those of the physiologist (although Descartes and Locke, for example, felt it necessary to mention what they called ‘animal spirits’ and the working of the nerves). In general philosophers have asked what we perceive; whether we are justified in saying that we perceive things or something else instead, such as sensations or sense-data, which are the means of our getting to know about things. Sometimes the physiologist’s story has been regarded as relevant here; it has for instance been claimed that because, ultimately, all perception occurs when our sense-organs are stimulated, we cannot really be said to perceive the objects which are the source of the stimulation, but only the sensations which are caused by this stimulation. Clearly it is the task of the philosopher to sort out and evaluate such conclusions as this. But where is there room here for the psychologist?

It must be admitted that it was once the case that there was little to distinguish the philosopher from the psychologist. Before the middle of the nineteenth century the main psychological investigations were carried out by philosophers, and there was an inevitable confusion of problems and techniques. When physiology began to emerge as a full-grown science, there was another intermingling of problems and techniques, and, strangely enough, as I shall indicate in brief later, the findings of physiology were originally thought to confirm the theories of the philosopher-psychologists. As a rule the philosophers maintained that it is our sensations that we perceive and that all these sensations are distinct and separate; the physiologists thought that their findings corroborated this theory.

At the end of the nineteenth century there were reactions against these views, and it was out of these reactions that the modern psychology of perception was bom. The psychological theories of perception of today all have their roots, in one way or another, in Gestalt Theory. This is generally recognized. It has not been so often recognized that Gestalt Theory had its roots in its own past. There has in fact been a conservatism of approach to the subject and there has been little attempt to consider what questions the psychologist ought to ask with regard to perception. The questions have been taken as self-evident, the answers as needing investigation. When the questions have themselves been made the subject of question the traditional (i.e. the nineteenth-century) viewpoint has been adopted. At the present time psychology is in the paradoxical position of taking up a genuinely independent attitude towards the subject of perception, without it yet being clear what questions are being asked or ought to be asked. There is necessarily a cleavage between techniques and individual investigations and findings on the one hand, and general theoretical pronouncements on the other.

Some questions which psychologists ask are purely factual. What colours can various animals see? Does the brightness or dimness of the illumination make any difference to what colours we can see, and what difference? What other factors affect what colours we can see? And so on. Some of these questions can be answered as a result of common-or-garden observation, others need more involved or experimental techniques. Sometimes theories are constructed to explain the findings, and in the cases corresponding to the questions noted above the theories are generally physiological in character. Thus the various theories of colour-vision which have been propounded have generally been physiological theories about the mechanisms through which we receive our impressions of colour. For this reason colour-vision and the like haye sometimes been thought of as the province of the physiologist. Yet reflection might lead one to think that there are further complexities here. Is perception merely a matter of having the requisite sensory equipment? Surely there are numbers of things which we do not perceive, not because we have not the requisite sense-organs, but because we are not paying attention, or for some similar reason. (The Gestalt Psychologists have pointed out that we do not generally perceive as such the gaps between things.) If a psychologist wants to find out whether an animal can perceive red things, he will have to make the animal perform some task which it is in general capable of performing, but which on this occasion depends upon its perceiving a red thing as being red. To put this in other words, the animal is required to recognize a red thing, to distinguish it from things of different colours, or, to use the psychologist’s jargon, to discriminate it. But to recognize something as what it is, to distinguish it from other things, may require practice; it is something which animals and human beings may have to learn to do. It is only after considerable experience that a child can recognize its parents and distinguish them from other people. It may seem that redness is a simple property, that recognition of it should be immediate; but it is impossible for something to possess the property of redness alone, and a thing which is different from others near it in respect of redness may be different from them in other respects also. Thus the physiological theories of colour-vision, which concern themselves with the characteristics of our eyes as sense-organs, cannot be sufficient to explain how an animal or person can recognize things of a particular colour or distinguish them from others.

The philosopher does not seem to be concerned here. He is not concerned with how we can recognize things as possessing one characteristic as distinct from another, but with the grounds which we have for saying that they have characteristics at all, and with the question of whether we really know that they do. (I do not intend to say anything here about these epistemological questions, or how they are to be answered. I merely want to indicate the fact that they differ from the other kinds of question under consideration.) There seems, therefore, to be a genuine class of questions which are neither the province of the physiologist nor that of the philosopher. Why not, then, of the psychologist? To say that these questions are the province of the psychologist is to say nothing as to how they are to be answered; it is merely to delimit the field. Nevertheless, the fact that the questions with which the psychologist might be expected to deal are questions concerned with recognition, discrimination and the like may serve to show that the psychology of perception is not so far from the popular conception of psychology after all. Might not an account of our recognition and distinguishing of things be described as an account of some of the ways in which our minds work? Moreover, the explanations which may be given of our recognition of things or of our distinguishing them from others are likely to be different from those appropriate to colour-vision simpliciter. They are not, that is, likely to be physiological in character.

What I have said so far may serve to indicate that the term ‘perception’ may not denote a single concept, but rather a family of concepts, which, whilst related, need to be distinguished from each other. In other words, the term ‘perception’ may signify, not just one thing, but a number of different, albeit related, things. It is important to point this out because psychologists sometimes indulge in a conceptual inquiry (an inquiry, that is, into what sort of thing perception is, or what the term ‘perception’ signifies), whilst giving the impression that they are doing something of a different kind. Thus we may be told that perception is an interaction between the organism and the environment, or that it is an achievement. And it is sometimes claimed that psychological discoveries, even empirical discoveries, are relevant to such characterizations. Whatever is the merit, however, of saying that perception is, for example, an interaction between the organism and the environment, it is clear that to say this is to say something about a concept, for it is to give an elucidation of what we mean when we say that someone perceives something. To this the empirical findings of psychology are relevant only in the most indirect way. That is to say that as a result of a factual investigation a person may incidentally come to understand something about what is meant by ‘perception’, but only in the ways in which he would come to do so, and perhaps more quickly, by a direct conceptual investigation, a direct inquiry into what we mean when we say that we or other people perceive something. On the other hand it is sometimes said that empirical findings are absolutely irrelevant to conceptual questions, and this would be grossly misleading if it were taken to mean that no conceptual statement made by an experimental psychologist is worth listening to. Indeed the refusal of the facts to fit in with their theories sometimes forces upon people the realization that their understanding of the concepts involved has been at fault. Thus a conceptual discovery may result incidentally from an empirical inquiry.

It remains true that a statement of the form ‘Perception is-------’ is a conceptual statement, no matter who makes it. Everyone knows what it is to perceive something, in the sense that he has first-hand experience of it. Not everyone knows how to give an account of it. In saying ‘Perception is------------’ the psychologist does not mean to tell us what we know already; he means to tell us something which perhaps we did not know. Knowledge of the facts would be required by a man who really did not know what it was like to perceive something. This ignorance is not merely an ignorance of what exactly anyone is saying when he says, ‘Yesterday I saw Mr. Smith’, but an ignorance which arises from a lack of acquaintance with the phenomena. If there were such a man, a man who was imperceptive in the strictest sense, the question ‘What is perception?’ would be to him like the question ‘What is a pterodactyl?’ to many of us; only more so, in that we can at least find out what a pterodactyl is like by means of pictures or descriptions, even if it is not possible for us to meet one, whilst our hypothetical man cannot even do this. To us, however, the question ‘What is perception?’ cannot have such a point. We all have experience of perception, but we may not know how to describe it or give an account of it; we may not have a full understanding of the concept of ‘perception’. It is here that the philosopher has his say.

It follows, then, that the dicta of psychologists which are of the form ‘Perception is--------------’ are not necessarily to be received with the respect which is always due to the facts; for no facts are here at stake. We have noted already that when questions are asked about the facts they are not always of the same kind. Sometimes the psychologist may ask, for example, what colours an animal can see (i.e. distinguish from each other) in general. Sometimes he may ask, given that the animal can see a certain number of colours, under what conditions it will see any particular colour. Even in the latter case a number of general conditions may have to be stated in order to specify the case. In addition to saying ‘given that the animal can see a certain number of colours’ it may be necessary to add ‘and given that it is paying attention, is not asleep, is sufficiently interested in colours as opposed to other qualities’ and so on. Reference to attention, the state of mind of the animal, its motivation and the like, is reference to general conditions which must hold if any psychological function is to go on. Whilst it is worth while referring to such general conditions on occasion, in case they should be forgotten, it is also worth while remembering that they are general. Nothing particular is pointed out by such reference to general conditions, and this fact limits the explanatory force of such reference. It is a truism to say that a man will not do something unless, in some sense, he wants to, although it is far from a truism to say that he will do some particular thing only when he wants something very badly. Again, the statement that a man will distinguish something from other things only when he is paying attention can likewise be construed as a truism; it is not a truism to say that he will do so only when he is paying attention to a certain degree. The concepts of attention and perception are closely connected, so that to indicate such a connection is to make at the most the minimum of a factual discovery, and indeed the discovery may be conceptual and not factual at all. The latter will be the case if we are not prepared to allow anyone to say of anyone else that he perceived something unless he was paying attention to it.

Experiments have been carried out in which some emotionally-charged word is exposed to a subject for a very short time in a tachistoscope, and it sometimes happens that the subject is unable to report seeing anything, although other tests (e.g. by means of the psychogalvanic reflex) may indicate that he has been emotionally roused. It has sometimes been suggested that we should call this ‘unconscious’ or ‘subliminal’ perception. The reverse may be true in other cases; a subject may be able to recall something of which he was unaware at the time, something to which he was not paying attention. It might be said here that perception can occur without any attention being paid to the object. In the first case, that the subject might be said to have paid some attention to the word might be inferred from the fact that he was emotionally aroused, in spite of his not being able to report having perceived the word. In the second case, that the subject might be said to have perceived the object might be inferred from the fact that he remembered it, in spite of his not, as it seems, having paid attention to it at the time. In each case there is an ostensible conflict between the conditions which are applicable. As I have said, in the first case it has been suggested that we should talk of ‘unconscious’ or ‘subliminal’ perception, and to do so is to decide that attention is the governing factor. In the second case we might be inclined to say that the subject must really have paid some attention to the object, just because we also wish to say that he must have seen it if he now remembers it. In either case a decision is being made, a decision to maintain the connection between the concepts of ‘perception’ and ‘attention’, although in the first case a qualification is made by the addition of such words as ‘unconscious’ to ‘perception’.

It is important to note, however, that the facts force us to make a conceptual decision; they do not reveal a factual connection or the lack of it between perception and attention. Yet, when we approach the facts with relatively fixed concepts, it may be that our view of the facts will require alteration. Thus in the second of the cases described above our decision to maintain the conceptual connection between perception and attention forces us to say that the subject must have paid attention, in spite of there being no evidence of this. It is always possible for the general conditions under which perception takes place to be written into our conceptual framework; perception generally occurs, for example, only when we are paying attention, and we may be prepared to say that this must necessarily be so. It is just this sort of development and application of a conceptual framework that tends to be involved in the construction of a theory. Yet, as I shall go on to show, the notion that a scientific theory of perception can be constructed involves serious difficulties.

Chapter Two
Explanation in the Psychology of Perception

FIGURE 1

IN the first chapter I referred to the general conditions which may have to be noted in relation to perception. As opposed to these general conditions there may be particular conditions of our perceiving things in a particular way. But here difficulties begin to arise by reason of the fact that the ways in which we may perceive something can be divided into two classes—the right ways and the wrong ways. Indeed, one way of perceiving something—the right way—may be distinguished from all others. It is clear that we can, in principle, always say something about the ways in which we may perceive things wrongly, for this is just to say something about the conditions under which illusions come into being. For example, in the light of the Muller-Lyer illusion (Figure 1) we can say that two lines of equal length look of different length (or, in other words, we see them as of different length) when, for example, they are furnished with arrowheads, as in the diagram. That is to say that we can state what precise factors may make them look different from their normal or correct length (I shall refer to such a case as Case (a)). On the other hand, if (Case (b)) we are asked under what conditions lines of equal length look of equal length, the only possible answer must be ‘Under any conditions except those which tend to make them look different’, and this is only another way, a negative way, of saying ‘Under normal conditions’. Indeed, to talk of lines of equal length looking of equal length at all is odd, for we usually use such words as ‘looks’, ‘appears’ and ‘seems’ in order to make a contrast with what is actually the case. Here no such contrast is being made. This help...

Table of contents

• Cover
• Half Title
• Title
• Copyright
• Original Title
• Original Copyright
• CONTENTS
• EDITORIAL PREFACE
• 1 INTRODUCTION
• 2 EXPLANATION IN THE PSYCHOLOGY OF PERCEPTION
• 3 THE HISTORICAL BACKGROUND OF GESTALT PSYCHOLOGY
• 4 GESTALT THEORY
• 5 FURTHER DEVELOPMENTS
• 6 FUNCTIONALISM
• 7 CONCLUSION
• BIBLIOGRAPHY
• INDEX