The Psychology of Attention

Elizabeth Styles, Elizabeth Styles

• Publisher: Psychology Press
• Year: 2006
• ISBN:
  9781135424008
• Edition: 2
• Topic: Psychology
• Subtopic: History & Theory in Psychology
• Index: Psychology

Research on attention has evolved dramatically in recent years. There are now many new ways of studying how we are able to select some aspects for processing, whilst ignoring others, and how we are able to combine tasks, learn skills and make intentional actions. Attention is increasingly seen as a complex process intimately linked with perception, memory and action. New questions are continually being addressed, for example in the area of cross modal attention, and the biological bases of attention.

After an initial consideration of what attention might be, this book charts the development in the ideas and theories which surround the field. An entirely new chapter addresses the nature of auditory attention and the question of how visual and auditory attention are combined across modalities. The problems of task combination, skill acquisition and automaticity are also considered, as well as the selection and control of action, and conscious and unconscious processing.

The Psychology of Attention, Second Edition provides a comprehensive and accessible introduction to this fascinating and rapidly developing field

1
Introduction

What is attention?

Any reader who turns to a book with the word “attention” in the title might be forgiven for thinking that the author would have a clear idea or precise definition of what “attention” actually is. Unfortunately, attention remains a concept that psychologists find difficult to define. William James (1890) told us that: “Everyone knows what attention is. It is the taking possession of mind in clear and vivid form . . . it implies withdrawal from some things in order to deal effectively with others.” However, it would be closer to the truth to say that “Nobody knows what attention is” or at least not all psychologists agree. The problem is that “attention” is not a single concept, but an umbrella term for a variety of psychological phenomena. Shiffrin (1988, p. 739) provides a more precise definition: “Attention has been used to refer to all those aspects of human cognition that the subject can control . . . and to all aspects of cognition having to do with limited resources or capacity, and methods of dealing with such constraints.” However, “all” is used twice here, suggesting that, even within this definition, there are many aspects of attention involved. There is, however, some agreement that attention is characterised by a limited capacity for processing information and that this allocation can be intentionally controlled. Desimone and Duncan (1995, p. 193) capture the properties of visual attention, and say that: “The first basic phenomenon is limited capacity for processing information. At any given time only a small amount of the information available on the retina can be processed and used.” Certainly, we have the subjective feeling that although we may be able to choose what we attend to in vision, there is a severe limitation on the amount of information that we can attend to at any one moment. We can only look in one direction at a time and only take in part of the visual scene. These are central characteristics of human performance, with which we are all subjectively familiar and for which there is a large body of empirical evidence. So, in this sense, we do know what attention is. Does this capture all varieties of attention? What if, while you look in one direction, you also listen to a conversation behind you? Can you choose to look in one direction but attend to something else “out of the corner of your eye”? To what extent can attention be allocated according to behaviourial goals? In Shiffrin’s definition, the subject is given the role of control. This is not a very scientific explanation and as we shall see in the chapters that follow, the nature of attentional control is the subject of some debate.

It is evident that “attention” is a term used to refer to different phenomena and processes, not only by psychologists, but also in common usage of the word. This seems to have been the case throughout the history of psychology. The same word is applied to different aspects of situations and experiences in everyday speech and defined differently by different psychologists. One of the reasons for the rise of the behaviourist movement in psychology was the difficulty psychologists at the turn of the 20th century were having in formulating precise definitions of terms such as “attention” and “consciousness”. Psychology had grown out of mental philosophy to become the “science of mind”, but unless it was clear what was meant by the terms used in explanations, psychology could not be truly scientific. The famous behaviourist J. B. Watson (1919) wrote:

If I were to ask you to tell me what you mean by the terms you have been in the habit of using I could soon make you tongue-tied. I believe I could even convince you that you do not know what you mean by them. You have been using them uncritically as a part of your social and literary tradition. (p.)

Behaviourism aimed to purge psychology of its use of everyday psychological terms and provide a true science of behaviour without recourse to any intervening variables in the “mind”. The problem for psychologists of the behaviourist tradition was that the “mind” was not so easy to banish from explanations of human performance. Behaviour could be scientifically observed and stimulus–response relationships discovered, but unobservable internal mechanisms such as “attention”, however poorly defined, which evidently allow adaptive goal directed behaviour could not be experimented on. They were not amenable to explanation in terms of simple stimulus response associations.

Treisman (1964d), who was one of the most important contributors to the development of theories of attention, started her paper “Selective attention in man” by saying:

Fifty years ago psychologists thought of attention as “the focalisation of consciousness” or “the increased clearness of a particular idea”. But these and other definitions in terms of mental faculties or subjective experience proved sterile for empirical research and ended in a series of inconclusive controversies. Recently interest in this problem has revived.

She goes on to identify the practical need to understand attention, the development of the information processing approach to psychology, which provides a metaphor for modelling internal processes and advances in understanding the neurophysiological bases of attention as important factors in this revival. Behaviourism fell from favour and the cognitive approach, in which humans were seen as information processors, took over as the predominant metaphor of mind. The cognitive approach provided a scientific way of modelling the intervening variables between stimulus and response. So, where are we after nearly another 50 years? This is what this book is about.

Varieties of attention

Attention is not of one kind, so rather than searching for a single definition, we need to consider attention as having a number of different varieties. Perhaps we cannot understand what attention is until we accept this. Allport (1993, p.) points out the problem that the same term “attention” refers to a wide range of situations:

It seems no more plausible that there should be one unique mechanism, or computational resource, as the causal basis of all attentional phenomena, than there should be a unitary basis of thought, or perception or of any other traditional category of folk psychology.

Let’s use a scenario from everyday life to illustrate the problem. We are out walking in a wood and I tell you that I have just noticed an unusual variety of butterfly land on the back of the leaf in a nearby tree. I point out the tree and where about the leaf is and tell you to pay attention to it. Following my instruction, you select one tree from many. You then “attend” to a particular leaf, rather than the tree itself, so presumably you and I share some common understanding of what attention is. You continue to look carefully, hoping you will see the butterfly when it moves out from behind the leaf. Now, you will try and keep your attention on that leaf so as not to miss the butterfly when it appears. In addition, you will have some expectation of what the butterfly will look like and how it may behave and be monitoring for these features. This expectation and anticipation will activate what psychologists call top-down processes, which will enable you to be more ready to respond if a butterfly appears, rather than some dissimilar animal, say, a caterpillar.

However, if while you are selectively focusing attention on the leaf an apple suddenly falls out of another part of the tree, you will be distracted. In other words, your attention will be automatically captured by the apple. In order to continue observing the leaf, you must re-engage your attention to where it was before. After a time you detect the beautiful butterfly as it flutters round the leaf, it sits a minute and you watch it as it flies away.

In this example, we have a variety of attentional phenomena that psychologists need to understand, and if possible explain, in well-defined scientific terms. We will see that no single term is appropriate to explain all the phenomena of attention and control even in this visual task. Let’s look at what you were asked to do. First of all, you translated the spoken words into an intention to move your eyes in the direction of my pointing finger. You then were able to search among the branches and leaves to attend to a particular leaf. In order to do this “simple” task, there had to be some kind of setting up of your cognitive system that enabled one tree, then the leaves rather than tree, to become the current object of processing. Finally, one particular leaf was selected over others on the basis of its spatial location. Once you are focusing on the leaf, you are expecting butterfly-type shapes to emerge and may occasionally think you have detected the butterfly if an adjacent leaf flutters in the breeze. Here the perceptual input triggers, bottom up, one of the attributes of butterfly, fluttering, that has been primed by your expectations and for a moment you are misled. The idea of “mental set” is an old one. Many experiments on attention use a selective set paradigm, where the subject prepares to respond to a particular set of stimuli. The notion of selection brings with it the complementary notion of ignoring some stimuli at the expense of those that are selected for attentional processing. What makes selection easy or difficult is an important research area and has exercised psychologists for decades. Here we immediately run into the first problem: Is attention the internal setting of the system to detect or respond to a particular set of stimuli (in our example, butterflies) the same as the attention that you “pay” or allocate to the stimulus once it is detected? It seems intuitively unlikely. Which of these kinds of attention is captured by the unexpected falling apple? We already have one word for two different aspects of the task. A second issue arises when the apple falls from the tree and you are momentarily distracted. We said your attention was automatically drawn to the apple, so although you were intending to attend to the leaf and focusing on its spatial location, there appears to be an interrupt process that automatically detects novel, possibly important, environmental changes outside the current focus of attention and draws attention to themselves. An automatic process is one that is defined as not requiring attention although, of course, if we are not certain how to define attention, this makes the definition of automatic processes problematic. Note now, another problem: I said that you have to return attention to the leaf you were watching, what does this mean? Somehow, the temporary activation causing the apple to attract attention can be voluntarily overridden by the previously active goal of leaf observation. You have remembered what you were doing and attention can then be directed, by some internal process or mechanism, back to the original task. To say that you, the subject, can voluntarily control this, as Shiffrin (1988) did in his definition, tells us nothing, we might as easily appeal to there being a little-man-in-the-head, or homunculus, on which many theories seem to rely.

To continue with the scenario, if you have to sustain attention on the leaf, monitoring for the butterfly for more than a few minutes, it may become increasingly difficult to stop your attention from wandering. You have difficulty concentrating, there seems to be effort involved in keeping to the task at hand. Finally the butterfly appears, you detect it, in its spatial location, but as soon as it flies away, you follow it, as if your attention is not now directed to the location that the butterfly occupied but to the object of the butterfly itself. The question of whether visual attention is spatially based or object based is another issue that researchers are interested in.

Of course, visual attention is intimately related to where we are looking and to eye movements, so perhaps there is nothing much to explain here, we just attend to what we are looking at. However, we all know that we can “look out of the corner of the eye”. If while you fixate your gaze on this *, you are able to tell me quite a lot about the spatial arrangement of the text on the page and what the colours of the walls are, so it is not the case that where we direct our eyes and where we direct attention are one and the same. In vision, there appears to be an obvious limit on how much information we can take in, at least from different spatial locations, simply because it is not possible to look in two directions at once. Although even when attending to one visual location, the question arises of how we selectively attend to one attribute from a number of sources of spatially coincident information, it is possible to attend to either the colour or the shape of the butterfly.

Auditory attention also seems to be limited. However, unlike our eyes, we cannot move our ears to select a location or search the environment. Of course, some animals can do this, you only have to watch an alert cat to know this. However, even though we do not physically move our ears to allow one sound source to be focused on, and therefore all sounds will be picked up, we can select what to listen to. In fact, when there are several different streams of sound emanating from different locations around us, the traffic outside, the hum of the computer on the desk, the conversation in the room next door, we do not appear to be able to listen to them all at once. Our inability to direct the auditory sensory apparatus mechanically cannot be the reason we cannot listen to two things at once. There must be another reason.

We all know that we can selectively listen to the intriguing conversation on the next table in the restaurant, even though there is another conversation, continuing on the table we are sitting at. This is an example of selective auditory attention and a version of the “cocktail party problem”. Somehow, internal processes can allow one set of auditory information to gain precedence over the rest. Listening to a conversation in noise is clearly easier if we know something about the content. Some words may be masked by other noises, but our top-down expectations enable us to fill in the gaps, we say that there is redundancy in language, meaning that there is more information present than is strictly necessary. We make use of this redundancy in difficult conditions. If the conversation were of a technical nature, on some topic about which we knew very little, there would be much less top-down expectation and the conversation would be more difficult to follow. Although we may be intent on the conversation at the next table, a novel or important sound will capture our attention, rather like the visual example of the apple falling out of the tree. However, as in vision, we are not easily able to monitor both sources of information at once, if we are distracted, we must return our attention back to the conversation.

Now we have another question: Is the attention that we use in vision the same as that that we use in audition? While it is difficult to do two visual or two auditory tasks concurrently it is not necessarily difficult to combine an auditory and a visual task. Of course, this is evolutionarily sensible. We need to know that the face we see moving in front of our eyes is the source of the words we are hearing or not, as the case may be. Attending to the moving lips of a speaker can help us disambiguate what is being said, especially in noise. We like people to look at us when they are speaking to us. While most research has been involved with vision and hearing, we can, of course, attend to smells, tastes, sensations and proprioceptive information. To date we know far less about these areas but we all know that a painful stimulus such as a bee sting will capture attention and a nagging headache cannot easily be ignored. The very term “nagging” suggests this constant reminding of its presence. Attention to pain is important for self-preservation and survival, but people with chronic pain can be compromised in performing other tasks because the pain demands attention. The question of why some tasks interfere with each other, while others seem capable of being performed independently, and how we are able to share or divide attention, may crucially depend on the modality of input and output as well as the kind of information processing that is required in the two tasks.

So, why do some tasks or kinds of processing require attention but others do not. While you were looking for butterflies, we may have been walking and talking at the same time. It is possible to continue eating dinner in the restaurant at the same time as listening to a conversation. Walking, talking and eating seem to proceed without attention, until the ground becomes uneven, a verbal problem is posed or your peas fall off your fork. At these moments, you might find one task has to stop while attention is allocated to the other. Consider learning a skill such as juggling. To begin with, we seem to need all our attention (ask yourself which kind of attention this might be) to throw and catch two balls. The prospect of ever being able to operate on three at once seems rather distant! However, with practice, using two balls becomes easy, we may even be able to hold a conversation at the same time. Now introduce the third ball, gradually this too becomes possible, although to start with we cannot talk at the same time. Finally, we can talk and juggle three balls. So, now it seems that the amount of attention needed by a task depends on skill, which is learned over practice. Once attention is no longer needed for the juggling we can attend to something else. However, if the juggler goes wrong, the conversation seems to have to stop while a correction is made to the ball throwing. It is as if attention is being allocated or withdrawn according to the combined demands of the tasks. In this example, attention seems to be either a limited “amount” of something or some kind of “effort”. Accordingly, some theorists have likened attention to resources or effort, while others have been more concerned with where a limiting attentional step operates within the processing system to select some information for further processing.

Memory is intimately related to attention. We seem to remember what we have attended to. “I’m sorry I was not paying attention to the colour of her dress, I was listening to what she said.” Although you must have seen the dress, and, in fact, assume that she was wearing a dress, you do not remember anything about it. If we want to be sure someone remembers what we are telling them, we ask them to pay attention. How attentional processing affects memory, as well as how a concurrent memory task affects attention, are other important issues. However, there is evidence that a considerable amount of processing is carried out without attention being necessary and without the subject having any memory of the event. Although the subject may not be explicitly able to recall, at a conscious level, that some particular information was present, subsequent testing can demonstrate that the “unattended” stimuli have had an effect, by biasing or priming, subsequent responses.

Note that for a stimulus to be apparently “unattended” it seems to have to be “unconscious”. This brings us to another thorny question: What is the relationship of attention to conscious experience? Like attention, consciousness has a variety of meanings. We usually say we are cons...