ATTENTION

the concentration of awareness on some phenomenon to the exclusion of other stimuli. In everyday waking life, attention is discontinuous, being interrupted by periods of absentmindedness and reverie. Attention is also selective, being focused on only a small set of the wide range of stimuli presented, and it is partly determined by motivational states. Severe pain, for example, may be ignored during the exigencies of battle or heroic acts. in psychology, the concentration of awareness on some phenomenon to the exclusion of other stimuli. Attention is awareness of the here and now in a focal and perceptive way. For early psychologists, such as Edward Bradford Titchener, attention determined the content of consciousness and influenced the quality of conscious experience. In subsequent years less emphasis was placed on the subjective element of consciousness and more on the behaviour patterns by which attention could be recognized in others. Although human experience is determined by the way people deploy attention, it is evident that they do not have complete control over such deployment. There are, for example, times when an individual has difficulty in maintaining as much attention on a task, a conversation, or other set of events as he would desire. At other times an individual's attention is captured by an unexpected event rather than voluntarily directed toward it. Attention has to do with the immediate experience of the individual; it is a state of current awareness. There are, of course, myriad events taking place in the world all of the time, impinging upon people's senses in great profusion. There are events taking place within the body affecting attention, and there are representations of past events stored away in memory but accessible to awareness under appropriate circumstances. At first sight it might be expected that current awareness is the totality of all those events at any given moment, but clearly this is not the case. Within this vast field of potential experiences an individual focuses uponor attends tosome limited subset, which constitutes the subjective field of awareness. It is possible to determine the reason for this limitation. Control and coordination of the many inputs and stored experiences and the organization of appropriate patterns of response are the province of the brain. The brain has impressive processing capabilities, but it has a limited capacity. A person simply cannot consciously experience all of the events and information available to him at any one time; nor is it possible to initiate at the same time an unlimited number of different actions. The question becomes one of how an appropriate subset of inputs, intermediate processes, and outputs are selected to command attention and engage available resources. Attention, then, may be conceived as a condition of selective awareness, governing the extent and quality of man's transactions with his environment, although it is not necessarily held under voluntary control. Some of the history of attention and the methods by which psychologists and others have come to characterize and understand it are presented in the discussion that follows. Additional reading D.E. Broadbent, Perception and Communication (1958), presents an approach that uses communication theory; D.R. Davies and G.S. Tune, Human Vigilance Performance (1969), is a review of vigilance research and theory; Daniel Kahneman, Attention and Effort (1973), is a textbook on the psychology of attention, with particular emphasis on selective and intensive dimensions; Steven W. Keele, Attention and Human Performance (1973), gives an account of human information processing and attention in relation to memory storage and retrieval; David I. Mostofski (ed.), Attention: Contemporary Theory and Analysis (1970), is a collection of papers on key issues; Raja Parasuraman and D.R. Davies (eds.), Varieties of Attention (1984), is a comprehensive series of review papers covering the major psychological and physiological aspects of attention; Carl M. Stroh, Vigilance: The Problem of Sustained Attention (1971), is an account of the factors influencing vigilance, its physiological correlates, and theories of vigilance performance. Current contributions of experimental psychologists can be found in the volumes entitled Attention and Performance, a collection of papers presented at various international symposia, beginning in 1966. W. Cheyne McCallum