Attention and performance - The impact on motor control and learning

Attention has always been a topic of major interest to psychologists and motor behaviour researchers. This post on attention and performance is taken from our new book Motor Control and Learning 6th Edition.

Early research and theorising began in the 19th century (Cattell, 1886; Welch, 1898), and interest in the topic remains high today. Much of the early work involved introspection; for example, William James (1890) one of the most renowned experimental psychologists, wrote:

Everyone knows what attention is. It is the taking possession by the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought. Focalization, concentration, of consciousness, is of its essence. It implies withdrawal from some things in order to deal effectively with others.

But does everyone agree on what attention is? Many theorists, such as Norman (1976) and Moray (1970), suggested that different definitions of attention exist and people use the term in a variety of ways. Consider the task of driving a car. Drivers must be aware of a preplanned route, as well as where they currently are in relation to the route, in order to make appropriate turns at the right times. The driver must also be aware of other traffic (e.g., cars, pedestrians and bicyclists) and be capable of responding to sudden changes. The control of movement requires another type of attention, although we spend less time and energy thinking about how to coordinate our limbs in time and space as skill develops. Still, other types of attention are required to offset the mental drowsiness that accompanies long periods of driving without rest. So, as we read in the quote from William James’ description of attention, a number of features of the phenomenon are considered important and reflect various ways to think about the different types of attention that may exist.

Types of Attention

There are many different ways to view the concept of attention. One of these is the notion that attention is limited: We can attend to only one thing at a time, or think only one thought at a time. In terms of motor behaviour, we seem strongly limited in the number of things we can do at a given time as if the limits to some maximum “capacity” would be exceeded if too much activity were attempted. Another important feature is that attention is selective: We can concentrate on one thing or on something else and can freely shift attention back and forth among numerous things. Here we discuss a few types of attention that are particularly relevant in the control of motor skills. Note, however, that the topic of attention entails a very broad research area—much more than can be covered in this post.

Attention and Consciousness

Early in the history of research on human performance, as implied by James’ (1890) statement, attention was linked to the notion of consciousness, which is defined loosely as “what we are aware of at any given time.” The term “conscious,” and in particular the concept of unconscious behaviour, fell out of favour during the growth of behaviourism after the turn of the 20th century. The measurement of consciousness was troublesome because at the time the only way to understand what was “in” participants’ consciousness was to ask them to introspect, or “search their own minds” and this was far too subjective for the behaviourists’ approach to accumulating data and theorising.

Toward the end of the 20th century, however, the concept of consciousness saw a resurgence in popularity among cognitive neuroscientists and that interest continues to grow (Cohen & Schooler, 1996; Posner & Petersen, 1990). Examining brain function using methods such as fMRI (functional magnetic resonance imaging) and TMS (transcranial magnetic stimulation) has allowed scientists to measure patterns of brain activity, revealing much more objective types of information than had previously been available through methods of introspection (Baars, 1997; Chalmers, 1995; Crick & Koch, 2003; Haggard, Clark, & Kalogeras, 2002). Consciousness has also been linked to the concept of controlled versus automatic processing. Performance on various memory tests (Roediger & McDermott, 1993) and the use of process-dissociation measures (Jacoby, Ste-Marie, & Toth, 1993), suggests an independence between conscious and unconscious influences on behaviour. For example, automatic (unconscious) processing appears to be preserved well in older adults, whereas controlled (conscious) processing is quite susceptible to decline with ageing (Craik & Jacoby, 1996; Hasher & Zacks, 1988). Performance errors such as action slips (Norman, 1981) are often explained as situations in which an unconscious or automatic action has not been successfully inhibited or counteracted by conscious, controlled processing (Hay & Jacoby, 1996; Reason, 1990; Reason & Mycielska, 1982).

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Attention and Performance – Effort or Arousal

Another way to operationalise the notion of attention is based on the idea that when people perform attention-demanding tasks such as reading a challenging scientific article or diving in competitive swimming, they are expending mental effort that is revealed in various physiological measures. For example, Kahneman (1973) and Beatty (Beatty & Wagoner, 1978) have used pupil diameter, measured by special techniques that do not interfere with eye movement, as an indirect measure of attention. When participants are asked to perform various memory tasks, pupil diameter increases when they are under pressure to provide an answer; the increase is larger for more “difficult” tasks. Similarly, it is useful to consider attention as reflected by various physiological measures of arousal, a dimension indicating the extent to which the participant is activated or excited. Kahneman (1973) used physiological measures of skin resistance (resistance to a weak current passed between two electrodes on the skin decreases with increased arousal) and heart rate as indirect measures of the attention demand of various tasks.

Attention as a Capacity or Resource

Another view of attention and one that is an important component of the information-processing concepts, suggests that humans possess a limitation in the capacity (or resources) available to handle information from the environment. The idea for the concept of a limited capacity of attention is illustrated in the ability to perform two tasks simultaneously. If one activity (A) requires attention, then some (or perhaps all) of the “pool” of a limited capacity of attention must be allocated to its performance. Because the amount of this capacity is thought to be limited, some other activity (B) that also requires a certain amount of this capacity will compete with A for these limited attentional resources. When the combined need for resources exceeds the total amount of attentional capacity available, then B will interfere with the performance of A and vice versa. Interference could be demonstrated in many ways: (a) B could suffer in performance speed or quality while A was relatively unaffected; (b) B could be unaffected while A suffered; (c) both A and B could suffer; or (d) B could be prevented from occurring altogether while A was in progress. These patterns of “interference,” or competition for attentional resources, could presumably tell us something about the nature of the limitations in capacity.

Interference as a Measure of Attention

If two tasks can be performed as well simultaneously as each can be performed individually, then at least one of them does not require attention or a portion of the limited capacity. You could say that at least one of the tasks is “automatic.” On the other hand, if one task is performed less well when it is combined with some secondary task, then both tasks are thought to require some of the limited capacity. In this instance, both tasks are attention demanding. Over the past few decades, this interference criterion became the critical test of whether or not a certain task “required attention.” Although this test for attention achieved popularity during the cognitive revolution, it is not really a new research method (Welch, 1898).

Structural Interference and Capacity Interference

The simultaneous performance of two tasks can result in interference between them for a variety of reasons, only some of which would be interpretable as interference due to limitations in some central capacity (attention). To confront this problem, researchers have defined two kinds of interference: structural and capacity. Structural interference results when physical (or neurological) structures are the source of the decrement. For example, the hand can be in only one place at a time and interference between using a touchscreen in a car dashboard to make a phone call and shifting gears in a car with the same hand would be due, at least in part, to this kind of limitation and not necessarily to a limitation in some central capacity. Also, the eyes can focus at only one signal source at a time and thus detecting two simultaneous visual signals presented in widely different locations could suffer in processing speed because of a structural limitation, again not necessarily due to limitations in attentional capacity. On the other hand, when one can reasonably rule out the possibility that structural interference between two tasks is occurring, then a capacity interference—or a decrement in performance due to some limitation in central capacity (i.e., attention)—is inferred.

The concerns about “distracted driving” provide a good example of the difference between structural and capacity interference. Many countries, including the UK, have banned the use of handheld communication devices. There are strong arguments stating that the perceptual and motor requirements for communicating with the device create structural interference with the hand and eye movements required for driving. The more important problem, however, is that the task of communication is not simply a structural interference issue—hands-free communication devices also interfere with the task of driving because of the attention (capacity interference) required to use them.

Selective Attention

Very closely related to the limited-capacity view is the concept that we can direct (or allocate) attention to different inputs or tasks. Selective attention can be either intentional or incidental, depending on how a specific allocation has been achieved (Eimer, Nattkemper, Schröger, & Prinz, 1996). Intentional selection occurs when we purposefully choose to attend to one source of information (e.g., listening to the radio) while avoiding or inhibiting attention to other sources (e.g., the television or someone talking to us). An involuntary capture of attention usually occurs as a response to an external stimulus—for example, when you suddenly pay attention to a loud or pertinent sound (e.g., the sound of two cars colliding). Theorists sometimes refer to intentional selection as “top-down” processing and involuntary selection as “bottom-up” processing, to indicate that the orienting of attention is conceptual versus perceptually driven.

Selective attention is readily observed in the patterns of interference already mentioned in dual-task situations. Directing attention toward activity A may reveal deficits in the performance of task B, although no performance deficit is observed for A. However, by shifting the attention to activity B, you may observe that activity A is now the one that suffers and that performance of B is very proficient.

Theories of Attention

If attention is defined as or measured by the degree of interference between two tasks, then which kinds of tasks do and do not interfere with each other and under what conditions might these patterns of interference be expected to occur? Most of the everyday tasks we perform can be thought of as collections of processes involving stimulus input and encoding, response selection and choice and motor programming and movement control. The fact that two complex tasks interfere with each other (or do not) might not be very meaningful by itself because it would not be clear what the cause of the interference was or where in the information-processing activities the interference occurred (Jonides, Naveh-Benjamin, & Palmer, 1985). Did the two tasks require response-selection activities at the same time, or did they require movement programming at the same time? As a result, simpler laboratory tasks are used often in this research so that the various processing stages can be more specifically identified and studied. To find out more about theories of attention Motor Control and Learning, 6th Edition will explain the patterns of interference found in performing these types of tasks, using various hypothetical structures and processes. The textbook looks at Single-Channel, Filter Theories, the Keele’s Late-Filter Theory and the Stroop Effect.

Summary

Even though attention has had a long history of thought in psychology, we are still unclear about its nature and the principles of its operation—indeed, even its definition. Many theorists think of attention as a single, undifferentiated, limited capacity to process information; others argue that attention is really a number of pools of capacity, each specialised for separate kinds of processing. The successful performance of various tasks together is presumably limited by these capacities; therefore, attention demand is usually estimated indirectly by the extent to which tasks interfere with each other. Processing of sensory stimuli (or performing other processes early in the sequence) can apparently occur in parallel, with little interference from other tasks. But processes associated with response selection or with response programming or initiation interfere greatly with other activities.

Characteristics of attention play an important role in motor performance. Psychological refractoriness—the delay in responding to the second of two closely spaced stimuli—provides evidence that some single channel, or bottleneck, in processing exists in the response-selection or response-programming stage, before which processing is parallel and after which processing is serial. Other limitations in attention, such as the Stroop effect, inattentional blindness and inhibition of return, reveal that attending selectively to some information may have consequences that are not intentional.

Other evidence, based on secondary-task techniques, suggests that attention demands are highest at both the initiation and termination stages of movements, particularly when the end of the action has an important precision component. The use of cell phones and other in-vehicle devices during driving provides an excellent example of attentional limits on daily activities. Some evidence suggests that directing one’s attention to movement or environmental cues may differ according to one’s skill level.

A person’s focus of attention (concentration) has an important influence on both performance and learning. An external focus on the intended movement effect results in greater movement effectiveness and efficiency, compared with an internal focus on body movements. Directing attention to one’s own movements disrupts automaticity. In contrast, an external focus promotes the use of the motor system’s automatic control capabilities.

Arousal and anxiety influence performance. The mechanisms that appear to limit performance under stress are related to perceptual inefficiencies, the selection of inappropriate actions, and disruptions of movement automaticity and fluidity.