Attention Limits

Broadly defined, attention is the focus of cognitive resources on processing information. Research on attention addresses the following questions: (a) What initiates the focus of cognitive resources on objects of psychological concern? (b) What causes the focus of cognitive resources to shift from one object to another? (c) How many objects, or how much information, can be kept in cognitive focus at one moment in time?

The psychological study of attention has investigated the three questions of initiation, change, and capacity of cognitive focus at many levels of information processing. At the lowest level are studies of how cognitive resources are focused when processing sensory information in the visual, auditory, olfactory, gustatory, and tactile domains. At the highest level are studies of cognitive focus on the rich, meaningful content of human thought that underlies making complex, real-world decisions such as those involved in medical diagnosis and treatment.

Attention has relevance to medical decision making at many levels of information processing. At the lowest level of information processing, attention supports a physician's detection of the physical characteristics of a patient that lead to a medical diagnosis of the patient's condition. This might include visual information about the patient's coloration; auditory information from their heartbeat, breathing, and gastrointestinal processes; and tactile and olfactory information that are unique to the patient's condition.

The important factors that initiate attention and limit the capacity of a medical decision maker's attention to sensory input are different from those for simple sensory events in abstract laboratory studies. Whereas the physical characteristics of a stimulus (such as its intensity and duration) have been shown to influence attention in simple laboratory tasks, a medical decision maker's expertise (as defined by his or her background, beliefs, and understanding) creates a mental model (or a schema) that plays a central role in determining what information, and how much information, the decision maker attends to and how that information is interpreted.

A medical decision maker's expertise also plays a central role in determining what information he [Page 37]or she pays attention to when using executive, cognitive processes, in the absence of sensory input, to reason through a patient's medical conditions either to arrive at a diagnosis or to select a treatment program. The interplay between a decision maker's mental model of a medical problem and the effect of that mental model on directing the decision maker's attention is very important. The importance of the interplay is shaped by (a) a limit on how much information a decision maker can hold in mind at one moment (also known as span of apprehension) and (b) the need of the decision maker to incorporate the most relevant and important information within the span of his or her limited attention if he or she has to make a wise decision.

The practical importance of attention limits on medical decision making is great. Since 1956, psychologists have recognized that the capacity of human attention, or the span of human apprehension, is limited to between five and nine items. Thus, a decision maker presented with a complex medical problem is unlikely to be able to incorporate all the available information about that problem into his or her cognitive focus. Because of these limits, it is exceedingly important that the decision maker has sufficient expertise to prepare him or her to attend to the most important information. Otherwise, the quality of a medical decision is likely to be compromised by being based on a small set of less relevant information. The long medical education, internship, and residency that most doctors go through help develop and hone their mental models for making good medical decisions.

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