Experts and Expert Systems
The study of expertise covers remarkably diverse domains, such as sports, chess, music, medicine, and
the arts and sciences, and examines the entire range of mastery from beginners to world-class per-
former. . . . Very high levels of achievement in virtually all domains are mediated by mechanisms
acquired during an extended period of training and development.
—K.A. Ericsson (2005)
In the previous chapters in this part, we have discussed the processes involved in attention, memory,
and thought, with a special empha sis on how people are limited in their ability to process
information. In Chapter 9, we discu ssed the limited capacity that people have for attending to
multiple sources of information. In Chapter 10, we emphasized that similar capacity limitations
inﬂuence our ability to retain and perform computations in working memory and retrieve informa-
tion in long-term memory. In Chapter 11, we showed that a person’s ability to perform abstract
reasoning is also limited, and because of these limitations, human reasoning relies heavily on
simplifying heuri stics and past experience.
Despite their informat ion-processing limitations, people can become highly skilled in speciﬁc
domains. An expert in a domain solves problems much faster, more accurately, and consistently than
does a novice. The question of how experts differ from novices, and therefore how novices can be
trained and supported to perform like experts, is a central concern for human engineering. As we will
see in this chapter, differences in performance between novices and experts do not seem to arise from
differences in general ability, but rather from the expert’s specialized knowledge (Ericsson, 2006b).
Experts see problems differently from novices and use different strategies to obtain solutions.
This chapter focuses on how people acquire specialized knowledge and how this knowledge
affects their information processing and performance. We will examine the way speed and accuracy
of performance varies as a function of how a task is learned and practiced. In order to explain and
understand the effects of training, it is useful to consider several different perspectives of skill
acquisition. A fundamental strategy that helps us understand what expertise really is to compare
expert and novice performance on a task. These comparisons can reveal why experts are able to
think more efﬁciently and how novices may best be trained.
Large, complex systems often require expertise to operate and to troubleshoot problems.
However, experts are usually in high demand and may not be available when the need arises.
Consequently, expert systems have been designed to help novices perform those tasks usually
performed by experts. These computer-based systems are designed from of our understanding of the
knowledge and reason ing processes that experts use in problem solving. This understanding, of
course, derives from research on the skilled performance of experts. Eberts et al. (1987, p. 985)
noted, ‘‘To design more effective expert systems, we must understand the cognitive abilities and
functioning of human experts.’’ In this chapter, we will also describe the characteristics of
expert systems and the crucial roles that human factors specialists can play in the development,
implementation, and evaluation of such systems.
Proctor/Human Factors in Simple and Complex Systems ER411X_C012 Final Proof page 315 28.2.2008 7:26pm Compositor Name: JGanesan