The need to represent and integrate large amounts of presented information
internally is common to a wide range of different types of expertise. Charness
(1989) showed that expertise at the game of bridge was closely linked with the
capacity to generate successful plans for playing the cards in the optimum
order. In medical diagnosis, the medical expert has to integrate many different
pieces of information that are not simultaneously available perceptually. The
internal representation of the presented medical information must be suffi-
ciently precise to allow extensive reasoning and evaluation of consistency, but
also must be sufficiently flexible to allow reinterpretation as new information
becomes available (Lesgold et al., 1985; Patel & Groen, 1991). Anzai (1991)
reviews the critical role of effective representations in solving physics problems
and how methods of generating such representations can be developed through
practice. In order to account for expertise, it is essential to describe emerging
skills for managing extended memory demands, as well as their efficient pro-
cessing and manipulation.
Comments on the Problem of Accounting for Expert Performance.Chaseand
Simon (1973) may have been correct in their claim that access to aggregated
past experience is the single most important factor accounting for the develop-
ment of expertise. More recent research, however, shows that to describe the
structure of expertise accurately, several other factors must be considered,
ranging from acquired skill allowing for an extended working memory to in-
creased physiological efficiency of the motor system due to adaptation to in-
tensive practice. We believe that the research on superior expert performance is
benefited more by the development of a taxonomy of different types of mecha-
nisms acquired through different types of learning and adaptation processes
than by restricting the definition of expertise to a specific type of acquisition
through learning.
Summary and Conclusion
In this chapter we initially contrasted the study of expertise with a number of
other approaches studying outstanding and superior performance, and we
found that one distinguishing feature was the claim that the superior perfor-
mance was predominantly acquired. Drawing on the pioneering work on chess,
we identified three important steps in the study of expertise: first, identification
of a collection of representative tasks by means of which the superior perfor-
mance of experts can be reproduced; second, analysis of the cognitive processes
mediating that performance, followed by design of experimental tasks to elicit
the critical aspects of such performance in a purer form; third, theoretical and
empirical accounts of how the identified mechanisms can be acquired through
training and practice.
The most effective approach to organizing the results across different domains
of expertise is to propose a small number of learning mechanisms that can ac-
count for the development of similar performance characteristics in different
domains within the limits of human information capabilities. There is now
overwhelming empirical support for the theory of acquisition of skill with
mechanisms akin to those originally proposed by Chase and Simon (1973). They
Prospects and Limits of the Empirical Study of Expertise 545