mance of the expert depends on the recognition of familiar patterns that index
previously stored relevant knowledge of successful methods (actions), the time-
consuming process of becoming an expert would consist in acquiring those
patterns and the associated knowledge. Simon and Chase (1973) estimated that
around 3,000 hours are required to become an expert, and around 30,000 hours
to become a chess master. They also commented that ‘‘the organization of the
Master’s elaborate repertoire of information takes thousands of hours to build
up, and the same is true of any skilled task (e.g., football, music). That is why
practiceis the major independent variable in the acquisition of skill’’ (p. 279).
Whether or not one agrees with the Chase and Simon theory of expertise, it
would be unwise to confound the methodology of their research with the the-
oretical assumptions of their specific theory. Indeed, Chase and Simon (1973)
were rather cautious when they proposed their theory, describing it as simply a
rough first approximation.
The Three Steps of the Original Expertise Approach
From our review of the pioneering research on chess expertise we have extracted
three steps. The first step involves capturing the essence of superior perfor-
mance under standardized laboratory conditions by identifying representative
tasks. In the following sections we try to distinguish between collections of
tasks that capture the superior performance and collections of tasks that mea-
sure a related function or ability. In our review of the initial work on chess, we
argued that only the task that required that subjects consistently select the ‘‘best
moves’’ meets the criterion of capturing the nature of superior performance.
Two other tasks, one involving perception and the other measuring memory for
briefly presented chess positions, assess related functions but do not directly
represent chess-playing skill.
The second step involves a detailed analysis of the superior performance. The
pioneering research on chess nicely illustrates the use of refined analyses of
sequences of verbal reports and placement of chess pieces to infer the underly-
ing cognitive processes mediating the superior performance, as well as the use
of experimental manipulation of stimulus materials.
The third and final step involves efforts to account for the acquisition of the
characteristics and cognitive structures and processes that have been found
to mediate the superior performances of experts. A persistent failure to identify
conditions under which the critical characteristics could be acquired or im-
proved would provide strong evidence that those characteristics are unmodifi-
able and hence basic and most likely inherited.
Our explication of the original expertise approach imposes clear limits for its
successful application. Unless the essence of the superior performance of the
expert can be captured in the laboratory (satisfying the criterion for the first
step), there will not be a performance to be further analyzed in terms of its
mediating processes. Similarly, failure to identify mediating processes that can
account for the superior performance during the second step will leave the in-
vestigator with only the original differences in overall performance and will
make the third step essentially superfluous.
Prospects and Limits of the Empirical Study of Expertise 527