ABSTRACT
Decades of research on performance in laboratory tasks have revealed general information-processing constraints on the acquisition of skilled performance. The most important constraint concerns the capacity of working memory-the amount of information about the task and generated results that subjects can keep continuously accessible during task-directed performance. Studies of short-term memory (STM) have shown that the amount of information subjects can maintain in temporary storage through rehearsal is very limited and sets limits for the capacity of working memory in laboratory tasks. The basic storage capacity of working memory is assumed to remain fixed and to be invariant across all types of cognitive activity. Models of cognitive processes in many laboratory tasks have shown that with appropriate strategies subjects can successfully execute their cognitive processes within the limited storage capacity of working memory. Even skilled and expert performance is assumed to be constrained by the same capacity limits. Under traditional theories of expert performance (e.g. Chase & Simon, 1973) and skill acquisition (e.g. Anderson, 1982; Fitts & Posner, 1967), superior performance levels attained after practice reflect the reduction of load on working memory through the automatisation of serial processes and the processing of more complex chunks of knowledge. Recently, however, evidence from expert and skilled performance has shown that the amount of information available in working memory can be dramatically increased for specific tasks and that the storage of this information is neither temporary nor critically dependent on active rehearsal.
