Expert systems: A cognitive science perspective

The theory and technology of knowledge-based systems are intrinsically interdisciplinary and are closely related to the formalisms of cognitive psychology. In this paper, strategies of incorporating intelligence into a computer program are described along with a common architecture for expert systems, including choices of representation and inferential methods. The history of the field is traced from its origins in metamathematics and Newell and Simon’s (1961) GENERAL PROBLEM SOLVER to the Stanford Heuristic Programming Project that produced DENDRAL and MYCIN (Buchanan & Shortliffe, 1984). MYCIN gave rise to EMYCIN and a shell technology that has radically reduced the development time and cost of expert systems. Methodology and concepts are illustrated by transactions with a shell developed for graduate education and a demonstration knowledge base for the diagnosis of senile dementia. Knowledge-based systems and conventional programs are compared with respect to formalisms employed, applications, program characteristics, procedures supplied by the development environment, consistency, certainty, flexibility, and programmer’s viewpoint. The technology raises basic questions for cognitive psychology concerning knowledge and expertise.