Proceedings of the Annual Meeting of the Cognitive Science Society

Problem solving Is known to vary in some predictable ways as a function of experience. In this study, we have Investigated the effects of experience on the problem solving behavior and knowledge base of workers In an applied setting: automobile mechanics. The automobile itself is a highly complex system with many interconnected subsystems.Problem descriptions (i.e., symptoms) presented to a mechanic who needs to diagnose a car, however, are usually quite sketchy, requiring the collection of more information before solution. Novices are less able than experts to diagnose any but the obvious problems, and w e are Interested in Identifying the qualitative differences between mechanics at different levels of expertise. In the study reported, w e observed three student mechanics in a postsecondary technical school, each at a different level of expertise, diagnose six problems Introduced Into cars In the school. W e then analyzed the protocols w e collected to find the knowledge and strategies used in solving each problem.W e also analyzed the series of protocols for each student to find the changes in knowledge and strategies used In solving later problems as compared to earlier problems. Differences were seen in both the knowledge used by the subjects and in their general approach to diagnosis. As a result of experience, the student mechanics seemed to Improve In three areas: (1) their knowledge of the relationships between symptoms and possible failures was augmented,(2) their causal models of the car's systems were augmented, and (3) their general troubleshooting procedures and decision rules were much Improved.