On the origin of intermediate effects in clinical case recall.

In two experiments, the effects of level of medical expertise and study time on free recall of a clinical case were assessed. In Experiment 1, a nonmonotonic relationship between level of expertise and recall was found: Subjects of intermediate levels of expertise remembered more information from the case than both experts and novices. This "intermediate effect" disappeared, however, when study time was restricted. Analysis of post hoc acquired protocols of pathophysiological knowledge active during case processing suggested that this phenomenon could be attributed to the nature of the pathophysiological knowledge mobilized to comprehend the case. In Experiment 2, this assumption was directly tested by priming relevant pathophysiological knowledge for either a short or a longer period, before enabling subjects to study the case briefly. Free-recall data confirmed and extended the results of Experiment 1. Again, an intermediate effect was found; this time, however, it was generated experimentally. The findings were interpreted in terms of qualitative differences in the nature of the knowledge structures underlying performance between novices, advanced students, and medical experts: Experts use knowledge in an encapsulated mode while comprehending a case, whereas students use elaborated knowledge.