Contextual factors in the activation of first diagnostic hypotheses: expert-novice differences.

According to Feltovich & Barrows (1984), the general frame used by medical experts to construct a mental representation of a particular patient problem contains a component part for those illness features that are associated with the acquisition of the illness. These 'enabling conditions' are related in several ways to the patient's disease. Examples are conditions like sex and age, or risk factors originating from work, behaviour and hereditary taint. Because of the sequential nature by which patient data become available during a clinical interview, contextual information is expected to play an important role in the generation of initial diagnostic hypotheses. To investigate the hypothesis that experienced doctors better utilize this kind of information, a group of 18 experts and 17 novices was confronted with 32 short case histories each presented on three slides: a portrait of the patient, the patient chart containing previous disease history, and a slide with the presenting complaint. It was hypothesized that differences in the number of correct diagnoses would emerge between the two groups, because the experts would use the contextual information, implicitly provided by picture and patient chart, in a more extensive way. If so, this would show in the amount of information that is explicitly recalled later. The data confirmed these predictions. The experts produced almost 50% more correct hypotheses as compared to the novices and were able to reproduce a larger amount of contextual information in particular information that was directly relevant to the patient's problem. Only the expert group showed a high correlation between accuracy of diagnoses and recall measures.