Normative and Information Processing Accounts of Medical Diagnosis

The field of Judgement and Decision Making has for some time been dominated by normative theories which attempt to explain behaviour in mathematical terms. We argue that such approaches provide little insight into the cognitive processes which govern human decision making. The dominance of normative theories cannot be accounted for by the intractability of processing models. In support of this view, we present a processing account of performance on a simulated medical diagnosis task. The performance of the model, which includes learning, is compared with that of a normative (Bayesian) model, and with subject performance on the task. Although there are some caveats, the processing model is found to provide a more adequate account of subject performance than the Bayesian model.