The representativeness and past-behavior heuristics in clinical judgment

To clarify how psychologists make judgments, 3 studies were conducted. The results from 2 studies indicate that the representativeness heuristic (D. Kahneman & A. Tversky, 1973) describes how diagnoses are made. That is, clinicians seem to make diagnoses by comparing patients to typical patients( e.g., the typical patient with schizophrenia). In a 3rd study, the representativeness heuristic did not describe how clinicians make behavioral predictions. Instead, the past-behavior heuristic was descriptive. The results can help psychologists understand why different problems occur in psychodiagnosis. For example, the results suggest that when race bias and gender bias occur in psychodiagnosis, they occur because race or gender are features of a clinician's stereotypes, not because clinicians are attending to base rates.