Determinants of Diagnostic Prototypicality Judgments of the Personality Disorders

We evaluated the impact of three factors that have been suggested to be important determinants of the diagnostic process pertaining to personality disorders: (a) the number of features representative of a personality disorder category; (b) the extent to which those features are typical of the category, and (c) the dominance or proportion of category features to the total number of features. Thirty-two clinical psychologists evaluated 12 profiles of hypothetical patients in which these factors were varied factorially. The results revealed strong effects of typicality and dominance, but no effects for number. Implications for the assessment and classification of personality disorders are discussed.