Base rates, representativeness, and the logic of conversation: The contextual relevance of ‘irrelevant’ information

According to the cooperative principle of conversation that governs social discourse, listeners expect speakers to be relevant, truthful, and informative. The applicability of the cooperative principle was varied to explore the impact of conversational principles on the apparent overreliance of individuals on nondiagnostic person information (NPI) at the expense of base-rate information (BSI). 44 German college students relied more on NPI than BSI when information was presented as a statement written by a psychologist than they did when information was presented as a random sample drawn by a computer. In Exp 2, a partial replication of Exp 1, 2 instances were found in which 48 undergraduates relied on individuating information. (PsycINFO Database Record (c) 2007 APA, all rights reserved)