Stereotypes as Bayesian prediction of social groups.

A stereotype is a generalization about a class of people which is often used to make probabilistic predictions about individuals within that class. Can stereotypes can be understood as conditional probabilities that distinguish among groups in ways that follow Bayesian posterior prediction? For instance, the stereotype of Germans as industrious can be understood as the conditional probability of someone being industrious given that they are German. Whether such representations follow Bayes' rule was tested in a replication and extension of past work. Across three studies (N = 2,652), we found that people's judgments of different social categories were appropriately Bayesian, in that their direct posterior predictions were aligned with what Bayes' rule suggests they should be. Moreover, across social categories, traits with a high calculated diagnostic ratio generally distinguished stereotypic from non-stereotypic traits. The effects of cognitive ability, political orientation, and motivated stereotyping were also explored.