Germs and the out-group: Chronic and situational disease concerns affect intergroup categorization.

Throughout human evolutionary history, members of unfamiliar out-groups are likely to have posed significant disease threats. The current studies assessed whether concerns about disease would bias people toward categorizing social targets as members of an unfamiliar out-group. Using a minimal group paradigm, 2 experiments assessed the extent to which perceivers categorized neutral targets and those displaying heuristic disease cues as members of the in-group versus the out-group. A bias toward categorizing targets with heuristic disease cues (but not neutral targets) as members of the novel out-group was observed among people high in chronic germ aversion and among those for whom disease threat had been experimentally primed. Consistent with theories emphasizing the pernicious dangers potentially posed by out-group pathogens, this bias was strongest if the targets were also a part of a racial out-group. Findings suggest a fundamental link between disease avoidance processes and biases in intergroup cognition.