Outgroup Homogeneity Bias

What is Outgroup Homogeneity Bias?

Outgroup homogeneity bias is the tendency to perceive members of another group as more alike than members of one’s own group. Demonstrating a relative perception does not by itself establish how much diversity either group actually has.

Outgroup homogeneity bias example

Imagine a student describing classmates in their own department as a varied mix of personalities, but saying that students in another department are “all the same.” That illustrates a relative judgment of sameness. Whether the second department is actually less diverse is a separate empirical question.

Evidence and Boundaries

Mullen and Hu’s 1989 meta-analysis found a significant but small average relative effect. Ostrom and Sedikides’s 1992 review found strong support in naturally existing groups but no consistent effect in minimal groups created for experiments.

This variation challenges explanations that assume categorization alone always produces the same result.

Outgroup homogeneity and stereotyping

Perceived sameness can encourage applying a generalization to individuals. However, it is distinct from disliking a group or discriminating against its members.

Can outgroup homogeneity bias be reduced?

Contact and perspective-taking should not be presented as guaranteed remedies from this evidence. Assessments need to consider the groups, the dimension being judged, and the available information about individual members.

Self-categorization theory explains how people understand themselves and others through group membership.

For the broader distinction between belonging to a group and standing outside it, see out-group.