The effects of ingroup and outgroup homogeneity on ingroup favouritism, stereotyping and overestimation of relative ingroup size

Abstract

An experiment (n = 61) investigated the effects of ingroup and outgroup homogeneity on ingroup favouritism, stereotyping and the overestimation of relative ingroup size. As predicted, outgroup homogeneity was conducive to ingroup favouritism. Ingroup homogeneity, however, failed to influence ingroup favouritism. Also unexpectedly, asymmetry in group homogeneity — irrespective of whether the ingroup or the outgroup was the more homogeneous group — led to pronounced stereotyping of both groups and to the overestimation of relative ingroup size.