The divisive potential of differences and similarities: The role of intergroup distinctiveness in intergroup differentiation

In this article we examine the relationship between perceptions of intergroup distinctiveness and intergroup differentiation. Research in this area has highlighted two contrasting hypotheses: high distinctiveness is predicted to lead to increased intergroup differentiation (self-categorisation theory), while low distinctiveness or too much similarity can also underlie positive differentiation (social identity theory). We argue for a theoretical integration of these predictions and outline their domains of applicability. In addition to empirical studies from our own laboratory, support for these hypotheses in the literature is examined meta-analytically, and we assess the power of a number of moderators of the distinctiveness ‐ differentiation relation. We focus on group identification and salience of the superordinate category as the most powerful moderators of this relation. We report evidence that low group distinctiveness leads to more differentiation for high identifiers, while high group distinctiveness leads to more differentiation for low identifiers. In addition, our meta-analysis revealed that when the superordinate category was not salient, low distinctiveness tended to lead to differentiation (albeit not significantly so) while high distinctiveness led to differentiation when the salience of the superordinate category was high. A model is proposed integrating our predictions concerning moderators of the distinctiveness ‐ differentiation relation. Theoretical implications of these findings are discussed and we suggest directions for future research.