Subgroup differentiation as a response to an overly-inclusive group: a test of optimal distinctiveness theory

Optimal distinctiveness theory (ODT; Brewer, 1991, 1993a,b) argues that people can respond to membership of an overly inclusive group by engaging in a drive for subgroup distinctiveness. To test this, 280 subgroup members (humanities and maths-science students) rated the extent to which they perceived their superordinate group (University of Queensland) to be inclusive. After performing a task designed to activate their superordinate category membership, participants completed a questionnaire assessing inter-subgroup attitudes. Consistent with ODT, ratings of superordinate inclusiveness explained a moderate amount of variance in subgroup bias (5–8 per cent), such that the more inclusive the superordinate category was seen to be, the more bias was demonstrated. The results are discussed in terms of their relevance for ODT and their implications for promoting subgroup harmony. Copyright © 1999 John Wiley & Sons, Ltd.