Self-categorisation, commitment to the group and group self-esteem as related but distinct aspects of social identity

The aim of this study is to show that, when examining social identification , it is both possible and important to distinguish between self-categorisat ion, commitment to the group, and group self-esteem, as related but separat e aspects of group members' social identity. This was demonstrated in an ex periment (N = 119), in which Ingroup Status (high/low), Ingroup Size (major ity/minority), and Group Formation (self-selected/assigned group membership ) were manipulated orthogonally. The results of this study confirm that the se three aspects of social identity can be distinguished as separate factor s in a principal components analysis. Furthermore, as predicted, the three aspects are differentially related to manipulated group features, as well a s displays of ingroup favouritism. Group members' self-categorisations were only affected by the relative size of the group, while group self-esteem w as only influenced by group status. Affective commitment to the group depen ded both on group status and on the group assignment criterion. Importantly , only the group commitment aspect of social identity mediated displays of ingroup favouritism. Copyright (C) 1999 John Wiley & Sons, Ltd.