Political identity and perceived intragroup homogeneity

A study is described combining the ‘out‐group homogeneity hypothesis’, which predicts greater perceived homogeneity in out‐groups than in‐groups, with the ‘depersonalization hypothesis’ derived from self‐categorization theory, which predicts greater perceived homogeneity in both in‐ and out‐groups as social identity becomes salient — particularly along those dimensions most relevant to the categorization criterion. An experiment was conducted in the context of political affiliation, where it is suggested that in‐group homogeneity along certain dimensions may be valued as a sign of unity and strength. Subjects were 64 supporters of the Labour Party. Strength of political affiliation and situational group salience were manipulated and perceptions of homogeneity within the Labour and Conservative Parties were measured along a number of dimensions of varying relevance to the categorization criterion. Results confirmed the hypothesized positive relationship between strength of political identity and perceived intragroup homogeneity in both the in‐ and out‐group, as well as illustrating the importance of the type of dimension involved. A significant main effect confirmed that the more relevant the dimension to the categorization criterion, the greater the perceived homogeneity in in‐ and out‐groups, whilst a significant interaction effect confirmed that there was greater perceived out‐group homogeneity along irrelevant personality dimensions but greater perceived in‐group homogeneity along highly relevant issue dimensions. The theoretical implications of the findings are discussed.