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Social Identity Theory

An account of intergroup behaviour holding that people derive part of their self-concept from group membership, and are motivated to see their own groups as positively distinct from others.

Definition

The theory has three linked processes:

Categorisation: perceiving self and others as members of groups, which accentuates within-group similarity and between-group difference.
Identification: taking on a group membership as part of the self-concept.
Comparison: evaluating one's group against relevant others, with motivation toward positive distinctiveness.

The theory also specifies what people do when their group compares badly: individual mobility if boundaries are permeable, social creativity if they are not, and social competition where the situation is seen as illegitimate and unstable.

History

Developed by Henri Tajfel and John Turner in the 1970s, growing out of the minimal group experiments: participants assigned to groups on an arbitrary basis, with no interaction, no history and no conflict of interest, still allocated more to their own group.

Self-categorisation theory, developed by Turner in the 1980s, extended the account to explain how the salience of a given identity shifts by context.

Theory

The theoretical significance is what it removed. Earlier accounts required realistic conflict over resources to explain intergroup hostility. The minimal group findings showed categorisation alone is sufficient to produce differential treatment.

The self-esteem hypothesis — that discrimination raises self-esteem and low self-esteem drives discrimination — was derived from the theory and has fared poorly. The first half has some support, the second very little, and most theorists no longer treat it as central.

Research

Minimal group effects replicate robustly. In-group favouritism, not out-group derogation, is the more consistent finding: people give more to their own group rather than taking from others, and treating the two as equivalent is a common error in applied writing.

Social identity accounts have been extended productively into health outcomes, where group membership predicts wellbeing and recovery, and into leadership, where effective leaders are those seen as prototypical of the group.

The framework has also reshaped how collective action is explained, with identification, injustice and efficacy as the standard predictors.

Applications

Intergroup conflict reduction, organisational identity and merger integration, health interventions built around group belonging, understanding polarisation, and the design of team structures.

The common in-group identity approach — recategorising two groups as one larger one — follows directly and has trial evidence, though it can be resisted where a subgroup identity is valued.

Criticism

The self-esteem hypothesis is largely unsupported and was long treated as a core prediction.
Minimal group findings admit alternative explanations, including norm-following and expectation of reciprocity, and the debate is unresolved.
Positive distinctiveness is post hoc-friendly: almost any intergroup behaviour can be described as serving it.
The theory predicts strategies but not which one, which limits its precision in real conflicts.

References

Tajfel, H., & Turner, J. C. (1979). An integrative theory of intergroup conflict. In W. G. Austin & S. Worchel (Eds.), The Social Psychology of Intergroup Relations (pp. 33-47). Brooks/Cole.
Tajfel, H., et al. (1971). Social categorization and intergroup behaviour. European Journal of Social Psychology, 1(2), 149-178.
Turner, J. C., et al. (1987). Rediscovering the Social Group: A Self-Categorization Theory. Blackwell.
Rubin, M., & Hewstone, M. (1998). Social identity theory's self-esteem hypothesis. Personality and Social Psychology Review, 2(1), 40-62.

Written for PsychologyOrbit and reviewed before publishing. It is a summary for professionals and students, not clinical guidance, and it is not a substitute for the primary sources listed above.