Social identity theory
IB Psychology· Sociocultural approach· 14 min read
1. Core concept
Social identity theory (Tajfel and Turner) explains behaviour through the groups we belong to. It runs in three steps: social categorisation (sorting people into 'us' and 'them'), social identification (taking on the identity of our in-group), and social comparison (judging our group against out-groups). Because our self-esteem is tied to our groups, we are motivated to see our own group as better — producing in-group favouritism and out-group discrimination, even when the groups are trivial and newly formed. It is widely used to explain prejudice, and to reduce it by reshaping group boundaries.
2. Key studies
IB Psychology answers must be supported by named studies. Learn these to cite as evidence:
Tajfel et al. (1971) Experiment 1
Using the minimal group paradigm, participants allocated more reward to in-group than out-group members, even though group membership was assigned on a trivial basis. — Shows in-group favouritism arising from mere categorisation — no history, contact or conflict required.
Tajfel et al. (1971) Experiment 2
Participants often chose to MAXIMISE THE DIFFERENCE in their in-group's favour, even when this meant less absolute reward for their own group. — Shows the drive for positive distinctiveness — the group wants to WIN, not just gain — supporting the social-comparison step.
3. Evaluation (AO3)
Strength — minimal conditions, large effect — Discrimination appeared between groups with no real stakes, isolating categorisation itself as a cause — a powerful, much-replicated finding.
Limitation — artificial and partial — Allocating points between anonymous strangers is far from real intergroup conflict, and SIT downplays personality and material self-interest as competing explanations.
4. Scope
5. Common Pitfalls
Wrong move:
In-group favouritism needs real competition or a history of conflict between the groups.
Why:
A frequently penalised misconception in IB Psychology exams.
Correct move:
Tajfel's minimal groups show that mere categorisation into 'us' and 'them' is enough to trigger in-group favouritism — no competition, contact or prior conflict is required.
Going deeper
- ConformitySIT explains WHY group membership pressures individuals to conform (SOC_3).