Social identity theory

In one line: Part of who we are comes from the groups we belong to — and we favour 'us' over 'them'.

Social identity theory is a sociocultural-approach term. It explains how simply belonging to a group changes behaviour.

Our sense of self isn't only personal ('I am kind'); it's also social ('I am a student here, a fan of that team'). These group memberships give us pride and belonging — and a tendency to favour our own group, which links to the concept of bias.

Memory hook: Us and them. Group membership shapes identity — and tilts us towards our own side.

Key idea: Social identity forms in three steps that end in favouring the in-group.

Take fans of two schools at a sports match. They categorise into 'our school' vs 'theirs', identify with their side (wearing the colours), and compare — seeing their own fans as fairer and more loyal. This in-group favouritism is a form of bias.

Worked example you could use: In classic 'minimal group' studies, people split into groups by something trivial (even a coin toss) still favoured their own group when sharing rewards. You may use this kind of study as an example, in your own words. No need to memorise details.

Go further — higher-level insight: In-group favouritism needs almost nothing. Because even meaningless groups trigger bias, social identity theory suggests prejudice isn't only about real conflict — the mere act of dividing into groups is enough to start it.

Key idea: The theory explains group behaviour powerfully, but it can understate individual and situational factors.

So social identity theory is a strong, well-evidenced account of group behaviour and prejudice, but a good evaluation notes it can be tested in artificial settings and doesn't fully explain individual differences in how strongly people favour their group.

Watch out: Groups aren't only negative. The same process that fuels prejudice also builds belonging, loyalty and cooperation — social identity has an upside too.