In-group bias
Favouring members of your own group in trust, judgement and resources, even when the group is trivial or arbitrary. Brewer's point matters: most of it is warmth towards 'us' rather than hostility towards 'them', though hostility follows under threat or competition.
What drives it
It boosts the group's standing and, through it, your own self-esteem, and it makes cooperation easy with people you can predict. The cost is paid by outsiders and by the group's own decision quality.
How it shows
Work
Hiring for 'culture fit' that turns out to mean people from the same schools, firms or backgrounds. Mistakes by your team are bad luck; the same mistakes by another team are incompetence. Promotions go to people the decision-maker has worked with before. Founding teams that only trust the original members and treat later hires as mercenaries.
Relationships
In-laws treated as permanent outsiders. A family that excuses its own members' behaviour while judging the same behaviour harshly in others. Friendship groups that close around a member in conflict with an outsider regardless of who was at fault.
Self
You give your own people the benefit of the doubt automatically and notice you need more evidence before trusting someone from a different background, school or political side. The tell is a double standard you would reject if you saw it written down.
What tells it apart
Social identity: Identification is how much the group matters to someone's self; in-group bias is the observable favouritism in decisions. Measure the decisions, not the declarations.
Halo effect: The halo effect spreads one good trait across all judgements about a person; in-group bias spreads a good impression across everyone carrying a group label.
Scapegoating: In-group bias is mostly favouring us; scapegoating actively blames an out-group or individual for the group's troubles. Watch for whether 'they' are merely less trusted or are being held responsible.
A test
Swap the group label on an identical piece of work or proposal and see whether the person's judgement of it changes.
Questions to carry
- If the same proposal came from the other team, how would it be judged?
- Whose work do I trust more because they are one of us, and what do I skip checking?
How strong the research is
strong
Where it comes from
William Graham Sumner, 1906 (ethnocentrism); Henri Tajfel and colleagues, 1971 (minimal group paradigm); Marilynn Brewer, 1999
Sources
- Henri Tajfel and John C. Turner, An Integrative Theory of Intergroup Conflict (1979)