Social Identity Theory: Why We Divide the World Into Us and Them

It was a simple enough experiment: 62 British teenagers, ages 14 and 15, were shown abstract paintings and asked which they preferred. Based on their answers, they were sorted into groups with names like the Triangle Group and the Circle Group—or, more abstractly, the Dichromatic Group and the Polychromatic Group. None of the kids actually had anything meaningful in common. They were arbitrarily assigned to teams they barely understood. Then the researchers handed them forms asking how much money each group should be paid for participating. The results were unsettling. When given the option to give both groups eleven dollars, many chose instead to give their own group ten dollars—as long as the other group got only five. They preferred a financial loss for themselves over equality with the out-group. This is the kind of behavior that social identity theory was built to explain.

The Puzzle That Needed a Theory