Tajfel sorted teenage boys into two groups on the flimsiest basis imaginable: which of two abstract painters they supposedly preferred. The labels were actually random. The boys never met, stayed anonymous, and could never keep a single point for themselves. All they did was split points between two strangers, one from their group, one from the other. Given the choice, they handed their own side less, as long as the other side got even less (Tajfel et al., 1971).
They were not trying to make their group rich. They were trying to make their group win. The gap mattered more than the gain.
A group built from nothing
Tajfel was hunting for the floor. Everyone assumed group hatred needed a cause: real competition, a history, a grudge. He wanted to strip all of it away and find the point where the bias finally vanished.
So he built the emptiest groups possible:
- The split was meaningless, a guess about dots on a screen, or a coin-flip dressed up as taste in art.
- The boys never interacted. No contact, no faces, just code numbers.
- And they could not benefit themselves. Each boy only ever divided points between two other people.
No self-interest. No history. No contact. No real group. Just a line, drawn at random.
What they did with the points
The bias showed up instantly. Boys gave more to their own side than the other, from nothing but a label.
But the point system let them pick a strategy, and that is where it got strange:
| The strategy on offer | What it gets you | Did they take it? |
|---|---|---|
| Most for everyone | both sides walk away richer | no |
| Most for your side | your group’s biggest possible haul | not even this |
| Biggest lead | your group ahead by the widest margin, even if it earns less | this one |
They repeatedly chose the biggest lead over the biggest haul. They left their own group’s money on the table, just to widen the gap over the other side.
Relative superiority beat absolute benefit. Being ahead felt better than being rich.
What it proves
This is the experimental floor under all of Social Identity Theory. It shows the starting premise is real: categorization alone is enough.
You do not need a reason to favor your group and discriminate against another. You do not need conflict, scarcity, or learned hatred. A label assigned by a coin toss will do it. The us/them line is not the result of the bias. It is the cause.
Why this matters
- Any line will do. Office team colors, school rivalries, a randomly assigned squad, a nation. The brain treats a trivial division and a meaningful one with the same machinery.
- It is trivially easy to manufacture. A leader who wants you divided does not need a real grievance. They only need to name an out-group. The bias supplies itself.
- The same lever runs in reverse. If an arbitrary line creates bias, a bigger line dissolves it. Fold “them” into a shared “us”, one team, one town, one species, and the favoritism follows the new boundary.
- Watch for the gap-chasing in yourself. The urge to see another group lose, even when their losing wins you nothing, is this experiment, running in your own head.
Prejudice does not always start with a reason. Sometimes it starts with a coin flip, and then goes looking for one.