Marek Kohn – Us and them: Setting up ‘minimal groups’ like these became standard procedure for researchers interested in what makes in-groups tick. The findings leave no room for doubt: people will coalesce into parochial groups at the drop of a hat, no matter how arbitrary, tiny, vague, esoteric or spurious the differences between them. Rewards, prizes or turf wars will bring the biases to light, but they aren’t necessary. In-group love and bias against out-groups can arise even if nothing at all is at stake.