Psychology
Social Identity Theory and Intergroup Discrimination
Quick fact
In the famous 'minimal group paradigm' experiments by Henri Tajfel, people who were placed into arbitrarily defined groups (like 'overestimators' vs. 'underestimators') still showed strong favouritism toward their own group when allocating rewards, even though they had no previous interaction or shared history.
Why this is interesting
Have you ever felt a surge of pride when your team wins, even if you had nothing to do with the game? What if that simple feeling can make us treat strangers completely unfairly?