Psychology
Social Identity Theory and Intergroup Conflict Resolution
Quick fact
People will favor their own group even when the group is assigned randomly and has no history, no competition, and no real meaning—a finding from the 'minimal group paradigm' that revealed the power of mere categorization.
Why this is interesting
Why do people show fierce loyalty to sports teams, political parties, or even arbitrary groups? And why does that loyalty sometimes turn into hostility toward outsiders?