“Seeking community with people is common throughout the world and the history of humans. People who join groups allow them to flourish and avoid harmful physical and psychological consequences of being alone. Yet in our modern era, groups have also formed around things that are much more loose and not tied to direct survival, such as sports teams, countries and so on. Yet the same kind of cognitive and social mechanisms can operate in these groups as well and this can bring with it both positive and negative consequences.
What happens if you get a bunch of people together in an experiment and create artificial groups based on completely arbitrary criteria and subject them to resource limitations? Will preference for in-group members and hostility towards the out-group develop rapidly? By what mechanism does this happen, and are there ways to reduce friction between competing groups?”