The evolution of the cognitive architecture humans use to sort themselves into coalitions of us versus them.
Considerable attention across the social sciences has been paid to understanding how people categorize individuals into groups and create group identities. Throughout human history, conflict between groups was founded on categorizing relationships into “us” and “them” and social psychologists have long recognized the importance of group membership to human social organization. The “minimal group paradigm,” established as a method for investigating the minimal conditions required for discrimination to occur between groups, has continued to show that even virtually meaningless distinctions between groups, such as shirt color, can trigger a tendency to favor one’s own group over others. It is clear that the ability to readily distinguish between in-groups and out-groups played a key role in our evolutionary.
