Outgroup derogation

Biological Parallel

Chimpanzee communities conduct lethal border patrols, systematically killing isolated members of neighboring groups in coordinated attacks. Jane Goodall's observations at Gombe revealed a four-year campaign where one community exterminated another through targeted violence. Outgroup derogation evolved as coalitional aggression: dehumanizing competitors reduced inhibitions against violence, enabling resource acquisition through intergroup conflict—ancestors who felt empathy for outsiders lost territory and died out.