ABSTRACT
Alien biologists collecting data about different life forms on Planet Earth would no doubt come up with contradictory claims about human nature. They would witness the human capacity to help complete strangers in sometimes large groups, yet they would also observe many incidents of extreme violence, especially between groups of males. To make sense of the data, the alien researchers would probably conclude that humans are a fiercely tribal social species. Some time ago, Charles Darwin speculated about the origins of human tribal nature: “A tribe including many members who, from possessing in a high degree the spirit of patriotism, fidelity, obedience, courage, and sympathy, were always ready to aid one another, and to sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection” (1871, p. 132). Unfortunately Darwin’s brilliant insight was ignored for more than a century by fellow scientists, yet it is now gaining impact. Here I offer an evolutionary perspective on the social psychology of intergroup conflict, offering new insights and evidence about the origins and manifestation of coalitional and intergroup aggression. 1
