MICHIGAN STATE (US) — Group conflict over the ages may have helped shape the way men and women respond to prejudice.
A new study finds prejudice is linked to aggression for men and fear for women, responses also seen in humans’ closest relative, the chimpanzee.
Researchers at Michigan State University report that throughout history men have been the primary aggressors against different groups as well as the primary victims of group-based aggression and discrimination.
“There is evidence going back thousands of years of bands of men getting together and attacking other bands of men, eliminating them and keeping the women as the spoils of war,” says Carlos David Navarrete, an evolutionary psychologist.
As modern examples, Navarrete notes the wars in Central Africa and the Balkans that were marred by rape and genocide.
The researchers analyzed current academic literature on war and conflict and found that the standard social science theory did not explain the sex differences in aggressive or discriminatory behavior between groups. Instead, they offer a new theory that integrates psychology with ecology and evolutionary biology.
Their “male warrior hypothesis” explains how a deep evolutionary history of group conflict may have provided the backdrop for natural selection to shape the social psychologies and behaviors of men and women in fundamentally distinct ways.
Essentially, men are more likely to start wars and to defend their own group, sometimes in very risky and self-sacrificial ways. Attacking other groups represents an opportunity to offset these costs by gaining access to mates, territory, resources, and increased status.
In a paper published in the journal Transactions of the Royal Society B, the authors complement these findings with results from lab experiments showing that men are more prejudiced toward other groups.
Women, meanwhile, live under the threat of sexual coercion by foreign aggressors, and are apt to display a “tend-and-befriend response” toward members of their own group, while maintaining a fear of strangers in order to protect themselves and their offspring.
“Although these sex-specific responses may have been adaptive in ancestral times,” says Melissa McDonald, the lead author of the study, “they have likely lost this adaptive value in our modern society, and now act only to needlessly perpetuate discrimination and conflict among groups.”
Navarrete adds that the behavior is seen in the chimpanzee. “Just like humans, they’ll attack and kill the males of other groups. They’ll also attack females—not to the point of killing them, but more to get them to join their group,” he says.
Since the behaviors are common among both humans and chimps, they are likely to have existed in our common ancestor millions of years ago, Navarrete says.
“This would have provided eons of time for the deepest workings of our minds to have been fundamentally shaped by these cruel realities,” he says.
“Coming to grips with this history and how it still affects us in modern times may be an important step into improving the problems caused by our darker predispositions.”
Mark Van Vugt of the University of Amsterdam and the University of Oxford also co-authored the study.
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