Monkey Study Suggests Human Prejudice Has Evolutionary Roots

GreenTracker| Yale psychologist Laurie Santos believes that human conflict is deeply rooted in the “us versus them” tendency of — not only humans — but also their primate cousins monkeys to treat individuals from outside their group with suspicion.

Her study of rhesus monkeys off the coast of Puerto Rico suggest that group-driven biases “have apparently been shaped by 25 million years of evolution and not only by human culture.”

 … the researchers used a well-known tendency of animals to stare longer at novel or frightening things than at familiar or friendly things. They presented subject monkeys with pictures of monkeys who were either in their social group or members of a different group. They found that monkeys stared longer at pictures of other monkeys who were outside their group, suggesting that monkeys spontaneously detect who is a stranger and who is a group member.

Santos took the research even further, studying whether the ‘in’ group and ‘out’ group monkeys were automatically associated with ‘good’ and ‘bad’, based on positive and negative imagery.

In the balance of nature vs nurture and social psychologists vs evolutionary theorists, this research weaves both disciplines together to understand the complexity of interaction in monkeys.

“The bad news is that the tendency to dislike outgroup members appears to be evolutionarily quite old, and therefore may be less simple to eliminate than we’d like to think,” Santos said. “The good news, though, is that even monkeys seem to be flexible about who counts as a group member. If we humans can find ways to harness this evolved flexibility, it might allow us to become an even more tolerant species.”

Besides Dr. Santos, other women researchers on the team included Mahzarin Banaji, of the Department of Psychology at Harvard University and a co-author of the paper, Margaret A. Martinez and Natashya Gutierrez.