Tough choices.
In a money game, New Guinea tribespeople were more likely to favor individuals from their own tribe.

Helen Bernhard

It Pays to be "One of Us"

When it comes to nepotism, people from indigenous tribes are not so different from you and me. Given the choice between punishing a fellow tribesman or a member of a neighboring tribe for the same crime, New Guinea natives protect their own, according to new research. The study suggests that favoritism knows no cultural boundaries.

An abundance of research has shown that people tend to give preferential treatment to others who are genetically similar to themselves, whether they're actual blood relatives or simply share an ethnic background. But most of this research has been done in Western countries.

To see if the behavior extended to indigenous people, economist Helen Bernhard of the University of Zurich in Switzerland and colleagues had two New Guinea tribes play a money game. Each round had three players: a "dictator," who starts out with 10 Kina (equivalent to wages for a day's labor) and can give any of the cash to the "recipient," and a "third party," who acts as the enforcer of societal norms. He or she must decide how the dictator should be punished if that person hasn't shared fairly with the recipient. To make the dictator turn over an additional 3 or 6 Kina to the recipient, the third party has to spend 1 or 2 Kina of his own.

A series of 65 games was played with various combinations of members of the Wolimbka and Ngenika tribes, who live 30 kilometers apart. Both tribes are accustomed to sharing their resources in an egalitarian fashion within the group. The investigators found that if all players were from the same tribe, the third party punished the dictator every time he shared less than half his money with the recipient. If the dictator were from a different tribe, he received even more punishment for being stingy. For example, if the dictator only gave 4 kina to the recipient, he would receive little or no punishment if all three players were from the same tribe, but the third party would pay more than 1 kina to punish the dictator if he were from a different tribe than were the other two players. If the recipient were the outsider, however, less than 1 kina would be spent to punish the dictator even if he gave nothing to the recipient. If the third party were the minority tribe member, the outcome would be similar, the researchers report in the 24 August issue of Nature.

The study demonstrates "ethnic nepotism," says altruism researcher Philippe Rushton, a psychologist at the University of Western Ontario in Canada. It's been shown many times, he says, but looking at the phenomenon in indigenous Papua New Guineans "is novel and attention grabbing, and it goes beyond the usual gaming experiments" by using indigenous subjects rather than undergraduates in a lab.

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