In Fiji’s northwest corner, the residents of the Yasawa Islands do many nice things for their communities. They put on village feasts, plant yams for their chiefs, and make sizable donations to their local churches, to name a few of their altruistic acts.
But when Yasawans fail to give enough, “it’s open season,” says Joseph Henrich, an anthropologist at Emory University. Villagers punish selfishness by ripping out the offenders’ crops, breaking their pottery, and throwing water on them in the middle of the night.
The Yasawans illustrate a broader trend among human societies: The more altruistic they are, the more harshly they punish unfairness, report Henrich and colleagues in their June 23, 2006, Science article. The authors conducted classic economic experiments with 1,762 participants in 15 societies around the world, from the fishing Yasawa of Fiji; to the nomadic Hazda of Tanzania; to the farming and wage-earning rural Missourians of the United States. Their findings suggest that human altruism coevolved with the human tendency to punish wrongdoing.
”It’s extremely important work,” says Dov Cohen, a cultural psychologist at the University of Illinois at Urbana-Champaign who studies politeness and violence in the American South. “Most research is with undergraduates, but these people went out to span the gamut of human societies,” including those with different ecologies and economic systems, he says. By examining altruism and punishment across such a broad swath of humanity, the researchers can deduce that their findings reflect something basic about human nature.
In one experiment, two people participated together. The researchers gave one of them a day’s wage in the local economy – a healthy chunk of change for a social science experiment. Researchers then invited the person with the windfall to offer some of it to the second person. How much money the first person offered to the second provided a measure of altruism.
In another experiment, if the second person rejected the first person’s offer, then neither received any money. In other words, the second person could punish the first person for offering too small – or, in some cases, too large – a cut of the funds. But punishment had its price. By rejecting the first person’s offer, the second person dashed his or her own hopes of getting any cash. Another experiment introduced a third person who could punish the first person for unfair allotments, but only at some cost to himself or herself.
Henrich and colleagues found that people in all societies are willing to ding unjust partners, despite the personal cost of punishment. They also found that a society’s readiness to reprimand depends on how altruistic it is on the whole. For example, the Au of New Guinea, who offered an average of 40 percent of their money to their partners, were considerably more generous than the Tsimane of Bolivia, who on average offered only about 25 percent. But the Au were quicker to castigate. While the Au tended to reject offers that were less than 20 percent of the initial sum, the Tsimane settled for a mere 7 percent.
These findings provide evidence for a new theory of why humans are so altruistic. Current biological and economic theories fall short when it comes to explaining altruism, because they assume that people should be self-interested or, at best, should only help their kin or those who have helped them in the past. But Henrich says that these models are incomplete because they do not account for the role of human culture (values, beliefs, and practices) in evolution.
“Human nature has been shaped by the interaction of cultures and genes over long periods of time,” Henrich says, describing a process called culture-gene coevolution. At the dawn of our species, as cultures increasingly punished unfairness and rewarded justice, people who were more punitive and fair had more kids. This led to a rise in more do-gooder genes in our species. At the same time, having more do-gooder genes made all human cultures both more punitive and more altruistic over time.
While societies today do vary in how punitive and altruistic they are, their differences are due to cultural practices and beliefs, not genetic differences, says Henrich. “No society goes down to zero” in these qualities, he says. And that conclusion, says Cohen, is “very reassuring.”
Read more stories by Alana Conner Snibbe.