Why it pays to cooperate with your enemies

When under fire, many soldiers risk their own lives for the good of the group, while attacking people labeled the enemy. The tendency to risk one’s life for community helps individuals thrive and pass on their genes, and is part of the reason we’ve evolved to be altruistic, scientists believe.

But a new study of cooperative behavior in ethnically divisive villages in Eastern Europe suggests that perceiving a threat doesn’t make you any less likely to cooperate with your enemies.

“That’s superinteresting,” says Thomas Zeitzoff, a political scientist at American University in Washington, D.C., who wasn’t involved with the study. “It suggests there’s nothing about ethnicity itself that makes people uncooperative.”

Researchers have long hypothesized that feeling threatened boosts cooperation within a group, as people band together against outsiders. In 2015, political scientist Max Schaub at Bocconi University in Milan, Italy, tested that idea by visiting Georgia’s Kvemo Kartli region, just outside Tbilisi, where a mix of ethnic Georgians and Azerbaijanis live in hundreds of villages. Some villages are ethnically homogenous whereas others are mixed. Georgians and Azerbaijanis face ever-present ethnic tensions that occasionally boil over into violent clashes.

Schaub visited six rural villages in the region and had dozens of ethnic Georgians in each play two different games. In the first, called the public goods game, players were matched with either two participants from their own village or two from a neighboring village and given about $10 in Georgian lari. Whatever they contributed to a communal pot was doubled and split among the three players. The optimal strategy for the group as a whole is for everybody to contribute their full share, but if an individual withholds their share, they wind up with more money than the rest.

Next, volunteers played a second game using their earnings from the first. In this “threat game,” players were paired with someone from either the same village or a neighboring one, although they weren’t explicitly told their partner’s ethnicity. The designated “predator” of the pair could take any amount of money from their partner, whereas the partner could invest in protection to keep part of their stash. The more players paid for protection, the more threatened they apparently felt, feelings Schaub codified in a “threat index.”

Schaub reasoned that ethnic Georgians would likely view an ethnic Azerbaijani partner as more threatening than a fellow Georgian. And indeed, he found that when a player was partnered with a neighbor, and his or her neighboring villages were more than 50% ethnic Azerbaijani, they spent about 9% more money on protection than players paired with fellow villagers. When participants' neighbors were mostly other ethnic Georgians, they only spent about 3% more on protection than when paired with fellow villagers.

Similarly, when players were paired with fellow villagers, they contributed about 8% more to the communal pot than when paired with neighboring villagers, regardless of the ethnic makeup of those villages.

So far, all of this fits predictions about altruism, although the effects were small. But when Schaub combined data from both games, he found something unexpected: When matched with partners from neighboring villages, whether they were surrounded by fellow Georgians or Azerbaijanis, they contributed equally to the collective pot—about 65% of their stash. That’s despite the fact that their later decisions in the threat game indicated they viewed their Azerbaijani neighbors as threats.

Schaub says that’s likely because cooperation is often in everyone’s best interest. Conflict is costly for both parties, so cooperation helps ease tensions and keeps mutually beneficial trade relationships flowing, he reports today in the Proceedings of the Royal Society B .

“If you think about how damaging conflict can be, it might be worth investing some in keeping the relationships positive, even when you feel threatened,” Schaub says.

However, it’s not certain that the villagers are truly reacting to feeling threatened, says Zeitzoff, who has done research of his own in Georgia. Despite occasional conflict, ethnic Georgians and Azerbaijanis are not riven by deep-seated enmity, he says.

Still, he says, it’s a heartening finding. “At the end of the day, when interacting with different ethnicities, it shows that cooperation isn’t destroyed,” he says.