Let’s say you’re playing a game with three other people, with each player having 20 poker chips. Each of you decides how many chips to keep for yourself and how many to pool. You get 0.4 chip for each chip tossed into the common fund, even if you yourself kicked in zero.

So if two players donate five chips each to the pool, for a total of 10, then you and the other free-loader have 24 chips each—your original 20 + (0.4 times 10 chips, or 4)—while the generous pair have 19: 20 minus the 4 they contributed plus (0.4 times the 10 in the pool, or 4). It looks like free-loading is the smart strategy. Except for one thing: if everyone kicked in all 20 of their chips, so the pool had 80, then everyone would do better, getting 0.4 times 80 = 32 chips.

When scientists have run this “public goods” game, they have found that, especially after a few rounds, volunteers tend to kick in quite a lot of chips. That’s particularly so if contributors can punish free-loaders. From this, scientists spun tales of a universal human impulse to punish defectors, to cooperate, and the like.

Not so fast. To their credit, scientists in England and Switzerland have now run the experiment in 16 different cities, from Bonn and Zurich to Muscat (Oman), Minsk (Belarus), Seoul and Riyadh. Suddenly, human "universals" didn’t look so universal.

Over 10 rounds of the game, 1,120 middle-class college students in Boston and Copenhagen contributed about 18 chips; those in Athens, Riyadh and Istanbul, only six. The most-cooperative participants, who kicked in 90 percent of their chips, contributed 3.1 times as much as the least-cooperative, who had an average contribution of 29 percent of their chips. Readers are invited to insert their own explanation here; extra points for resisting ethnic slurs.

Then the scientists added another layer to the game. Not only were freeloaders punished. Now they could meekly accept their punishment, or retaliate—by docking their punishers for, well, enforcing the social ideal of cooperating for the common good. The frequency of “revenge punishments,” which the scientists call “antisocial punishment of prosocial cooperators,” was all over the map and “widespread in many participant pools,” they write in tomorrow’s issue of the journal Science—but, crucially, not in societies where most of earlier work on altruistic punishment has been done and which served as the basis for conclusions about universal human nature. That undermines the claim that lack of revenge punishments--that is, accepting your punishment gracefully--is part of human nature.

Students in Boston and Copenhagen accepted their slap-down, rarely seeking revenge on their punishers, perhaps because they knew that free-loading was reprehensible. Those in Athens and Muscat had the highest level of revenge punishments, retaliating against the enforcers about six times as often as did students in Seoul, Bonn Nottingham and several other cities. Samarra, Minsk, Istanbul and Riyadh were in the middle.

Punishment did not always increase cooperation in subsequent rounds, as had been reported in studies of the public-goods game that used only American college students; sometimes, people responded to being punished by getting huffy and refusing to kick in chips to the pool.