The mystery that the idea of prosocial behavior may help resolve is the mystery of why we cooperate at all. Societies and organizations work only if people cooperate. It’s impossible for a society to rely on law alone to make sure citizens act honestly and responsibly. And it’s impossible for any organization to rely on contracts alone to make sure that its managers and workers live up to their obligations, So cooperation typically makes everyone better off. But for each individual, it’s rarely rational to cooperate. It always makes more sense to look after your own interests first and then live off everyone else’s work if they are silly enough to cooperate. S0 why don’t most of us do just that?
The classic and canonical explanation of why people cooperate was offered by political scientist Robert Axelrod, who argued in the 1980s that cooperation is the result of repeated interactions with the same people. As Axelrod put it in his classic The Evolution of Cooperation, “The foundation of cooperation is not really trust, but the durability of the relationship . . . Whether the players trust each other or not is less important in the long run than whether the conditions are ripe for them to build a stable pattern of cooperation with each other.” People who repeatedly deal with each other over time recognize the benefits of cooperation, and they do not try to take advantage of each other, because they know if they do, the other person will be able to punish them. The key to cooperation is what Axelrod called “the shadow of the future.” The promise of our continued interaction keeps us in line, Successful cooperation, Axelrod argued, required that people start off by being nice—that is, by being willing to cooperate—but that they had to be willing to punish noncooperative behavior as soon as it appeared. The best approach was to be “nice, forgiving, and retaliatory.”
Those rules seem completely sensible, and are probably a good description of the way most people in a well-’functioning society deal with those they know. But there’s something unsatisfying, as Axelrod himself now seems to recognize, about the idea that cooperation is simply the product of repeated interactions with the same people. After all, we often act in a prosocial fashion even when there is no obvious payoff for ourselves. Look at the ultimatum game again. It is a one-shot game. You don’t play it with the same person more than once. The responders who turned down lowball offers were therefore not doing so in order to teach the proposer to treat them better. And yet they still punished those whom they thought were acting unfairly, which suggests that the “shadow of the future” alone cannot explain why we cooperate.
The interesting thing, ultimately, isn’t that we cooperate with those we know and do business with regularly. The interesting thing is that we cooperate with strangers. We donate to charities. We buy things off eBay sight unseen. People sign on to Kazaa and upload songs for others to download, even though they reap no benefit from sharing those songs and doing so means letting strangers have access to their computers’ hard drives. These are all, in the strict sense, irrational things to do. But they make all of us (well, aside from the record companies) better off. It may be, in the end, that a good society is defined more by how people treat strangers than by how they treat those they know.
Consider tipping. It’s understandable that people tip at restaurants that they frequent regularly: tipping well may get them better service or a better table, or it may just make their interactions with the waiters more pleasant. But, for the most part, people tip even at restaurants that they know they’ll never return to, and at restaurants in cities thousands of miles away from their homes. In part, this is because people don’t want to run the risk of being publicly reprimanded for not tipping or undertipping. But mostly, it’s because we accept that tipping is what you are supposed to do when you go to a restaurant, because tips are the only way that waiters and waitresses can make a living. And we accept this even though it means that we end up voluntarily giving money to strangers whom we may never see again. The logic of this whole arrangement is debatable (as Mr. Pink asked in Reservoir Dogs, why do we tip people who do certain jobs and not even think of tipping people who do other jobs?). But given that logic, tipping, and especially tipping strangers, is a resolutely prosocial behavior, and one that the shadow of the future alone cannot explain.
Why are we willing to cooperate with those we barely know? I like Robert Wright’s answer, which is that over time, we have learned that trade and exchange are games in which everyone can end up gaining, rather than zero-sum games in which there’s always a winner and a loser. But the “we” here is, of course, ill defined, since different cultures have dramatically different ideas about trust and cooperation and the kindness of strangers. In the next section, I want to argue that one of the things that accounts for those differences is something that is rarely associated with trust or cooperation: capitalism.