www.newscientist.com/channel/being-human/mg18524901.600
Enlarge image When it pays to play along IN THE aftermath of the Indian Ocean tsunami last year, people from the w orld's richest countries were falling over each other to make donations to help rebuild the lives of the survivors. Perhaps it was the conjuncti on of this terrible natural disaster with the consumerist orgy of Christ mas that spurred so many of us to greater generosity. Whatever the reaso n, conspicuous donation suddenly became the vogue. Individuals, and even entire countries, competed to see who could send most money to people o n the other side of the world whose identity they did not know and who t hey were highly unlikely ever to meet. Not that Homo sapiens is the only species in which individuals bestow kin dness on others. Many mammals, birds, insects and even bacteria do likew ise. But their largesse tends to be reserved for their genetic relatives ; this makes sense in evolutionary terms, because by helping someone who shares many of your genes you improve the chances of propelling this co mmon DNA into the future. Humans are different, for we cooperate with co mplete genetic strangers - workmates, neighbours, anonymous people in fa r-off countries. For several decades, researchers have had a possible explanation: apparen tly selfless acts are nothing of the kind, but are instead a clever way of promoting individual self-interest. When rivals meet again and again, for example, the rewards of cooperation can outweigh the costs of confl ict, so getting along pays dividends. Scientists have also come to reali se what philanthropists such as Getty and Gates have long known: that al truism does wonders for your reputation (see "Why are we so generous? Over the past decade, experiments devised by Ernst Fehr of the University of Zurich in Switzerland, among others, have shown that many people wil l cooperate with others even when it is absolutely clear they have nothi ng to gain. A capacity for true altruism seems to be a part of human nat ure. It is a heartening discovery, yet one that has also touched off a f irestorm of debate. The experiments at the centre of the controversy are as simple as they ar e illuminating. They ignore theory-based preconceptions about how indivi duals ought to behave and focus instead on finding out what they actuall y do when playing games in which there is real money at stake. One of the most basic of these games is the "ultimatum game". An experime nter gives one of two players some cash, say $20, and asks that person, called the "proposer", to offer a fraction of it to the second player, c alled the "receiver", whose identity is hidden from the other player. Th e proposer can offer any amount they choose, from nothing up to the enti re $20. The receiver then has the choice of accepting or rejecting the o ffer. If he or she accepts, the cash is shared according to the original offer. For the receiver, self-interest would seem to dictate accepting the offer no matter how small it is, since getting something is better than getti ng nothing. Knowing this, a similarly self-interested proposer should of fer as little as possible. But over the past decade or so, research on s tudent volunteers has shown that proposers in such experiments typically offer anything from 25 to 50 per cent, while receivers tend to reject o ffers of less than 25 per cent. "People reject low offers," says anthropologist Joseph Henrich of Emory U niversity in Atlanta, Georgia, "because they view them as unfair." And t hrough their rejection, they show a willingness to punish the unfair off ers even at a cost to themselves. A vast number of other experiments illustrate the same point. Last year, for example, Fehr and his colleagues had students play a version of the famous prisoner's dilemma game, in which two people can prosper through cooperation but are also given strong incentives to cheat on one another . In this game, if the participants cooperate, each receives a worthwhil e monetary pay-off. But either player can get an even higher pay-off by cheating while their opponent cooperates (see Diagram). In this particular version of the game, the researchers got people to pla y sequentially: one would go and then the other, fully aware of what the first had done. In theory, anyone thinking only of their own personal g ain would always cheat, as this pays more than cooperating. But in the e xperiments, although many of players who went first did cheat, others co operated, despite knowing that the second player could sucker them by ch eating. What's more, roughly half those who went second rewarded coopera tion by treating their opponent fairly, even though that meant forgoing an easy pay-off for themselves (Human Nature, vol 13, p 1). "Many people are willing to cooperate and to punis h those who don't, even when no gain is possible." Many people will cooperate, and punish those who don't, even when no gai n is possible This tendency - which researchers call "strong reciprocity" - throws into question the assumption that apparently selfless behaviour must have so me selfish explanation. Across disciplines, researchers now agree that p eople often act against their own self-interest. "This is the most impor tant empirical work on the human sense of justice in many years," says e volutionary biologist Robert Trivers of Rutgers University in New Jersey . But when it comes to explaining the origin of our altruism, matters get a whole lot more contentious. In evolutionary terms it is a puzzle becaus e any organism that helps others at its own expense stands at an evoluti onary disadvantage. So if many people really are true altruists, as it s eems, why haven't greedier, self-seeking competitors wiped them out? One possibility, Trivers suggests, is that evolution actually is wiping t hese people out - it just hasn't finished the job yet. He, along with ma ny anthropologists, takes the view that humans evolved to cooperate when our ancestors lived in small, isolated groups of hunter-gatherers. In t his setting, they learned through repeated interaction with others that cooperation generally pays because it induces other members of the group to return a favour in the future. Biologists refer to strategic coopera tion of this kind as "reciprocal altruism". It cannot directly explain t he true altruism found in experiments in which anonymous players meet on ly once, offering them no hope of future gain. But it is the benefits we gained from reciprocal altruism in our evolutionary past that lead us t o behave with "inappropriate" altruism in experiments like Fehr's, Trive rs says. "Our brains misfire when presented with a situation to which we have not evolved a response." If Trivers is right, then true altruism is what evolutionary biologists c all a "maladaptation". Evolved to respond in a certain way to a given si tuation, we find it hard to act differently in the changed circumstances of the modern world. That would make strong reciprocity just another in a long list of maladaptations found in modern human behaviour, accordin g to anthropologist John Tooby of the University of California at Santa Barbara. To make his point he gives the example of sexual desire, which most biologists agree evolved to spur the conception of offspring. Today , however, individuals experience sexual desire in many situations in wh ich procreation is clearly impossible, "even when they know the object o f their desire is imaginary, or a piece of paper", as Tooby says. Any organism that helps others at its own expense stands at an evolution ary disadvantage Undoubtedly adaptations that evolved to help us cope under specific condi tions can backfire when situations change. But not everyone is convinced by the idea that true altruism is such a maladaptation. He believes that while our ancesto rs lived in small, close-knit groups, one-shot interactions with strange rs would have been common even then. What's more, these interactions cou ld have been crucial to people's survival, because they would have occur red over shared resources such as water holes and prey animals and, more crucially, in times of catastrophe such as flood or drought. "Environ...
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