..."The facts are clear," [economist Ernst] Fehr says. "Many people are willing to cooperate and to punish those who don't, even when no gain is possible."
This tendency - which researchers call "strong reciprocity" - throws into question the assumption that apparently selfless behaviour must have some selfish explanation. Across disciplines, researchers now agree that people often act against their own self-interest.
...
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 because any organism that helps others at its own expense stands at an evolutionary disadvantage. So if many people really are true altruists, as it seems, why haven't greedier, self-seeking competitors wiped them out?
One possibility, [evolutionary biologist Robert] Trivers suggests, is that evolution actually is wiping these people out - it just hasn't finished the job yet. He, along with many anthropologists, takes the view that humans evolved to cooperate when our ancestors lived in small, isolated groups of hunter-gatherers. In this 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 cooperation of this kind as "reciprocal altruism". It cannot directly explain the true altruism found in experiments in which anonymous players meet only 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 to behave with "inappropriate" altruism in experiments like Fehr's, Trivers says. "Our brains misfire when presented with a situation to which we have not evolved a response."
...
Undoubtedly adaptations that evolved to help us cope under specific conditions can backfire when situations change. But not everyone is convinced by the idea that true altruism is such a maladaptation. [Anthropologist Joseph] Henrich disagrees with the theory's central premise. He believes that while our ancestors lived in small, close-knit groups, one-shot interactions with strangers would have been common even then. What's more, these interactions could have been crucial to people's survival, because they would have occurred over shared resources such as water holes and prey animals and, more crucially, in times of catastrophe such as flood or drought. "Environmental shocks would have guaranteed that strangers encountered one another during fitness-critical times," Henrich says.
If both one-shot and repeated interactions were routine in ancestral life, Henrich argues, evolution would presumably have prepared us to distinguish between the two with some precision. And that does seem to be the case. Two years ago economists Simon Gächter of the University of St Gallen in Switzerland and Armin Falk of the University of Bonn, Germany, looked at how people alter the way they play the prisoner's dilemma game depending on whether the game involves one-shot or repeated encounters with others. If people treat one-shot encounters as if they were repeated - as the maladaptation idea suggests - then there shouldn't be a difference. But they found that repeated play more than doubled cooperation levels, indicating that we are fully capable of adapting our behaviour to the situation at hand...
Further support for the idea that strong reciprocity is an adaptation in its own right comes from the theoretical studies of economist Herbert Gintis of the University of Massachusetts, Amherst, anthropologist Robert Boyd of the University of California at Los Angeles, and others. They set up a computer model in which groups of individuals interacted, and watched how their behaviour evolved. Individuals were set up in the model to behave initially either as cheats or as cooperators, and in personal interactions the former came off best. When groups competed with one another, however, cooperation came into its own: groups with more cooperators were likely to flourish.
But that was only the start. The individuals, whether initially cooperators or cheats, were also programmed to copy successful behaviour. In simulations with groups ranging from 4 to 256 individuals, the team found that altruism could evolve. The benefits that cooperation conferred on a group outweighed its costs to individuals - but only in groups of less than about 10. Ancestral human hunter-gatherer bands are thought to have numbered 30 or more individuals, so how could cooperative behaviour have evolved and spread in these groups?
The answer lies in the fact that strong reciprocity is not simply a matter of cooperation; it also requires punishment of those who fail to toe the line. When the team added punishment to their models, they found it made a huge difference. In a second round of simulations, they included a new kind of individual: the "punishers". These punishers were not only willing to cooperate with others but also to punish cheats. By making cheats pay for their antisocial actions, they tipped the balance towards cooperation. This time, competition between groups led to the emergence of cooperation in groups of up to 50 individuals...
Which is good to know - but here's a cautionary note:
Despite our altruism, generosity may not be in our genes. If true altruism has evolved through competition between groups, as some researchers maintain ..., then it is more likely to be the product of cultural evolution. Genetic evolution works by selecting individuals [or genes - strange to see a British science mag taking the Gouldian line - RW] with traits that are well adapted to their environment, but it has a far weaker grip on traits that benefit the group. So altruism is more likely to be learned. After all, every human culture invests considerable effort in instilling children with moral norms that help further cooperation.Which means that a culture devoted to rewarding cheaters may eventually weed out strong reciprocity, and the devotees of those pseudo-scientific dogmas that claim human nature is innately selfish will succeed in creating a society in their own sociopathic image.