...does cooperation always have self-interested roots? Some researchers are starting to have their doubts.
Over the past decade, experiments devised by Ernst Fehr of the University of Zurich in Switzerland, among others, have shown that many people will cooperate with others even when it is absolutely clear they have nothing to gain. A capacity for true altruism seems to be a part of human nature. It is a heartening discovery, yet one that has also touched off a firestorm of debate...
Across disciplines, researchers now agree that people often act against their own self-interest. "This is the most important empirical work on the human sense of justice in many years," says evolutionary 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 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, 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."
If Trivers is right, then true altruism is what evolutionary biologists call a "maladaptation". Evolved to respond in a certain way to a given situation, 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, according 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 which procreation is clearly impossible, "even when they know the object of their desire is imaginary, or a piece of paper", as Tooby says.
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. 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...
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 (Proceedings of the National Academy of Sciences, vol 100, p 3531).
Could competition between small groups of our ancestors somehow have turned them into strong reciprocators? Gintis, Boyd and their colleagues believe so. What's more, subsequent research by Fehr, working with economist Urs Fischbacher of the University of Zurich, suggests that as humans came to live in larger groups, their attitudes towards reciprocity may have become even more hard-line. Using a similar model to Gintis and the others (Nature, vol 425, p 785), they found that cooperation can become the default behaviour in large groups provided punishers are willing to punish not only those who cheat, but also those who fail to punish cheats (see Graph). "In this case," Fehr says, "even groups of several hundred individuals can establish cooperation rates of between 70 and 80 per cent."
These findings suggest that true altruism, far from being a maladaptation, may be the key to our species' success by providing the social glue that allowed our ancestors to form strong, resilient groups. It is still crucial for social cohesion in today's very different world. "Something like it had to evolve," Gintis says.
That makes more sense and it's an important issue for this phase of human cultural evolution as we interact with ever more remote and numerous people, most of whom will forever be strangers by classical definitions. Far from being a maladaptation strong reciprocity is essential to an internetworked world. It's important to highlight the need to punish wrong doers and those who fail to punish wrong doers though they have otherwise done no wrong themselves. Clearly spammers should be stabbed to death along with their accomplises.