One of the enduring questions of human existence relates to the tension between private and common interest. Often framed as the distinction between cooperation and individualism, it can be summarized as asking, “to what extent are my actions determined by my desire to pursue my own self-interest versus the interests of others.” The dilemma was certainly recognized by Darwin, but has been the focus of several bursts of academic interest in the last 50 years. In the 1960s, William Hamilton began to formalize the idea that altruism towards kin – those with whom we share some genetic heritage – made sense using the tools of evolutionary theory, and Richard Dawkins famously added a laser-like focus to this formalism with his selfish gene hypothesis.
But what are we to make of the fact that humans regularly help individuals who are not kin? In the 1970s, Robert Trivers developed the notion of reciprocal altruism to explain such cooperative behaviour – essentially, if you help me I’ll help you. Soon thereafter, game theory began to be applied to the paradigm, and has turned out to be an exemplary way of probing the tension between cooperation and selfish behaviour (a previous post dealt with game theory and reciprocal altruism). In one prominent series of studies, Ernst Fehr and his colleagues have amassed a substantial body of data showing that the kind of large scale cooperative behaviour exhibited by humans is dependent primarily upon the threat of punishment: the tit for tat hypothesis. Now, in a new paper in Science, Rand et al. challenge this view, showing that in a public goods game, positive interactions promote cooperation when repeated interactions are expected to occur. From the abstract.
The public goods game is the classic laboratory paradigm for studying collective action problems. Each participant chooses how much to contribute to a common pool that returns benefits to all participants equally. The ideal outcome occurs if everybody contributes the maximum amount, but the self-interested strategy is not to contribute anything. Most previous studies have found punishment to be more effective than reward for maintaining cooperation in public goods games. The typical design of these studies, however, represses future consequences for today’s actions. In an experimental setting, we compare public goods games followed by punishment, reward, or both in the setting of truly repeated games, in which player identities persist from round to round. We show that reward is as effective as punishment for maintaining public cooperation and leads to higher total earnings. Moreover, when both options are available, reward leads to increased contributions and payoff, whereas punishment has no effect on contributions and leads to lower payoff. We conclude that reward outperforms punishment in repeated public goods games and that human cooperation in such repeated settings is best supported by positive interactions with others.
This work from Nowak’s group reprises a theme that is important in considering neuroeconomic studies of human behaviour: it is important to model the behaviour as closely as possible on the real world conditions in which humans live (and thrive), while trying to limit confounding variables as laboratory experiments are wont to do. [For another take on the issue, see this paper in Nature from earlier in the year, also from Nowak’s group. Also, there is an excellent commentary in the recent issue of Science on the origins of cooperation by Elizabeth Pennissi.]
The tension between private and common interest is certainly of interest to academics studying the evolution of social behavior, but it is also central to nearly every debate about political life in the modern world. Examples abound (the current health care debate in the US is an obvious one), but as a citizen of both the US and Canada, one comment in a recent issue of The New Yorker by Adam Gopnik strikes me as particularly relevant. The article is a profile of Michael Ignatieff, Leader of the Official Opposition and the Liberal party in Canada, and possibly the next Prime Minister of the country. Because Ignatieff is both a politician and a political philosopher who spent 25 years abroad including a long stint on the faculty of Harvard, it was perhaps inevitable that Gopnik’s prose would wander into describing the unique brand of glue that holds together the country known as Canada.
We are not, and have never been, the Canadian collectivists argue – in conscious opposition to older Anglo-American traditions – the rational individuals of liberal contract theory. No man is an island, and rules made for imaginary islands ignore the fragile ecology of the archipelago. We are people who live in communities, and our sense of who we are derives from what the people around us are like. To exalt the individual and his rights at the expense of nurturing the tenuous threads of togetherness leads to violence, alienation, political apathy, and the growth of crazy movements that can supply, in moonshine form, the sense of solidarity that pure “rights” liberalism can’t – the very traits that Canadians see in a nearby country, they name no names.