Literature

There has long been a quest for evolutionary explanations of altruistic human behaviour and various mechanisms have been proposed (kin selection, reciprocal altruism). However, these have not done justice to the range of cooperative behaviours exhibited by humans. Animals, particularly chimpanzees, have been extensively studied to gain insights into the evolution of human behaviour. The public are treated to stories of tool use and non-verbal communication and many think that the gulf between humans and the great apes is not a big one to jump. So it is of interest to note a recent study that demonstrates that chimpanzees have no detectable sense of fairness.
The researchers developed an experimental programme based on an exercise known as the ultimatum game. With humans, an individual presents a proposal to share money with a second player. If the second player accepts, the proposal is implemented. If the second player declines, no one gets anything. It is found that if the proposer is not generous enough in the proposal, the responder thinks the deal is unfair and declines, so the proposer gets no benefit.
With chimps, raisins rather than money were used as currency. Also, the 'proposer' chimps were not expected to choose the division of raisins in their proposal - this was controlled by the researchers. It was found that the 'responder' chimps accepted any offer that brought them a finite number of raisins, and the researchers detected no trace of the chimps refusing proposals that were unfair. Traditional models of economic behaviour describe these responders as "rational maximizers" - who make judgments based on self-interest, without reference to other parties.
The researchers conclude: "It thus would seem that in this context, one of humans' closest living relatives behaves according to traditional economic models of self-interest, unlike humans, and that this species does not share the human sensitivity to fairness."
The paper suggests this research makes "an important contribution to the debate on evolution and possible uniqueness of human cooperation", but does not comment further. The sense of fairness implies a sense of right and wrong (morality) and an ability to analyse the situation abstractly (an aspect of consciousness). Evolutionary theorists have struggled with both these elements. Their discussion revolves around genetics and the environment (nature and nurture), but this is as far as their conceptual model permits them to go. A design perspective does not place restrictions on the explanatory framework adopted, allowing a richer set of hypotheses to be explored.

Chimpanzees Are Rational Maximizers in an Ultimatum Game
Keith Jensen, Josep Call, and Michael Tomasello
Science 318, 5 October 2007: 107-109.

Traditional models of economic decision-making assume that people are self-interested rational maximizers. Empirical research has demonstrated, however, that people will take into account the interests of others and are sensitive to norms of cooperation and fairness. In one of the most robust tests of this finding, the ultimatum game, individuals will reject a proposed division of a monetary windfall, at a cost to themselves, if they perceive it as unfair. Here we show that in an ultimatum game, humans' closest living relatives, chimpanzees (Pan troglodytes), are rational maximizers and are not sensitive to fairness. These results support the hypothesis that other-regarding preferences and aversion to inequitable outcomes, which play key roles in human social organization, distinguish us from our closest living relatives.

See also:

Fair Play in Chimpanzees, Max Planck Press Release, 5 October 2007

Patience, fairness and the human condition, The Economist, Oct 4th 2007