early age, but with important developmental changes in play. There is a tendency for children to bot

early age, but with important developmental changes in play. There is a tendency for children to both recognize inequities early in life, but to act selfishly when possible. The envy game shows this beautifully. When another child could receive more, children rejected this option even though it wouldn’t cost them directly: the decider always gets just one candy. Though no one has yet worked out what causes a developmental shift from more to less selfishness, most agree that it is driven by maturation of brain regions guiding self-control, together with social factors that make young children increasingly aware of and sensitive to their own and others’ reputations. Fehr’s studies also show that playing fair is not just about the distribution of resources, but about who gets them. Early in life, children have already carved up the world into those they know and those they don’t. This division drives their thinking and feeling, and in cases like this, their sense of fairness. Young children are well on their way to developing parochial altruism. Fehr’s research, and the majority of studies on the child’s developing sense of fairness, focus on children living in large-scale Western societies. Most of the work on fairness in adults is similarly focused on large scale societies. The precise structure of these societies may directly impact how individuals decide when to share, what commodities enter into the distribution, and whether sharing depends on effort invested, needs, and power. As noted in the last section, those who support an egalitarian society are more likely to feel empathy toward those in pain than those who support a hierarchical society. Individuals who are more empathic are also more altruistic. Hunter-gatherer societies tend to be more egalitarian, and highly cooperative. These differences predict further differences in how those living in small-scale societies, including the hunter-gatherers and subsistence farmers of Africa, Asia, and South America, should respond to unfair exchanges. The American anthropologist Joseph Henrich and his colleagues presented a set of bargaining games to adults living in different small-scale societies across the globe. Though the subjects in this study played a number of different games, the basic goal was similar to those deployed by Fehr in his studies of children and adults: under what conditions will individuals choose to share an equal as opposed to an unequal distribution of resources? Consider the ultimatum game. One individual decides how to distribute a fixed amount of money to an anonymous partner; in the Henrich games, he always used the local currency and an amount that was appropriate for the society. The partner had two options: keep what is on offer or reject it. Rejection is costly to both players as they leave empty handed. Rejection is both an expression of sour grapes for what could have been — a fair offer — and punishment for selfish behavior. In large scale societies, offers typically range from 40-50% of the initial pot, and rejections are common for offers less than about 20%. Hauser Chapter 2. Runaway desire 71 HOUSE_OVERSIGHT_012817