Bailey House and his colleagues who tested 326 children aged three to fourteen from six different cultural groups: urban Americans from Los Angeles; horticultural Shuar from Ecuador; horticultural and marine foraging Fijians from Yasawa Island; hunter-gathering Akas from the Central African Republic; pastoral, horticultural Himbas from Namibia; and hunter-gatherer Martus from Australia.
In one game, the children had to choose whether to take two food rewards for themselves or take one and give the other to their partner. When this partner was sat before them, a similar pattern was found across the diverse cultural groups - progressively from age three to about seven or eight the children grew more selfish. That is, the older the child, up to seven or eight, the more likely they were to keep both treats for themselves.
Intriguingly, aged eight to fourteen, the behaviour of the children varied depending on the culture they belonged to. For instance, the American children showed a sharp up-turn in making the selfless option. The Aka showed a similar increase in selflessness, but starting at a slightly later age. The Fijian children, by contrast, became even more likely to choose the selfish option right into early adolescence.
The older children's choices tended to mirror the behaviour of the adults from their culture on similar games, suggesting they were gradually acquiring the social norms around altruism and reciprocity for their specific society.
The emergence of cultural differences in the older children's choices only appeared for this costly version of the game, in which giving to another person meant sacrificing their own gain. In a different version, in which they could be generous at no cost to themselves, no such differences emerged across cultures.
Bailey House and his team said their results illustrated how cultural norms interact with children's developing sense of fairness, which is consistent with theories that emphasise the role of genes and culture in human altruism and how it varies between societies. The results also reinforce past evidence suggesting that cultural norms particularly influence how people choose to behave when altruistic choices are costly to themselves.
"Our findings contribute to ongoing discussions of the processes that underlie both uniformity and diversity in social behaviour across societies," the researchers said, "and highlight the importance of expanding the scope of developmental studies to encompass a wider range of extant human diversity." Indeed, psychology has long been criticised for focusing too much on rich, Western participants and this study is to be applauded for its cross-cultural reach.
House BR, Silk JB, Henrich J, Barrett HC, Scelza BA, Boyette AH, Hewlett BS, McElreath R, and Laurence S (2013). Ontogeny of prosocial behavior across diverse societies. Proceedings of the National Academy of Sciences of the United States of America, 110 (36), 14586-91 PMID: 23959869
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.