The ontogeny of human prosociality: behavioral experiments with children aged 3 to 8

Humans regularly engage in prosocial behavior that differs strikingly from that of even our closest living relatives, the chimpanzees (Pan troglodytes). In laboratory settings, chimpanzees are indifferent when given the opportunity to deliver valued rewards to conspecifics, while even very young human children have repeatedly been shown to behave prosocially. Although this broadly suggests that prosocial behavior in chimpanzees differs from that of young human children, the methods used in prior work with children have also differed from the methods used in studies of chimpanzees in potentially crucial ways. Here we test 92 pairs of 3-8-year-old children from urban American (Los Angeles, CA, USA) schools in a face-to-face task that closely parallels tasks used previously with chimpanzees. We found that children were more prosocial than chimpanzees have previously been in similar tasks, and our results suggest that this was driven more by a desire to provide benefits to others than a preference for egalitarian outcomes. We did not find consistent evidence that older children were more prosocial than younger children, implying that younger children behaved more prosocially in the current study than in previous studies in which participants were fully anonymous. These findings strongly suggest that humans are more prosocial than chimpanzees from an early age and that anonymity influences children's prosocial behavior, particularly at the youngest ages. (C) 2012 Elsevier Inc. All rights reserved.