It Makes a Village : Allomaternal Care and Prosociality

We examine a novel hypothesis that roots human prosociality in the need to elicit and sustain help from others for the purpose of raising children, i.e. allomaternal care. We design an economic experiment to characterize the relationship between allomaternal care and cooperative behavior among a sample of 820 adults in the Solomon Islands. Our results show that receiving help with child care nurtures reciprocity and altruism towards those who provide help. Moreover, help from non-relatives predicts impersonal prosociality toward strangers, suggesting an important foundation for the development of impersonal prosociality. As evidence of a mechanism sustaining the prevalence of allomaternal care, we document large socio-cognitive benefits to children from care by non-relatives, based on daylong vocalizations of 200 children analyzed using a multilingually-trained neural network