DP17731 It Makes a Village: Allomaternal Care and Prosociality
A recent hypothesis suggests that an impetus for human cooperation could have emerged from the needs of mothers to elicit and sustain help from others, i.e. allomaternal care, for the purpose of bringing offspring to maturity. We design a novel economic experiment to elucidate the relationship between allomaternal care and cooperative behavior among a random sample of 820 adults and 200 children in the Solomon Islands. Our results show that allomaternal care, especially by non-kin, nurtures adult reciprocity and altruism, and impersonal prosociality among mothers. We also document socio-cognitive benefits to children from child care by non-kin, based on daylong vocalizations analyzed using a multilingually-trained neural network. Further analysis utilizing cross-cultural ethnographic data shows a positive relationship between allomaternal care and societal orientation toward trust. Altogether, our findings suggest an important role for allomaternal care - especially by non-kin - in supporting societal cooperation.