ABSTRACT
Yet non-parents have always looked after children. It is likely that evolutionary processes selected infants who developed ways of attracting adults who were not parents, such as with big eyes or symmetrical features, optimising their chances of survival by gaining wider sources of care. Humans, but certainly not all primates, have an evolutionary history of breeding cooperatively, or in other words there have always been people other than mothers who have shared in the task of childcare. Although paying for childcare is a recent phenomenon, mothers leaving children at nurseries or with childminders is part of a long tradition of nonmaternal care. Humans produce some of the costliest infants, in terms of the required investment of time and energy, and by the time the next child comes along, it is extremely unlikely that the previous one will be anywhere near independent. A human infant requires more physical and emotional resources than a mother alone can provide, and the cooperative nature of human childrearing allows more offspring to survive and also allows reduced intervals between births.
