How Reliance on Allomaternal Care Shapes Primate Development With Special Reference to the Genus Homo

Abstract

According to the Cooperative Breeding Hypothesis, slow-maturing apes with the life history attributes of those in the line leading to the genus Homo could not have evolved unless male and female allomothers had begun to help mothers care for and provision offspring. The unusual way hominins reared their young generated novel phenotypes subsequently subjected to Darwinian social selection favoring those young apes best at monitoring the intentions, mental states, and preferences of others and most motivated to attract and appeal to caretakers. Not only were youngsters acquiring information in broader social contexts than other apes, but they also would have been emotionally and neurophysiologically different from other apes in ways relevant to how humans learn. Contingently delivered rewards to dependents who attracted and ingratiated themselves with allomothers shaped their behaviors and vocalizations and transformed the way developing youngsters learned from others and internalized their preferences