In the view of the primatologist Sarah Blaffer Hrdy, the extraordinary social skills of an infant are at the heart of what makes us human. Through its ability to solicit and secure the attentive care not just of its mother but of many others in its sensory purview, a baby promotes many of the behaviors and emotions that we prize in ourselves and that often distinguish us from other animals, including a willingness to share, to cooperate with strangers, to relax one’s guard, uncurl one’s lip and widen one’s pronoun circle beyond the stifling confines of me, myself and mine.