The neuroscience of social relationships in early development.

Abstract

H uman beings are a remarkably social species. We consider how our actions will impact our reputations and relationships, read others' facial expressions to decipher their emotions, forge lasting relational bonds, collaborate to care for each other's children, and build complex economies of scale (Bowlby, 1969(Bowlby, /1982Hrdy, 2009Hrdy, , 2014Nowak, 2006). Humans' social capacities are deeply rooted in our evolutionary history, and many of these capacitiesincluding aspects of empathy and cooperative behavior-are observable in our closest living primate relatives: chimpanzees and bonobos (Horner et al., 2011;Tomasello, 2020;Wobber et al., 2014).Yet humans also possess unique social cognitive abilities-abilities which emerged as adaptations to the socioculturally complex groups in which we live (see the social brain hypothesis in Dunbar, 2003), and which appear early in ontogeny (Tomasello, 2020). For example, human children as young as 2 years old outperform juvenile great apes on tasks requiring social cognition (e.g., imitation, intention reading); moreover, human children continue to