This presentation describes young children's social development, beginning with infancy and spanning the early childhood years. Topics include: (1) attachment when the infant is very young; (2) a social-learning theory view of the early months of life; (3) the onset of prosocial behavior and responsibility; and (4) competence in the early childhood peer group. An hypothesis is proposed to explain why attachment theory predicts early competence better than research from a social learning orientation, and the hope is expressed that attachment theorists and social learning theorists can pool their insights regarding development. The discussion of prosocial behavior and responsibility focuses on a cluster of child behaviors that are central to socialization and that require the caregiver to take the best from attachment theory and social learning theory: non-egocentric behaviors such as empathy, sympathy, consideration for others, fairness, and social responsibility. Particular attention is given to the work of Baldwin (1948), Hoffman (1963), and Baumrind (1971) concerning, respectively, discipline styles, parent influence on children's consideration for others, and parent-child interaction styles and social responsibility in young children. Early childhood settings appear to be effective training grounds for young children's social competence; in particular, social perspective-taking and consideration for others. (RH)