Beyond the family, the forces that most strongly influence children and adolescents are peers, media, and school. Peer bonds are vital for social competence, and parent and peer relations complement one another. Among preschool children, social development begins with nonsocial activity, then shifts to parallel play, then to two forms of true social interaction: associative play and cooperative play. All of these types of play coexist during the preschool years. Sociodramatic play, an advanced form of cooperative play, supports many aspects of cognitive, emotional, and social development. Sharing, helping, and other prosocial acts increase in middle childhood, as does rough-and-tumble play, which may help children establish a dominance hierarchy that serves the adaptive function of limiting aggression.
Parents exert both direct and indirect influence on peer sociability; situational factors, such as age mix, and cultural values also play a role. Authoritative parenting provides a firm foundation for competence in relating to agemates. Children benefit from both same-age and mixed-age relationships. In collectivist societies that emphasize group harmony, children play in large groups requiring high levels of cooperation. Peer contact rises in adolescence in all societies, but especially in industrialized nations.
In early childhood, friendships are based on shared pleasurable activity; as children grow older, friendship becomes more abstract, and trust becomes its defining feature. Teenagers emphasize intimacy, mutual understanding, and loyalty as the qualities they seek in a friend. Friendships are remarkably stable at all ages. Friends behave more prosocially with one another but also disagree and compete more; friendship provides a context in which children learn to tolerate criticism and resolve disputes. Children generally choose friends who resemble themselves in attitudes and values; teenagers, as part of the process of forging a personal identity, choose some friends who differ from themselves. In middle childhood, sex differences emerge: girls’ friendships are more likely to include emotional closeness and self-disclosure. Warm, gratifying childhood and adolescent friendships are related to psychological health and competence into emerging adulthood.