Judith Rich Harris is a developmental psychologist who has looked at the influences on young people of their friends and peer groups. She argues that three main forces shape our development: personal temperament, our parents, and our peers. The influence of peers, she argues, is much stronger than that of parents. “The world that children share with their peers,” she says, “is what shapes their behavior and modifies the characteristics they were born with, and hence determines the sort of people they will be when they grow up.”
