Harris's brilliant stroke was to change the discussion from nature (genes) and nurture (parents) to its older version: heredity and environment. ''Environment'' is broader than nurture. Children, like adults, have two environments: their homes and their world outside the home; their behavior, like ours, changes depending on the situation they are in. Many parents know the eerie experience of having their child's teacher describe their child in terms they barely recognize (''my kid did what?''). Children who fight with their siblings may be placid with friends. They can be honest at home and deceitful at school, or vice versa. At home children learn how their parents want them to behave and what they can get away with; but, Harris shows, ''These patterns of behavior are not like albatrosses that we have to drag along with us wherever we go, all through our lives. We don't even drag them to nursery school.''
Harris has taken a factor, peers, that everyone acknowledges is important, but instead of treating it as a nuisance in children's socialization, she makes it a major player. Children are merciless in persecuting a kid who is different -- one who says ''Warshington'' instead of ''Washington,'' one who has a foreign accent or wears the wrong clothes. (Remember?) Parents have long lamented the apparent cruelty of children and the obsessive conformity of teen-agers, but, Harris argues, they have missed the point: children's attachment to their peer groups is not irrational, it's essential. It is evolution's way of seeing to it that kids bond with each other, fit in and survive. Identification with the peer group, not identification with the parent, is the key to human survival. That is why children have their own traditions, words, rules, games; their culture operates in opposition to adult rules. Their goal is not to become successful adults but successful children. Teen-agers want to excel as teen-agers, which means being unlike adults [emphasis added].