Bringing up children is a hard work, and you are often to blame for any bad behavior. of your children, If so, Judith Rich Harris has good news for you. Parents, she argues, have no important long-term effects on the development of the personality of their children. Far more important are their playground friends and neighborhood. Ms. Harris takes to hitting the assumption, which has dominated developmental psychology for almost half a century. Ms. Harris's attack on the developmentalists' 'nature' argument looks likely to reinforce doubts that the profession was already having. If parents matter, why is it that two adopted children, reared in the same home, are no more similar in personality than two adopted children reared in separate homes? Or that a pair of identical twins, reared in the same home, are no more alike than a pair of identical twine reared in different homes? Difficult as it is to track the precise effects of parental upbringing, it may be harder to measure the exact influence of the peer(同龄人) group in childhood and adolescence. Ms. Harris points to how children from immigrant homes soon learn not to speak at school in the way their parents speak. But acquiring a language is surely a skill, rather than a characteristic of the sort developmental psychologists hunt for. Certainly it is different from growing up tensely or relaxed, or from learning to be honest or hard-working or generous. Easy though it may be to prove that parents have little impact on those qualities, it will be hard to prove that peers have vastly more. Moreover, mum and dad surely cannot be ditched completely. Young adults may, as Ms. Harris argues, be keen to appear like their peers. But even in those early years, parents have the power to open doors: they may initially choose the peers with whom their young associate, and pick that influential neighborhood. Moreover, most people suspect that they come to resemble their parents more in middle age, and that people's child bearing habits may be formed partly by what their parents did. So the balance of influences is probably complicated, as most parents already suspected without being able to demonstrate it scientifically. Even if it turns out that the genes they pass on and the friends their children play with matter as much as affection, discipline and good example, parents are not completely off the hook. According to Ms. Harris, ______.