If you never allow your children to exceed what they can do, how are they ever going to manage adult life - where a lot of it is managing more than you thought you could manage?

Cultural expectations shade and color the images that parents-to-be form. The baby product ads, showing a woman serenely holding her child, looking blissfully and mysteriously contented, or the television parents, wisely and humorously solving problems, influence parents-to-be.

Often, when there is a conflict between parent and child, at its very hub is an expectation that the child should be acting differently. Sometimes these expectations run counter what is known about children's growth. They stem from remembering oneself, but usually at a slightly older age.

In families children tend to take on stock roles, as if there were hats hung up in some secret place, visible only to the children. Each succeeding child selects a hat and takes on that role: the good child, the black sheep, the clown, and so forth.