Because parents love their children and want the best for them, they
worry about them a lot, and one of the things that parents worry about
most is whether their children are hitting age-appropriate targets for
behavior. Shouldn't a child be toilet trained by the age of 4? Should a
10-year-old to be able to sit down and do an hour of homework? One
reason why such questions produce so much conflict and woe in the home
is that parents' expectations for their children's behavior tend to be
too high. I'm not talking about permissiveness or strictness here; I'm
talking about accurately estimating children's actual abilities. A
reliable body of research shows that we expect our children to do things
they're not yet able to do and that we judge and punish them according
to that expectation. http://www.slate.com/articles/life/family/2008/11/why_cant_johnny_jump_tall_buildings.html