Most cartoon children seem to act like miniature adults vs actual children; see: Bart Simpson, Lisa Simpson, Timmy Turner, etc. When *I* was 10, I was way more occupied with toys or watching cartoons than, uh, knowing who Liza Minelli or Pablo Neruda were... or so forth...
For teenagers, this seems less so, maybe since they're supposed to be (somewhat) more mature than children. Though even the teenagers seem to have way more freedom than I ever had as an adolescent (getting to stay out *very* late, rarely seeming to check in with parents, etc.---see: the Scooby Doo gang).