"There are clear differences between child and adult artistic activity. While the child may be aware that he is doing things differently from others, he does not fully appreciate the rules and conventions of symbolic realms; his adventurousness holds little significance. In contrast, the adult artist is fully cognizant of the norms embraced by others; his willingness, his compulsion, to reject convention is purchased, at the very least, with full knowledge of what he is doing and often at considerable psychic cost to himself."