I think I read some old science paper that said as a species our brains are hard wired that when we enter a new environment to check around where everything is and make sure we don't have something dangerous we are walking into. Not sure that is true because I have yet to find a snake in the kitchen and my daughter was the only one I know that retains the skill of seeing everything in every room.
@Pfuzylogic: I didn't know people were [b][i]supposed [/i][/b] to become forgetful after 40. Now I don't feel so bad. Maybe if I hadn't become forgetful, that would have been bad?
However, I've been forgetful, in the way mentioned by the OP since I was very* young.