If my basic wm has 9 good buckets in it, I may have two working on something curious I saw earlier. If you ask me to remember 7 numbers, I may eat another bucket or two noticing patterns between the numbers rather than just the mundane dropping them into the buckets. Suddenly I seem to have only five buckets!
Also, if he sees/hears/notices something he doesn't understand, he keeps it in his head and has a hard time moving on to another task or attending to another task until he has figured whatever it is out. I notice this with him a lot. He has actually started saying it to us.... "wait! I need to go aback and understand what you were saying in your conversation about [such and such] befroe I can do [x]" And it is usually and adult matter that he shouldn;t be listeing to....LOL
