Ill tell you one thing about retarded people or people considered "slow". They are some smooth wheeling and dealing characters when they see an opening
Alot of them have just been treated like prisoners their whole lives. They downplay alot of what they know,what they can do. I assume its just them trying to be who their caretakers expect them to be,not wanting to dissapoint them.
Yeah they are on their best behavior when parents,teacher aint around. Whole different ball game when they are seperated and you get to talking to them normal.