Ok, since I can't edit my post I'll do that here.
When it comes to knowledge Sam can retain general facts for over a year, if he reads several articles/ books on a subject, it varies on the complexity of the knowledge ex: If he read a whole book on astrophysics, he would be an expert on it for about a week. If he read a book on the history of Japan, he would know all of it for about a month or so.
When he copies physical movements involved in fighting techniques, unless he is trained for at least several months like a normal human, he tends to forget the style within a few days. He is a black belt in karate since he trained at a dojo for six months. Also he does learn exceptionally faster than others, which is why it only took six months to be a black belt.
I'm being a bit more detailed on his being "in tune with his environment" By just glancing at a room, such as a classroom, he knows just about every factor in said room, that can be used to his advantage or disadvantage, when he watches someone display a power, he can quickly determine how it works. He can basically learn anything with little information to work with.
Hope that is okay :)