I'm going to take off my "mature adult" hat here, and say something I think which is probably totally groundless, but I want to talk about it anyways.
A lot of little boys are hyper as fuck, and I don't think that's a social construct. I think that's just how little boy bodies tend to produce energy: in excess.
Also, a good description for most games might be "twitchy." I think these two line up.
But in answer to your question, Nature vs Nurture: the answer is always both, but far more nature than we'd like. When we hit the cyborg/embedded computers line, that's when I think it'll be 50/50.