I think
ADD, or the
brain functions affected by ADD, are a large cause of this phenomenon. Folks with ADD swing between a
total lack of focus and a frighening
hyperfocus. I'm told that there's a mechanism in the brain which regulates your attention, a sort of
traffic cop for your CPU.
Ritalin and related drugs stimulate the traffic cop.
Everyone I know with ADD is quite brilliant. I'll bet folks who can play with a paper clip for hours, whether or not they have ADD, have a wider range of abilities in that attention regulator. It seems like an important tool in problem solving- looking at the big picture, then at a detail. Folks who can do both become great minds.