Comment by nomel

For me, when I'm really concentrating, the imagined becomes more dominant.

I like to do mechanical/visual designs in my head, intentionally avoiding whiteboards and whatnot, so I don't lose the ability! When I do this, I've had people come up to me and wave their hands right in my face to get my attention, because I don't see them. I "spaced out" alll the time as a kid.