Ze Frank can be fairly entertaining on his video blog there. On this particular episode, he discusses the limitations of consciousness:

the show with zefrank: 01-08-07

I post it here, because I think the point he makes connects well with the idea of improvisation. When a person learns to improvise, he begins to harness a sort of voice within. The aspects of conscious choice may enter from time to time, but avoiding active decisions seems much more the task at hand.

“The Way is not difficult, just avoid picking and choosing.” – Seng-Tsan Hsin Hsin Meng