Your comment reminds me of something I read in Ouspensky's narrative of the teachings of Gurdjieff: (from memory) most people are automatons, so they don't actually operate at a very high level of intelligence to begin with.

The above was also expressed (in less cruel terms) by DFW in his "what is water" commencement speech at Kenyon College: (again, from memory) it is our natural tendency to operate in "default mode", which we must fight.