Scientists claim to have mapped unconscious human thought
haaretz.com
haaretz.com
That rang true to me because I've always noticed a phenomenon that occurs when I go to the mall. I get extremely tired (mentally) after just 2 hours. Why? My hypothesis is that I've taken in an unusually high amount of stimuli in those 2 hours by seeing, and possibly not even being aware of, thousands of items, prices, and faces.