Perhaps only brain scanning would reveal this to us. And it would probably be hard to tell from the scan what was OTC and what conscious. Anyway you could try it: set aside one hundred books to PhotoRead in a tired state, and one hundred to PR in a normal state of wakefulness, and then see which books you have better grasp of. The books you PR in a tired state may benefit from the incubation that occurs as you go to sleep afterwards. This might distort the experiment somewhat.
