Which books has Strauss told Charlie he cannot read?

From the text:

Prof. Nemur gave me some more tapes to play while I sleep. I still don't know how the conscious and unconscious mind works, but Dr Strauss says not to worry yet. He made me promise that when I start learning college subjects in a couple of weeks I won't read any books on psychology-that is, until he gives me permission. He says it will confuse me and make me think about psychological theories instead of about my own ideas and feelings.