He looks up and to the left. The next time you ask him a sticky
question or he wants to explain himself to you, notice which way he looks. If
his eyes move up to the right, he's recalling information from his memory. If he
looks up to the left, there's a good chance that he's inventing the
answer.
Isn't that neat? Our eyes subconsciously dart to the different sides of our brain to recall a memory or to make up a new story. Pretty interesting.