Robert Caro says that he sometimes wants to talk with someone but avoids calls and conversation because he is concentrating on his book and fears losing concentration.

“Sometimes that very fact is hard, as a matter of fact, you know? You'd like to pick up the phone and chat with somebody, but just, you say, "I'm concentrating on the book," you know?”

“"I can't do that. It's gonna break the concentration," you know? And well, that's such a, sounds like such a phony, uh, thing.”

“But you say, "I ca- I can't really do that. I'm trying to think about this oth- other thing."”