Charlie Rose recently conducted an interview with Norman Mailer. Mailer has just written a book on the life of the young Adolf Hitler, The Castle in the Forest . In the interview, the discussion turned to Hitler's personality and tendencies.
At one point, Rose asked if Hitler was an intelligent man. He also asked if he read a lot. Mailer said that he was not overly intelligent but that he was extremely driven and went on to mention a couple of negative characteristics. In particular, Mailer said that Hitler was a lousy, careless reader with a penchant for searching out what he wanted to find in order to validate his preconceptions. Mailer said that Hitler would regularly peruse books searching for ideas and quotes to use rather than genuinely trying to understand the books in their totality. In fact, he called Hitler a "pig". A pig, Mailer said, will take a perfectly good piece of food and consume only the small part it wants and discard the rest.
Of course, this is a logical characteristic for an ego-maniacal propagandist. Many people have at least some tendency to search out only what they want to find. But not everyone then becomes consumed with convincing everyone else of their own delusion.