It's possible that information which a person reads doesn't synthesise as well with other ideas and information once it's in the mind. When you discuss somethi

It's possible that information which a person reads doesn't synthesise as well with other ideas and information once it's in the mind. When you discuss something complex with a teacher in an interactive way, the teacher can probe for subtle gaps in your knowledge to make your understanding more complete. With reading, you build a foundation of knowledge with many gaps and you just hope that they will consolidate over time but the foundation is weaker and so you can't synthesise that knowledge as well until those gaps are closed off through random learning events. It requires a more flexible kind of intelligence and a modest personality to be able to constantly keep adjusting your old knowledge.