Discuss the difference between concrete and abstract thought?

A person usually had two kinds of thinking, the is the way of concrete thinking and the other one is through abstract thinking. By concrete thinking, a person will just be able to rely on facts that surrounds that person. This kind of thinking doesn't go beyond facts or not be able to think out of the box. Concrete thinkers always generalized the concept of all things. The abstract thinker on the other hand, they tend to understand things through different meanings, they look things with different perspective. In simplest terms, Concrete thought is based on facts while abstract thought is based on ideas.

They probably don't understand either 1. what the nightmare is about or 2. his anxiety and stress