Those who like fantasy and those who do not.
No doubt this schism is evident to anyone who reads fantasy literature, but scientists are now studying the phenomenon.
From an article on MSNBC that rather needlessly ties itself into the release of the new Twilight movie:
Webster had noticed that while some friends loved to read fantasy novels others just hated them — and he wondered why. One possibility was that people who hated fantasy just didn’t have good imaginations. Another was that people couldn’t accept the rules of an imaginary world and immerse themselves in it.
So Webster designed some experiments to look at how people experienced fantasy, which he defined as a type of narrative — such as a book, film, piece of art — that included supernatural, unreal or impossible aspects.
The article goes on to conclude:
But, there was a clear difference between people who were prone to fantasizing and daydreaming and those who were not. People who were comfortable with fantasy tended to be more absorbed by what they read and saw. They also tended to have an emotional reaction. Many said they felt good after reading the narratives or looking at the paintings.
Another interesting feature of the fantasy prone people was that even when they were confronted with a realistic narrative or painting, they inserted fantastical elements when they mulled things over. “On their own they began to picture themselves flying while watching the sun rise,” Webster said.