I'm always thrilled to find articles about how fiction changes us, so I like to pass these articles along when I come across them. In this Boston Globe article Why Fiction is Good for You, by Jonathon Gottschall, many interesting points are made.
Among others, "For example, one study showed that small children (age 4-6) who were exposed to a large number of children’s books and films had a significantly stronger ability to read the mental and emotional states of other people. Similarly, Washington & Lee psychologist Dan Johnson recently had people read a short story that was specifically written to induce compassion in the reader. He wanted to see not only if fiction increased empathy, but whether it would lead to actual helping behavior. Johnson found that the more absorbed subjects were in the story, the more empathy they felt, and the more empathy they felt, the more likely the subjects were to help when the experimenter 'accidentally' dropped a handful of pens — highly absorbed readers were twice as likely to help out. 'In conclusion,' Johnson writes, 'it appears that ‘curling up with a good book’ may do more than provide relaxation and entertainment. Reading narrative fiction allows one to learn about our social world and as a result fosters empathic growth and prosocial behavior.'”
The site that the link goes to has a few ads between the paragraphs, and the short article is extended over several pages because of the ads, but it's worth reading.