Book recommendation.
In The Storytelling Animal, Gottschall asks us to consider whether this proclivity towards story is an evolutionary adaptation or simply a happy side effect. Then he explores the answer from several different angles – dreams, education, religion. In so doing, Gottschall taps into a number of evolutionary benefits that story holds for us, one of which is the idea of practice.

http://contemporarylit.about.com/od/socialsciences/fr/storytelling-animal-gottschall.htm?nl=1