Brian Boyd on Why We Love Fiction. He asks, "if fiction offered no benefits in terms of reproductive success, those of us with less inclination to engage in it would thrive, and fiction would fade away as a human behavior. Manifestly, it has not. What benefits does it offer?" Indeed, this is one of the main things that interests me as a literary scientist.
One thing Boyd points out is that music and dance precede literature by quite a bit -- being found in other species (gobies dance, after all). Literature is thus one of that last of the arts to be invented. Indeed, this would seem to support my belief that literature began as a primate mating call which first bifurcated into music and language, and then recombined into song, which then evolved into poetry, which then evolved into prose. The history of literature seems to support this as well. While we can find prose literature quite far back, it's certainly not the dominant form. As literature, song was first dominant; then spoken poetry; then written poetry; then written prose. Among the "high arts," I think there would be little argument about this developmental line. At the same time, however, song is still in fact the dominant literary form -- more people listen to songs than read novels.
Boyd also connects the arts to play, something which I did in my dissertation, Evolutionary Aesthetics, and in my article Literature as a Game: Game-Play in Reading, Creating, and Understanding Literature. I think much more can and needs to be done with this connection, inlcuding the nature of and reasons for play, and the evolution of play.