Genre

I think both the artist and the scholars make a genre.  First off, the artist is the creator whether it be in movies, music, literature, etc..  He decides what to base his work on and goes from there.  What the scholar does is add on to any extra genres the artist may have portrayed.  For example, say the artist made an action movie.  Maybe there's a couple funny scenes, but enough to also label the movie under comedy as well.  The artist is important but I think the scholar deserves a lot of the credit as well.

The function a genre serves is to give the audience something to expect.  You don't go into a movie theatre and watch The Dark Knight, for example, expecting to see a romantic comedy (unless you're an idiot).  Basically, you have an idea of what type of movie you're watching.