It's an interesting topic and im only giving an opinion here.
But i definatly think that music can be related to instincts, i think the main purpose of music is for the social aspect.
If you take a group of teenagers from this modern era, they are typically all going to like the same music, no matter how bad it is, and not only will they like it, but instinctively they will like it, they will feel something good in the pit of there stomach when they hear it. BUT, if you take the same group of teenagers from this era, and showed them all music from the 70's chances are they won't like it. Even though, if you took a group of teenagers from that era, they would have liked it.
But i think theres a lot more too music as well. My dad for example, he is a great musician and he loves playing the piano (and many other insterments) .
He plays in bars and hotels sometimes, but he only ever plays the music that he likes, the music that makes him feel good. So thats generally a problem because other people don't like it that much, but it doesn't stop my dad. He wont change his style to impress others even though he easily could with his talent.
So in that example we can defiantly see that music serves another purpose, that doesn't quite fit into evolution. Although maybe you could say its there to increase happiness, and motivation, therefore increasing work ethic etc.
Please give any opinions