Here is the situation: I'm at a friend's house, and he plays a song in the guitar. I never heard it before, but somehow I know it's John Mayer, even though I don't like him very much (I can't even name one song of his).
Based on this kind of situation I have always wondered what is there in a song, that lets us know who composed it, even when another person is playing. Most songs are very "generic", but some have something special, so that my brain tells me who the composer is, but I can't find out why.
So, is it possible to enumerate aspects of a song that might give away its composer? How can I know it and not know why I know? Is it too broad or too subjective to be put down in words?