Music Art as Thesis Idea

I was listening to the radio on my way to work and thought of a decent thesis for those interested in using music. I'm a firm believer in what Frank Zappa thinks when he commented to congress in the 80's, "I wrote a song about dental floss but did anyone's teeth get cleaner?" If you don't feel this way, a good thesis would be on how the artistic differences of metal and hard rock can induce negative action. This can be explored through rhythms, subliminal messages, lyrics, and how each caused some effect in individuals. Just an idea.