I used to think more intelligent brains could digest complex music a lot easier but now I know I'm wrong. I'm just an average person when it comes to intellect, but I love complex adventurous music. I think it might come down to the personality type. Some people aren't as musically inclined as others, especially when it comes to learning an instrument. That doesn't mean they are less intelligent, they just don't have the passion, love, or sense of adventure for music itself. There are physicists out there that can do complex mathematical equations in their head, but they can't carry a tune in a bag.
I have a friend just like that who is a physicist, artist, mechanic, and an extremely smart business man among many other things yet he prefers simple music. I've let him borrow some of my prog music cd's and he couldn't stand the bands I love like DT, and I know he is far more intelligent than me. It just comes down to a matter of taste, I think... Everybody's brain perceives things differently and that's why there are so many different kinds of music.
If you like country and rap, then your just stupid...JK.