I personally think it's down to lyrics. Most metal has a real message behind it, it's not just trying to sell itself like pop music - so people who would rather listen to proper music tend to be more intelligent than those who accept the crud that plays on their radio. I suppose the same can be said about old school rap, like ICE-T for instance, his stuff was always full of meaning, yet I can't say the same for 50-cent. Rap music used to be about the state of play in the Ghetto, now it's about, well can anyone explain!?.
I like SOAD and KoRn, and a little Slipknot, and I would consider myself above average intelligence, but I suppose it could be phrased like an IQ test...
Q.16
If most metal heads are smart, and Andrew is a metal head, then the following statement can be considered true:
a) Andrew is smart
b) Andrew is dumb
c) It's impossible to tell
We're going down... in a spiral to the ground...