This was in the chapter I was reading from my textbook the other day.
The answer to the question on that page is yes, which is probably not surprising at all, but when they studied specific types of lessons in correlation to intelligence test scores, this is what they found.
Apparently I should have taken voice lessons as a child...
Just kidding. I'm pretty sure I wouldn't have wanted to, seeing as how I don't sing alone in front of people. This is interesting though, isn't it?