Studies show active and prolonged study of music throughout life leads to higher IQ scores:

Music lessons are linked to higher IQ throughout life, according to research by E. Glenn Schellenberg, a psychology professor at the University of Toronto at Mississauga. Six years’ lessons lifted children’s IQ scores an average 7.5 points[…]

In a study this year, researchers at the University of Kansas found practicing musicians who are active for a decade or more continue to post higher IQs beyond age 60.

via Ways to Inflate Your IQ –

Learning music in children leads to higher IQs, better grades, and improved academic capabilities. Practicing music is exercise for the brain. Music practice involves daily, sustained concentration tied to physical movement. The act of reading and playing music involves much counting and division – stimulating the same parts of your mind that process things like math and science – all the while linking it to artistic concepts such as emotional music performance and beautiful sound. The more you practice, and the longer you do this in your life, the more benefit you receive. Music lessons are one of the best things you can do for your child; it will give them a leg up in their school years and will give them a skill that they will carry for the rest of their lives.