Looks like they do! The most recent issue of the peer-reviewed psychology journal “Advances in Cognitive Psychology” contains a study examining the link between intelligence and music. The researchers asked the parents of 194 boys about their musical activities since preschool, and looked at the boys' reading and spelling performance. The results concluded:
Intelligence was higher for boys playing an instrument. To control for unspecific effects we excluded families without instruments. The effect on intelligence remained. Furthermore, boys playing an instrument showed better performance in spelling compared to the boys who were not playing, despite family members with instruments. This effect was observed independently of IQ. Our findings suggest an association between music education and general cognitive ability as well as a specific language link.
Meaning–kids who had been given music lessons had higher IQs, and did better in spelling and reading than kids who were not given music lessons. This was true even when the non-music-lesson-having kids lived in a household with a musical instrument in it.
This is not the first study to show a link between music lessons, academic performance, and intelligence. In 2006, an article published in the Journal of Educational Psychology demonstrated not only that music lessons are strongly correlated with good academic performance among 6- to 11-year olds, but also that the duration of music lessons correlated positively with IQ. Meaning, the better a kid is doing in school, the more likely he or she had music lessons, and, the longer a kid had been given music lessons, the higher his or her IQ. This was the case even when the researcher controlled for differences in the parents' economic background or own involvement in music abilities.
While listening to music as a child leads to (very, very) short-term gains in intelligence, taking music lessons as a child is associated with small but long-lasting benefits to the intellect that aren't explained by class, family involvement in education, or other confounding variables.
Some of this makes sense, but some of it doesn't: It naturally follows that learning to play the piano, for example, could help a kid develop fine motor skills; it's less clear, however, why those piano lessons might help with spelling.
So how to explain the connection between music lessons and spelling? Some researchers hypothesize that the connection between music lessons and increased language skills can be explained by a “transfer effect”: Learning to read written music might help a child learn how to read the written language. Learning how to pay attention to musical sounds might lead a child to more easily pay attention to spoken sounds, thereby increasing spelling ability.
Another theory is that music lessons simply exercise your brain and ergo boost your IQ. This would naturally transfer to anything requiring intellectual ability–music, math, spelling, whatever.
But of course, the correlation between music and intellectual ability may just be that–correlation, even when income, education, and other confounding factors are controlled. For example, parents might know their kids well enough to know that they will or won't enjoy music lessons in the first place, and the kids that enjoy the structure of music lessons might be the same kinds of kids that can enjoy the structured learning environment of school, where “intellectual abilities” are measured.
What do you think? Do music lessons cause people to be more intelligent, or is it just a coincidence?