In my last post I explored my own thoughts about this question. This second part is a mini-review on the science that has been done in this area.

There is actually quite a bit of scientific literature on the intersection of music and language in the brain - a Web of Science search on "music brain language" produced over 600 citations, a sample of which I skimmed.

The overall gist of the papers is that there is quite a bit of overlap in brain regions that are activated during language vs. music processing, but these areas are by no means congruent. In fact it was amusing to me that many authors appeared to be arguing either that language and music matched up well, or that they did not, and both "sides" had plenty of evidence to support their case. Both music and language are complex, with several components, and the similarity between processing seems to depend on what components are compared.

Excerpts from the abstract of the first example (Brown et al., 2006. Music and language side by side in the brain: a PET study of the generation of melodies and sentences. European Journal of Neuroscience 23:2791-2803):

Parallel generational tasks for music and language were compared using positron emission tomography. Amateur musicians vocally improvised melodic or linguistic phrases in response to unfamiliar, auditorily presented melodies or phrases...Direct comparisons of the two tasks revealed activations in nearly identical functional brain areas, including the primary motor cortex, supplementary motor area, Broca's area, anterior insula, primary and secondary auditory cortices, temporal pole, basal ganglia, ventral thalamus, and posterior cerebellum. Most of the differences between melodic and sentential generation were seen in lateralization tendencies, with the language task favouring the left hemisphere. However, many of the activations for each modality were bilateral, and so there was significant overlap...

Thus the tasks of improvising a sentence (something we all do several hundred times a day) and improvising a melody (something only a subset of us do regularly) were clearly related but not identical. I assume they used amateur musicians in order to make it easier for the subjects to improvise a melody, but anyone really could do this (even if they hummed random notes that were "ungrammatical" compared to their sentences), so I wish they had done a group of nonmusicians as well, to see if there are any differences. If so, it would suggest (although obviously not prove) that experience affects musical processing.

Vuust et al. (2006. It don't mean a thing ... Keeping the rhythm during polyrhythmic tension, activates language areas (BA47). Neuroimage 31:832-841) examine a specific feature of music, especially common in jazz music - the use of a counter rhythm on top of the main rhythm of a piece - on processing of the music:

...We here demonstrate that Brodmann area 47, an area associated with higher processing of language, is activated bilaterally when musicians tap the main pulse in a polymetric context where the music emphasizes a counter meter. This suggests that the processing of metric elements of music relies on brain areas also involved in language comprehension. We propose that BA47 is involved in general neuronal processing of temporal coherence subserving both language and music.

So it appears that the rhythm associated with music and the rhythm associated with language could be related, as far as our brains are concerned. Rhythm in language is not something I have previously thought much about, but it is certainly part of the package. One reason early computer voices sounded so mechanical was the lack of cadence to the spoken word. This seems to be something that is variable not only among languages but among dialects - accents (e.g. the many accents that exist just in the U.S.) are not only about word pronunciation, but the rhythm of speech as well. So I found this result very interesting.

Slevc, and Miyake (2006. Individual differences in second-language proficiency: Does musical ability matter? Psychological Science 17:675-681) start from the question: why do some people pick up second languages so much easier than others? They hypothesize musical ability affects second-language acquisition, much as it apparently affects first-language skills such as reading in children. "Musical ability" was measured using something called the Wing Measure of Musical Talents (taken from Wing, H.D. 1968. Tests of musical ability and appreciation: An investigation into the measurement, distribution, and development of musical capacity (2nd ed.). London: Cambridge University Press). There is no attempt here to distinguish innate from learned musical ability, so the term means simply some combination of the two.

They found, essentially: "Although the link may be restricted to L2 [second language] phonology, individuals who are good at analyzing, discriminating, and remembering musical stimuli are better than other people at accurately perceiving and producing L2 sounds." The connection to musical ability is specifically the ability to reproduce the sounds associated with a foreign language (all the subjects were Japanese who began speaking English after age 11). The authors are quick to point out that musical ability is not essential for good second language acquisition, but it appears to facilitate it.

Peretz (2006. The nature of music from a biological perspective. Cognition 100:1-32) agrees with me:

Paradoxically, the musical capacity appears to be fully developed in only a minority of humans who can make music. Becoming a proficient musician requires thousands of hours of practice and, in most case, explicit transmission. This is often taken as an argument against the notion that the musical capacity is innately determined. If genes were responsible for the human musical capacity, then everyone should be able to engage in musical activities. In fact, everyone does. Nearly everyone can carry a tune (Dalla Bella, Gigue`re, & Peretz, submitted) and move to music. The problem arises from the association of music-making with an elite of professional musicians. What is usually forgotten is that music is meant for the ears of the majority. Everyone from all walks of life and all cultures is musical to some extent. Unless they are tone-deaf, all humans exhibit a precocious inclination for music. In short, music appears as natural as language is.

But what about those tone-deaf people we all know? More from Peretz: "...there are cases of musically inept individuals who have normal language and intelligence. As noted, these individuals exist and are commonly called tone-deaf...The selectivity of the musical disability is remarkable. These tone-deaf individuals can have above average language skills, and may speak several languages without accent... However, they are unable to sing, dance or recognize music, despite formal training. This condition is termed congenital amusia...illustrating exceptional isolation of musical modules in the developing brain."

This and evidence from brain-damaged people suggests that language and music are indeed quite separate in the brain, at least for some people. I suspect that the separation or overlap is variable among people; the brain is well known to be plastic in its regional specialization. People with disabilities for certain senses are known to co-opt the brain regions normally responsible for processing those senses for other tasks, such as the processing of the remaining senses.

My conclusion from my snippet of light research is that language processing and music processing are largely overlapping yet different tasks; that musical functionality is present in nearly everyone at birth, and that proficiency in music is probably due to practice. If we all practiced music skills as much as language skills, it might not be a world of Mozarts, but it might at least be a world of Salieris. We might indeed have better language skills as a consequence of exercising the relevant parts of our brains that much more.

Labels: brain, humans, music