The role of melody in helping recall
The most obvious connection between language and music is that music can be used to help us remember words. It has been convincingly shown that words are better recalled when they are learned as a song rather than speech - in particular conditions.
Melody is what is important. Rhythm is obviously part of that. We are all aware of the power of rhythm in helping make something memorable. But melody, it seems, has quite a lot of attributes, apart from rhythm, that we can use as cues to help our recall. And what seems to be crucial is the simplicity and predictability of the melody.
But the connection between language and music is much more profound than this.
The evolution of language
One of my favorite books is Robin Dunbar's Grooming, gossip and the evolution of language . In it he moves on from the fact that monkeys and apes are intensely social and that grooming each other is a major social bonding mechanism, to the theory that in humans language (particularly the sort of social language we call gossip) has taken the place of grooming. The size of human social groups, he argues cogently, was able to increase (to our species' benefit) because of the advantages language has over grooming. For example, it's hard to groom more than one at a time, but you can talk to several at once.
Language, music, and emotion
I mention this now because he also suggests that both music and language helped humans knit together in social groups, and maybe music was first. We are all familiar with the extraordinary power of music to not only evoke emotion, but also to bind us into a group. Think of your feelings at times of group singing - the singing of the national anthem, singing 'Auld Lang Syne' at New Year's Eve, singing in church, campfire singing, carol singing ... fill in your own experience.
Dunbar also observes that, while skilled oratory has its place of course, language is fairly inadequate at the emotional level - something we all have occasion to notice when we wish to offer comfort and support to those in emotional pain. At times like these, we tend to fall back on the tried and true methods of our forebears - touch.
So, while language is unrivalled in its ability to convey "the facts", there is a point at which it fails. At this point, other facilities need to step in. At an individual level, we have touch, and "body language". At the social level, we have music.
Language and music then, may well have developed together, not entirely independently.More evidence for this comes from recent neurological studies.
The neural substrates of language and music
Language is a very important and complex function in humans, and unsurprisingly it involves a number of brain regions. The most famous is Broca's area. Recent research into neurological aspects of music have held some surprises. Imaging studies have revealed that, while the same area (the planum temporale) was active in all subjects listening to music, in non-musicians it was the right planum temporale that was most active, while in musicians the left side dominated. The left planum temporale is thought to control language processing. It has been suggested that musicians process music as a language. This left-brain activity was most pronounced in people who had started musical training at an early age.
Moreover, several studies have now demonstrated that there are significant differences in the distribution of gray matter in the brain between professional musicians trained at an early age and non-musicians. In particular, musicians have an increased volume of gray matter in Broca's area. The extent of this increase appears to depend on the number of years devoted to musical training. There also appears to be a very significant increase in the amount of gray matter in the part of the auditory cortex called the Heschl's gyrus (also involved in the categorical perception of speech sounds).
An imaging study1 investigating the neural correlates of music processing found that " unexpected musical events" activated the areas of Broca and Wernicke, the superior temporal sulcus, Heschl's gyrus, both planum polare and planum temporale, as well as the anterior superior insular cortices. The important thing about this is that, while some of those regions were already known to be involved in music processing, the cortical network comprising all these structures has up to now been thought to be domain-specific for language processing.
People are sensitive to acoustic cues used to distinguish both different musicians and different speakers
Another study2 has found that people remember music in the same way that they remember speech. Both musicians and non-musicians were found to be equally accurate in distinguishing changes in musical sequences, when those changes were in the length and loudness of certain tones. This discrimination appeared to also be within the capabilities of ten-month-old babies, arguing that the facility is built into us, and does not require training.
These acoustic characteristics are what make two musicians sound different when they are playing the same music, and make two speakers sound different when they are saying the same sentence.
So, if this facility is innate, what do our genes tell us?
Williams syndrome is a rare genetic disorder. Those with this syndrome have characteristic facial and physical features, certain cardiovascular problems and mild to moderate mental retardation.
They are also markedly social, and have greater language capabilities than you would expect from their general cognitive ability. They score significantly higher on tests measuring behavior in social situations, including their ability to remember names and faces, eagerness to please others, empathy with others' emotions and tendency to approach strangers.
This connection, between sociability, language skills, and memory for names and faces, is what makes Williams syndrome interesting in this context. And of course, the final characteristic: an extraordinary connection with music
(see http://www.the-scientist.com/yr2001/nov/research_011126.html )
A Canadian study is now underway to look at whether musical training gives children an edge over non-musical counterparts in verbal and writing skills (as well as perhaps giving the elderly an edge in preserving cognitive function for as long as possible). In view of the factors discussed here, the idea that music training benefits verbal skills is certainly plausible. I discuss this in more detail in my discussion of the much-hyped Mozart effect.
* I'm sorry, I know this is expressed somewhat clumsily. More colloquially, many people would say they co-evolved for this purpose. But functions don't evolve purposively - the eye didn't evolve because one day an organism thought it would be a really good idea to be able to see. We know this, but it is ... oh so much easier ... to talk about evolution as if it was purposeful. Unfortunately, what starts simply because as a sloppy shorthand way of saying something, becomes how people think of it. I don't want to perpetuate this myself, so, I'm sorry, we have to go with the clumsy.