Tuesday, October 29, 2013

The Perception of Rhythm: Localized of Bilateral?

In both educational discourse and popular psychology, the notion of left brain and right brain dominance has been prevalent since the early 1980’s. A ramification of this thinking was the idea that some people are more “creative” while others are more “logical.” In the field of music, it is important to recognize what parts of our brain are active while we perform and listen to different aspects of music. Jourdain suggests that rhythm is lateralized in the left hemisphere of the brain, while pitch perception is seated in the right side of the brain. This idea seems to be an oversimplification and reductionist view of the matter. In reality, both hemispheres of the brain play a role in rhythmic perception, which is further complicated by the amount of musical training one has.
In his chapter on rhythm, Jourdain states that in contrast to melody,  “rhythmic skill favours the left brain” (149). Furthermore, he asserts that rhythmic perception and harmonic perception are favoured by different sides of the brain so that some musicians are naturally better at tonality, while others are natural better at rhythm. This thinking is analogous to the older notion that some people are more right brain dominant, while others are more left brain dominant. While it may often be the case that some people are more naturally talented at rhythm than others, it could be suggested that this has to do in large part with deficits in their musical training, their specific musical enculturation, and a tendency in music education to emphasize rhythmic training and melodic training separately.  Furthermore, several recent studies show that rhythmic perception utilizes both hemispheres of the brain, and so this issue may not be as simple as Jourdain suggests.
In the study Passive Rhythm Perception in Musicians, it was discovered that in both the musician and non-musician test groups, a basic network for processing the quantized rhythms was activated. This “may reflect an innate musical competence that is independent of training” (Limb et. al., 386). This finding also helps to clarify previous studies regarding the contributions of the right hemisphere to rhythm processing. It was found that formal musical training does not lead to a decrease in right-sided activity in terms of rhythmic processing, but that formal training activates additional areas of the brain. Thus, musicians “utilized an analytic mode of processing concentrated in the left hemisphere” (Limb et. al., 388). This is corroborated by Jun who found that “playing music professionally develops analytical processes in the left hemisphere, whereas other individuals process music in their right hemispheres” (Jun). Thus, musical training shows a heightened use of the left hemisphere in the perception and performance of rhythm.
The brain’s perception of rhythm can also be dependent on what music we are listening to and whether that music has a constant groove or not. For example, “studies have pointed to regions in the brain, such as the basal ganglia and supplementary motor areas, which are activated during listening to music with a beat structure versus music without a regular beat structure” (Phillips-Silver, 299). In other words, the innate heartbeat of music triggers areas in the brain that music without a regular beat does not. Furthermore, some researchers have studied the connections between movement and music, and the effect of that movement on our rhythmic perception. The goal of one such study was to explore the effects of movement on our bilateral perception of rhythm. Based on the fMRI data that was collected, it was found that “a bilateral network of motor areas is activated when rhythms are perceived, even when no movement is made” (Brett & Grahn, 902). These findings are supported by a number of other studies which confirm that “a bilateral network of motor areas mediate perception of rhythm in addition to rhythmic production” (Brett & Grahn, 902). As a result of these findings, it is clear that rhythm is not localized to just one side of the brain. The perception and production of rhythm is complex and utilizes the whole brain in a fluid way depending on the types of rhythm, their complexity, and a person’s level of musical training. Later in his chapter on rhythm, through a discussion of how musical perception is altered as a result of brain injuries, Jourdain clarifies his position by stating “rhythmic ability is clearly much less localized than harmonic skill” (Jourdain, 151). This further supports the idea that our perception of rhythm activates more areas of the brain than traditional thinking may suggest.
Based on this research, it is clear that rhythm is perceived in a bilateral way, in both hemispheres of the brain. The way in which the brain perceives rhythm is further complicated by the metrical complexity of the rhythm, the existence of a regular beat structure, and how much musical training an individual has. Recognizing the fact that rhythmic and melodic perception and performance aren’t localized to one hemisphere of the brain has strong implications for music education. In terms of skill acquisition, tonal abilities and rhythmic abilities can’t be seen as separate and distinct. Melody and rhythm must be taught in a holistic way and not seen as two distinct entities that some have natural aptitude for, and others do not. Connecting music to movement in a non-Western way allows for rhythm to be grounded, internalized and made a whole-body pursuit – not just a cognitive function of the brain.

Works Cited

Grahn, Jessica A., and Matthew Brett. "Rhythm and Beat Perception in Motor Areas of
            the Brain." Journal of Cognitive Neuroscience 19.5 (2007): 893-906.

Jourdain, Robert. Music, The Brain, And Ecstasy. New York: HarperCollins, 1997. Print.

Jun, Passion. "Music, Rhythm and The Brain." Brain World. N.p., 7 Mar. 2011. Web. 26
          Oct. 2013. <http://brainworldmagazine.com/music-rhythm-and-the-brain-2/>.

Limb, Charles J., Stefan Kemeny, Eric B. Ortigoza, Sherin Rouhani, and Allen R. Braun.  
           "Left Hemispheric Lateralization of Brain Activity during Passive Rhythm      
            Perception in Musicians."
 The Anatomical Record Part A: Discoveries in 
           Molecular, Cellular, and Evolutionary Biology
 288A.4 (2006): 382-89

Phillips-Silver, Jessica. "On the Meaning of Movement in Music, Development and the  
            Brain." Contemporary Music Review 28.3 (2009): 293-314. Web. 24 Oct. 2013.

1 comment:

Russell Hamer said...

Dear Will, I know this is an old post, but I wonder if you could comment on Jourdain's notion that rhythm is preferentially lateralized in the left hemisphere and melody in the right. This seems, prima facie, very simplistic to me, and perhaps wrong altogether in one key aspect: namely that melody and rhythm are inextricably linked. If you change the temporal pattern of a sequence of musical tones, you transform the perceived melody into a different one altogether, or even disintegrate it into a sequence that cannot hang together as a perceived melody.