Da Musically Inclined Bomb

DePauw University's First Year Seminar on Writing about Music

Sunday, December 03, 2006

Musical Rhythm, Linguistic Rhythm, and Human Evolution by Aniruddh D. Patel

A recent debate has been one of the evolutionary status of music. Some argue that humans have been shaped by evolution to be musical while others say that there is no natural selection involved in the process and that music is merely an alternative use of our basic cognitive skills. In order to solve this debate, we have to look at a couple of questions. First we have to ask if basic components of music are innate, specific to music, and unique to humans. There have been studies to prove that musical pitch perception does not involve natural selection. However, to answer this question we can use musical rhythm as an example. Unfortunately this subject has been left highly unexplored. So our question now is whether or not musical rhythm can be proven to be evolutional in humans.

This hypothesis was first explored by Darwin. Arguments were started when skeptics claimed that love of music is “a mere incidental peculiarity of the nervous system, with no teleological significance.” In simpler terms this means that we can understand music because we are interested in it; we were not designed to automatically know about it. So to prove these skeptics wrong, we need to find the basic musical concepts that cannot be an alternative use of basic cognitive skills.

When we look at musical rhythm, we have to look at its similarities with the rhythm of language. Both types of rhythm have group boundaries, pitch, and duration. Grouping in both musical rhythm and linguistic rhythm use the same part of the brain. Every type of music, from every culture, uses a regular beat that nay listener can recognize and clap along with. Unlike music, however, there is no recurring syllable stress in language. In other words there is no recognizable pattern in the rhythm of language. The two rhythms are still related in that they both have meter which means that some beats are stronger than others. Even though the stressed syllables in linguistic rhythm do not create a regular pulse, it can be assumed that this grouping of stressed and unstressed beats originated in language and was later used in music. So here is the argument: Humans can follow language which consists of complex and irregular beats. Therefore we can assume humans are more than suitable to be prepared for a regular beat. The proof to support this argument is that listeners usually tap ahead of the beat while listening to music. The ability to recognize beat is called beat perception and synchronization or BPS. BPS is unique to music and did not originate in language so separate studies are required for BPS.

When talking about BPS, we need to know several factors. One factor is whether or not BPS is innate or present at birth. The argument for BPS being innate is that babies cannot tap a beat yet they also cannot speak. Since speech is considered innate it would be illogical to claim that BPS is not innate. Therefore BPS would have to be studied developmentally. There are factors preventing this study. We do not know how old a child is when he can tap a beat and we do not know the percentage of adults who can tap a beat.

Another factor of BPS we need to know is if it is specifically related to the brain. There are two different ways to look at this. The first is that brain damage that affects BPS also affects other nonmusical cognitive skills. The second is that brain damage that affects certain functions does not harm others. An example of this is when rhythmic abilities are affected, pitch processing remains relatively undamaged. As you may have guessed, there are factors preventing this study as well. There are no studies on relationship between shortage in BPS and other cognitive skills. Nothing proves that music is a byproduct of other brain functions.

The third and final factor of BPS is whether or not it is specific to humans. The question here is if nonhuman animals naturally produce music. If an animal can acquire or develop the ability to produce music, then the ability would not be an adaptation of music. So can animals learn beat? Primates are taught sign language, but there is no record of anyone ever teaching an animal to tap, peck, or move to a beat. If animals could learn beat, then natural selection for music is not necessary for BPS. The animals we would choose to study would be chimps and bonobos because they already drum with their hands and feet voluntarily as part of their behavior and they are the most intelligent of their kind. The question that follows is whether or not apes are capable of BPS. To figure this out we need to understand basal ganglia. Basal ganglion are any of four deeply placed masses of gray matter in each cerebral hemisphere of the brain. Rhythms with regular beat are associated with increased activity in the basal ganglia. Basal ganglia are also involved in interval timing, motor control, and sequencing. Therefore, the brain structure that keeps beat also controls the coordination of patterned movement. So if BPS only required interval timing and motor control, apes would be capable of BPS because they have basal ganglia as well. However, BPS also requires a relationship between being able to hear intervals and tap them out. The reason we are able to do this is because human evolution has modified our basal ganglia to have that relationship. BPS also requires a relationship between auditory input and motor output, which is also known as vocal learning. This trait has also been a modification of our basal ganglia through evolution.

The conclusion is that being capable of vocal learning is absolutely necessary in order to synchronize with an auditory beat. This hypothesis shows that teaching primates BPS would be unsuccessful, which would prove that it is too early to conclude that BPS is unique to humans.


At 12/03/2006 8:43 PM, Blogger Godfather Outlaw said...

you did a good job of putting this article into words much easier to understand

At 12/03/2006 10:46 PM, Blogger Becca said...

Good use of quotes to support your presentation.

At 12/03/2006 11:03 PM, Blogger iheart-t-ravs said...

you presented this really nicely, it was easy to follow.

At 12/03/2006 11:48 PM, Blogger Andrew said...

easy to understand


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