Music Disorders: What Are They And What Can They Tell Us?

28 Nov

Researchers of music cognition have speculated about an evolutionary or biological basis to explain music.  These propositions state that the capacity to acquire language and music abilities is an intrinsic aptitude of humans and that many of the cognitive processes used during the listening and creation of music are relative to cultural constructs and malleable to environmental influences.  These observations have resulted in researchers to conclude that our “musical system” is implicitly assembled during development (see: critical periods for absolute pitch and rhythm perception).  Research has also proposed that biological factors influence our musical ability (see: working memory and sight reading).  However, little is known about the biological factors that influence our music systems.  As Isabelle Peretz observes individuals with congenital amusia, or musical disorders, offer a rare to chance to study these biological components.

Music disorders occur in about 4% of the population and consist of a life-long deficit in pitch perception.  What makes these individuals unique is their ability is not a result of hearing loss, brain damage, or lack of music exposure, but rather differences in neuronal or genetic make up.  Amusics lack a cognitive function independent from speech that is fundamental to processing music.  Additionally, individuals with congenital amusia demonstrate deficits in the acoustic stage of pitch processing.  For instance, amusic individuals are incapable of discerning whether a pitch pattern moves up or down.  Furthermore, these individuals are also unable to distinguish small pitch differences (smaller than two semitones) when presented with pitch sequences.

As we understand the behavior and abilities of amusics, one might ask if there differences in the brain which could account for the pitch disorder.  As Peretz summarizes, amusic brains when compared to a control group, tend to have a decreased amount of white matter in the right inferior frontal cortex (BA 47).  Amusic individuals also have thicker cortex in the right inferior front area and the right auditory area (BA 22).  These brain areas have already been found to play an important role in pitch processing and understanding musical structure.  Other research found deceases of grey matter in these same regions but on the left half of the brain.  There also seems to be a hereditary attribute.  After a study conducted on smusic families, researchers found that 39% of first-degree relatives possess congenital amusia.  In control families however, the pitch disorder was only found in 3% of the family members.  Despite this data, it is still ambiguous as to how social influences affect these genetic predispositions.  Peretz concludes, future research must address how the environment and genes are related and produce cogenital amusia.

Peretz, I. (2008). Musical disorders: from behavior to genes . Current Directions in Psychological Science, 17(5), 329-333.

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One Response to “Music Disorders: What Are They And What Can They Tell Us?”

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  1. On Language, Cognition, & Song « The Proteus Experiment - July 28, 2012

    […] Music Disorders: What Are They And What Can They Tell Us? […]

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