0.7 Music, biological evolution, and the brain  (Page 20/30)

Why would music drive plasticity in these networks? One idea is that music is often more exacting than other domains in terms of the degree of precision that it demands. For example, music and speech both involve the control of pitch, but music demands a higher degree of precision for both the control and perception of pitch than does ordinary speech (Patel, 2008, Ch. 4). Thus, musical experience may sharpen cortical and subcortical pitch processing mechanisms shared by music and language, leading to the observed superior processing of linguistic pitch contours by musicians (Wong et al., 2007; Patel and Iversen, 2007). Similar arguments may help explain why musically trained individuals show superior perception of speech in noise (Parbery-Clark et al., 2009) and other nonmusical auditory processing benefits.

Apart from the demands of high-precision processing, another factors that may promote music’s ability to drive plasticity is the fact that musical behaviors are often frequently repeated (e.g., frequently singing or playing a particular piece) and often involve heightened emotion. Repeatedly engaging in high-precision processing in the context of heightened emotion seems likely to promote functional and structural changes to the brain.

6. a non-genetic explanation for music’s universality

Thus far, this essay has argued that music is an invention. Yet if it is an invention, why is it universal in human culture? Section 3 pointed out that human cultural universals can originate as inventions, as illustrated by the control of fire. TTM theory posits that music resembles fire-making in being an ancient invention that has become universal because it provides things that are universally valued by humans. In the case of fire, these things include the ability to cook food, keep warm, and see in dark places. In the case of music, I suggest that the valued things it provides are mental rather than physical: namely, emotional power, ritual efficacy, and mnemonic efficacy.

6.1 emotional power

Many people report listening to music for the emotion it induces (Juslin and Sloboda, 2001; Benzon, 2001). Emotions are important for humans everywhere from the very beginning of life, and hence one reason for music’s universality may be its deep connection to the brain’s emotional circuitry (Peretz, 2010, Koelsch, 2010). This connection could help explain the human proclivity for music without postulating any “innate proclivity for musical sounds and actions” (Kirschner and Tomasello, in press).

However, this is a rather unsatisfying explanation for music’s universality, because it only serves to raise more questions. Why does music have these connections to the emotion circuits of our brains? Can the remarkable power of music to induce emotion be explained without appealing to an evolutionary specialization of the brain for music? In this regard, a recent theory of emotional induction by music is of interest (Juslin and Västfjäll, 2008). According to this “multiple mechanisms” theory, music can induce emotion in several different ways, namely via 1) expectancy and its fulfillment or violation; 2) activation of the brainstem by arousing acoustic features (e.g., sudden, sharp onsets); 3) association with past events; 4) visual imagery; or 5) acoustic cues that resemble the sounds of emotional voices. For the current purposes, the salient aspect of Juslin and Västfjäll’s theory is that none of the proposed emotion-inducing mechanisms is unique to music. For example, focusing on the first mechanism, auditory expectation and its relationship to emotion may be a very general aspect of human cognition, not shaped for music but exquisitely exploited by music (see Huron, 2006, for a detailed theory, and Steinbeis et al., 2006, for empirical data linking musical expectancy to emotion). Focusing on the final mechanism, the authors postulate that this aspect of music’s emotional power is due to brain mechanisms that evolved to perceive and respond to vocal affect (cf. Patel 2008b).