0.7 Music, biological evolution, and the brain  (Page 18/30)

An example from research on dyslexia helps illustrate how music might benefit the nonmusical abilities of children. Research has revealed that many children with developmental dyslexia have reduced sensitivity to auditory cues related to the amplitude envelope of sounds, such as the rise-time of syllables (the rate of sound amplitude increase at syllable onset). This auditory deficit appears to be related to their dyslexia: individual differences in rise time discrimination are predictive of phonological awareness, even when factors such as age, verbal and nonverbal IQ, and vocabulary are controlled (Goswami, 2009). Thus, sensitivity to the details of speech amplitude envelopes may play an important role in speech comprehension and in the development of the phonological system (cf. Greenberg, 2006). Neural studies using EEG have shown that the right cerebral hemisphere is particularly adept at tracking the amplitude envelope of speech in normal children (Abrams et al., 2008) and that poor readers have a degraded neural representation of the speech amplitude envelope (Abrams et al., 2009).

What does this have to do with music? Rise-time is not only an important cue not only for speech, but also for music, e.g., in specifying the “perceptual attack” of musical sounds (Caclin et al., 2005). Thus, musical activities that make acoustic onsets salient and focus on the ability to accurately perceive such onsets, such as games involving clapping to syllable onsets of words in songs, may help refine brain networks involved in encoding amplitude patterns in ordinary speech (Goswami, 2009; cf. Overy, 2003; Tallal and Gaab, 2006). Experimental studies are needed to address this issue.

Studies of the biological power of music need not be limited to individuals with neural anomalies. There is considerable scope for the study of how music affects the development of nonmusical abilities in ordinary individuals, both children and adults (Moreno, 2009). For example, Moreno et al. (2009) recently conducted an experiment in which normal third graders were pseudo-randomly assigned to nine months of music vs. painting lessons. They found that after musical (but not painting) training, children showed enhanced reading and improved pitch discrimination in speech, with the latter improvement shown by both behavioral and neural measures. While the study of how music lessons influence the development of reading is of great practical interest, the relationship between musical training and proficiency at second-language learning also merits study (Patel and Iversen, 2007), as does the relationship between musical training and executive function (Bialystock and DePape, 2009). In addition to these cognitive effects of music, the influence of group musical activities on the development of empathy and cooperative behavior also deserves research attention (cf. Kirschner and Tomasello, in press).

5. why would music have lasting effects on nonmusical brain functions?

The preceding section provided two examples of the lasting effects of music on nonmusical cognitive abilities. I suspect that in the coming years, more and more evidence will accrue for the lasting effects of music on diverse aspects of human brain function. Thus, it is important to begin thinking about why music sometimes has these effects. That is, what mechanisms underlie these effects? A firm answer to this question requires a large set of empirical studies from which to draw inductive conclusions. In the meantime, however, it is possible to set forth some hypotheses that may help guide future work.