0.7 Music, biological evolution, and the brain  (Page 13/30)

Crucially, parrots (as far as is known) do not entrain rhythmic movements to rhythmic sounds as part of their natural behavior, indicating that BPS does not require a brain that has been shaped by natural selection for this ability. Furthermore, modern neuroanatomical research suggests that vocal learning in birds and mammals uses homologous brain circuits involving the thalamus, striatum, and forebrain, despite the fact that the mammalian and avian lineages diverged over 200 million years ago (Jarvis, 2007). In other words, there seem to be genetic and neural constraints on how vocal learning is acquired in vertebrate brains, so that even when the ability arises in distantly related vertebrate groups, similar underlying brain mechanisms are at play. This idea of “deep homology” underlying vocal learning circuitry in birds and humans suggests that a brain shaped by evolution for vocal learning has “BPS potential” as a byproduct of its wiring (see Patel et al., 2009a, for further discussion).

3.3 music as a human invention: summary

The above sections indicate that two core components of music cognition—tonality processing and entrainment to a musical beat—have strong relationships to nonmusical brain functions. Notably, while these aspects seem domain-specific to music at first glance, research grounded in neuroscience points to their underlying connections to nonmusical brain functions. Thus, these aspects of music cognition can be explained without invoking evolutionary brain specialization for music, which is consistent with the idea that music is an invention.

If music is an invention, then future research will show that every component of music cognition can either be related to a nonmusical brain function or be explained via learning in the absence of any evolutionary specialization for music. Of course, even if this is shown to be the case, music cognition as a whole will still be special because it creates a unique confluence of different processing components in the human mind. It is interesting to speculate that the nature of this confluence may vary in interesting ways across cultures and historical epochs, depending on which processing components a culture uses in building its musical system.

4. the biological power of music: two examples

Challenges to the most prominent nonadaptationist theory of music (Pinker, 1997), which views music as a “biologically useless” invention, come from studies showing that regular engagement with music can result in lasting changes to nonmusical brain functions. Importantly, such studies concern individuals who are not professional musicians. There has been a good deal of research on structural brain differences between professional musicians and non-musicians (e.g., Elbert et al., 1995; Schneider et al., 2002; Bengtsson et al., 2005; Stewart, 2008), with recent research supporting the idea that many such differences can be explained by experience-dependent neural plasticity (e.g., Hyde et al., 2009; Schlaug, Forgeard et al., 2009). The current focus, however, is on evidence that regular engagement with music can exert lasting effects on brain functions in a wider range of individuals (e.g., Sacks, 2007; Dalla Bella et al., 2009; Bradt et al., in press).