0.7 Music, biological evolution, and the brain  (Page 9/30)

The examples of fire-making and reading show that the evolutionary null hypothesis for music is not challenged by music’s universality, age, association with some degree of brain specialization, or its influence by specific genes. Challenges to the null hypothesis thus must come from other sources. Patel (2008: 367-400) reviewed a wide range of evidence in this regard, including data from neuroscience, infant studies, and animal studies, and argued that at present the null hypothesis for music could not be rejected.

Rather than rehearse those arguments here, sections 3.1 and 3.2 below take a different approach and illustrate two lines of research that support the idea of music as an invention. These studies illustrate a comparative approach to the evolutionary biology of music (McDermott and Hauser, 2003; Justus and Hutsler, 2005). The basic logic of this approach is as follows: If one can show that an aspect of music cognition is rooted in other, nonmusical human brain functions or is shared with other species, then it is parsimonious to assume that this aspect has not been shaped by natural selection for music. This approach is particularly powerful when applied to aspects of music which seem domain-specific, i.e., not related to other types of cognition, such as tonality processing and synchronization of movement to a musical beat (Peretz and Coltheart, 2003; Bispham, 2006).

3.1 tonality processing: connections to language

Most of the world’s musical systems use discrete pitches and intervals to create melodies, with the pitches drawn from musical scales of five to seven tones per octave (Reck, 1997). A widespread feature of music is the differential use of scale pitches such that some are perceived as more stable or structurally significant than others (Krumhansl, 1990). This differentiation of scale pitches in terms of stability or prominence has been termed a “tonal hierarchy,” and implicit knowledge of such hierarchies develops without any special musical training (Tillmann et al., 2000). This knowledge contributes to our subjective impressions that tones in a musical context have abstract perceptual properties, such as tension or resolution, that are distinct from standard psychophysical tone properties such as “higher or lower” or “louder or softer.”

Krumhansl and Cuddy (in press) argue that “tonal hierarchies…play a central role in how musical sequences are perceived, organized, remembered, and how expectations are formed during listening.” Furthermore, they note that this way of organizing pitch is unique to music, an assertion supported by the fact that language, which can use pitch in highly structured ways, has nothing resembling tonality (cf. Patel, 2008, Ch. 2). Indeed, Peretz and Coltheart (2003) have proposed that processing of tonality in music uses domain-specific brain mechanisms. This view is supported by neurological cases in which brain damage selectively impairs tonality processing while leaving more basic forms of auditory processing, as well as language processing, intact (e.g., Peretz, 1993).