The Evolution of Music

In the May 15 issue of Nature Josh McDermott discusses ideas about the evolution of music:

The mere presence of music in every known culture implies some genetic basis. But music varies dramatically from culture to culture, and many aspects of musical behaviour seem at best only weakly constrained by genetics. Whereas our ability to hear pitch intervals, for instance, could well be biologically rooted in the hardware of the auditory system, our emotional response to particular scales or chords seems likely to be acquired from exposure to a particular culture. Interactions between genes and environment are complex, and unravelling their contributions is not easy, but studies of music in different cultures and of musical development offer some hope.

A number of interesting music-related traits emerge in human infants with fairly minimal musical input, providing some evidence for innate constraints. Babies notice when the notes of a melody are reordered, but not when they are shifted to a different pitch range. Infants, like adults, are sensitive to the relationships between notes, which is preserved in transposition, but altered by reordering. Infants also tend to be captivated by music relative to many other stimuli. Not all music is equivalent to them — they prefer combinations of notes that are judged by adults to sound pleasing, or consonant (the perfect fifth, for instance), over combinations that are less pleasing, or dissonant (a minor second). Infants may even extract metre from music: they react when the rhythm changes from a march to a waltz.
Universal appeal

Features of music that occur repeatedly around the world despite the substantial cultural variation in music also provide clues to genetically constrained mechanisms. Lullabies seem to qualify as a rare universal — nearly every culture has a genre of music geared towards infants, and there is considerable consistency in how they sound, generally being slow, repetitive and featuring descending pitch contours. Other features that are common, if not completely universal, among cultures include the inclination to dance to music, musical metre, and the hierarchical organization of pitch, giving structural prominence to particular notes over others.