Tuesday, January 1, 2008

Music as a drug: Musicophilia and This Is Your Brain On Music

Two books have been published recently on music and the brain: Oliver Sacks' Musicophilia: Tales of Music and the Brain (2007) and Daniel J. Levitin's This Is Your Brain On Music: The Science of a Human Obsession (2006). Both offer fascinating insights into the way brains perceive and process musical information, and the sometimes startling effects music can have (or fail to have) on us. However, both books are ultimately unsatisfying, because they bring us no closer to understanding the deepest mysteries of music: why it is so necessary to us, and why it can have such profound emotional (and even physical) effects.

To take the books in reverse chronological order, Musicophilia offers anecdotes about "the overwhelming and at times helpless sensitivity of our brains to music." Sacks introduces us to Alzheimer's patients who can still play Bach fugues flawlessly, even though they can't remember doing so five minutes later; virtually immobilized Parkinson's patients who, under the influence of music, can temporarily regain smooth, controlled movement; an unmusical man who, after he is struck by lightning in early middle age, is compelled to become a pianist and composer; people with perfect pitch who don't enjoy music, and profoundly musical people who can't carry a tune. (Incidentally, Sacks offers evidence that as infants, most of us possess perfect pitch--an ability, like that of learning languages, that we lose to a greater or lesser extent as we grow older.)

Although Sacks devotes a chapter to the question of music and emotion--pointing out, for example, the apparent paradox that when you're sad, happy music can seem trivial and sad music can be consolatory--the chapter concludes where it should begin, telling us, in effect, what we already know. Most of us have direct experienced of music's power to evoke deep emotions and bring long-buried memories to the surface of our consciousness. So most of us would expect, for example, that the emotional centers in the brain would be involved in musical perception. While the experimental confirmation of this is a dazzling technical achievement (in which Daniel Levitin has played a large role), it gets us no closer to understanding why this should be so.

In This Is Your Brain On Music, Levitin attempts to provide an explanation. Levitin's own curiosity about musical effects dates from his days in the punk rock scene in San Francisco. Today he is a neuroscientist who performs functional MRIs on the brains of people listening to music, and tries to elucidate the synaptic structures in the brain that are involved in musical perception. As you might guess with something as complex as music (which has rhythm, absolute and relative pitch, melody, harmony and dissonance, timbre, loudness and softness, etc.) many areas of the brain are involved, including the areas considered to be the earliest to evolve.

Levitin spends the final part of his book speculating about why music might be adaptive in an evolutionary sense. But this "explanation" can only ever remain speculative. Yes, as language developed it would clearly have been advantageous for our ancestors to be able to distinguish the nuances of meaning carried by variations in pitch and rhythm. However, it's a long way from figuring out whether a particular grunt means "I'm threatening you" or "So what?" to creating a musical passage that causes otherwise rational adults to break down and weep helplessly. Like all explanations proposed by evolutionary psychology, Levitin's for the adaptive role of music can't be tested; in Karl Popper's famous formulation, it's unscientific because it's not falsifiable.

In any case, it strikes me that it is equally probable that musical appreciation might be, in Stephen Jay Gould and Roger Lewontin's term, a "spandrel"--that is, something that arose as a side-effect of other evolutionary developments, rather than directly as a product of natural selection itself.

Levitin's evolutionary explanation also ignores music's huge cultural dimension: we learn to hear particular sounds in particular ways. It's not clear that a passage of music that sounds mournful in the context of the familiar Western diatonic scale would necessarily sound the same way to an auditor who was only familiar with, say, a pentatonic scale. And if not, music is like language: something for which there seems to be an innate propensity in most of us from birth, but whose specific meanings (including emotional content) are culturally determined.

In any case, despite my criticisms, I found both books to be highly interesting. And I applaud both authors for wrestling, even if unsuccessfully, with the ultimate mystery of their subject: what gives rise to our hunger for, profound pleasure in, and deep emotional response to, music of many different kinds. Perhaps there are some questions that brain-imaging technology, amazing as it is, will forever be powerless to answer.

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