DISCOVER Vol. 22 No. 8 (August 2001)
The Genetic Mystery of Music
Does a mother's lullaby give an infant a better chance for survival?
By Josie Glausiusz
Photography by Greg Miller
Thousands of babies have passed through this facility at the University of Toronto at Mississauga in the past 25 years, and each one has departed with a diploma attesting to his or her contribution to "the advancement of science and the understanding of child development." Here Trehub has observed parents singing to their babies and watched how the babies respond to those songs (they are mesmerized). She has studied the history and universality of lullabies (they sound the same the world over). She has documented the power of a mother's singing (it decreases stress hormones in her child). She also has found that babies seem to have an innate appreciation for music.
In one study, for example, a pudgy-faced, redheaded 8-month-old sits on his mother's lap in a soundproof booth, fascinated by the fluffy toy a smiling lady is waving in his face. In the corner, an audio speaker spits out a tinny little tune over and over— the sequence of notes arranged on the Western major scale (do re mi fa sol la ti do) familiar to fans of The Sound of Music. At first, the baby seems indifferent. Then an anomalous note— one that doesn't belong in the scale— intrudes on the recording, and he suddenly turns his head toward the speaker. He'll do this repeatedly when the wrong note is played.
Some might argue that the baby has learned since birth to recognize notes common to Western music. But a second experiment casts doubt on that assertion. This time the tune played has an inherently musical structure, yet it's built on an invented scale unfamiliar to Westerners. Nevertheless, Trehub's infant subjects still pick out anomalous notes— even better than adults do. "I'm convinced that there's a biological basis for the babies' abilities," Trehub says. "Music making is so successful in managing the baby's state and getting the baby to sleep that it makes the task of caring for the baby easier. It takes the edge off this enormous burden."
A baby that's better cared for is more likely to survive to adulthood and reproduce. And that gets to the crux of a debate that has galvanized evolutionary biologists, psychologists, and neuroscientists alike. If the ability to appreciate music is ingrained in the human brain, could music making have evolved to help us survive and reproduce? Is it akin to language and the ability to solve complicated problems, attributes that have enhanced human survival? Or is it just "auditory cheesecake," as cognitive scientist Steven Pinker of the Massachusetts Institute of Technology has called it— a phenomenon that pushes pleasure buttons without truly filling an evolutionary need?
Why? Why has music spread to every country and every people in the world? Why is music used to rouse armies, praise God, and bury the dead? Charles Darwin, for one, thought music helped humans find mates. In his 1871 book, The Descent of Man, he suggested that early men and women, unable to express their love in words, "endeavored to charm each other with musical notes and rhythm," as birds do. But proof is still lacking.
Geoffrey Miller, an evolutionary psychologist at the University of New Mexico, has looked at thousands of jazz, rock, and classical music albums and noted the age and sex of the musicians. In every genre of music, he says, men produce about 10 times as much as women, and their output peaks at around age 30— near the time of their peak reproductive years. "Good musicians, particularly good singers, attract sexual interest," Miller says. "Successful male musicians are notoriously promiscuous and tend to produce a lot of children— and that's how the genes for musical ability tend to be passed on."
Still, there's no evidence that women are any less musically inclined than men. Women in all cultures sing to their infants, Trehub points out, and there is no hard evidence that talented musicians are particularly prolific. In fact, Hajime Fukui, an evolutionary psychologist at Nara University of Education in Japan, maintains that music reduces sexual activity. In one study, Fukui gathered 35 male students and 35 female students, measured their hormone levels, and then played them half an hour of music of all types. Afterward, Fukui found, the men's testosterone levels had gone down and the women's had gone up. Silence had no effect.
Fukui believes that when early humans formed communities, they had to develop ways to alleviate sexual tensions. "We may assume that their solution was music," he says. If music lowered testosterone levels in men, it made them less sexually active. If it increased testosterone in women, it made them more aggressive and less social. The net result was less sex, and less sexual tension. "National anthems, work songs, party music, and war music all have the same effect," Fukui says. "They diminish fear, relieve tension, and boost people's sense of solidarity. Music moves people, throws them into a trancelike state, and paralyzes their ability to think logically. We might think that we are the users of music. In fact, we are not the puppeteers but the puppets of music."
Bittman believes that group drumming, through its camaraderie, support, exercise, and music making, signals the brain to lower the production of cortisol, a stress hormone secreted by the adrenal glands. Less cortisol has been associated with a heightened immune response and may help the body fight off infection. "I'm not saying I have a cure for cancer," Bittman cautions. "But what I am saying is that we have a very important step in understanding a delightful, enjoyable, and fun way for people to reverse the stress response in a manner that leads us to positive biological changes."
None of that impresses MIT's Steven Pinker. "I think people who argue that music is an adaptation have confused the everyday meaning of the term— meaning something that is beneficial or salubrious— with the biological meaning of the term, which is something that causally increases the rate of reproduction or survival," he says. "Now, it's not enough just to show that something is correlated with reproduction. Wearing a linen suit or driving a Porsche might help you find a sex partner, but that doesn't mean it's an adaptation. What you need to do is show, on sheer engineering grounds and in terms of cause and effect, that some particular trait would lead to an adaptive outcome."
To prove that having two eyes is an adaptive trait, for instance, one first has to use geometry to show that stereoscopic vision enables depth perception. In turn, one can argue that animals that perceive depth are better at foraging, escaping predators, and finding a mate. It's not enough to point out that guitar heroes tend to be sexually successful, or that making music helps foster social unity. One has to explain why "rhythmic plinking sounds," as Pinker calls music, are sexually appealing or conducive to bonding. If music is about sexuality, why do children and the elderly care for it? And if it's all about bonding, why do people like to listen to it alone?
Not every common trait is adaptive, Pinker adds, citing his favorite example: "Let's say someone asked, what's the adaptive value of cheesecake? The answer is, there is none. It's bad for you. But it is a by-product of other adaptations, namely a taste for sweets and fats, which were adaptive in an environment in which sweets and fats were rare." A chemist can prove the adaptive value of sweets and fats by burning them— just as the body does— and measuring the energy released. But cheesecake is a kind of perversion of that process. "What we do with cheesecake is we start off with the fact that the brain is tickled by certain kinds of pleasure. We concentrate them, purify them, pack 'em together to give ourselves a big sensory wallop. We give ourselves pleasure by taking advantage of preexisting pleasure buttons."
Pinker agrees that lullabies could be adaptive: They may reinforce certain natural soothing sounds that send a signal to relax. But he has reservations. "If all music were mothers singing to babies, I would accept that theory," he says. "But that's a fraction of all music. And it doesn't explain why a 17-year-old listens to heavy metal."
Not surprisingly, Pinker's views have made him something of a whipping boy in certain musicological circles. At a recent conference on the biological foundations of music at Rockefeller University in New York City, speaker after speaker rose to denounce the analysis in Pinker's most recent book, How the Mind Works. Pinker has long championed the evolutionary roots of language, Trehub says, although "we don't have any more evidence that links language in any direct way to survival; all we have is the belief that it's likely to promote survival." Definitive proof will always be elusive, she says; yet the evidence for music as a survival tool is all around us. "When you have something that's in every possible culture and in every historical period, you have to ask yourself: Why? If it's an accident, why did this accident happen everywhere?"
Even if music isn't rooted in evolution, there is something about its sheer power to heal and revive the human spirit that seems to set it apart from other arts. In one of his scholarly studies on music and the brain, neurologist Oliver Sacks noted that the philosopher Friedrich Nietzsche continued to improvise at the piano long after he had been rendered mute, demented, and partially paralyzed by tertiary syphilis. Sacks has also testified to the uncanny gift that music has for drawing people out of comas and catatonic states.
No place better demonstrates this power than New York's Beth Abraham health center in the Bronx, home to the Institute for Music and Neurologic Function. Here, twice a week, music therapist David Ramsey plays host to stroke patients who can no longer speak. But they can sing.
One Wednesday morning in the middle of winter, Bertha, a 67-year-old patient with thick glasses and thinning gray hair, sits silently in a wheelchair with a yellow blanket over her knees. Ramsey, a sprightly man of seemingly infinite patience, strides in and says hello. Bertha only smiles faintly: A left-hemisphere stroke has left her all but paralyzed. Beside her sits Keith, a Nigerian-born former university professor in his fifties who until recently refused to leave his room. When Ramsey greeted him, Keith tried to respond, but his words were slurred and indistinct. He, too, has suffered a left-brain stroke.
Watching them sing— this man and woman so recently incapable of speech— it's hard not to believe there's something in music that runs deeper than speech, something that reaches places mere language can't get to. "The patients, as soon as they see that they can sing, that they can communicate, they break into tears," says Renato Rozental, a neuroscientist at New York City's Albert Einstein College of Medicine. "How is music doing this? I personally don't know."
Rozental plans to use MRIs to study precisely what goes on in these patients' brains. It's believed that healthy areas of the brain compensate for injured parts, enabling the patients to sing. But he knows his work will offer only crude answers. "There are a lot of myths and dreams about music," he says. "The point is that it works." And here even Pinker is willing to concede: "I suspect that music still is a mystery, and we shouldn't fool ourselves into thinking that we understand it. I think it genuinely is an unsolved problem, which is all the more reason not to accept glib explanations without making sure they really cut the mustard, in terms of science."
