If you were to peek inside Sandra Trehub's lab, you might easily mistake it for one of those obnoxious superbaby classes. Beaming 6- to 9-month-olds sit transfixed in a parent's lap as a few seconds of melody pours from the speakers, and become more alert when the tempo or pitch changes. But the University of Toronto psychologist isn't trying to teach infants the finer points of Vivaldi. She is, instead, trying to shed light on whether the human brain comes preloaded with music software the way a laptop comes preloaded with Windows. In one test, Trehub varies the pitch, tempo and melodic contour of music, and finds that babies can detect changes in all three. The infants recognize that a melody whose pitch or tempo has changed is the same melody, for instance, suggesting that they have a rudimentary knowledge of music's components. The real surprise, though, comes when Trehub plays consonant (pleasant) and dissonant passages in an attempt to tease out whether our musical preferences are shaped by culture alone or wired into our brain from birth. Infants, she finds, smile when the air is filled with perfect fourths and perfect fifths--chords or sequences separated by five half steps, like C and F, or seven half steps, like C and G, respectively. But babies hate the ugly tritone, in which two notes are separated by six half steps, like C and F sharp, and sound so unresolved and unstable that in medieval times it was known as "the devil." What seems to be a biologically based preference "may explain the inclusion of perfect fifths and fourths in music across cultures and across centuries," says Trehub.
Music has charms to soothe a savage breast, but scientists are finding that it works those charms through the brain. At a recent conference of the New York Academy of Sciences, Trehub and dozens of other scientists interspersed their PET scans and MRIs with snatches of Celine Dion and Stravinsky as they reported on the biological foundations of music. Besides the musical babies, several other lines of evidence suggest that the human brain is wired for music, and that some forms of intelligence are enhanced by music. Perhaps the most striking hint that the brain holds a special place in its gray matter for music is that people can typically remember scores of tunes, and recognize hundreds more. But we can recall only snatches of a few prose passages ("Four score and seven years ago..."). Also, music affects the mind in powerful ways: it not only incites passion, belligerence, serenity or fear, but does so even in people who do not know from experience, for instance, that a particular crescendo means the killer is about to pop out on the movie screen. All in all, says psychologist Isabelle Peretz of the University of Montreal, "the brain seems to be specialized for music."
The temporal lobes of the brain, just behind the ears, act as the music center. When neurosurgeons tickle these regions with a probe, patients have been known to hear tunes so vividly that they ask, "Why is there a phonograph in the operating room?" The temporal lobes are also where epileptic seizures typically begin, and for some epilepsy patients "the power of music" is no cliche: music triggers their seizures. But not any music. The seizures are style-dependent. In one patient only salsa triggers seizures; in another, only classical does; in others, only operatic arias or pop tunes do.
The most controversial finding about the musical mind is that learning music can help children do better at math. When a researcher at the recent conference in New York brought up these studies, he got an auditoriumful of laughs. Yet the link, reported in 1997 by Gordon Shaw of the University of California, Irvine, and Frances Rauscher at the University of Wisconsin, has held up. Last year Shaw compared three groups of second graders: 26 got piano instruction plus practice with a math video game, 29 received extra English lessons plus the math game and 28 got no special lessons. After four months the piano kids scored 15 percent to 41 percent higher on a test of ratios and fractions than the other kids. This year, Shaw reported that music can help bridge a socioeconomic gap. He compared second graders in inner-city Los Angeles to fourth and fifth graders in more affluent Orange County, Calif. After a year of piano, the second graders who received twice-a-week piano training in school scored as well as the fourth graders, who did not; half of the second graders scored as well as fifth graders.
But might music work its magic simply by making school more enjoyable, or because music lessons bring kids more one-on-one time with teachers? If that were so, then music should bring about improvements in many subjects. But it doesn't. Although kids who receive music training often improve somewhat across the board due to the "good mood" and attention effects, finds psychologist Martin Gardiner of Brown University, "they just shoot ahead in math. This can't be explained by social effects or attention alone. There is something specific about music and math." That something might be that music involves proportions, ratios, sequences--all of which underlie mathematical reasoning.
The brain seems to be a sponge for music and, like a sponge in water, is changed by it. The brain's left and right hemispheres are connected by a big trunk line called the corpus callosum. When they compared the corpus callosum in 30 nonmusicians with the corpus callosum in 30 professional string and piano players, researchers led by Dr. Gottfried Schlaug of Beth Israel Deaconess Medical Center in Boston found striking differences. The front part of this thick cable of neurons is larger in musicians, especially if they began their training before the age of 7. The front of the corpus callosum connects the two sides of the prefrontal cortex, the site of planning and foresight. It also connects the two sides of the premotor cortex, where actions are mapped out before they're executed. "These con-nections are critical for coordinating fast, bi-manual movements" such as those a pianist's hands execute in an allegro movement, says Schlaug. The neural highway connecting the right and left brain may explain something else, too. The right brain is linked to emotion, the left to cognition. The greatest musicians, of course, are not only masters of technique but also adept at infusing their playing with emotion. Perhaps this is why.
Whatever music does to the brain, scientists figured you would have to actually do music to get the effects. Well, maybe not. Researchers led by Dr. Alvaro Pascual-Leone of Beth Israel taught nonmusicians a simple five-finger piano exercise. The volunteers practiced in the lab two hours a day for five days. Not surprisingly, the amount of territory the brain devotes to moving the fingers expanded. But then the scientists had another group think only about practicing--that is, the volunteers mentally rehearsed the five-finger sequence, also for two hours at a time. "This changed the cortical map just the way practicing physically did," says Pascual-Leone. "They make fewer mistakes when they played, just as few mistakes as people actually practicing for five days. Mental and physical practice improves performance more than physical practice alone, something we can now explain physiologically."
Pianists Artur Rubinstein and Vladimir Horowitz were legend-ary for hating to practice. Rubinstein simply disliked sitting in front of the piano for hours on end; Horowitz feared that the feel and feedback of pianos other than his beloved Steinway would hurt his concert performance. But both men engaged in extensive mental rehearsals. "Mental imagery may activate the same regions of the brain as actual practice, and produce the same changes in synapses," says Josef Rauschecker of Georgetown University. Advice to parents trying to get children to practice: keep this to yourself.