We Got Rhythm; the Mystery Is How and Why

Medicine, Science & Technology Forum

We Got Rhythm; the Mystery Is How and Why
By NICHOLAS WADE


In lovers' songs, military marches, weddings and funerals ・every occasion where a degree of emotion needs to be evoked ・music is an indispensable ingredient.

Yet the ability to enjoy music has long puzzled biologists because it does nothing evident to help survival. Why, therefore, should evolution have built into the human brain this soul-stirring source of pleasure? Man's faculties for enjoying and producing music, Darwin wrote, "must be ranked among the most mysterious with which he is endowed."

Music is still a mystery, a tangle of culture and built-in skills that researchers are trying to tease apart. No one really knows why music is found in all cultures, why most known systems of music are based on the octave, why some people have absolute pitch and whether the brain handles music with special neural circuits or with ones developed for other purposes. Recent research, however, has produced a number of theories about the brain and music.

It could be that the brain perceives music with the same circuits it uses to hear and analyze human speech, and that it thrills to its cadences with centers designed to mediate other kinds of pleasure. Dr. Anne Blood and Dr. Robert J. Zatorre, of the Montreal Neurological Institute, recently took PET scans of musicians' brains while they listened to self-selected pieces of music that gave them "chills" of euphoria. The works included Rachmaninoff's Piano Concerto No. 3 and Barber's Adagio for Strings. The music, the researchers reported, activated similar neural systems of reward and emotion as those stimulated by food, sex and addictive drugs.

If music depends on neural circuits developed for other reasons, then it is just a happy accident, regardless of evolution, that people enjoy it. This is the position taken by Dr. Steven Pinker, a psychologist at Harvard University. Music, he writes in his 1997 book "How the Mind Works," is "auditory cheesecake" ・it just happens to tickle several important parts of the brain in a highly pleasurable way, as cheesecake tickles the palate. These include the language ability (with which music overlaps in several ways); the auditory cortex; the system that responds to the emotional signals in a human voice crying or cooing; and the motor control system that injects rhythm into the muscles when walking or dancing.

That music can activate all these powerful systems at once is the reason it packs such a mental oomph, in Dr. Pinker's analysis. But since each of these systems evolved for independent reasons, music itself is no more an evolutionary adaptation than is the ability to like dessert, which arises from intense stimulation of the taste buds responsive to sweet and fatty substances.

But other evolutionary psychologists believe the faculty of enjoying music is no accident. Darwin suggested that human ancestors, before acquiring the power of speech, "endeavored to charm each other with musical notes and rhythm." It is because of music's origin in courtship, Darwin believed, that it is "firmly associated with some of the strongest passions an animal is capable of feeling."

In his theory of sexual selection, Darwin proposed that traits found attractive in courtship would enable their owners to get more genes into the next generation. The upshot would be the emergence of adornments that had no immediately obvious survival value in themselves, like the peacock's tail or the troubadour's ballads.

Darwin's ideas about music have been extended by Dr. Geoffrey Miller, an evolutionary psychologist at the University of New Mexico. Dr. Miller notes their potency in pointing to the opportunities open to popular musicians for transmitting their genes to the next generation. The rock guitarist Jimi Hendrix, for instance, had "sexual liaisons with hundreds of groupies, maintained parallel long-term relationships with at least two women, and fathered at least three children in the United States, Germany, and Sweden. Under ancestral conditions before birth control, he would have fathered many more," Dr. Miller writes.

Why on earth would nubile young women choose a rock star as a possible father of their children instead of more literary and reflective professionals such as, say, journalists? Dr. Miller sees music as an excellent indicator of fitness in the Darwinian struggle for survival. Since music draws on so many of the brain's faculties, it vouches for the health of the organ as a whole. And since music in ancient cultures seems often to have been linked with dancing, a good fitness indicator for the rest of the body, anyone who could sing and dance well was advertising the general excellence of their mental and physical genes to a potential mate.

"Music evolved and continues to function as a courtship display, mostly broadcast by young males to attract females," Dr. Miller writes in "The Origins of Music," a collection of essays by him and others.

But other psychologists argue that Dr. Miller's courtship theory does not do full justice to another important dimension of music, its role in cementing social relationships and coordinating the activities of large groups of people. Dr. Robin Dunbar, of Liverpool University, has shown that monkeys spend a large amount of time grooming other members of their social group, so much so that they would scarcely have time to look for food if their 50-strong groups were to grow any larger.

Dr. Dunbar believes that the much larger human groups, of 150 members or so, overcame the grooming barrier by developing a new kind of social glue, namely language. Group singing, or chorusing, may have been an intermediate step in this process, he suggests. He has preliminary evidence that singing in church produces endorphins, a class of brain hormone thought to be important in social bonding, he said in an e-mail message.

Others, like Dr. Edward Hagen of Humboldt University in Berlin and Dr. Gregory A. Bryant of the University of California at Santa Cruz, believe the role of music in human evolutionary history was not to create social cohesion but to signal it to rival groups. By putting on a better song-and-dance display, a group could show it had the coordination to prevail in a scrap, and could thus avoid a fight altogether, they write in an article available on the Web.

Male chimpanzees sometimes chorus in a call known as a pant-hoot, though usually to attract females to a new source of fruit they have found. For human ancestors, musical displays of this kind "may have formed the evolutionary basis for the musical abilities of modern humans," Dr. Hagen and Dr. Bryant write. The Pentagon's vigorous support of military bands ・$163 million in 1997 ・lends a certain resonance to this view.

The courting and social cohesion theories of music's origins assume that there are structures in the human brain that have evolved specifically to handle music. If no such structures exist, then Dr. Pinker's theory or something like it is correct.

A leading clue that points to music-specific structures, yet is so far not conclusive, is that many features of music are universal as well as apparently innate, meaning present at birth. All societies have music, all sing lullaby-like songs to their infants, and most produce tonal music, or music composed in subsets of the 12-tone chromatic scale, such as the diatonic or pentatonic scales. Some of the earliest known musical instruments, crane bone flutes from the Jiahu site in China, occupied from 7000 to 5700 B.C., produce a tonal scale.

Dr. Sandra Trehub, of the University of Toronto, has developed methods of testing the musical preferences of infants as young as 2 to 6 months. She finds they prefer consonant sounds, like perfect fifths or perfect fourths, over dissonant ones. A reasonable conclusion is that "the rudiments of music listening are gifts of nature rather than products of culture," she wrote in the July issue of Nature Neuroscience.

But although certain basic features of music, such as the octave, intervals with simple ratios like the perfect fifth, and tonality, seem to be innate, they are probably not genetic adaptations for music, "but rather appear to be side effects of general properties of the auditory system," conclude two Cambridge scientists, Josh McDermott of the Massachusetts Institute of Technology and Dr. Marc Hauser of Harvard, in an unpublished article.

The human auditory system is probably tuned to perceive the most important sounds in a person's surroundings, which are those of the human voice. Three neuroscientists at Duke University, Dr. David A. Schwartz, Dr. Catherine Q. Howe and Dr. Dale Purves, say that on the basis of this cue they may have solved the longstanding mysteries of the structure of the chromatic scale and the reason why some harmonies are more pleasing than others.

Though every human voice, and maybe each utterance, is different, a certain commonality emerges when many different voices are analyzed. The human vocal tract shapes the vibrations of the vocal cords into a set of harmonics that are more intense at some frequencies than others relative to the fundamental note. The principal peaks of intensity occur at the fifth and the octave, with lesser peaks at other intervals that correspond to most of the 12 tones of the chromatic scale, the Duke researchers say in an article published last month in the Journal of Neuroscience. Almost identical spectra were produced by speakers of English, Mandarin, Persian and Tamil.

The Duke researchers believe the auditory system judges sounds to be pleasant the closer they approximate to this generalized power spectrum of the human voice. "A musical tone combination whose power is concentrated at the same places as a human speech sound will sound more familiar and more natural," Dr. Schwartz said.

Some people are unable to appreciate music, raising the question of whether some music-specific faculty has been damaged. People who are tone deaf also fail to hear pitch changes in the human voice, so this deficit does not seem specific to music. Some patients have music agnosia, an inability to recognize familiar melodies, even ones to which they know the lyrics. But the brain has to store memories about music somewhere, and the music agnosia patients could have incurred memory damage that just happened to hit the music archive, Mr. McDermott, of M.I.T., said.

"Any innate biases on music must derive from something in the brain, but at present there is little evidence for neural circuitry dedicated to music," Mr. McDermott and Dr. Hauser conclude.

Dr. Zatorre, of the Montreal institute, takes a similar view. The brain has evolved faculties for perceiving sounds, organizing events in time and maintaining memory stores, he said. "Once you've got all that hardware in place, it can be used for a lot of different purposes. But I don't think it follows that music was selected for."

Whether music is cheesecake, courtship or cohesion, its mystery remains unbreached.

http://www.nytimes.com/2003/09/16/science/16MUSI.html

PHOTO: A flutelike object made from a cave bear's femur, found in northwestern Slovenia in 1995, was dated at 43,000 to 82,000 years old.

Twin Study Reveals Genetic Link to Musical Pitch Recognition


Marin Allen, Ph.D.
Thursday, March 8, 2001

Variation in the ability of humans to recognize musical pitch appears to be primarily due to highly heritable differences in auditory neural functions. These functions are not measured by conventional audiologic methods, according to the lead article in Science, March 9, 2001.

Controlling for environmental differences, two teams in an international collaboration employed a twin study to determine the extent to which genes and/or environment influence musical pitch recognition ability. A twin study can discriminate the effects of environment from those of genes. The collaboration between scientists at the National Institute on Deafness and Other Communication Disorders and a team at the Twin Research and Genetic Epidemiology Unit, St. Thomas' Hospital in London employed an updated Distorted Tunes Test (DTT) and a standard Five Minute Hearing Test to (FMHT) used to help identify subjects with possible confounding hearing loss.

The DTT was developed in the 1940s, but was updated and validated for the current U.S. and British populations. To test the validity of the updated DTT, first, 50 unrelated males and 50 unrelated females were tested on the new DTT. The distribution scores on males and females did not differ. Test and re-test scores on the same individual were highly correlated, which confirmed that the updated DTT is reproducible in individuals.

The updated DTT was recorded on a compact disc and presented to all subjects in the same setting. Subjects were presented with 26 short popular melodies, ranging in length from 12 to 26 notes. Tunes were presented once, and after each presentation, subjects were asked to score whether the melody was correct or incorrect and whether they were familiar or unfamiliar with that melody.

A total of 284 female Caucasian twin pairs; 136 identical and 148 non-identical twins aged 18-74, participated in the study. The twins were part of an ongoing study of common complex diseases, were unaware of the specific hypothesis tested, and were not screened for IQ, musical training or musical experience.

Following the FMHT and the DTT, the teams subjected the data to genetic model fitting techniques using a structural equation modeling package. This was applied to determine estimates of the genetic and environmental factors. Model fitting allows separation of the observed phenotypic variance into additive or dominant genetic components and common and unique environment. The last also includes measurement error. Heritability estimates the extent to which variation in a trait in a population can be explained by genetic variation.

Heritability for pitch recognition was estimated at 71-80%, depending upon how subjects were categorized. No dominant genetic effect nor significant effect of shared environment were detected. The heritability estimates observed for measures of deficit in pitch perception were very substantial and are high or higher than those for many complex traits in humans.

Dennis Drayna, lead author on the paper and a special expert, section on Genetics of Human Communication, Laboratory of Molecular Biology at NIDCD, notes "Since the FMHT serves as a rough estimate of peripheral hearing, its poor correlation with DTT suggest that musical pitch perception is largely independent of peripheral hearing. This would mean that variation in pitch perception originates in portions of the auditory system that are not dependent upon peripheral hearing, " adding, "the next important steps are finding the number of genes involved and the relative effects of those genes."

"Drs. Drayna (NIDCD) and Spector (St. Thomas') have demonstrated the importance of applying genetic approaches to biochemical or cellular mechanisms underlying neural function. Genetic modeling will yield substantial new understanding of the mechanisms applied to human communication research," said James F. Battey, Jr. M.D., Director of the NIDCD.

The Twin Research and Genetic Epidemiology Unit, St. Thomas' Hospital, uncovers the genetic basis of common diseases and traits associated with aging using twins. The unit has already made progress on the genetic basis of a number of diseases, including, osteoporosis, back pain, osteoarthritis, cataract, obesity, blood clotting, hypertension and asthma.

NIDCD conducts and supports research and research training in the normal mechanisms and diseases and disorders of human communication. Within NIDCD's research efforts, scientists are using molecular genetics to understand both the normal and disease processes of human communication and the effects of inheritance and environment on those processes. NIDCD is one of the Institutes of the National Institutes of Health.

http://www.nih.gov/news/pr/mar2001/nidcd-08.htm

By NICHOLAS WADE


ne of the most puzzling aspects of the brain's faculty for music is perfect or absolute pitch, the ability to identify a note without any reference point. Only a few musicians have the skill. Most rely on relative pitch.

Ordinary listeners can identify six to eight categories of pitch within an octave, but people with absolute pitch can assign notes to much finer subdivisions, approaching 70 or more, Dr. Robert J. Zatorre of the Montreal Neurological Institute wrote in a recent issue of Nature Neuroscience.

The mysterious ability can be helped with training but is so easily learned, by those so gifted, that just the exposure to notes and their names is sometimes enough. After a young age, about 9 to 12, however, absolute pitch apparently cannot be acquired, and no amount of training will bring it about.

Two aspects point to a genetic component, Dr. Zatorre said. One is the 8 to 15 percent chance that if one sibling has absolute pitch, the other will have it too. Another is that Asians have a much greater incidence of absolute pitch than other ethnic groups. That includes Asians who are culturally distinct and who speak tonal languages like Chinese and nontonal languages like Korean and Japanese. Absolute pitch is also more common among Asian-Americans, who often speak only English.

The brain's auditory cortex is arranged in maps of neurons that respond to a particular frequency, with high-frequency neurons at one end and low-frequency at the other.

"It should be relatively trivial to read out the absolute pitch of a stimulus," Josh McDermott of the Massachusetts Institute of Technology said. Assessing relative pitch involves comparison and a complicated neural computation. "So it's a mystery why absolute pitch is such a rare phenomenon."

One possible explanation, he said, is that everyone is born with absolute pitch, but most people lose it in favor of relative pitch. Dr. Zatorre also sees absolute pitch as a possible slight derangement of normal brain processes, rather than an enhanced natural ability. In some forms of autism, he said, people see trees and not the forest. Possibly, absolute pitch is a mild form of the same disorder in the auditory domain.

Some musicians with absolute pitch find it hard to transpose melodies, he said, and they cannot shut off their absolute pitch even when they would like to.


http://www.nytimes.com/2003/09/16/science/16PITC.html

Interesting topic - I'll read more into it as time permits. I've always been intrigued by this as well. Something that has always amazed me about both the ear and the eye and the brain's abilities in processing the information retrieved by both is pattern recognition. The ear recognizes complex patterns in the form of speech, pieces the bits together and unfolds a meaningful message from soundwaves passing through the air - amazing! To me music (at least that which does not include vocals) almost represents a rest for the brain's pattern recognition capabilities when it comes to sound signal processing.

Further, "they" say that it's good for pregnant women to give their babies a head start with listening to music by using special headphones which broadcast sound into the womb. Even more interesting is that "they" specifically call for classical music which supposedly activates more areas of the brain than other types of music. Did you ever wonder why that is about classical music? Well I've done some studying on that and it turns out, much to my amazement, that many classical instruments produce incredibly pure waveforms. A violin, for example, while sustaining a given note produces an almost perfect sine wave. If you take those very basic wave forms and combine them all together into a musical score and then transfer that to the ear of an undeveloped brain, it seems to me that the brain will have the ability to develop initial pattern recognition capabilities one the most fundamental sound shapes possible while at the same time finding patterns of change amongst those fundamental shapes. Ideally, this would pave the way for a brain that after birth is ready to recognize and respond to more complex patterns more immediately than a brain which was not introduced to such initial input.

Regarding visual stimulus which I find equally fascinating, just think of how incredible the proceessing capability of your brain is when regarding any given scene. Take where you are right now: you look to one side ant there are books on a shelf and you recognize the books, the shelf, the colors, the materials from which those things are made of; they exist within a three dimensional space that is a room with walls and you sense the depth of the space and that there is physical motion that your body must engage in in order to obtain one of the books and that the three dimensional space must be traversed in order to do so - all this information that comes flooding to you from a single snapshot. Would the snapshot be any different if it were rotated fifteen degrees to one side or the other? Or if it were upside down?

I believe that somehow, the brain's capability for pattern recognition in general is a major influence for how we think and perceive the Universe around us. The same pattern recognition affects all of our senses. The eye's ability to detect a faint line which hints at depth, even in darkness - I can't even begin to imagine about how to program a computer to recognize these things, much less know what to think about them.. and upside down!? forget about it!

If you were ever worried about robots taking over the world, rest assured: we're nowhere near.

Sean,
Music is fascinating and you are right about classical music... it is like mathematics for the brain. I guess the fetus can hear in the womb (can sense light and dark but can't see... no taste... no smell... feeling self and inside of the womb... no language... so for the brain music would be a logical sound pattern.
Rock ec... is great for us, for dancing, for sex, etc but I don't think it does much for the fetus not much variation in the scales and fibrations.

I just read a few days ago about a man who went blind at the age of 3 and them gained his vision later in adulthood. I could no longer find the whole article just this short version on CNN:

Man's restored sight offers new view of vision
Monday, August 25, 2003 Posted: 11:43 AM EDT (1543 GMT)

Michael May, with wife Jennifer and 9-year-old neighbor Aaron Hills, tests out his Braille GPS equipment at home in Davis, California.


(AP) -- After 43 years of blindness, Michael May can see again.

He can play soccer with his sons, enjoy movies and, for the first time, gaze on the Sierra Nevada slopes he has expertly skied -- sightless -- since the late 1970s.

But May can't recognize his sons, Carson, 11, and Wyndham, 9, by their faces alone. The same goes for identifying Jennifer, his wife of 15 years.

People "can't fathom that," said May, who owns a company in Davis, California, that makes navigational software for the blind.

Three years after surgery restored sight to May's right eye, researchers say May's case shows how vision is more than just eye function. Blindness has long-term effects on how the brain processes information and constructs one's view of the world.

May lost his sight to a chemical explosion when he was 31/2 years old. He eventually lost his left eye and remained blind in his right until the surgery in 2000.

But testing since that surgery has showed that May's ability to interpret what he sees through his good eye is decidedly mixed, said Ione Fine, lead author of a study appearing in the September issue of the journal Nature Neuroscience.

May can identify simple shapes and colors. He can interpret objects in motion. He can spy faraway peaks. He marvels at the vibrancy of plants and flowers unseen since he lost his vision.

But three-dimensional perception and the ability to recognize complex objects such as the faces of family and friends remain severely impaired. He strains to tell the difference between a man and a woman. He describes a cube as a square with extra lines.

Written history mentions perhaps 30 people who reacquired vision after protracted periods of blindness, said Fine, a neuroscientist at the University of California, San Diego. She and her colleagues leapt at the chance to study May and began testing him just months after his cornea- and stem cell-implant surgery. The stem cells formed a protective layer over his new cornea to prevent clouding.

"There has always been this question: What would happen if a blind man got his vision back? Is it something innate or is it something we learn from first principles?" Fine asked. "Is it something that happens or is it something we learn, like language?"

New dimensions
Repeatedly, the researchers combined vision tests with scans of May's brain activity to study how blindness had affected him.

When asked to identify a cube illustrated on a two-dimensional computer screen, for example, May failed. But once Fine commanded the cube to rotate, simulating motion in three dimensions, he immediately recognized it.

"It was really weird to have a three-dimensional sense of something on a flat surface, because it was such a foreign experience to someone dominated by a tactile ability," May said.

Scans of the region of May's brain associated with the processing of complex forms revealed patchy responses when he was shown the still cube.

But once the cube moved, his motion-processing region came ablaze with activity, Fine said. That suggests the region was fully developed when May lost his sight, Fine said.

Since May's ability to recognize complex forms showed such impairment, it suggested that region is much slower to mature, Fine said. Once deprived of visual experience, it likely ceases to develop and languishes, she added.

Since humans constantly encounter novel objects and new faces -- and aging in familiar faces -- the processing region in the brain must remain flexible, Fine said.

Jon Kaas, a Vanderbilt University neuroscientist, said the findings were consistent with what has been shown in studies with laboratory animals reared in darkness or with their eyelids artificially kept sealed shut.

Kaas, who was not connected with the study, said it was the most thorough of its kind on an individual.

May agreed with Fine's theory that vision, like language, appeared to be a skill honed through experience.

"I will never be fluent visually, but I get better the more I work at it," he said.

MM's website http://www.senderogroup.com/perception.htm

Another interesting article about music for humans and animals...

http://www.sciam.com/article.cfm?ar...21&chanID=sa008

Music may be even more ancient than the human race, over which it holds tremendous sway. Scientists are beginning to find out why
By Kristin Leutwyler
January 22, 2001


[photo] "NEANDERTAL FIREPLACE in France may have offered warmth to our ancestors as they joined to play and listen to the animal-bone flutes recently found in the area. The remarkable musical instruments are as much as 53,000 years old—more than twice as old as the famed cave paintings in Lascaux."

It can bring us to tears or to our feet, drive us into battle or lull us to sleep. Music is indeed remarkable in its power over all humankind. Perhaps for that very reason, no human culture on earth has ever lived without it: people making music predates agriculture and perhaps even language. Take, for instance, the recent discoveries in France and Slovenia of surprisingly sophisticated, sweet-sounding flutes, made by our Neandertal cousins. Some of these instruments, carved from animal bones, are as much as 53,000 years old—more than twice as old as the famed cave paintings in Lascaux .

Despite the ancient and primal nature of music, though, scientists have struggled with some very fundamental questions about its origins and purpose. How does the brain process music? Are there special neural circuits dedicated to creating or interpreting it? If so, are they, like language, unique to human beings? Or do other animals possess true musical ability? Why is an appreciation for music practically universal? Has it conveyed some evolutionary advantage through time? The field of biomusicology is still fairly young, but during the past few years, it has started to answer some of these questions.

Perhaps most basic, researchers have discovered that music—like language—stimulates many areas in the brain, including regions normally involved in other kinds of thinking. For this reason, Mark Jude Tramo of the Harvard Medical School argues in a recent issue of Science that the brain doesn't have a specific "music center," as others have suggested. As an example, he points to the left planum temporale. This tiny brain region is critical to the golden musical gift of perfect pitch—the rare ability to recognize by ear a perfect middle C hit on the piano, or the E of a passing car horn. But the left planum temporale also plays an important role in language processing. Thus, Tramo writes, there is "no grossly identifiable brain structure that works solely during music cognition. However, distinctive patterns of neural activity within the auditory cortex and other areas of the brain may imbue specificity to the processing of music."

Some of the patterns Tramo talks about have revealed themselves through neuroimaging studies—others through tests on patients that, like the subjects of Oliver Sacks's popular books, have suffered unusual forms of brain damage. In the late 1990s, for instance, Isabelle Peretz at the University of Montreal and Catherine Liégeois-Chauvel of INSERM in Marseilles ran several experiments on 65 people who, because of epilepsy, had had part of one or the other temporal lobe surgically removed. From these studies they concluded that musicality resided primarily on one side of the brain—the right hemisphere.

The experiments were simple: Peretz and Liégeois-Chauvel played different songs for each patient twice. Sometimes the melodies were exactly the same. Other times, they had changed in one of several attributes, which researchers describe as "dimensions": first among them is pitch, which pertains to the actual frequency of a particular tone; the second is rhythm, or the duration of series of notes; the third is tempo, the overall pace of a piece; the fourth is contour, which describes the shape of a melody, or its pattern of rises and falls in notes; the fifth is key, or the set of pitches to which notes in a melody belong; other dimensions include timbre, loudness and spatial location.

The scientists found that people with damage to the left temporal lobe had difficulty recognizing changes only in key, whereas those with damage to the right side struggled to recognize changes in both key and contour. Later imaging studies showed a similar bias toward the right hemisphere—particularly among nonmusicians—although Tramo notes that more recent work calls some of this "musical hemisphere" hypothesis into question. "The belt and parabelt areas [of the auditory cortex] in the right hemisphere discriminate local changes in note duration and separation," he writes, "whereas grouping by meter involves mostly anterior parabelt areas in both hemispheres."

From Mind's Eye to Emotion's Seat

[Image]: "NATIONAL MARINE FISHERIES SERVICE
HUMPBACK WHALES use many of the same rhythms and patterns as human composers in their songs, tempting some scientists to speculate that a universal music awaits discovery."

For certain, it is becoming apparent that unexpected and unsophisticated areas of the brain are sometimes involved in interpreting, writing, feeling or performing music. As some research has showed, even the visual cortex sometimes gets into the act. Hervé Platel, Jean-Claude Baron and their colleagues at the University of Caen used positron emission tomography (PET) to monitor the effects of changes in pitch. What they found—much to their surprise—was that Brodmann's areas 18 and 19 in the visual cortex lit up. These areas are better known as the "mind's eye" because they are, in essence, our imagination's canvas. Any make-believe picture begins there. Thus, Baron suggests that the brain may create a symbolic image to help it decipher changes in pitch.

But music goes much deeper than that—below the outer layers of the auditory and visual cortex to the limbic system, which controls our emotions. The emotions generated there produce a number of well-known physiological responses. Sadness, for instance, automatically causes pulse to slow, blood pressure to rise, a drop in the skin's conductivity and a rise in temperature. Fear increases heart rate; happiness makes you breathe faster. By monitoring such physical reactions, Carol Krumhansl of Cornell University demonstrated that music directly elicits a range of emotions. Music with a quick tempo in a major key, she found, brought about all the physical changes associated with happiness in listeners. In contrast, a slow tempo and minor key led to sadness.

Robert Zatorre and Anne Blood at McGill University corroborated Krumhansl's findings with PET imaging experiments. They created original melodies containing dissonant and consonant patterns of notes, and played them for a group of volunteers willing to be scanned at the same time. As expected, dissonance made areas of the limbic system linked to unpleasant emotions light up in the PET scans, whereas the consonant melodies stimulated limbic structures associated with pleasure.

That music strikes such a chord with the limbic system—an ancient part of our brain, evolutionarily speaking, and one that we share with much of the animal kingdom—is no accident, some researchers assert. In another recent paper in Science, Patricia Gray, head of the Biomusic program at the National Academy of the Sciences, and several colleagues from around the country propose that music came into this world long before the human race ever did. "The fact that whale and human music have so much in common even though our evolutionary paths have not intersected for 60 million years," they write, "suggests that music may predate humans—that rather than being the inventors of music, we are latecomers to the musical scene."

[Image]: "OHIO STATE UNIVERSITY
Humpbacks, Hummingbirds and Human Composers
SINGING BIRDS often pitch their songs to the same scale as Western music—which may explain at least in part why people find them so attractive."

Gray and company note that humpback composers employ many of the same tricks human songwriters do. In addition to using similar rhythms, humpbacks keep musical phrases to a few seconds, creating themes out of several phrases before singing the next one. Whale songs in general are no shorter than human ballads and no longer than symphony movements , perhaps because they have a similar attention span. Even though they can sing over a range of seven octaves, the whales typically sing in key, spreading adjacent notes no farther apart than a scale. They mix percussive and pure tones in pretty much the same ratios as human composers—and follow their ABA form, in which a theme is presented, elaborated on and then revisited in a slightly modified form.

Perhaps most amazing, humpback whale songs include repeating refrains that rhyme. Gray and her colleagues say that whales might use rhymes for exactly the same reasons we do: as devices to help them remember. As a recent study showed, whale songs are often rather catchy. When a few humpbacks from the Indian Ocean strayed into the Pacific, some of the whales they met there quickly changed their tunes—singing the new whales' songs within three short years.

Back on land, birds, too, make music much like people. "When birds compose songs they often use the same rhythmic variations, pitch relationships, permutations and combinations of notes as human composers," Gray and her colleagues write, citing work done by their late co-author Luis Baptista. "Thus, some bird songs resemble musical compositions; for example, the canyon wren's trill cascades down the musical scale lie the opening of Chopin's 'Revolutionary' Etude." That same bird sings in the chromatic scale, which divides the octave into 12 semitones, and the hermit thrush sings in the so-called pentatonic scale. It is perhaps because these birds pitch their songs to the same scale as Western music that people find them so attractive.

Why would such different creatures—with such different physical means for making sound—all adopt such astonishingly uniform patterns for their melodies? Gray and her colleagues conclude that the similarities "tempt one to speculate that the platonic alternative may exist—that there is a universal music awaiting discovery." But in fact, there is currently considerable debate over the purpose of music, and whether it was adaptive for humans in evolution or not.

"Auditory Cheesecake" or Evolutionary Advantage?

Linguist Steven Pinker of the Massachusetts Institute of Technology has proposed that music is merely "auditory cheesecake," or "an evolutionary accident piggy-backing on language," as Daniel J. Levitin at McGill University explained in a recent issue of the journal Cerebrum. But many scientists—Levitin among them—don't agree. "Some researchers are finding that listening to familiar music activates neural structures deep in the ancient primitive regions of the brain, the cerebellar vermis ," Levitin writes. "For music so profoundly to affect this gateway to emotion, it must have some ancient and important function."

Geoffrey Miller of University College London has proposed that musical ability—like broad shoulders or showy plumes—may serve to demonstrate fitness to a potential mate. After all, singing or playing an instrument well requires dexterity and good memory. Another suggestion Levitin makes is that music functions as communication, perhaps mimicking the rhythm and contour of our species' primitive calls. So, too, he proposes that perhaps music conveys an advantage through stimulating our primitive timing mechanisms.

Most interesting, he suggests that music stimulates our drive to find patterns in the environment. "Our brain is constantly trying to make order out of disorder, and music is a fantastic pattern game for our higher cognitive centers," he writes. "From our culture, we learn (even if unconsciously) about musical structures, tones and other ways of understanding music as it unfolds over time; and our brains are exercised by extracting different patterns and groupings from music's performance." It is this very kind of pattern recognition—which is extremely important for making sense of the world around us—that Keith Devlin suggests in his book The Math Gene gave rise to language and stands behind mathematical ability as well. To be certain, researchers won't agree on the purpose of music anytime soon—which fortunately shouldn't stop any of us from enjoying it.