As a recreational vocalist, I have spent some of the most moving moments of my life engaged in song. As a college student, my eyes would often well up with tears during my twice-a-week choir rehearsals. I would feel relaxed and at peace yet excited and joyful, and I occasionally experienced a thrill so powerful that it sent shivers down my spine. I also felt connected with fellow musicians in a way I did not with friends who did not sing with me.

I have often wondered what it is about music that elicits such emotions. Philosophers and biologists have asked the question for centuries, noting that humans are universally drawn to music. It consoles us when we are sad, pumps us up in happier times and bonds us to others, even though listening to an iPod or singing “Happy Birthday” does not seem necessary for survival or reproduction.

Some scientists conclude that music’s influence may be a chance event, arising from its ability to hijack brain systems built for other purposes such as language, emotion and movement. As Harvard University psychologist Steven Pinker famously put it in his 1997 book How the Mind Works (W. W. Norton), music is “auditory cheesecake,” a confection crafted to tickle the areas of the mind that evolved for more important functions. But as a result of that serendipity, music seems to offer a novel system of communication rooted in emotions rather than in meaning. Recent data show, for example, that music reliably conveys certain sentiments: what we feel when we hear a piece of music is remarkably similar to what everybody else in the room is experiencing.

Emerging evidence also indicates that music brings out predictable responses across cultures and among people of widely varying musical or cognitive abilities. Even newborn infants and people who cannot discern pitch enjoy music’s emotional effect. “Certainly music seems to be the most direct form of emotional communication,” opines renowned neurologist Oliver Sacks of Columbia University, author of the recent book Musicophilia (Knopf, 2007). “It really seems to be as important a part of human life and communication as language and gesture.”

Such dialogue provides a way for people to connect emotionally and thus may reinforce the ties that underlie the formation of human societies, which have clear survival advantages. Musical rhythms may have even facilitated certain physical interactions such as marching or dancing together, further cementing our social ties. In addition, tunes may work to our benefit on an individual level, manipulating mood and even human physiology more effectively than words can—to excite, energize, calm or promote physical fitness. All these benefits are causing people to reconsider whether music is truly as frivolous as it seems.

Mosaic in the Mind
Throughout recorded history, people have attempted to explain music’s sway over the human spirit. Music has been labeled everything from a gift of the heavens to a tool of the Devil, from an extension of mathematics to a side effect of language processing. Charles Darwin was famously stumped by music’s ubiquitous presence around the world: man’s predilection for music, he wrote in 1871 in The Descent of Man, “must be ranked among the most mysterious with which he is endowed.”

Since the 1950s many psychologists have attempted to explain music’s power by comparing music appreciation with speech. After all, an understanding of both music and speech requires, at its most primitive level, the ability to detect sounds. The brain’s auditory cortex, an area dedicated to hearing, is now known to process basic musical elements such as pitch (a note’s frequency) and volume; the neighboring secondary auditory areas digest more complex musical patterns such as harmony and rhythm. [For more on how the brain processes music, see “Music in Your Head,” by Eckart O. Altenmller; Scientific American Mind, January 2004.]

In addition, language and music both contain a grammar that organizes smaller components such as words and musical chords, phrases made up of melody or prosody (the melodic line of speech), and tension and resolution. Indeed, music has been found to excite brain regions involved in understanding and producing language, including Broca’s area and Wernicke’s area, both located in the left hemisphere on the surface of the brain. (The majority of people process language mainly in the brain’s left hemisphere but encode most aspects of music in the analogous regions on the right.) Thus, musical syntax—for instance, the order of chords in a phrase—could have arisen from the mechanisms that evolved to organize and understand grammar.

But tunes also recruit other brain systems, principally perhaps those governing emotions such as fear, joy and sorrow. For example, damage to the amygdala, the brain’s fear hub, impairs a person’s ability to feel scared and, in some studies, sad in response to song. Many modern researchers thus conjecture that music evolved by piggybacking on a unique constellation of brain regions dedicated to language, feelings and other functions. “I think there’s a very good chance that music is simply a side effect of things that evolved for other reasons,” says auditory scientist Josh McDermott, now at New York University.

Universal Language
Music’s simultaneous activation of diverse brain circuits seems to produce some remarkable effects. Instead of facilitating a largely semantic dialogue, as language does, melody seems to mediate an emotional one. When a composer writes a lamentation or a toddler exuberantly bangs out a rhythm on a pot, that person is not only revealing his or her own emotional state but also causing listeners to share those feelings. Several pieces of research indicate that music reliably conveys the intended emotion in all people who hear it. In the late 1990s neuroscientist Isabelle Peretz and her colleagues at the University of Montreal found that Western listeners universally agree on whether a song using Western tonal elements is happy, sad, scary or peaceful.

Music’s emotional content may even be culturally transparent. This past April neuroscientist Tom Fritz of the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, Germany, and his colleagues exposed members of the Mafa ethnic group in Cameroon who had never heard Western music to excerpts of classical piano music. The researchers found that the adults who listened to the excerpts consistently identified them as happy, sad or scary just as Western listeners would. Thus, the ability of a song to elicit a particular emotion does not necessarily depend on cultural background.

The musical tongue may also transcend more fundamental communication barriers. In studies conducted over the past decade, cognitive psychologist Pam Heaton of Goldsmiths, University of London, and her research team played music for both autistic and nonautistic children, comparing those with similar language skills, and asked the kids to match the music to emotions. In the initial studies, the kids simply chose between happy and sad. In later studies, Heaton and her colleagues introduced a range of complex emotions, such as triumph, contentment and anger, and found that the kids’ ability to recognize these feelings in music did not depend on their diagnosis. Autistic and typical children with similar verbal skills performed equally well, indicating that music can reliably convey feelings even in people whose ability to pick up emotion-laden social cues, such as facial expressions or tone of voice, is severely compromised.

Recently, in a clever experiment, acoustics scientist Roberto Bresin and his co-workers at the Royal Institute of Technology in Stockholm garnered quantitative support for the idea that music is a universal language. Instead of asking volunteers to make subjective judgments about a piece of music, scientists asked them to manipulate the song—in particular, its tempo, volume and phrasing—to maximize a given emotion. For a happy song, for instance, a participant was supposed to manipulate these variables by adjusting sliders so that the song sounded as cheerful as possible; then as sad as possible; then scary, peaceful and neutral.

The researchers found that the participants—expert musicians and, in another study, seven-year-old children—all landed on the same tempo for each song to bring out its intended emotion, be it happiness, sadness, fear or tranquility. These findings, which Bresin reported at the 2008 Neuromusic III conference in Montreal, bolster the idea that music contains information that elicits a specific emotional response in the brain regardless of personality, taste or training. As such, music may constitute a unique form of communication.

Choral Bonding
Music’s ability to convey feelings may underlie one of its most important benefits. In most cultures, music is almost always a communal event: everyone gets together to sing, dance, and play instruments. Even in Western societies, which uniquely differentiate musical performers from listeners, people enjoy music together in a wide variety of settings: dancing at a wedding or a nightclub, singing hymns in church, crooning with their kids, Christmas caroling and singing “Happy Birthday” at a party. The popularity of such rituals suggests that music confers social cohesiveness, perhaps by creating empathetic connections among members of a group.

But empathy may not be the only means by which music facilitates unity. Studies show that when people listen to music, the motor regions of the brain are also active—probably for the purpose of processing rhythm. These include premotor areas, which prepare a person for action, and the cerebellum, which coordinates physical movement. Some researchers have a hunch that part of music’s power stems from its tendency to echo and synchronize our activities. “I can see how rhythm and physical action would have mutual resonance in the nervous system,” speculates neuropsychologist Robert Zatorre of McGill University. “All sound is produced by movement. When you hear a sound, it’s because something has moved.”

Then it is a small step from walking, breathing, and hearing a heartbeat—natural rhythmic sounds that are not intrinsically musical—to purposely keeping time or matching another’s gait. “Part of the reason music works is that when you hear a pattern, you can join in. You know how to organize your muscles to produce the sound you are hearing,” Zatorre explains. In this way, the rhythm of a song could also serve as social glue by promoting a kind of physical bonding.

The idea that music may promote a type of nonverbal togetherness gains additional support from a 2008 study by neuroscientists Nikolaus Steinbeis of the Max Plank Institute for Human Cognitive and Brain Sciences and Stefan Koelsch of the University of Sussex in England. Steinbeis and Koelsch used functional magnetic resonance imaging to pinpoint a brain area that responded to chords but not to words, in a task in which volunteers listened to both. The responsive region turned out to be the superior temporal sulcus, a part of the brain’s surface near the ears that responds to nonverbal social cues such as nonspeech vocal utterances, eye movements and body movements. The activation of this region hints that music may indeed be helping to forge social ties.

Whatever its origin, such cohesiveness is extremely valuable to a communal animal such as ourselves; traits that enhance such unity tend to persist. “Music is usually a social activity,” Koelsch explains. “While people make music, they communicate and cooperate with one another. In a way, they practice social activity and social functions. This social behavior is highly important for the human species.”

Musical Medicine
Music also bestows advantages on us as individuals. Underlying our conscious impressions of a tune are physiological effects that can improve our mental and physical well-being. Studies show that upbeat, tense or exciting music can physically excite the listener, triggering the body’s fight-or-flight response: heart and breathing rates increase, a person may break out in a sweat, and adrenaline enters the bloodstream. This “pumping up” effect explains why so many people enjoy listening to rock or hip-hop while they work out—the music primes the physiological systems needed for high-energy movement. The psychological effect is important, too; music is a welcome distraction, making exercising more fun. Energizing melodies tend to boost mood in general, waking us up if we are feeling tired and creating a sense of excitement in any situation.

On the other hand, music can be calming, reducing the levels of the stress hormone cortisol in the blood, lowering heart and respiration rates, and alleviating pain, according to several studies. The classic example of this anxiety-reducing effect is a mother soothing her baby to sleep with a lullaby. In addition, clinical studies have shown music to be a powerful tool for relaxing patients about to undergo surgery, controlling their pain, and ameliorating behavioral issues in children and people with dementia.

In 2000 gerontology researcher and nurse Linda A. Gerdner of the University of Arkansas for Medical Sciences exposed 39 severely impaired Alzheimer’s patients to music they liked twice a week for six weeks. The favored music, as determined by a questionnaire, reduced the patients’ agitation levels during and after the listening period much more than did a similar schedule of classical “relaxation” music they heard at a separate time. Beloved music also has been found to reduce pain during surgery and child labor. The analgesic effect apparently outlasts the listening: exposure to music during labor or a medical procedure can lessen the soreness experienced afterward, even after the music has stopped.

And of course people self-medicate with music all the time. Broad surveys have found that nearly everybody reports listening to music by themselves for the purpose of enhancing or altering their emotional state.

Built for Song?
Given its undisputed allure, might music have some unique roots in the brain in addition to piggybacking on other systems? Researchers have described several cases of brain damage that impaired a person’s capacity to feel emotions inspired by music but not by other stimuli. Lawrence Freedman, a friend of Sacks’s, selectively lost his passion for classical music after a concussion from a bike accident. Freedman could still recognize the classical works he used to love, Sacks says, and he was still moved by visual art and other experiences, but music gave him no pleasure. Presumably the accident damaged a part of the brain dedicated specifically to enthusiasm for music, although no one knows exactly what part of the brain that is.

Other researchers argue that music has independent origins because the capacity to appreciate it appears to be hardwired at birth. Various studies show that infants pay rapt attention to song and even seem to prefer song to speech. In preliminary findings published in July 2008 in Nature Precedings, neuroscientists Maria Cristina Saccuman and Daniela Perani of Vita-Salute San Raffaele University in Italy and their colleagues showed that music activates regions in newborns’ brains similar to those activated in more mature listeners. Saccuman and Perani used fMRI to see how the brains of one- to three-day-old newborns responded to classical music and found a pattern that mirrored music processing in adults: the infants’ right hemisphere auditory system responded more strongly than the left. The researchers also altered the music by either making a section in the middle of the excerpt suddenly jump into another key or playing the entire musical segment in clashing keys. These more jarring passages preferentially activated the infants’ left inferior frontal cortex, an area implicated in musical syntax processing in adults, and the limbic system, the seat of emotional response, just as happens in adults. “The brain seems to be born ready to process music,” Saccuman concludes.

This innate readiness for music is thought to be tied to the phenomenon of motherese, the peculiar singsong way people instinctually talk to babies. The universal use of motherese has led some experts to speculate that it may be the original starting point for both music and language. Some experts, notably cognitive archaeologist Steven Mithen of the University of Reading in England, theorize that language and music both evolved from a musical protolanguage that our hominid ancestors used. Neandertals and other extinct hominids appear to have vocal chord structures that suggest they could sing, according to Mithen. Ancient humans certainly played instruments: researchers have uncovered bone flutes that are tens of thousands of years old.

The truth is that we may never know why music exists; evolutionary theories are very difficult to test. But even amid uncertainty about music’s origins, we can still use songs to pump ourselves up or calm ourselves down, ease pain and anxiety, bond with others or simply move people to tears. “Music is the most direct and mysterious way of conveying and evoking feeling,” Sacks professes. “It is a way of connecting one consciousness to another. I think the nearest thing to telepathy is making music together.”