(Darthmouth Journal of Science)
Music is everywhere — and we wouldn’t have it any other way. Whether we use it to get ourselves out of bed in the morning, energize our exercise workouts, soothe a crying infant, or calm down after a stressful day, it’s safe to say that people love music.
Music is unique among human activities not only for its ubiquity, but also for its antiquity: music has been a part of every known human culture in all of recorded history. Nearly 40,000 years ago, early humans carved bones and stretched animal skins over hollow tree stumps to make rudimentary musical instruments. It seems that our deep-rooted appreciation for music is innate; human infants react and respond to music even before they have learned to talk.
The seventeenth-century poet William Congreve claimed that “Music has charms to soothe a savage breast / To soften rocks, or bend a knotted oak.” Few would disagree: music is powerful. Recent brain imaging studies have helped reveal why we get so much pleasure from music. Researchers at the Montreal Neurological Institute scanned musicians’ brains and found that when they experienced “chills” while listening to stirring passages of music, the same pleasure centers in the brain were active that are normally active when people engage in other rewarding activities such as eating chocolate and having sex (1). This might explain why, for example, Americans spend more each year on music than on prescription drugs.
We do not possess a music “center” that processes all musical input. Our brains are programmed to comprehend and enjoy music from a variety of regions that vary from individual to individual.
In his book, This is Your Brain on Music, Daniel Levitin says that, “to ask questions about a basic, and omnipresent human ability is to implicitly ask questions about evolution (2).” Although we know that music has been a part of human life for a very long time, its evolutionary benefits are somewhat of a mystery. What function did music serve humankind as we were evolving and developing?
In Charles Darwin’s 1890 book, The Descent of Man, he proposed that “musical notes and rhythm were first acquired by the male or female progenitors of mankind for the sake of charming the opposite sex (3).” Another popular theory is that music arose as a way for mothers to soothe their crying babies. On the other hand, author and Harvard University psychologist Steven Pinker argues that music is nothing more than “auditory cheesecake:” it merely manages to “tickle the sensitive spots” in areas of the brain that evolved for other purposes (4).
While the evolutionary purpose of music remains a subject of controversy, neuroscientists are beginning to better understand music as a perceptual experience: how and where is music processed in the brain? Recent findings show that there is no “center” for music in the brain, and our ability to perceive music involves a variety of regions throughout the brain. The brain areas active while listening to music even vary from individual to individual depending on musical training and experience.
Making Sense of Sound
Before exploring the brain’s response to music, it is important to understand the physical events that give rise to the experience of sound. How does the ear transfer sound waves into neuronal signals? Processing sound begins with the inner ear, where the cochlea analyzes the sound vibrations for frequency and intensity. Most importantly, the cochlea converts sound energy into the only form of information that the brain understands, neural impulses. This neural information is carried out of the inner ear by the auditory nerve. The auditory nerve branches into several pathways that reconverge within the auditory cortex. Finally, the auditory cortex decodes the neural patterns of the sound to determine their significance. These high levels of acoustic processing and auditory pattern recognition are essential for understanding speech and recognizing music.
The Neural Rewards of Music
Brain imaging studies have revealed that processing music involves a variety of brain structures. Daniel Levitin looks to cognitive neuroscience to help explain why music is so important to us. According to Levitin, “the story of your brain on music is the story of an exquisite orchestration of brain regions, involving both the oldest and newest parts of the human brain (2).” Levitin recounts his own brain imaging research on the subject of emotional responses to music, involving musicians who reported that they experienced intense emotions that they described as “thrills and chills” while listening to stirring passages of music. Levitin analyzed brain images of the activity in the brains of these musicians while they listened to classical music in an effort to identify the brain regions that contribute to their emotional experiences. He found that listening to music activates many particular brain regions in a certain order: “first, the auditory cortex for initial processing of the components of the sound. Then the frontal regions…previously identified as being involved in processing musical structure and expectations. Finally, a network of regions — the mesolimbic system — involved in arousal, pleasure, and the transmission of opioids and the production of dopamine, culminating in activation in the nucleus accumbens.” Levitin adds that “the rewarding and reinforcing aspects of listening to music seem, then, to be mediated by increasing dopamine levels in the nucleus accumbens (2).” These findings provide insight into how music can be a profoundly powerful force on our emotions.
How are we able to classify some tunes as “sad” and others as “happy”? Why do we experience a sense of pending doom when we we hear the opening measures of Beethoven’s 5th symphony? Music has a mysterious capacity to evoke emotional reactions of every sort. One of the most important figures in the field of music psychology is Leonard Meyer, author of the book Emotion and Meaning in Music. In his book, Meyer says that “from Plato down to the most recent discussions of aesthetic and the meaning of music, philosophers and critics have, with few exceptions, affirmed their belief in the ability of music to evoke emotional responses in listeners … Past and present, [listeners] have reported with remarkable consistency that music does arouse feelings and emotions (5).” Indeed, many studies confirm that music evokes emotion in listeners. In a study by John Sloboda of Keele University, 80% of sampled adults reported physical responses to music ranging from laughter to tears and in between (6). Although most would agree that music can elicit emotions, is there any objective evidence that confirms this?
In addition to being one of the greatest physicists of the 20th century, Albert Einstein was also an avid violinist.
According to Meyer, there is: “on the physiological level music evokes definite and impressive responses (5).” In studies that record pulse, blood pressure, and respiration while individuals listen to various types of music, subjects exhibit physiological changes when they listen to different passages of music considered to convey different types of emotions.
Some have suggested that these emotional reactions are conditioned by our exposure to the Western tonal system of major and minor keys. In other cultures with different tonal systems however, music also has distinct emotional connotations. If our emotional reactions to Beethoven are the result of exposure to the Western tonal system, it would be reasonable to assume that Westerners would not get the same emotional reactions when listening to non-Western music for the first time, and vice-versa. Surprisingly, this is not the case.
In a 1999 study by Laura-Lee Balkwill and William Thompson at York University in Toronto, students and staff at the university were asked to listen to excerpts of native musicians of India playing Hindustani ragas, which are pieces that are common in Indian instrumental music. Different ragas were improvised to convey sadness, anger, joy, or peace. The Canadian listeners had no difficulty categorizing each raga’s dominant emotion, despite the entirely different tonal system around which ragas are based (7).
This evidence suggests not only that there are salient auditory cues that specify emotional content in music, but also that these cues transcend cultural differences in musical style. Some of the most important acoustic cues to musical emotion include tempo, loudness, and the key in which a piece is played.
Practice Makes Permanent
Imaging studies of musicians reveal that the brain can undergo a variety of physical changes in response to musical exposure, training, and practice. Children exposed to music lessons often develop better listening skills and enhanced brain cell responses to musical tones. One of the most striking ways that musical training can affect the brain is that training can alter functional organization of the somatosensory representation cortex (SRC). The SRC is a brain region that contains a map of the sensory areas (fingers, lips etc.). The representation of the fingers of a given hand may not be equal if they are not equally used, for example. Musicians that practice and train for many years show dramatic differences in cortical representations of the fingers that are most important for playing their instruments. A study by Christo Pantev and Thomas Elbert at the Institute for Experimental Audiology at the University of Munster in Germany measured the somatosensory cortical representations of the fingers on the left hand in violinists — the hand that requires the most precision in playing violin–and compared them to the cortical representations in control subjects who had no experience playing an instrument. To measure the representations of the fingers in the brain, pressure was applied to each fingertip during a brain imaging session. They found that the representations of the fingers of the left hand are greater in violinists than in non-musicians, particularly so for the pinky (8).
These findings provide evidence that the brain is capable of physically changing as a result of musical practice.
The Future of Music & Brain Research
So far, research into which brain regions are involved in processing music has offered some explanation for the seemingly ancient human obsession with music. Science has also provided possible explanations for the powerful emotional effects of music. As neuroscientists continue to explore music in the brain, they will come closer to explaining the evolutionary purpose of music. The findings so far indicate that music has a biological basis, and that the brain has a functional organization for music. In addition, more recent studies have shown that music activates reward pathways in the brain.
A better understanding of the way our brains process music will also pave the way for medical applications, extending the benefits of music beyond mere enjoyment. Many of these applications are already under way in the field of music therapy, where music is used to treat neurological conditions ranging from Alzheimer’s to Parkinson’s disease. As research continues, we can look forward to greater insight into why music is so strangely powerful and pervasive.
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References
1. A. J. Blood, R. J. Zatorre. Proc. Natl. Acad. Sci. U. S. A. 98, 11818-11823 (2001).
2. D. Levitin, This is Your Brain on Music: the Science of a Human Obsession (Penguin Group Inc., New York, NY, 2006).
3. C. Darwin, The Descent of Man, and Selection in Relation to Sex (Princeton University Press, Princeton, NJ, 1981).
4. S. Pinker, How the Mind Works, (W. W. Norton & Company Inc., New York, NY, 1999).
5. L. Meyer, Emotion and Meaning in Music, (University of Chicago Press, Chicago, IL, 1961).
6. J. Sloboda, Psychology of Music. 19, 110-120 (1991).
7. L. L. Balkwill, W. F. Thompson. Music Perception 17, 43-64.
8. C. Pantev, A. Engelien, V. Candia, T. Elbert, Annals of the New York Acad. of Sci. 930, 300-314 (2006).
9. A. M. Lamont, “Infants’ preferences for familiar and unfamiliar music: A socio-cultural study” (2001). Paper read at Society for Music
Perception and Cognition, Kingston, Ont., 9 Aug 2001.
2. D. Levitin, This is Your Brain on Music: the Science of a Human Obsession (Penguin Group Inc., New York, NY, 2006).
3. C. Darwin, The Descent of Man, and Selection in Relation to Sex (Princeton University Press, Princeton, NJ, 1981).
4. S. Pinker, How the Mind Works, (W. W. Norton & Company Inc., New York, NY, 1999).
5. L. Meyer, Emotion and Meaning in Music, (University of Chicago Press, Chicago, IL, 1961).
6. J. Sloboda, Psychology of Music. 19, 110-120 (1991).
7. L. L. Balkwill, W. F. Thompson. Music Perception 17, 43-64.
8. C. Pantev, A. Engelien, V. Candia, T. Elbert, Annals of the New York Acad. of Sci. 930, 300-314 (2006).
9. A. M. Lamont, “Infants’ preferences for familiar and unfamiliar music: A socio-cultural study” (2001). Paper read at Society for Music
Perception and Cognition, Kingston, Ont., 9 Aug 2001.
