Daniel Levitin—neuroscientist, musician, psychologist and visiting professor this quarter—is not on record regarding his personal music classification system. But it's not implausible to think he'd be in the same camp as Rob, the protagonist of Nick Hornby's book (and movie) High Fidelity, who sorted records not alphabetically, not chronologically, but autobiographically.
Rob was no neuroscientist, but he knew there was a thin line between him and his music. "Did I listen to pop music because I was miserable?" he asks. "Or was I miserable because I listened to pop music?"
For Levitin, music is not simply a distraction or a pastime, but a core element of our identity as a species." We have a "musical brain," he says, one of the big differences between us and the rest of the species with which we share the planet. Humans create music and art and they represent ideas. He believes those features were evolutionary adaptations.
Levitin is at Stanford precisely to teach that connection. His course (HumBio188) explores the evolutionary advantages that musicality might have conferred upon early human beings and the neurological underpinnings of musical experience.
He also is a lab scientist. His questions include: What is the brain doing when it hears music? What do we remember? What do we like? What do we expect? Setting lyrics aside, what makes a piece of music happy or sad or impossible to get out of your head?
After his first book, This Is Your Brain on Music, did well, his peers and publisher suggested he write another, aimed at a wider audience. At first he resisted, figuring it would take him away from his lab work.
"But then I read a study that said 80 percent of the American public doesn't believe in evolution," he recalled. "I've been interested in evolution and music for years. So I thought, maybe I could change their mind and bring evolution to the average reader by using music."
The result was The World in Six Songs: How the Musical Brain Created Human Nature. In it, he argues that six basic song types—friendship, joy, comfort, knowledge, religion and love—give us a composite portrait of humans' biological, social and musical development.
Levitin's professional life is more like a long musical suite than a song. It contains many parts, each in a different key, style and rhythm. He started off as a Stanford undergraduate, wandered around a bit at other schools, quit the scholarly thing and went into music for 20 years—playing, producing, engineering. Eventually, he found his way back to Stanford and wrote an honors thesis on absolute pitch. From there he earned a PhD in psychology at the University of Oregon and today holds the James McGill Chair in Psychology and Neuroscience at McGill University.
The 50-odd Stanford students in his HumBio class are a tribute to Levitin's eclectic trajectory. They hail from human biology, math, education, philosophy, psychology, communications, sociology, chemistry, mechanical engineering, music, biology, electrical engineering, American studies and film studies.
They all love music, and they all have brains. The conversation (it's a conversation, despite being a lecture course) ranges from music to gestures to art to linguistics to the frontal lobe to genetics to the behavior of dogs.
Levitin also has research partners at Stanford. He and Vinod Menon, for example, an associate professor (research) of psychiatry and behavioral science, are working on a comparative study of how the brain sorts out musical and speech patterns.
"Music can be thought of as a type of perceptual illusion in which our brain imposes structure and order on a sequence of sounds," Levitin has written. "Just how this structure leads us to experience emotional reactions is part of the mystery of music."
Scientists like Levitin and Menon learn which neurons are firing when music is playing by taking functional magnetic resonance images, or fMRIs. These track the flow of blood in the brain as it is activated. "With fMRI, I can tell that you are listening to music as opposed to watching a silent film, but we can't yet tell if you're listening to hip-hop versus opera," he said.
So those moments when the cellos move you to tears, or the singer transposes up a key sending a chill down your spine, or the guitarist plays a bridge and he takes you back home—they're not magic. They're numbers.
"With fMRIs, there could be an illusion of precision, an illusion of rigor," Levitin said. "We're acutely aware of the limitations, and we're careful to not draw unwarranted conclusions. But all science is reductionist. That's what theories do, they pull disparate ideas together and they reduce things to a single equation. fMRIs help us understand the mental process; they show us neural correlates."
The field of music cognition existed before fMRI, though there has been a qualitative leap since its invention. The field's professional journals showcase such questions as how we process a piece played at different speeds, how infants perceive music, what audiences notice (and don't) and how musical skills can be transposed to other abilities.
Stanford has long been a pioneer in the field. The Center for Computer Research in Music and Acoustics (CCRMA) was founded in the early 1980s. The fourth annual Music and the Brain Conference at Stanford will be held in April.
"We're very lucky at Stanford and McGill to be at universities that embraced the multidisciplinary movement early on," Levitin said. "There are people from lots of different fields in my department. In my lab, they come from computer science, education, psychophysics, psychology, music—and we all work together and it feels very comfortable. All the careers I've had have been interdisciplinary; working in a studio is like being an engineer and a musician and a therapist."
And, of course, he's a teacher, one whose big ideas, both the numbers and the magic, find resonance in his students.
"Music benefits all species," one student pointed out one day, "so why can't all animals make music?"
"Music carries a huge metabolic cost," Levitin replied. "Our fancy brains require a lot of support structure. Evolution doesn't just look for things that are fun; if it did, we'd know how to fly. We're a social species. Sociability, flexibility, our ability to escape predators and find food and cooperate—those things require the ability of abstract representation. Humans took over the whole globe. To do that, we needed a complex social structure. "We're not the best, but we happen to be what evolution came up with."