How Do Our Brains Process Music? 

I listen to music only at very specific times. When I go out to hear it live, most obviously. When I’m cooking or doing the dishes I put on music, and sometimes other people are present. When I’m jogging or cycling to and from work down New York’s West Side Highway bike path, or if I’m in a rented car on the rare occasions I have to drive somewhere, I listen alone. And when I’m writing and recording music, I listen to what I’m working on. But that’s it.

I find music somewhat intrusive in restaurants or bars. Maybe due to my involvement with it, I feel I have to either listen intently or tune it out. Mostly I tune it out; I often don’t even notice if a Talking Heads song is playing in most public places. Sadly, most music then becomes (for me) an annoying sonic layer that just adds to the background noise.

As music becomes less of a thing—a cylinder, a cassette, a disc—and more ephemeral, perhaps we will start to assign an increasing value to live performances again. After years of hoarding LPs and CDs, I have to admit I’m now getting rid of them. I occasionally pop a CD into a player, but I’ve pretty much completely converted to listening to MP3s either on my computer or, gulp, my phone! For me, music is becoming dematerialized, a state that is more truthful to its nature, I suspect. Technology has brought us full circle.

I go to at least one live performance a week, sometimes with friends, sometimes alone. There are other people there. Often there is beer, too. After more than a hundred years of technological innovation, the digitization of music has inadvertently had the effect of emphasizing its social function. Not only do we still give friends copies of music that excites us, but increasingly we have come to value the social aspect of a live performance more than we used to. Music technology in some ways appears to have been on a trajectory in which the end result is that it will destroy and devalue itself. It will succeed completely when it self-destructs. The technology is useful and convenient, but it has, in the end, reduced its own value and increased the value of the things it has never been able to capture or reproduce.

Technology has altered the way music sounds, how it’s composed and how we experience it. It has also flooded the world with music. The world is awash with (mostly) recorded sounds. We used to have to pay for music or make it ourselves; playing, hearing and experiencing it was exceptional, a rare and special experience. Now hearing it is ubiquitous, and silence is the rarity that we pay for and savor.

Does our enjoyment of music—our ability to find a sequence of sounds emotionally affecting—have some neurological basis? From an evolutionary standpoint, does enjoying music provide any advantage? Is music of any truly practical use, or is it simply baggage that got carried along as we evolved other more obviously useful adaptations? Paleontologist Stephen Jay Gould and biologist Richard Lewontin wrote a paper in 1979 claiming that some of our skills and abilities might be like spandrels—the architectural negative spaces above the curve of the arches of buildings—details that weren’t originally designed as autonomous entities, but that came into being as a result of other, more practical elements around them.

Dale Purves, a professor at Duke University, studied this question with his colleagues David Schwartz and Catherine Howe, and they think they might have some answers. They discovered that the sonic range that matters and interests us the most is identical to the range of sounds we ourselves produce. Our ears and our brains have evolved to catch subtle nuances mainly within that range, and we hear less, or often nothing at all, outside of it. We can’t hear what bats hear, or the subharmonic sound that whales use. For the most part, music also falls into the range of what we can hear. Though some of the harmonics that give voices and instruments their characteristic sounds are beyond our hearing range, the effects they produce are not. The part of our brain that analyzes sounds in those musical frequencies that overlap with the sounds we ourselves make is larger and more developed—just as the visual analysis of faces is a specialty of another highly developed part of the brain.

The Purves group also added to this the assumption that periodic sounds— sounds that repeat regularly—are generally indicative of living things, and are therefore more interesting to us. A sound that occurs over and over could be something to be wary of, or it could lead to a friend, or a source of food or water. We can see how these parameters and regions of interest narrow down toward an area of sounds similar to what we call music. Purves surmised that it would seem natural that human speech therefore influenced the evolution of the human auditory system as well as the part of the brain that processes those audio signals. Our vocalizations, and our ability to perceive their nuances and subtlety, co-evolved.

In a UCLA study, neurologists Istvan Molnar-Szakacs and Katie Overy watched brain scans to see which neurons fired while people and monkeys observed other people and monkeys perform specific actions or experience specific emotions. They determined that a set of neurons in the observer “mirrors” what they saw happening in the observed. If you are watching an athlete, for example, the neurons that are associated with the same muscles the athlete is using will fire. Our muscles don’t move, and sadly there’s no virtual workout or health benefit from watching other people exert themselves, but the neurons do act as if we are mimicking the observed. This mirror effect goes for emotional signals as well. When we see someone frown or smile, the neurons associated with those facial muscles will fire. But—and here’s the significant part—the emotional neurons associated with those feelings fire as well. Visual and auditory clues trigger empathetic neurons. Corny but true: If you smile you will make other people happy. We feel what the other is feeling—maybe not as strongly, or as profoundly—but empathy seems to be built into our neurology. It has been proposed that this shared representation (as neuroscientists call it) is essential for any type of communication. The ability to experience a shared representation is how we know what the other person is getting at, what they’re talking about. If we didn’t have this means of sharing common references, we wouldn’t be able to communicate.

It’s sort of stupidly obvious—of course we feel what others are feeling, at least to some extent. If we didn’t, then why would we ever cry at the movies or smile when we heard a love song? The border between what you feel and what I feel is porous. That we are social animals is deeply ingrained and makes us what we are. We think of ourselves as individuals, but to some extent we are not; our very cells are joined to the group by these evolved empathic reactions to others. This mirroring isn’t just emotional, it’s social and physical, too. When someone gets hurt we “feel” their pain, though we don’t collapse in agony. And when a singer throws back his head and lets loose, we understand that as well. We have an interior image of what he is going through when his body assumes that shape.

We anthropomorphize abstract sounds, too. We can read emotions when we hear someone’s footsteps. Simple feelings—sadness, happiness and anger—are pretty easily detected. Footsteps might seem an obvious example, but it shows that we connect all sorts of sounds to our assumptions about what emotion, feeling or sensation generated that sound.