Music is choreography of our expectations – cognitive scientist
An art, a science, a means of spiritual expression – music is all these things. So how do mere vibrations of the air become such a powerful medium for us? We talked about the neuroscience of music with Elizabeth Margulis, head of the Music Cognition Lab at Princeton University.
Sophie Shevardnadze: Elizabeth Margulis, head of the Music Cognition Lab at Princeton University. Great to have you with us and what a great topic we're discussing today. Welcome to our show.
Elizabeth Margulis: Thanks. So happy to be here.
SS: So all right, in a nutshell, what happens in our brain when we hear music? Is there some special musical region in a brain that gets activated?
EM: That's, that's a wonderful question. And I think it's the kind of intuition people had before we started getting in there and looking at what really happens because it turns out, in fact, that rather than musical perception being consigned to one special area, it's really distributed throughout the brain, and resides in areas that are more commonly used for many other kinds of phenomena. So ranging from, you know, an emotional response to motor response, and I think one of the most interesting findings is that even when you're passively listening to music, so you're just sitting there, you're not even moving overtly, perhaps, still, there's activity that we can show on a brain scanner in your motor regions, so the areas that subserve motor control and movement. So there's this sense of kind of embodied sympathetic movement, while you're listening to music that seems pretty special.
SS: Does it matter what kind of music we're listening to? I mean, will the same brain regions be affected if I’m listening to say, Chopin, or if I'm listening to heavy metal stuff?
EM: I love that question because actually one of the biggest myths in this area that's kind of proven hard to retract, centers around the Mozart effect, where people have this kind of sense that science has decreed that listening to Mozart especially would make you smarter whereas, in fact, that is not true at all. And sort of the studies that initially seemed to imply that proved to be really just demonstrating an arousal effect. So the original study, people listened to some Mozart, and then they did a spatial reasoning task. So where you have these kinds of images that you're trying to rotate and identify which one was the correct rotation. And people did do a little better on that, if they'd listen to a Mozart piece first. But the comparison condition there was just silence. And it turned out that if you listened to anything moderately upbeat, from whatever genre, you get the same effect because it's really just a kind of effect from getting more alerts and aroused and into what's happening around you, that leads to better performance on the task.
SS: But how does our brain actually know that it is listening to music and not just, you know, some random sequence of random noises? Is there some filter in it that helps tell one from the other?
EM: Yeah, that's a wonderful question. And it turns out that actually, the boundaries between those different kinds of stimuli are less kind of hard than you might imagine. So there are lots of conditions under which something that you could hear as noise, or you could hear as speech can actually end up being heard as music, most famously the Speech-to-Song Illusion where you can take a short clip of speech, repeat it a number of times, and it sounds like it's being sung after the string of repetitions. What's really great about those kinds of examples is we have then a sound sequence that is the same, nothing's changing about that, it's just being repeated, but the perceptual apparatus that we're bringing to it is transforming across those repetitions and we can take advantage of that to try to understand what's happening when people hear something as music.
SS: But I mean, music is technically a sequence of noises, air vibrations coming into the braincase through the ear. How exactly does the brain turn air into dopamine that releases in the brain when we hear something we like?
EM: I think that's the million-dollar question. I think you've just pinpointed it right there. And basically, the way people go about tackling that is trying to understand the various stages. So you start at the ear, start at the periphery, you go through kind of the basic processing levels and up and up till the cortex and you can kind of trace how different aspects of music are represented and, you know, processed along the way. And I think one of the most surprising findings there is it some of the earliest processing stages at the level of the brainstem, for example, when really, you just get this what's called a frequency-following response, where you have neurons firing in sync to the frequency of the sounds that they're encountering… that that’s actually malleable to experience. So when people have musical training that started early enough, this very, you know, early representation of sound is more accurate, more faithful, and, you know, at this very kind of early stage of processing. And this is one of the hypothesized mechanisms for how musical training can impact things like language acquisition and reading skills because if you're… you're really tuning into the sounds more accurately, you could see how that could underlie lots of other kinds of skills in other domains beyond music.
SS: Can music alter my brain for the best, even if I'm not a kid? Can it help me with Alzheimer's or Parkinson’s?
EM: There's really fascinating emerging research along those lines. And yeah, I think you've highlighted two of the best studied cases. One, that’s when people have dementia, often exposure to music can unlock memory abilities that seem to be dormant otherwise; and the case of Parkinson's, where when people are exposed to music while attempting to walk, that the gait becomes more stable and regular. The third kind of case that's been quite well studied is cases of aphasia, where people lose the ability to speak, but often the ability to sing is preserved. And you can kind of scaffold on that, to build back that capacity for spoken language.
SS: Yeah, I mean, there was this little famous video that went viral where a ballerina in her 90s, who had, I believe, Alzheimer’s, hearing the music to which she danced when she was a young girl made her reconstruct the dance patterns. I don't know if you've seen that video.
EM: Yeah, I have seen that. Yeah, I know of similar cases where it's, you know, it's not just, ‘Oh, this is so great. This person didn't remember these songs. That's wonderful for them.’ I mean, that is wonderful. But the fact that that can also kind of bring in or unlock other types of memory capacities makes it particularly powerful.
SS: Can music actually mend our brain injuries? And I don't only mean emotional part, I mean, on the neural level.
EM: Right, I guess in a way these examples from aphasia are like that, right? Because those are cases where the part of the brain that is devoted to language processing or language production is damaged. But people are still able to produce song. And what you want to do is kind of build new circuitry in these areas that aren't damaged, that capitalizes on these kinds of ability to sing the syllables and develop or reconstruct this ability to speak in a non-kind of singsong way. So that, you know that is this kind of reparative phenomenon. And these kinds of relationships between music and clinical practice haven't received quite the level of study that would allow really robust kind of treatment interventions in some cases. And so there's a big initiative right now from the NIH to fund research that really brings together people in clinical medicine and people who study music and the brain to really get a better handle on all of this and how it can be used for good. So that's a really positive, ongoing kind of initiative.
SS: I mean, brains change because they're so flexible, right? What if you're playing music or if you're listening to music, what kind of brain areas can develop and how quickly?
EM: So one of the most kind of easy to see changes in the brains of people who've spent a lot of time playing an instrument or making music or singing, our brain regions devoted to motor control, because there's all this kind of specialized experience with, say, finger movements that are relevant to a lot of instrument playing. And then I think the one that's maybe a little more surprising, and possibly even a little more interesting is that the corpus callosum, so the part of the brain that's really getting the two hemispheres to talk to one another, is bigger in people who had a lot of experience playing an instrument. So this kind of a fanciful interpretation of that might go something like, okay, well, maybe, you know, because playing music draws on so many different parts of the brain, so many different capacities, that experience doing it helps these kinds of various parts really work together, in a more general sense.
SS: Here's a million-dollar question, why is music exclusively a human thing? I mean, why don't animals have music, for instance?
EM: Right. There's so many different perspectives out there on this question because the way people go about addressing that usually is trying to figure out, “Okay, what are the individual components that we think are really essential to something we might want to call music?” So this could be something like, okay, synchronizing to a beat. And then people go around, actually starting sometimes from these viral YouTube videos, and, you know, finding cockatoos who seem like they can do it and then, you know, testing them and seeing whether it's really true that they can synchronize to a beat. And it's really about pulling apart these individual capacities that together, comprise something we might want to think about as “musicing.” And I think that there is really out and there are real, very real disagreements in the field about the extent to which various non-human animals are or are not musical.
SS: So, when you look at it, everyone is musical, everyone listens to some kind of music. Someone listens to heavy metal, someone listens to rap, someone listens to jazz, someone listens to classical, but everyone listens to music. And anyone pretty much can learn how to sing and how to play an instrument, if there is a will. Why is it? Is everyone musical? Why is everyone musical? That's a more correct question. Is it something innate that is coded into us?
EM: Right. So this is, I mean, these are some very key questions. And I think it can help to think about the way that culture and biology really are co-constitutive in some ways. So people look at me and say, “Okay, well, really tiny babies respond preferentially to song from their parents, right?” Many people have the experience, you're trying to kind of soothe the baby and you're talking to them, and if you just kind of slow your speech down –
SS: [I] just had a baby, so… Yeah.
EM: – and repeatedly exaggerate the pitch contours, you can get the baby to stare at you with these adoring curious eyes. So, people do that, right? There's a special kind of infant-directed speech that people often use, it's this kind of quasi musicalized version of speech. Or even singing to infants – and sometimes people will say, okay, well, that's some kind of evidence of this innate proclivity to a musical kind of interaction. And it is true that in any culture that has been studied and is known about, that people do something that is thought about by researchers anyway as music. So, all these things kind of point to this having some kind of fundamental role in human life.
SS: Why do some people are more developed musically, their ear is naturally developed than others’, and others need to train really hard to get where these people are from birth? And what is it really? What defines this, like, a special place in the brain, genes, something else?
EM: Right. I mean, so most of the studies that look at the effects of musical training on the brain are correlational in nature. And that's because it's not ethical at birth to say, ‘I'm going to randomly assign this group of babies to have the benefit of musical training and these ones can't have any musical training for 20 years. And then we'll check out what their brains are like once they're adults’. So we don't have you know, rightfully studies like that. Rather, there are studies that say, ‘Okay, here's a group of people that have had a lot of training, here's we try to match as well as possible demographic characteristics of these kids who have not had musical training, and then they'll say, ‘Okay, well, the brains of the kids who've had training look different in XYZ way.’ But, of course, it's possible that those brain differences existed prior to the training, and in fact, are related to why this group pursued and stuck with training over this group. So it's really hard to kind of pull apart that question, given the methodological limitations that exist.
SS: Leonard Bernstein, who, for me is like a definition of what a musician should be in the whole encompassing sense, he said that music is mostly about establishing a repeating pattern of tones or beats, and then breaking it. How does repetition in music work from a neural point of view?
EM: Right. So I think there's a lot to say about repetition. To me, repetitions are especially interesting because it's so common, so prevalent in music, and less so in many other similar domains. And I think one of the things that's going on there is that repetition is really drawing us into a kind of participatory relationship with music. So once you've heard something a number of times, you feel like you can kind of sing along with it, like, you're a part of it in some important way. But as you just mentioned there, it also sets up expectations that then the music can violate. And we know that violating expectations in that way, can be a really pleasurable experience for listeners. So it’s been tracked really well through studies using a number of different methods that, you know, when you listen to a sequence of tones, and you think x is going to happen, and you know, y happens instead, that kind of distinctive brain responses engage, that are relevant to how we experience reward and pleasure while listening. So some people look at music as a kind of choreographing of our expectations where a certain kind of surprise is the most valuable and pleasurable kind of experience. So I think that's not the only way to have musical pleasure. But one of the options in this toolbox of musical reward-making.
SS: Is music somehow helping us perceive sound? You often bring up an example of how if we repeat a word a million times, its meaning will disintegrate and only sound will be left.
EM: Yes, so, right, that's a case where it seems particularly rewarding in the case of music to really listen to those basic kinds of sonic attributes. And in a way, that's not so important necessarily in speech, where we're just kind of trying to listen through the idiosyncratic pronunciation or something that somebody is using to get to the meaning behind the word. Whereas in music, it's sort of …, there's not this summary, this capacity for summarizing or paraphrasing what you just heard, it's really you want to kind of get into the juiciness of what you're actually hearing. So repetition helps with that.
SS: Is the rhythm that we hear in the womb connected to the love of repeating rhymes, or, you know, the rhythm we have? Why do hearts beat in the same rhythm everywhere but musical rhythms are actually wildly different from culture to culture?
EM: Imagine a process of musical tradition or musical culture building, where there are these kinds of rhythms to which people tend to be exposed generally, right? So that's like, the kind of rhythms you're mentioning, like the heartbeat or the rhythm of walking or what have you. But there are others that are kind of built up iteratively over time in terms of practice within a language, I mean, there are a number of studies showing that the rhythms of the linguistic environment, that music is made in, imprint on the rhythms that you find in the music of that place. So there's this kind of building up of certain rhythmic practices and conventions over time, similar to how you end up getting languages that show such amazing variety around the world.
SS: You know, when people are having a real musical trip, I’m not talking about listening to hold music on the phone, but like really getting into their favourite Bach or Beatles, for a brief moment, everything just sort of disappears and you become one with music, – I'm sure you know that feeling, – how does that work exactly, especially on the level of a brain?
EM: Yeah, people talk about this and study these experiences as so-called peak experiences of music. And one way they've been studied that's pretty interesting actually is just surveying 1000s of people and looking at the descriptions they provide of these experiences and trying to understand what they have in common from person to person and place to place. And people also study them in terms of neuroimaging, so bringing people into the fMRI scanner, asking them to bring their self-selected, most powerful, chills-inducing music. And then what's really cool about this design, because, you know, what causes you chills when listening might be really different from what does that for me, then these kinds of studies will use the music I bring in as a control stimulus for you. So you're kind of balancing out the features of the music itself, and just looking at these extreme reactions. And you find that reward circuitry of the same kind that is relevant for other kinds of highly pleasurable experiences, like food or sex or illicit drugs, is outlined in much the same way when people are having highly pleasurable musical experiences.
SS: How does music get stuck in my head? And I'm not only talking about like, top-10 hits that you hear everywhere, I'm talking about anything, like a movie soundtrack, or someone not even singing – humming, not even humming – talking about Marlon Brando and boom! a sequence from Godfather just pops into my head. What happens there? What's the process behind that?
EM: So earworms are actually a pretty tantalizing, fascinating kind of window into how we process music in the brain because this kind of stickiness doesn't seem to apply to other similar kinds of sound stimuli, like it's much rarer to get little clips of speech, for example, stuck in your head. And it seems to be related to how repetitive music is. And in fact, when tunes get stuck in our head, they tend to loop and repeat in a way that, you know, sometimes people think is wonderful and sometimes people are really annoyed by. But I think it really speaks to the way this kind of blurring in the representation of music between hearing something and doing something because it kind of feels like we're singing it in our head, and this goes back to this idea that even when you're passively listening those regions of your brain devoted to motor control are active. So there's something really a lot more participatory about musical listening and musical representation than other kinds of auditory perception.
SS: Thank you so much for being with us today. It was one of the most fascinating talks I've had this season.
EM: Thank you. I really appreciate it. Great to talk with you.