Latest / Art of the Question / The Neuroscience of Musical Pleasure - Prof. Robert Zatorre - #52

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The Neuroscience of Musical Pleasure - Prof. Robert Zatorre - #52 · Art of the Question

• Julius Moorman: Robert, thank you so much for for coming on the show. ⁓ like I just said, I am really into music. I love to listen to music. I love to play music. and it has always been so fascinating to me what a powerful impact music can have on our mood, on our behavior, on our motivation. And yeah, given the fact that I love to do scientific episodes. A a ⁓ an episode about the science of music was long overdue. So I'm really excited to get into it. I thought a great starting point would be to understand your own passion of for music and and how you ⁓ got into playing music as a musician yourself and ⁓ when the crossover with ⁓ neuroscience started to happen. Yeah, well thank you ⁓ very much for the invitation. ⁓ I appreciate it. And ⁓ yeah, I'm delighted to chat to you about music and neuroscience, because that's really what I do. ⁓ and in terms of my background, ⁓ I guess like many ⁓ many people, when I was an adolescent, I got really, really hooked by music. And we might come back to that in our conversation, because that's actually an interesting phenomenon of itself. and so, you know, ⁓ at the time when I was you know, twelve or thirteen, I was listening to a lot of rock bands that were popular at the time. Of course, everyone listened to the Beatles, but there were other other bands around ⁓ that I liked. ⁓ you know, the moody blues come to mind or the doors, you know, this is the kind of thing I was listening to. And it was it was great and I liked it a lot. and a lot of those bands, in fact, ⁓ the last two I mentioned, ⁓ feature an organ. If you if you look up, you know, the doors they have a famous organ solo, right? Da da da da da da da da da da da da da da da da da da da da da da da da da and so I thought this is really cool, this is what I want to do. And so I went to look for ⁓ an organ teacher, and I found one and the guy says to me, Well, why do you want to study the organ? What's what's up with that? So I explained, you know, that I wanted to be really cool and grow my hair long and ⁓ be a a rock star, you know, the kind of fantasy that a a fourteen year old boy might have. And so he looked at me and he said, No, he said, if I teach you the organ, it's going to be Bach. And I was like, No, that's no, that's not what I want. I I want to play this stuff. He said, No. You come to the church, he played in a church. He said, You come to the church on ⁓ on Sunday and I will play Bach for you and then we talk. So I went and I listened and I thought, ⁓ okay, he's right. This is like transcendent, transcendent music, you know. ⁓ And ⁓ so that was kind of my my epiphany there. There were there were other I had similar experiences, ⁓ kind of epiphanous experiences with other kinds of music. You know, ⁓ somebody lent me a a record of Bartok and I had no idea who Bartok was or what his music was. I had never been exposed to anything like that. And again I was mesmerized by by the rhythms, by the unusual ⁓ melodies and so on. And so I decided, okay, I should study music ⁓ to try to gain a better understanding of it and maybe to try to play it and and be able to ⁓ to really enjoy it for myself. ⁓ but at the same time I was always very interested in science. Even as a kid, I was always kind of oriented in that direction. So when I went to university, I decided to study both ⁓ psychology and music, sort of two simultaneous streams, which in those days didn't have a single course in common, which is sort of funny. ⁓ nowadays you can take a lot of courses on the psychology of music or ⁓ you know, musical ⁓ cognition, music perception, etc., but that didn't exist. We're talking about, you know, the early nineteen seventies. ⁓ so ⁓ at some point I realized that although I was I was an okay musician, I wasn't really ⁓ exceptionally good by any means. whereas in in science I was actually, you know, pretty good. So I thought, well, in terms of career options, maybe science is a better option. Also, a career as an organist is kind of hard. ⁓ and I'm not even a religious, so it's it's a little strange to be associated with ⁓ with the church. ⁓ And so when I went to do my PhD, I decided to maybe ⁓ focus on science, but try to use my knowledge and interest that I had developed in music and try to use science to understand music and vice versa, use music as a platform to understand certain ⁓ certain types of of phenomena, including this phenomenon of extreme pleasure that ⁓ we can talk about later. Where you know you listen to music and you just have this this experience that you feel chills, you feel ⁓ very strong emotions. ⁓ and so that that's a fascinating phenomenon. And so I thought I want to understand what's going on at a psychological level and maybe at a at a neurological level. ⁓ so that's how I got started. And ⁓ eventually ⁓ I ended up ⁓ where I am ⁓ today at the Montreal Neurological Institute, which is part of McGill University. And I was very lucky to be able to get a position here to study not only music, but more generally how the brain processes sound. and you know both the sort of elemental level, the aspects of sound that are are not specific to music but are very, very necessary for music, things like pitch, ⁓ which is all also exists in speech, of course, and things like timing and ⁓ and so forth. So in my laboratory now, many, many years later, we we ⁓ cover the whole range from the very basic level of how does sound get into the brain and ⁓ how what are the initial ⁓ levels of processing of those sounds, all the way to the highest level, I think, which is the emotional response that we have to very complex sounds, such as musical patterns. Yeah, that's what that's an incredible introduction. Thank you. Thank you so much. And yeah, it's it's so what what's so fascinating about the emotional response ⁓ we have to music is that ⁓ music is something kinda strange if you think about it. Of course, music consists of audio, it it it is sound, but it is sound in a specific order. There's usually some some harmony and Going on, there's a beat, there's a rhythm to it, and if we just structure these sounds, these beats, into a specific order with a specific timing, then all of a sudden it can invoke very strong emotions. why is it that we experience such Yeah, strong emotions, associations when we when we listen to music. Yeah, well that that is exactly the the key question, I think, which ⁓ which, you know, everyone wants to wants to answer. And indeed it's sort of the like I mentioned, it's the ⁓ the one of the motivations for me to study music was the fact that I myself had experienced these emotions. And so have many other people. And so I was very curious to try to address what you just raised, which is how could it be that a pattern of sounds that doesn't actually have any specific meaning? how could it be that it it raises emotions? Because people say, well, if you if you listen to a story or you watch a movie, you also have emotions, which is absolutely true. but in those cases, the emotions are driven by the elements of the story, you might feel something about the character in the story, right? You might feel compassion or you might feel hatred for, you know, the bad guy in the story, or whatever it is. But th those emotions make sense because they're about people, they're about events, they're about ⁓ situations, right, that make you happy, that might make you sad, that might make you angry, you have all these emotions. Whereas in the case of music, with some exceptions, there is music that does make specific reference to certain events, but most of the time music is just abstract. It's just a pattern of sounds. And so indeed, how is it that it it raises these emotions? So to answer that, I again have to kind of recapitulate ⁓ a little bit our our scientific approach, which is that we spent a good, I don't know, 15 years or more just trying to understand the pattern processing part. without getting into the emotion because it seemed to me that we needed to figure that out before we could answer the more the broader and and possibly more interesting question. So we spent a lot of time looking at, well, how does the brain, you know, encode sounds? How does the brain put those sounds together into to ⁓ to look at relationships between the sounds, and that's a very important factor because when we hear sounds, ⁓ we don't just hear them in isolation one from another. Quite the contrary, we hear each sound in the context of the previous set of sounds. Right? So if I play for you, ⁓ I don't know, the note G by itself, it's just a note. If I precede it by C E G, well then it's part of a major triad, right? Whereas if I ⁓ precede it with ⁓ I don't know what, A, C sharp, E, G. Well now it's the seventh of the A major chord. It has a totally different function, has a totally different sort of sound, even though it's the same physical sound entering your ear. So this means that the brain is constantly not just ⁓ encoding the sounds, it does that at very early levels of the nervous system, but then it's constantly like holding those sounds in what we call working memory and building these ⁓ structures, which ⁓ musicians might call motifs or themes or or progressions. ⁓ you know, there's a lot of terminology that musicians use and music theorists have developed ⁓ to describe exactly this phenomenon. So we un we try to understand how does that work. What parts of the brain, what circuits in the brain are responsible for this. And as we moved along, we realized that a very good way to describe what's going on as you listen to music is the concept of prediction or anticipation. And this is an idea that comes from a lot of neuroscience research. there's a whole theory called the predict predictive coding theory. which is very prominent in in not just in in ⁓ music or in ⁓ sound research but also in all aspects of cognition and perception in vision and in the motor system, etc. ⁓ and basically what this says is that not only do you assemble these sounds so that they form some kind of a pattern, which you recognize because you've heard such patterns before. So you ⁓ you understand what a major triad is, because you've heard ten trillion major triads in your life, right? If you had never heard a major triad, and this this could happen if you're brought up in a in a culture that doesn't use major triads, and there are some, ⁓ then ⁓ your perception would be very different, right? Yeah. So that's how you form these these patterns. But then what is really interesting is that The brain automatically makes a prediction about what the next sound will be. So if you hear a C, an E, and a G, there's an X percent probability that the next sound will be another C. That's probably the most likely scenario. ⁓ there's a slightly less probability that the next sound could be an A, for instance, that would be the seventh. ⁓ or you might go back to the E and so on. And so you can actually ⁓ look at, you know, a corpus of music, you can take ten thousand songs and compute the probabilities, and that becomes your your predictive model. So your brain knows this. Your brain has basically what we this is a bit of jargon, we call it an internal model. By listening, right? Throughout your whole life you've been listening to music. And your brain hasn't just been sitting there passively. It's been very sensitive to each of those contingencies or probabilities. So it knows if you hear, you know, X and Y, Z is probably the next sound. And it also knows like what is the least what's the h most common, what's the intermediate, and what's the least common. So if I play C E G and then I play ⁓ I don't know D flat, that's gonna sound really weird because it's totally out of key and and ⁓ you know it's It would be a it would be a strange tritone, right? It wouldn't really fit. ⁓ so this is something that is really interesting because it turns out the music theorists have come to the exact same theory without any, you know, neuroscience behind it, but ⁓ just from analysis of music and thinking about what music is all about, They've come to the same conclusion, essentially, that you're always anticipating what's going to come next, and that a lot of the emotions that arise from music have to do with the musician or the composer or the arranger playing with that level of ⁓ expectation. And so, for example, ⁓ a very common concept in music theory is tension and resolution. Where does that come from, right? Tension and then resolution, that implies a prediction. If you hear a chord, if you hear a chord progression and then it's ⁓ it's not resolving, right, the tension remains. That's because you expect something to happen. If it doesn't happen, then you have some emotion associated with it. If it does happen, you also have some emotion associated with that. None of that would be possible if your brain were not this predictive engine. If your brain were not constantly trying to anticipate what's happening next. And again, when you talk, it's not just music theorists, you talk to any performing musician and they instantly know what we're talking about. They say, ⁓ well, of course, of course I know that. I know that when I'm ⁓ you know, singing, ⁓ and I know the cadence is coming up, I might do something a little tricky. I might delay the cadence by just a few seconds, or I might add some additional notes. Or I might you know go into a different key. I might suddenly modulate to give the listener something quite unexpected before I return to the home key, if it's tonal music. So these are the kinds of tricks that musicians sort of intuitively understand, and now we can understand them in the context of some very basic concepts of brain function, which is this concept that we're constantly making predictions, we're constantly anticipating what's coming next. And then we evaluate the outcome of that prediction to see how correct or incorrect is it. And that's where the emotion comes in. That's so interesting because it's it's it kind of seems surprising if you are unaware of the mechanics of how we process music. That music can invoke such strong emotions. And what I mean by this is if you music has been around for a very, very long time, but ⁓ on an evolutionary scale, it's not as long as some other of the environmental things we've had to deal with as a species. So music seems relatively new in the context of evolution. Yet it is still able to produce such extreme feelings of motivation, of sadness, of of happiness. So that may intuitively feel as a surprise. However, the way we process music and the way our brains have evolved to work, given the the expectations we have, ⁓ the the dopaminergic system. those have evolved over millions of years. So in in that sense, because they play, they use the same mechanisms as those, it becomes a lot more understandable. ⁓ so is there is there any ⁓ theories as to like this is just my my summary Of of of the understanding. Is there an understanding of of why we have evolved to to react to music even though on an evolutionary scale it is relatively ⁓ novel? Yeah. Well, ⁓ it's not really clear whether it's novel or whether it's ancient. People really argue a lot about that. But I wanna pick up on your point about the dopaminergic response. and ⁓ because this is This is a big, big part of the research that we've done. And and by the way, ⁓ I have a book that is really focused on this entire story. It's called From Perception to Pleasure: The Neuroscience of Music and Why We Love It. It's Oxford University Press. And the whole book is exactly about answering these questions. ⁓ and the reason I titled it From Perception to Pleasure it goes back to what I said earlier, that we spent a good 15 or 20 years looking at perception in our laboratory, trying to understand the how sounds are processed. And then we spent another now twenty-five years looking at the pleasure part. Because at some point it became clear that we needed to really understand these emotions. And you mentioned the dopaminergic system, that's why I'm I I want to address that. Because ⁓ there so I mentioned the circuits that are involved. in ⁓ perception and anticipation. These are all cortical circuits, involving primarily the auditory cortex and regions in the frontal cortex and a few other ⁓ areas as well in the in the more dorsal parts of the brain. but whenever we feel pleasure or reward or emotion, those aren't the areas that are really responsible for that. It's the so-called reward system that's responsible for that. And the reward system, as you ⁓ sort of ⁓ suggested, is extremely ancient. It's millions of years old because the reward system in a human and the reward system in a rodent are really not that different. They're they're quite you know, they they carry out a lot of the s similar ⁓ sort of processes, and that's because It's a system that's absolutely essential for survival. So the reward system signals if ⁓ an event in the environment is positive or negative, which is why it's necessary for survival. And it was discovered way back in the nineteen fifties, actually here at McGill University, ⁓ with ⁓ with rats, where ⁓ they were ⁓ looking at responses in certain nuclei of the brains of the rats, and they found that there's an area which ⁓ seems to be like a motivation region that rats will ⁓ demonstrate a lot of activity in that particular set of neurons in their brains if they're hungry and they receive food. Mm-hmm. So this is what psychologists call a primary reinforcer, right? Makes sense. This is highly important for survival. So if you're hungry, you need to eat. How do you know? How do you know that eating will, you know, ⁓ address that feeling you have of hunger? Well, there's some kind of instinct to, you know, put stuff in your mouth. The stuff that you put in your mouth, if it tastes good, right, then the reward system lights up and says, Yes, this is what you need. Go and get more of that. Right? It's an internal signal. To motivate ⁓ feeding. If you didn't have that, you would starve to death, right? It's the same for water, it's the same for other physiological things, like if ⁓ if you're very cold, you seek warmth, right? If you're excessively hot, you seek cool. So this is homeostasis, you're regulating your body temperature. This also activates a reward system, right? When ⁓ I was just in Europe during the heat wave, I think you're You're having another one now and you know, it was thirty four degrees and you just you just want to get into a cold shower and ⁓ it feels so good. Right. That's the reward system responding. ⁓ similarly, the reward system responds to sexual cues. This is obviously important for survival, not necessarily of one individual, but for the species to survive, you need to reproduce. Why would you go to the trouble of you know, mating if it didn't feel good. Right? So if the reward system were not involved, right, there would be no mating, there would be no reproduction, and the species would die within one generation. So these are all these interesting signals that have been described in certain structures collectively known as the reward system. There's one particular nucleus called the striatum, which is especially critical. It contains these dopamine neurons that you mentioned. So Somewhere around the year two thousand, we started thinking, well What about music? Because we know music feels pleasurable, but it's not a primary reinforcer. It's not like food. You don't need it to survive. and furthermore, it's culturally conditioned, right? You you listen to music that fits within your culture, which goes back to this idea of the internal model, what you've learned from your environment. And, you know, food and water aren't exactly like that. They're they're much more instinctual, although there are learned aspects of of food as well. But you know, the the infant, human or any mammal really, it it knows to ⁓ to drink its mother's milk. And the mother's milk presumably activates the reward system, right? It tastes good and it's what you need to survive. It has all the nutrition that you need. ⁓ but music isn't like that. It's just a series of sounds, like you said. It's completely abstract. So we showed in in a series of experiments, ⁓ to everyone's surprise, including ours, that the same reward system that is active for ⁓ for food and for other biologically important stimuli is also recruited for music ⁓ musical pleasure. So whenever you listen to music that you find pleasurable, your reward system, particularly the stratum, will be active. If you listen to music that you do not find pleasurable, you will not see the same response. And so it's actually an individual response. Right? If I listen, you know, to your house music, it probably won't do much for me. It's not not my favorite thing. ⁓ so my reward system wouldn't be active the way it is to ⁓ you know, a Bach organ fugue. And for you, I don't know how you feel about Bach organ music, it's not everyone's cup of tea, but it's it's very ⁓ it's very individualistic. So ⁓ this is a big discovery, and we've we've gone on, you know, to study a lot more about it, but ⁓ coming back to the title of my book, From Perception to Pleasure, the basic idea is that you have all this hardware in your brain to do the perception part. And to figure out patterns and to make predictions about events, all of that. And then you have the reward system, which u evaluates how well those predictions are working out. And so it's the interaction between those two systems: perception system and pleasure system, cortical and reward systems. It's the interaction between them that gives rise to this ⁓ all of the complex. emotions and sensations that we have to music. That's that's very interesting. So as if I understand correctly, ⁓ we have certain ⁓ predictions, certain expectations of what the next bit of the music is going to sound like. And if that matches our expectations, it is very similar to what we would encounter, for example, if we forage for food and we expect to get a reward and then we indeed find something nutritious or ⁓ s something that c ⁓ clenches our thirst ⁓ in in in a similar fashion. So it's the expectation and then the meeting of set expectation. Yes. That's a theory. That's correct. That's the sort of first level of the theory. There's a little wrinkle in it, however, which is that in fact our ⁓ this is kind of a universal ⁓ preference that was described by Wilhelm Wundt in the nineteenth century. It's a very old concept, which is that in fact what we actually most value is not the most predictable thing, nor the most unpredictable thing, but something in between. Something that is is partially predicted, but is still somewhat surprising. So it's a balance between predictability and surprise. And we can actually quantify this now. ⁓ you know, music theorists have developed computational models. So you can take a piece of music and you can evaluate, well, how predictable is it? Right? And we we've done this experiment, so have other other labs. And what you find is that super predictable music tends to be ⁓ quite boring. So people don't like it. ⁓ To give you an example, ⁓ a lot of ⁓ children's music is super repetitive and super predictable. I don't know if you have kids, but I I remember when I had toddlers, my kids are very grown up now, but when they were very small, they would listen to the same exact boring little song over and over and over and over. It just drives the adults crazy. Why? Because because it's so repetitive that you know exactly what's coming, right? And so it's it's very not rewarding. If you go to the other extreme, completely chaotic random sounds are also kind of boring. And this is the case, you know, people have tried composers have tried to, you know, create kind of a ⁓ alleatoric music. ⁓ by and large, it has not been a success. and I think the reason is, you know, because our our brains aren't able to track anything, right? If it's completely random, you just can't track anything. So you can't make predictions. Therefore your predictions do not you don't have predictions ⁓ that then allow fulfillment or not fulfillment of them. So the two extremes are bad. Somewhere in the middle is this sweet spot where you have the balance between predictability and surprise. And like I mentioned, this concept is is quite old in ⁓ in aesthetics. It's not just music. It's also true for, you know, visual art. It's true for, you know, if you show people different kinds of plants or trees or flowers, the preferred ones are the ones that are not absolutely perfectly symmetrical, nor completely, you know, ugly with all kinds of weird branches coming off, but the one that has some kind of balance, right? Again, you talk to artists, they intuitively understand this. So, ⁓ This is a peculiarity of the r of the reward system. And to go back to your your example of foraging for food, ⁓ if you forage for food and you find it, okay, that's rewarding. But if you always find the exact same food in the exact same place, your reward system system kind of you know goes down because it's like, okay, this is I don't need to sort of worry about this and know what's happening. ⁓ and you can do this with experiments with animals. If you s if you give them the same reward time after time, and you see the reward system coming down, and then you suddenly give them something that tastes a lot better. Like if you give a like if you give a monkey like a cucumber, which they'll eat, but it's not their favorite. ⁓ it's not my favorite either, so I I know what they're talking about. and then So it expects a cucumber, right? It's like, okay, a cucumber. And then suddenly you give it, I don't know, ⁓ a dried ⁓ raisin, right, which is sweet and ⁓ and tastier, or ⁓ or some fruit or something that they really like and that's sweet. Suddenly the reward system will go woof. It'll suddenly respond a lot more, and it'll respond more than if it had all if it had always received the same fruit. So it's the unexpected value. It's like, ⁓ this is really good and I wasn't expecting it. Right? This is also the same principle, by the way, in in gambling, right? ⁓ gambling gets you hooked because every so often you get a payout, right? But it's rare. And so on every trial, right, you're doing the slot machine or you're you're putting your bet on the roulette, most of the time you lose. But every so often you get a reward. And it's unexpected. And so your ward system is like, wow, this is fantastic. Let's waste more money. Right? It becomes addictive, in fact. So, ⁓ so there are a lot of very interesting parallels with other other situations, you know, way beyond music. So these these phenomena that I'm talking about are not exactly unique to music. They they make contact with a lot of other phenomena. what's unique about it, I would say, is the peculiarity that we have the hardware in our brains to listen to these patterns of sounds and to make predictions about them. That's something that monkeys don't have, even though they have a reward system that looks a lot like ours. Same for rats, same for you know, almost all all ⁓ vertebrates. ⁓ but none of those creatures Have the ability to figure out the sound patterns. They respond to more basic rewards, just as we do. But we, in addition, respond to these abstract level of rewards. ⁓ and music is perhaps one of the strongest abstract types of stimuli that engages our our reward system. So so fascinating. And one thing that it made me ⁓ think about what you said there is about the the following. Sometimes when I hear music, I when I immediately like a song, whether I listen to it on the radio or or someone sends it to me, I hear it out in the open. If I immediately like it, it usually also means that I'm ⁓ easily bored of it. Probably because it's very recognizable. Therefore, in fur at first glance, my brain goes, Hey, I I recognize these patterns. Therefore, I like this. But it's also why I get bored of it. And then there is music that is more complex, perhaps, and it takes a while. I have to listen to it a bunch. And then maybe after the fifth or sixth time I start to recognize these. complexities within the music and then it grows on me and those are usually the songs that I keep listening to for for a longer time. ⁓ does that indeed tie into the same systems we we discussed? Yes, yes, yes, absolutely. That's that's ⁓ a very astute observation because ⁓ that phenomenon that you just described ⁓ is exactly based on similar principles to to what I just mentioned. So if the music is only ⁓ is highly predictable, maybe not quite as repetitive as a children's song or, you know, like a scale, if I play a scale for you up and down, da da da da da da da da da da da da da da da da da da da da da da da da da it's it's not gonna catch you. But if okay you hear a pop song, and like you said, at first listen, it's pretty nice. And you you sort of like it, and you listen to it for a little bit. but It's predictable enough that your brain can figure out basically the whole thing after just a couple of tries. And then the reward system sort of starts to shut down because it's like, well, okay, I know exactly what's coming. It's no longer rewarding because it's so predictable. And in fact, even if you even if you're a super fan of pop music, you notice that in the pop charts, the ⁓ people always want to hear new stuff. Why is that? With some exceptions, right? There's the occasional, I don't know, Michael Jackson song that people still listen to thirty years later, 'cause it's actually got a lot of interesting things going on in it. But those are the exceptions. The majority of pop music is is for the moment. And even, you know, pop music fans demand new things all the time because they too listen to it and after a little while they get bored with it 'cause it's sorta simple. ⁓ Whereas more complex music, whether it's whatever genre it is, though all of these concepts apply to any genre of music, by the way, it's not it's not only one type of music, although there are some genres that by definition tend to be more complex, like you know, avant-garde jazz is is way out there in the highly complex version. Maybe ⁓ you know, contemporary ⁓ art music, ⁓ classical music, ⁓ But even, you know, late Beethoven is it's really pretty complex. ⁓ there's stuff that I s I still don't quite understand some of the late quartets. It's like what what is he doing? You know. so ⁓ so yeah, so absolutely. ⁓ it it in order to really, you know, get that reward, you need a lot more exposure. bit to build up that internal model of this complex piece of music. And you probably never completely master it, which is why you like to hear it again, ⁓ you know, multiple times, right? Which is an interesting characteristic of music, is that people generally love to listen to the same piece of music, not immediately, not five times in a row, but like over your lifetime, right? There are certain pieces of music that you consistently come back to. And that's not so much the case for other art forms. When you read a novel, you might possibly if you really love it, you might come back and read it again a few years later. You're ⁓ very unlikely to read it ten, ten, twelve, fifteen, twenty times, right? That would be weird. Even if it's a really fantastic novel. ⁓ whereas a piece of music, it's it's not uncommon, right? ⁓ I don't know. How many times have I heard Sibelius Six in my life? I don't know, it's probably thirty or forty. And I still want to hear it some more, right? so there's enough going on in those pieces of music that you always discover something new. and your your internal model can never be so complete. So you're always still surprised. There's always still some element of surprise, even when you've heard it, you know, quite a bit. Because it Yeah. Complex music tends to violate your expectations. Right. And and you bring up jazz there, which is something I wanted to bring up as well, because ⁓ in an extreme form and it's not really the house music I like to listen to. I there there's very simple house music and there's complex house music, but I think in general electronic music, whether it's techno or or whatever, it it has the anticipation. it's the most extreme form of s of of of Building towards something and then releasing it, right? Which is called the drop. The beat the beat drop, yeah. Yeah, the beat drop. so there is an obvious rise, there's a build-up, there's tension, and then there is release of the tension. Like mechanically, based on everything we just discussed, that makes a lot of sense to me why humans would like that. ⁓ on the other side of the spectrum is jazz, as you already mentioned, which is more on the chaotic side and ⁓ very unpredictable, if you will. kind of all over the place. I love to listen to jazz, but it's a very weird form of music in the sense that it doesn't follow similar beats or mechanisms as most other music. So so what do we make of jazz? Why why does it work? Yeah, that's interesting. I'm I'm far from a jazz expert, so I won't claim ⁓ to know the answer. But I think that it appears chaotic, but I think it really isn't. I think there is structure behind it. and in I my my sense is that the structure is there, but it's hard to grasp. But it's but it is there. So I think to some extent your your brain is trying to make predictions about what's happening and it's it's constantly fooled, right? ⁓ but it it's not the case that it's completely random. And I here's here's a good thought experiment to prove that it isn't random. Suppose you take, you know, the MIDI file of a of a jazz performance and then you put it through ⁓ a permutation ⁓ algorithm. So that the notes are all randomly modified, right? They're or reordered in a completely random order. If jazz were completely random, then it shouldn't make a difference. I guarantee you that if you were to listen to that, you would go, Wow, what is this? This is this is garbage, you're right. Obviously the musician knows exactly what they're doing, right? Maybe maybe not consciously, which is interesting. But at some level, the jazz musician has some kind of schema that they're putting out there with maybe a lot of, you know, surface modifications to make it hard. And in that sense, it's it's not that different than, like I said, like Beethoven or other, you know, other complicated styles, some some Stravinsky is like that. ⁓ And so you might spend, you know, a lifetime trying to figure it out, and you may never figure it out exactly, but there's enough there that your brain is able to do it. I I will add one more factor which we haven't discussed, which is we discussed exposure, which is very important. So the more you are exposed and the earlier you are exposed to certain styles or genres of music, the better able you will be to understand that music. If you grew up with avant-garde jazz, if your mom and dad were ⁓ you know, jazz musicians, ⁓ and you are now an adult, you probably understand a lot more and you get a lot more out of jazz than the average listener. And then there's also just individual differences in the capacity to perceive those patterns. I talked at the very beginning about your brain's ability to form these schemas, these little motifs, and to make predictions about them. ⁓ we know that different people are better at it and other people are worse at it. For example, working memory is what I mentioned that I think at some point. Working memory is just the capacity you have to retain X number of tones, right? And so that can vary from a low of, I don't know, four or five to a high of ten or twelve. That's just something that varies. The more you train with music, if you become a trained musician, you will improve your working memory by exercising it, right? So it's not necessarily fixed. ⁓ there's probably a a fixed component as well. It's probably a heritable component, because everything everything is heritable to some extent. ⁓ but that would make a difference. So if you're one of those people who were never exposed to jazz growing up, your working memory is relatively more limited. And ⁓ You don't you don't have, you know, ⁓ a good capacity to make these predictions. If you listen to something like jazz or like complicated classical music, it'll it'll just not be very meaningful for you. So, you know, we talked about that sweet spot earlier. That sweet spot can shift depending on your own knowledge and abilities, right? You can prefer something more on the complex side if you have all that background and experience, or you prefer something more on the simpler side if you lack that particular ⁓ experience. We'll go back to the conversation in just a second, but first I have an important announcement to make. If you've made it this far, I'm going to assume that you're enjoying the show. If you want to support the show, you can do so by leaving a like or a comment if you're watching on YouTube, or by rating the episode if you're listening on Spotify or Apple Podcasts. However, the single biggest thing you can do to support the show is by sharing it with someone you think might enjoy this episode. This could be a friend, it could be a family member, it could be a colleague. It doesn't really matter. If everyone who's currently listening to this episode would share it with just one person, the show would blow up in no time. Which also means that I could go full time. That means more episodes, it means better episodes, and it also means a happy host. So Please consider sharing the episode. It really helps me a lot and I thank you. Now let's get back to talking. And ⁓ Yeah, th that that was part of your own research, right? I because I was just going to ask you about it that ⁓ not everyone responds to music ⁓ the same way, that there are are if you so called hyper responders, there's a different term for it, but I forgot it. Yes. And there's people were almost feel yeah, literally feel nothing when they hear music. So it's a spectrum. There's a big spectrum. And I believe it was it was your Yeah. So so how how did you figure that out? Yeah, yeah. It was our our team ⁓ in collaboration with ⁓ some colleagues at the University of Barcelona. And it was, you know, we had reached a point where we we understood a lot about how music pleasure works. And then we started thinking, okay, but is it the same for everyone? Because in in science, you you tend to sort of make the assumption that, okay, I've I've figured out the mechanism for perception, the mechanism for memory, the mechanism for whatever. Sure, there's a common mechanism that we all have, but every individual human is a unique person, right? In fact, every Every animal is a unique animal. If you look at its brain, it's not absolutely identical, right? You have to go down to like a fruit fly before the the brain is is pretty ⁓ identical. As soon as you have a certain level of complexity, ⁓ the brain is very different, and of course it's influenced by different experiences that you've had during life, right? So we started looking ⁓ at individual differences in music response. And we discovered that indeed there are people who so we looked at w what we call hedonia, which is just ⁓ yes a word for pleasure. ⁓ and there's a ⁓ a phenomenon called anhedonia, which just means lack of pleasure. ⁓ there's generalized anhedonia, which people have known about for a long time. It's basically people who are depressed And are not enjoying anything in life. ⁓ it could be due to clinical depression, it could be due to even ⁓ a disease, like in Parkinson's disease. Some people often have ⁓ anhedonia, which is ⁓ a sad state, and you know, there are treatments for it. But what we found is that there are people who have anhedonia for music, but only for music. Everything else is fine. So when you interview them, They say, nope, music just doesn't do it for me. And then you say, Well, but what about other things? They say, Well, of course, ⁓ I love to eat, I love to cook, ⁓ I love to go out with my friends, ⁓ have social activity, ⁓ you know, ⁓ I I like to watch movies, I like to have sex, I I like to, you know, drink beer, I like to watch sports, like all the things that that people enjoy, right? So their life is perfectly normal. In fact, we don't call it a disorder. We call it, you know, diversity, which is a bit of a of a I don't know, ⁓ it's a bit of a the term is a bit ⁓ overused, I would say. But ⁓ in this case I think it applies because these people just say no, it's just music, right? And it's not a particular genre. They just don't get music and they never have, even when they were kids. They never experienced any any pleasure to music. So when we study them, we put them in a brain scanner and we look at what's going on, what we see is very interesting because their perception is fine. So they can recognize music. If you play music for them, they tell you what it is. So it's not that they don't perceive it. ⁓ so their perception system is fine. I talked about, you know. Perception and pleasure, right? Their perception system is fine. Their pleasure system is fine because it responds to all these other things, but not music. And what we find is that the connection between them, actually, literally, the fibers in the brain that connect those circuits I talked about in the cortex with the stratum and other parts of the reward system, that ⁓ connection is actually reduced. in people with musical anhedonia. And it's probably a congenital variation, right? Just like some people are bad at faces, I'm actually a good example. I'm very bad at at recognizing faces. If I see ⁓ I I I use a lot of cues to recognize people. If I have a friend that has a beard and they shave it off, I have no idea who they are, right? Or if my If my students, you know, ⁓ dye their hair or change their hairstyle or get new glasses, it takes me a few seconds to wait, who are you? ⁓ right. So, you know that's just a variation. and so this is a variation as well. But what's important about it scientifically is that it really proves our theory that musical pleasure arises from the interaction between the perception and the pleasure systems. Because in people who don't experience the pleasure, it's the connection between them that is reduced. It's not the perception system itself and it's not the pleasure system itself. It's the interaction between them that is affected. So when we we've done a lot of studies on this with different kinds of techniques, and I think we've really shown that this is the case, ⁓ And by the way, the other side of the coin, people who we call hyper hedonic, these are music lovers, you know. in French they say meloman, which is like maniacal about melodies, right? It's ⁓ it's a term I like meloman. these people actually have a stronger connection than average between the perception and the reward systems. So the the two systems are communicating even more. than usual, which again explains why they get a lot of reward, why they like music so much. It's it's really, really interesting. I I I love that and yeah, it's it's fascinating and it it ⁓ it makes ⁓ makes a lot of lot of sense. And another one of your studies I believe I ⁓ came across when I was ⁓ preparing our conversation was ⁓ that you had people bidding real money on music they never heard before. ⁓ what what was that about? Yeah, yeah, that was a fun study. One of my Ph students came up with that idea. And ⁓ the idea was that ⁓ in most of the research we had done up until that point, we had usually used very familiar music. Because as I mentioned earlier, ⁓ the pleasure that you derive from music ⁓ is not for all music, it's for the music it's very individualistic, right? Some people like jazz, some people like house, some people like Indian music if you grew up in India, ⁓ etc. And so therefore we said, Okay, we're gonna study the response to familiar music. And that's fine. We did a lot of experiments like that. But then some of our critics said, Well, how do you know that the pleasure response that you're observing isn't related to something about the familiarity? Maybe it isn't the music itself, but it's some memory that's associated with the music. And that's a fair critique Because there are ⁓ associative aspects of music, which we haven't talked about, but music can indeed be ⁓ related to certain memories. And so if those memories are positive, you might get ⁓ a positive response. But it's not really the music, it's just that the music reminds you of something. So we started thinking, okay, how can we address this critique? And my student came up with the idea that we would ⁓ look at ⁓ we were looking at like ⁓ indie and electronic music websites and there are you know thousands of them, right? And so we looked at fairly obscure ones that were not, you know, very they were not the top top bands that most people would be listening to. And we looked for new music that they posted very recently. So the reason for doing that was because we thought, okay, If it's a fairly obscure group of music and it's very recently posted music, the participant is unlikely to have ever heard it before. So we recruited participants who liked this style of music, but who had not heard the music. And we gave them the exp excerpts, and then we asked them to bid money, and the amount of money was our index of how much they ⁓ liked it, how much value they assigned to it. And this is not this was not our idea. This has been used in other other types of research. So if you really like something, you value it a lot and you pay money for it. And the trick was that in those days, this is before like streaming services, ⁓ we we gave people recordings of the music that they paid for. So we said if you really like it, you get it pay your money for it, and then you're gonna get to take the recording home with you. And if you don't like any of them, you can keep the money. So there was no obligation. But these are people who really like music, so most of them bid different amounts. And so the amount of money they were willing to spend was our index of how much they liked it. And we knew that they had never heard it before. ⁓ and so then we looked at what parts of the brain responded as a function of the amount of money, and we indeed found that the stratum was. the biggest response. In other words, the more money you you gave indicating that you really valued this music, the more the activity in the streetum was active. So that proved that ⁓ you don't need to have familiar music to experience pleasure, and that the response of the reward system to pleasurable music is not predicated solely on its familiarity. Familiarity does contribute, but as we talked about before, the more familiar you get with something, the more pleasure you might get. ⁓ But it's not essential. So that was an important detail to our theory to show that it really is the patterns of sound. It isn't all about some extraneous feature that is you know, not inherent to the music. So it's we we like to say that music is intrinsically rewarding. It's not extrinsically rewarding. It's not rewarding because it leads to something else. In this respect it's very different from money, right? So money is rewarding, right? We all try to get money in various ways, but the reason we try to get it is because we can use it to buy stuff that's rewarding. It's not the money itself. Right? The money has no actual value. And in fact, you know, I I come from Argentina, where ⁓ there were numerous times when the currency was completely devalued. And so all my relatives back home from one day to the next, any money they had was useless. They like tossed it into the trash because it's worthless. ⁓ so money is only valuable insofar as you can use it for something, right? It doesn't actually have intrinsic reward. Music is not like that. Music is intrinsically rewarding. You don't need to use music to obtain some other reward. And that's a very interesting sort of distinction. Right. No, I agree. That's that it's it's an i a great finding and it also brings me to to this next ⁓ part and next question I have is can we use music to our advantage? Because sometimes when people are sad, they like to listen to sad music, for example. But given how much of a strong emotions music can invoke. For example, if I need to do a lot of work and it isn't work that involves any writing or ⁓ other communication with other people, I like to play very fast music that gets me into the rhythm and it allows me to get into a certain zone. When I'm working out, I l I like to listen to specific music that energizes me. So I feel like there's a lot of ways I can use music to my advantage in order to help me with a certain scenario, whether it's getting the work done, whether it's working out harder, ⁓ or whether it's it's shifting my mood. ⁓ is this ⁓ yeah, this is anecdotal, but this is this backed by the science as well? Yes, yes, yes, absolutely. Yeah. So ⁓ yeah, what you're saying is is spot on. So music obviously ⁓ can ⁓ can serve as a as a mood intensifier. it in more more generally can it's ⁓ it's a way to self-regulate mood, right? ⁓ you can either intensify the mood, like you said, if you're sad, you might want to work through that sadness, right? Particularly if it's if it's a very I mean if if you're sad for a really good reason, right? If someone close to you has passed away, you don't want to just you know, dismiss it and and listen to happy music. No, you need to think it through. You need to ruminate. You need to work through it. You need to grieve. And music can help you with that, right? Conversely, if, you know, my grant wasn't funded and I come home and I'm like, ⁓ I'm gonna have to rewrite that grant, what a pain. ⁓ I don't want to really ruminate on it. I want to be distracted. So I'll put on, you know, music that is going to be much more sort of engaging that will put me in a in a better mood. You mentioned working out, and that's really interesting because there's a ton of evidence that the rhythmic aspects of music engage the motor system. In fact, we did experiments way back ⁓ thirty years ago or so showing that the motor parts of the brain, which are located up here, the parts that control your body, ⁓ are actually active when you hear highly rhythmic music. even though you're not moving, so there's no physical movement. But the motor system is very much engaged. And that has been explored ⁓ in many, many different contexts. ⁓ in the context of like, you know, exercise physiology and and sports psychology and sports medicine, it's very often used ⁓ as part of the training. ⁓ but also in ⁓ therapeutic ⁓ situations. So there's a lot of people who do who have developed sort of ⁓ very specific music ⁓ therapies for people with movement disorders. So in Parkinson's, for example, people who often have trouble walking or their their walking is very unsteady, also with strokes, if you have, you know, you have some movement but it's it's spastic, it's not well it's not well ⁓ coordinated. ⁓ you can use rhythmic music to help the patient use the music as a cue because ⁓ the music actually ⁓ engages the motor system directly. So it sort of lowers the threshold for motor activation, which makes it easier to move than if you don't have the music. And so that's an area of ⁓ of great interest in these different domains, like I mentioned in sports excuse me. ⁓ it's an area of great interest in sports, in in ⁓ therapies for for movement ⁓ problems. ⁓ you know, dance therapy also ⁓ is something that's being used. ⁓ in the case of dance and well, I guess other other types of movements that you do in a group, like sometimes you might do ⁓ you might do a workout in a group, right? There's another interesting phenomenon, which is the synchronization that you have in the group. And that also turns out to be very interesting. Music can serve to synchronize groups of people when they're they're dancing or they're marching, right? This is why armies have marching bands. Right? Why why do armies invest money to have people play music? Well, it's because it helps the soldiers to march in synchrony. But what's really interesting is that that synchronization whether you're, you know, dancing or marching in the army, ⁓ helps bond people together. And so there's a social aspect which is really interesting. ⁓ and if you're if you're in the army, you need to have, you know, your your your buddies, you need to you need to know that you're you're wor you're gonna help each other out, right? Because you might be in a situation where you need help. That's very important. If you're dancing, ⁓ you're not only dancing with your partner, that's Obviously bonding, but you might be dancing in a group. ⁓ this is being used a lot in ⁓ therapies for ⁓ elderly people, especially elderly people who have some ⁓ cognitive decline, ⁓ and people who are isolated, socially isolated and lonely. ⁓ there's a lot of evidence that you bring them together and you have them dance together, and they feel enormously better. ⁓ also singing together works. And it's a similar phenomenon. You're you're not necessarily moving so much, but you're moving b you know your your vocal system to create sound, and you have to coordinate with the other person. So you have to synchronize. The synchronization makes you feel more bonded, makes you feel part of a group. And this can be extremely important ⁓ in many, many situations. ⁓ I think people are applying it to To children as well, children that might have behavioral disorders or whatever. So it has a an enormous ⁓ set of applications. And like I said, it's something that ⁓ people more in the therapeutic side are really very very actively exploring these days. Yeah, it's it's no surprise to me because I mean it's what happens also at large scale and and smaller scale music festivals. is ⁓ concerts, ⁓ DJ concerts, you're all dancing and experiencing the same to the same music and it can create such a sense, of course, in in some festival scenarios there are other substances and and alcohol involved that may drive people closer together, but the music plays ⁓ a huge huge part of it and harmony that you can feel on these dance floors all dancing to the same music. It's an incredible feeling. It's ⁓ it's no surprise ⁓ to me. Well one thing we we haven't really touched on, and I I I hope ⁓ we have ⁓ some time for it is ⁓ you mentioned there that we haven't really touched on dancing other than just now is that ⁓ music apparently lowers the threshold for ⁓ movement and activation ⁓ in the body. so it helps in th therapeutic sense. But of course, if you listen to to very good music, it makes you want to move. It's almost impossible to sit completely still if you're listening to a song you like, whether it's tapping on your leg to match the beat of the drums, or whether it's literally standing up, moving your shoulders. So What is the mechanics behind that? Why do we want to move if we listen to music we like? Yeah, yeah. So I think this goes back to the idea of ⁓ prediction and reward, because we talked about prediction mostly in terms of sound patterns, but part of that sound pattern is also the timing, right? So you might have a prediction if you hear a chord progression, you know what chord is coming next. But also if you hear a certain temporal pattern. Da-da-da-da-da-da-da-da-da. You know when the next event will come. It's going to be ta-da-da-da. It's so you have a window of time when you expect the event to be on the beat. And of course, you can have syncopation, which is literally when the ⁓ event happens off the beat, right? ⁓ and so what happens is that you're you're making these predictions and The movement is sort of part of the prediction, right? Your your motor system is engaged. Yes. Because ⁓ really sound and action are very closely linked. In fact, I I always like to point out that sound can only be the outcome of an action, or at least until we had electronic devices to generate sounds. Right? ⁓ The only sounds in the environment would be produced by something moving. Right? If you have a static environment, there is no sound. Right? It's just a basic it's basic physics. Yeah. Sound is vibration of air molecules. Something has to set those molecules into vibration. In action. If I do this, I compress the air and the wave expands. If the wind blows through the trees, the wind is the action, the trees are are waving, causing the air molecules to to be ⁓ Modulated, it reaches your ear, it's a sound. So there's this very, very close link. I even like to say that your very first action upon birth is to produce a sound, right? Namely, you cry. Right? The instant you emerge from the womb, what's the first thing you do? You go, wah. Which which of course clears your your your air ⁓ waves so that your your air intake so that you can breathe. ⁓ but also constitutes the initial link between action and sound. You make an action, right? You scream, ⁓ ha and you hear it. So it's very fundamental. It's really, really from literally from the moment you're born. and so ⁓ in the case of music What makes it ⁓ interesting is this ⁓ ability to predict when the event is going to come. Right? And so that's ⁓ sometimes referred to as groove, which is the the level of syncopation, which by the way obeys the same rule as we talked about before. If something is completely steady, da dot da it's really boring. If it's completely unpredictable, Ta ta ta da Can't follow it, right? But if it's ta ta ta it it's much more interesting, right? So if there's that there's that sweet spot again, which some people refer to as groove, and that activates your reward system in conjunction with your motor system to a much greater degree Than the very simple rhythm or the completely chaotic rhythm. Yeah, that's that's that's great. And and I ⁓ one thing I wanted to know, we briefly touched on ⁓ animals ⁓ earlier in our ⁓ discussion. you mentioned, I believe, that animals do recognize sounds, of course, and they have ⁓ a relation to to sounds, but not all animals seem to be equipped with the brains or capacity to really appreciate the complexity of the music produced by humans. Are there some examples where animals do seem to enjoy certain pieces of of music, or is that simply like asking them to enjoy ⁓ a good conversation? It's it's it's I think it's a bit like that. I think it's a bit like that. It's like, you know If you ⁓ show them a painting by Velasquez, you know, do they ⁓ do they respond, you know? Not really. ⁓ well I mean my view of it is that each animal, including us, is specialized for certain sound patterns that are important for its life and its survival. And ⁓ you know, we don't respond to the calls of bats. We don't even hear them, right? We don't have the hardware. Right? There's their sounds are ultra high frequency. Obviously they hear them, and those sounds are meaningful to them. But why should they be meaningful to ⁓ why should they be meaningful to us? Or even the sound of, you know, primates, like we can hear the monkeys calling to each other. Those sounds are meaningful. They might be ⁓ alarm calls, they might be mating calls, they might be ⁓ you know, the Mother looking for the child calls, there's any number of calls. We don't interpret them in any particular way. It's not they're not meaningful to us. Music, I think, is our species specific communication system. It's specific to our species. We have the right hardware to generate it and to ⁓ perceive it and to enjoy it. ⁓ different animals have know, may respond to different elements of it. There is, for example, some very intriguing evidence that ⁓ monkeys may be able to track some aspects of the beet. And that's interesting to know. ⁓ So the the research on animals is super interesting. ⁓ But I think it's it's probably it's it wouldn't be the right question to ask, do they enjoy it? I think the right question to ask is what elements Especially for primates, what elements ⁓ do we have in common with them? Because that helps us understand more about how our system evolved over time. We can't go back in time and study early humans, you know, five hundred thousand years ago. ⁓ but we can study, you know, our close ⁓ evolutionary relatives and we can see If if it's true that monkeys have some ability to track a beat, even though it's not part of their repertoire, it's not something that they use, but their brains are capable of it, that's super interesting because it suggests that maybe some aspect of the temporal ⁓ portion of music may be ⁓ may have developed earlier, and maybe the more pitch based aspects may have developed later. So it's interesting from that perspective. Yeah. No, f for sure. And I was I was wondering, ⁓ we've discussed a lot of your your previous ⁓ research. Is there anything that you are currently ⁓ working on that ⁓ is ⁓ that you're allowed to talk to already and that we ⁓ will be cool to to mention while we're on the topic? Well we're doing yeah, we're doing a lot of different things. ⁓ with some colleagues we're developing some different ⁓ applications that might be interesting. I have group of colleagues who study pain. And ⁓ it's it's been shown that ⁓ the right kind of music can il alleviate pain to some extent, but the mechanism for it has not been fully established. And so we think again that the reward system is very likely to be ⁓ to have some ⁓ some role to play here. And so we don't know is it dopamine, is it endogenous opioids? what's going on. so that's ⁓ an area of research that I think is is scientifically interesting because it will inform our understanding of ⁓ the brain's response and it also has potential practical applications. It's already being used, you know, in in ⁓ music therapy with people who have chronic pain, for example, therapists try to find music that will soothe them or calm them or ⁓ distract them, et cetera. So that's an interesting area. another ⁓ very new ⁓ area of research is to find ways to make music more accessible to people with hearing loss. This is a this is a very underappreciated problem. There are, you know, many millions of people throughout the planet with hearing loss. ⁓ And ⁓ as I get older I'm also experiencing this, so it's coming home to to me personally. And for many of those people they they have trouble ⁓ perceiving music. And you know, hearing aids don't really help because hearing aids are really designed to hear speech. So, you know, they they can be very good for that, but they they don't really work for music very well. And so I think this is this is a kind of a an area where ⁓ there's a crying need because there's so many millions of people who used to enjoy music and now are are having more trouble. And so with some colleagues, we're developing ⁓ a a glove basically ⁓ that you that vibrates. So it's this we call it a vibra tactile glove. You put on this glove and it has little little vibrators on the fingers. And what we're doing is we're training people who have hearing loss to both hear what they can from their ears and to simultaneously perceive the vibrations that correspond to the music through their hands. Because their hands are intact. Their hearing loss has affec you know has affected their hearing system, the peripheral hearing system, the cochlea, so the sound is is being distorted in some way. ⁓ so it's nothing wrong with their brains, it's just the the hearing system itself. But their hand is also intact. There's nothing wrong with their hand. So our hope is that by putting together vibration and hearing, people will learn to pick out different ⁓ elements of music that their ears alone are maybe no longer able to to do so well. And so that again is interesting. That's both scientifically it's interesting because It raises many questions about ⁓ how where in the brain do these signals come together? The signal that's going, you know, up your arm and up your spinal cord into the brain, and then the other one that's going into your ear, somewhere they have to interact. So we're trying to figure that out. ⁓ and it has a practical application as well. That's that's ⁓ that's incredibly interesting. I'm I'm really curious to ⁓ follow that closely and and and would love to know when there are any ⁓ any updates on that. Robert, we've we've covered so much ground today. ⁓ do you think there is something missing from our discussion? I mean obviously the f this the field is huge and there's endless more things we could ⁓ discuss, but For purposes of of today's ⁓ discussion. Do you think there's ⁓ more we should touch on today? No, I think this is a very thorough, very, very thorough discussion. ⁓ I would you know of course there are other other topics, a lot of details, ⁓ but I would I would refer your your listeners again to to my book if they want more more information. There's a lot of detail in there for those who seek it. And I guess I would also say that ⁓ you know, this is ⁓ an area of research that has grown a lot over my career. When I first started, it was me and, you know, a couple of other crazy people who were looking at this and everyone was like, what are you talking about? Music and the brain. And now it's become really a worldwide phenomenon. ⁓ actually a team right there in in Amsterdam that ⁓ is working on this at the University of Amsterdam ⁓ and throughout the world. so it's ⁓ it's very exciting and ⁓ it's very r rewarding ⁓ for me to ⁓ to see the area of research grow and and to see you know the the potential applications that are coming down the road. So thank you for ⁓ exploring it. ⁓ with me in in such detail. Yeah, I mean this was so incredibly fascinating. I really, really enjoyed our conversation and I learned so many new things and ⁓ I'm sure the people listening will too. I will also make sure to include ⁓ the link to your book ⁓ in the show notes. ⁓ are there any other places people can go to keep up with ⁓ things you're doing? Perhaps a website or or some other ⁓ pages that you might be active on. Yeah, I can ⁓ I can maybe Send those to you. Yeah. That's perfect. All right. ⁓ Robert, thank you so much. ⁓ I I really enjoyed it. And yeah, if ⁓ if some of that new research ⁓ comes out, maybe we should ⁓ run it back in the future one day because ⁓ this was ⁓ really, really interesting. Great, thank you very much for all your insightful questions.