How much of your intelligence is inherited? Which is more important: nature or nurture? Smoking during pregnancy results in dumb babies… right?
We answer all these questions and more in Episode 158. Geoff Der, Senior Research Fellow at the University of Glasgow, joins Jesse to talk about the genetic link between parental intelligence and children’s cognitive development.
Nature vs Nurture
It’s an old debate, and one that won’t be entirely settled here. But Der’s research can shed some light.
Probably the most striking finding from crunching huge amounts of data (we’re talking millions of data points here) is that many of the maternal behaviors we thought caused decreased intelligence, don’t. Instead, it’s the mother’s own intelligence (or lack thereof) that is passed on to her offspring.
Example: women who smoke while pregnant have children with impaired cognitive ability. But is it the smoking that causes this drop? Or are less intelligent women more likely to smoke, and then pass on those genes to their kids?
We’re about to turn conventional wisdom on its head. After crunching the numbers, it turns out that at least half of the variation in cognitive outcome is due to the mother’s own intelligence, not the smoking. What’s more: maternal education level completely accounts for the relationship between smoking during pregnancy and the child’s cognitive ability. Once you take education level into account, there is no statistical significance between maternal smoking and cognitive ability.
The same thing applies to birth weight — two-thirds of the correlation between birth weight and later intelligence is explained by the mother’s own level of intelligence.
And again to breastfeeding. When researchers looked at sets of twins where one twin was breast fed and the other wasn’t, there was basically no connection between breastfeeding and intelligence. Of course, this is assuming non-breastfed babies are getting high-quality, sterile formula.
What About Dad?
Unfortunately, we don’t have much data on the paternal intelligence connection. Partially this is because researchers haven’t collected as much data, and partially because it’s more difficult to be certain that a given guy is the biological father who contributed genetic material.
Live Long and Prosper
Another interesting connection in the data is that between early life intelligence and a longer life. It’s more or less an upward-trending linear line: the smarter you are, the more likely you are to live a long life. You’re both less likely to die of external causes of death (murder, car accidents, etc.) and internal causes of death (cardiovascular disease, etc.).
Interestingly, there’s only one internal cause of death where the correlation does not apply, and that’s cancer. There is one exception to this exception: lung cancer.
PS: It’s too late to be born to a smarter mom, but it’s not too late to make the most of what you were born with by signing up for our newsletter.
Dr. Robert Zatorre: As a kid, I was always interested in science, in fact. But somewhere in adolescence I got stung by the music bug, which happens to a lot of adolescents. So, I did an undergraduate degree in music and simultaneously did a science degree at the same time, and at some point I realized all my friends who are in a music program are actually way better than I am, but when I'm in my science classes, I can pretty much do pretty well. And so I thought, okay, if I'm going to go for advanced studies, I really should go for the science, but I didn't want to give up on the music because it was very meaningful to me and I had learned a certain amount. And so when I went to do my PhD, I somehow convinced my PhD supervisor that, well, maybe one should study music, because at the time there was hardly anything at all scientific looking at how people perceive and process music. I think as soon as I began working on this, I realized there was an entire kind of open area of research that hadn't been touched much.
Dr. Assal Habibi: We know that children from underserved communities do not get opportunities as frequently as children from more affluent backgrounds to be exposed to music, and that was a thought in mind when we started this study of the observation of knowing that a lot of art education and music education programs are being carved out of the budget within our public education system, and figuring out what is the best way to push for policies to bring these programs back to at least give that opportunities to kids who cannot afford having private lessons. We looked at many programs in Southern California, that's where our institute is at at USC, and we came across a program that is called the Youth Orchestra of Los Angeles, and it's a program that is supported by the Los Angeles Philharmonic. Now, this was inspired by the famous music training program from Venezuela called El Sistema, that it was not only a music training program, it was using music to introduce social change and to bring social justice.
So the idea was that we bring all these children, we give them a musical instrument, we take them off the streets, and that would already induce this cohesion in society in how when kids play together, they are able to understand each other better. We thought that this was really an interesting idea, and the L. A. Philharmonic was supporting the program in the L. A. area, so it's a free program that is offered to families from underserved communities. Children go to this program five days a week for about two hours a day, and they're provided with free instruments. Now, everything is done in a group setting, so there is no one-on-one instruction. Everything is an ensemble training, so there is a teacher assistant and a conductor, or the main teacher who leads the orchestra.
Jesse: Do all known human cultures engage in some form of music? Are there any music-less tribes hidden in the far reaches of the Amazon or anything like that?
Dr. Robert Zatorre: As far as I know, music really is found in every culture. However, it varies tremendously in the way that it's expressed. There are some common features that are found in essentially all cultures, and others that are sort of optional that are found in some cultures and not others. Of course, there are cultures where they've tried to suppress the music even though it exists. Famously, the Taliban, when they were in charge in Afghanistan, actually banned music because they felt it was too dangerous and it takes people away from appropriate worship. It didn't work, by the way.
Jesse: I would think that would be a tough thing to stamp out. I think they tried that in that 1980s movie with Kevin Bacon.
Dr. Robert Zatorre: Yeah, right, exactly. So then it goes underground. Like most things that are really part of human nature when you try to control them and try to eliminate them, it's almost impossible. But yeah, I think music is found in all cultures, and in that respect it's universal, and I think that's because it is an expression of our human brain. It is much like language in that respect. All human cultures have language. Every infant is born with the capacity to speak very complex languages, and so similarly every infant I think is born with the capacity for music—with some interesting exceptions that I think I'd like to get to later on.
Dr. Assal Habibi: So there's an aspect of cohesion and helping each other that is part of the program that we thought was really interesting. Given that the cost of these group training programs are a lot less than having to provide one-on-one individual training for each student, we figured that if we could show these programs are successful both in terms of creating benefits in emotional and social domains for children, and also in biological brain development, we could argue that if we cannot afford having one-on-one private lessons for every child, we can bring these group music lessons back to school, either as part of the school curriculum or as an after-school program that is offered in the public school education system.
Jesse: So in your current study, at what age did the kids start, what age are they typically now?
Dr. Assal Habibi: Yeah, so they start at six. So, we collected a series of measures from them, including both measures of their brain function and their brain structure using Magnetic Resonance Imaging, looking at the physiology of their nervous system using electroencephalography, and a series of psychological measures, like looking at their language development, their cognitive abilities, also social and emotional abilities, like how much empathy they have towards each other, how much compassion, would they go out of their way to help each other. We did all of these measures right before they went through their music program and right before they started school, so in the summer before the school started, when they were six. Right now, we are in year four of our data collection and the kids are about to go through fifth grade and finish their elementary school years.
This study was originally designed for five years, so between 6 and 12. However, we are very much interested to see, because we have all these great measures and data from these students, the benefits that we have seen that we can talk about—we are really interested to see if those benefits carry on. In middle school, your social environment is more complex and you have to do more complicated decision-making, so we want to see if the benefits that we have seen during these younger ages can extend to those older ages.
Jesse: That feeling of intense and emotional chills going up or down the spine that can sometimes happen near the crescendo of a song that a person really likes—it can happen in other things too, like the emotionally moving parts of movies and things like that, but music seems to be a particularly reliable way of bringing that feeling out… What exactly is going on there?
Dr. Robert Zatorre: Yeah, music is a very strong trigger of that kind of emotion and, in fact, it's relatively rare in other art forms. You mentioned movies, but I wouldn't be surprised if in the movie it's largely related to music. Not to take anything away from visual arts, but if you look at a magnificent painting, it may be absolutely wonderful in many respects, but it's unlikely to give you the sort of chills or shivers. But the reason we started looking at that, it's kind of a funny story. I had a very good postdoctoral fellow, Anne Blood, who actually is now on the faculty at Harvard, and she came to work with me and said, "Robert, we have to study how people respond to music emotionally," that different people have really different tastes and, "How are we going to do this? " So we started talking and I said, "Well, for instance, what's your favorite music? " and she said, "Well, I'm a drummer, and I like hard rock and metal. " I'm an organist and I like 17th century North German baroque music. How can we study this?
Then we got to talking and we realized that although our styles are extremely different, we both felt this intense pleasure at certain moments of the music, and we felt this response that we'd call chills, or shivers, or it's called frisson as well. Then we said, "Ah ha, that's the way we're going to study it," because even though our musical tastes may differ, the physiology that we're experiencing during a particularly pleasurable moment of the music is the same. So, what if we scan people's brains when they're in that state? That was the reason we started looking at it, was because it was a way to kind of get rid of this pretty complex problem of why different people have different tastes in music, which is not what we were interested in. What we were interested in is what is happening when you do experience pleasure. So, given that you're experiencing the pleasure irrespective of how that state was arrived at, what's going on in the brain?
And so that was really the start of it all, this was back in the year 2000, and what we found was that there were certain brain structures that were active, and these structures are very relevant because they had been long ago identified as being involved in what psychologists call reward. In fact, the very first few studies of this were done in rats—actually it was done here at McGill University back in the 1950s by Olds and Milner, and what they found was the famous rewards center, which is kind of slightly a misnomer. The point is that if you give a rat a certain amount of food when it's hungry and you measure its responses from different areas of the brain, there are a few particular regions that respond very, very strongly when the animal receives this reward, in other words something that it really is craving because it's hungry, it wants food. And so those regions, which are known under various names, as a reward circuit or a more particular part of the reward circuit called the striatum, this area of the striatum had been known for a long time as being important—50 years, at least.
When we looked at our brain scans, we said, "Wait a second, this is the striatum, this is the part of the brain that is supposed to be important for these biologically meaningful stimulants, like food for a hungry animal. " Then we started delving into this literature and we found that this reward circuitry is also involved in other biologically meaningful activities. So, for example, sex results in activity of the striatum because, it makes sense, it's a stimulus, if you will, that's important for survival, maybe not of the individual but of the entire species. Then we started finding other things, like, for example, certain kinds of drugs activate some portions of the reward circuitry, in particular things like amphetamines and nicotine, as well as cocaine. So, we thought, "Maybe we're onto something here that should be explored further. " That was sort of the beginning of that whole story.
Dr. Assal Habibi: Using music as really an intervention to understand brain plasticity has really gained strength in the field of neuroscience. Because it's still a young field, it's still not as established to be able to get these larger grants to support a large study like this, so we had help from fundraising given that we had really promising findings and we established a really good relationship with participants of ours study, which on its own was challenging, but we were able to maintain a very high percentage. Around 80% of the originally recruited participants in the study.
Jesse: What was the cohort size of the kids in this study originally?
Dr. Assal Habibi: We had recruited 25 students from this group of children who are doing music. Now when you look at child development, you always also want to look at a comparison group, because children obviously get better with their language and their reading ability and their cognitive abilities and understanding of emotion as they get older, so some of these effects could be just because of development itself. And then our other idea was also that maybe some of the effects that we see have nothing to do with music training, but it could just being exposed to a group activity. So you go somewhere, you get attention, you play with your peers, and you feel you belong, in a sense, to a community. So, we also wanted to control for that factor.
So in all, we had three groups. The music group, as I said has 25 students, and we have also two comparison groups, children from the same communities. One group, we call them sports, and they were recruited from community soccer programs or swimming programs in the area. Also, we started to test them prior to their enrollment of their sports program, and they have been following with their sports respectively for the past four years, and that's also a group of 25. And then for the third group, we have a comparison group of children who are from the public education systems around the area. They're not necessarily enrolled in any specific after-school program, so we call them control comparison, and they're also 25. So, three groups of 25 children for a total of 75.
Now, because I said this control comparison group, I just wanted to clarify, because I always get a lot of questions of, "Well, how do you stop them from doing music, or how do you stop them from doing sports? " and of course we don't, because it's not ethical, for one thing.
Jesse: "You're only allowed to play video games!"
Dr. Assal Habibi: Yes, exactly. "For the next five years, don't do anything that benefits your life. " No, we kind of looked at the frequency that the children in the music and the sports group take lessons. So as I said, the music group is five days a week and the sports program is about as frequent, it's about four days a week. It's a little less amount of time just because physically children, especially when they're younger, they can't play for two hours every day. So, they were frequent and they had some intensity that were close to each other. Now, if a child from our third control group, let's say, took recorder lessons one hour a week in the school, we don't count that against them. However, if they move to a more intense program, we continue to study them but we don't count them in our analysis.
Jesse: It's funny to think exactly what the evolutionary advantage of humans liking music is.
Dr. Robert Zatorre: There are different models about this. There is good evidence that young infants do respond to music-like sounds, in particular the intonation patterns of voices. They're very sensitive to voices, particularly the mom's voice. And, of course, moms sing to their children in practically every culture, so it's a way of interacting with the child and either soothing it if it's upset or arousing it if it's kind of sleepy. But I think music serves many, many different functions, different people have speculated about the origins of music. There's also a social function—social bonding, for example. There are a number of different explanations. The one that we're focusing on is a little bit different. These are not mutually exclusive, so our idea is not really in conflict with any of the others, it's just an additional idea, which is more about the abstractness of music. So, a lot of music is quite abstract in the sense that it doesn't refer to any specific item. This is different than language, because when we're speaking, what we're speaking about, there's a reference to what we're talking about. We're talking about something and we can give quite precise instructions when we're speaking. With music for the most part, with some exceptions, it's not really about that, it's more about the patterns of sound. The patterns themselves are intrinsically beautiful. A number of music theorists have proposed that what happens is that when you hear a sequence of sounds, it sets up an expectation of what the subsequent series of sounds ought to be, and that the musician or the composer or the person who's singing or playing will kind of manipulate that degree of expectancy to create a pleasurable sensation. So, it's this idea of tension and resolution, for example.
There was a famous theorist named Leonard Meyer who proposed this model back in the 1950s. What we found in our neuroscience experiments, in fact, is quite consistent with this, because in further studies that we did after those initial ones, one of my former PhD students, Valorie Salimpoor, did some very nice studies where she looked at this chills phenomenon and looked at the brain responses before and after the chills. In other words, we scanned people, we asked them to indicate when they felt the chills, and we knew this anyway because we could measure the physiological responses, we could see that the heartrate goes up and that the respiration rate goes up and that the skin conductance, which is an index of arousal, it all goes up at that moment. Then we looked in the brain to see what's happening in the few seconds before and the few seconds after, and what we saw was there were two separate regions of the striatum—this is the same structure I mentioned before, two separate subregions, both of which involve dopamine by the way—so what we saw was that just prior to the moment of maximum pleasure, we call it the anticipation phase, 10 seconds to 15 seconds prior to that moment there's a response in what we call the dorsal striatum, which is just a little bit above the ventral striatum, so there's two subsections. Then at the moment of the peak pleasure, the dorsal striatum drops down in its response and then ventral striatum goes up in its response, and the reason that's important is because of the way that those two subregions are connected.
So, the first one, the dorsal striatum, which is active during this anticipation, that part of the brain is connected to all the most evolutionarily recent structures in the brain, like the frontal cortex and the cingulate cortex and other areas, although these are involved in things like prediction, anticipation, decision-making, trying to figure out what's coming next. Whereas the other one, the ventral striatum, is more connected to more ancient structures, like the amygdala and parts of the brain stem, which are involved—if I can sort of oversimplify it a bit—they're involved in things that might be called raw emotion, so the actual feeling, the actual hedonic response. It's the pleasure, the moment when you feel the chill and you go, "Ahh…" And so there's this interplay between the more advanced part of the brain, which is the frontal cortex—by advanced, I mean more highly developed in humans—which allows us to make predictions, it allows us to anticipate what's coming up, and that's sort of the circuit that's more active at the beginning, prior to the moment of peak pleasure. And then the other circuit kicks in, which is sort of pure pleasure. This finding, this result from the brain actually makes perfect sense with respect to what the musicologists were telling us 50 or more years ago. So, a nice way that these results are sort of coherent with existing theories.
Jesse: I'm curious as to whether something that has a physical instrument versus something like choir, where a person's just bringing their voice, whether you suspect there might be any differences there. And also the differences between the type of training you did as sort of an intensive single person but not a group activity versus something that's more like a choir, or a band, or an orchestra, where you're working with other kids.
Dr. Assal Habibi: Yeah, no, the question of choir is a really good question and I think it's a lot of fun for kids to be part of a choir. Especially when kids are young, holding a physical instrument is difficult for them, they can't do it for a long time. There's a lot you can do with your voice: you can sing along, you can just go low, high… I mean, it's more of an engagement. So, I think that's a really good introduction for the kids. A lot of the early childhood music programs have an aspect of choir or singing along together.
Also, one of the things that I think is important—so, I was trained in classical music and even the program we're studying has a classical model, so the kids get to play the classical repertoire. But in addition to that, if children also get to play things that they can relate to emotionally, whether that's music from their culture… So, a lot of the kids that are in our study are from Latino backgrounds, so if they can play the music that their parents listen to at home or that they heard at a family party, or if they can play music from the movies they like, if they want to play Star Wars, it's okay. Star Wars has a melody, they can play that. That brings some connection that maybe those more classical repertoires by themselves would not, because they probably cannot connect with music from two centuries ago in the same way that they can go to their friends and say, "Oh, I know how to play the theme for Star Wars!" So, I think being sort of open-minded in the sense of we are trying to teach music, and then once they learn the basics and if they understand, they make the connection emotionally and cognitively understand the value that this brings to their lives, they will gravitate to more complicated and more of the classical repertoires that we know of.
Jesse: What do you feel like the evolutionary pressure was for us to gain this strong species-wide appreciation? Like this dramatic and predictable release of dopamine, it seems like normally it would be there to motivate us to do something. But in the case of music, there's not a clear result that our biology seems to be aiming us to do, other than to just appreciate.
Dr. Robert Zatorre: I'd like to cite the work of a friend of mine who has thought about this carefully, Aniruddh Patel, a psychologist at Tufts. He has a theory, he basically says, "Well, maybe music kind of evolved almost by accident in the sense that the individual capacities that are necessary for music each evolved for a separate reason. " So, our ability to perceive certain patterns of sound evolved long ago because it's really important to perceive sound because it helps you navigate your environment and listen for different events that might be important to listen for—a predator who's after you, or to listen for prey that you may want. Similarly, the ability to move, the ability to manipulate our fingers and hands, that's incredibly useful for survival, for making tools, for everything. Once you have all these capacities together, then making music kind of emerges. But the point he makes is that this doesn't mean that music has no function, it just means that you don't need to assume that there was evolutionary pressure to develop music. Then it becomes useful, and it becomes useful in many ways, including things like we were saying earlier, such as social bonding, the mother/child interaction, synchronizing activities, people singing together when they're working together on a task, etc.
The analogy that he draws is something like fire. So, our ability to control fire did not evolve specifically. It evolved because we have the cognitive capacity to understand that when you rub two sticks together, they heat up and then they eventually flare up into a fire, and then we had the visual capacity to recognize when there's smoke and how it's related to fire, and we have the motor capacity to make fire occur, etc. But you've got the fire. Well, then you have an incredibly useful tool that you can use for all kinds of other purposes. But the capacity to create fire was not selected for as such. Other capacities were selected for, which then allow us to develop the technology. And so fire is a technology in that sense, and music can be thought of in the same way, as a technology that we sort of were lucky to hit upon, but now that we have it, well, we realize that it has lots of useful properties.
Jesse: It's interesting, I find that a very compelling argument, and yet what you showed with the brain's response, the striatum's response to musical pleasure—I mean, there isn't like a parallel to something like that with the relief that we get when we get a campfire started. The fact that there is such a measurable physiological response in the case of music, it just makes it feel like it's maybe something a little deeper.
Dr. Robert Zatorre: Yeah, so the parallel with fire I don't think extends to the emotional response. However, this whole idea of making predictions and getting the outcome, humans are very sensitive to that. This is why things like puzzles and riddles have been very popular in all human cultures, I think. And games—-lots of games have to do with anticipating a certain outcome, and then you get surprised when the outcome is different than what you predicted. So, I think the many forms of complex human activity, including stories and poems and dances and so forth, all have this element of making predictions and anticipating the outcome and then being rewarded when you get a certain outcome.
Jesse: What are some of the things that we might expect to see in a study like this and what has your data actually shown so far in the first four years?
Dr. Assal Habibi: Part of our expectation as we went—so, pre-hypothesis was to see differences in the abilities that rely on sound. So, processing of sound, whether it's pitch and rhythm perception, and areas of the brain that are engaged in that processing, the auditory cortices, the areas of language processing, and the motor cortex because you are training this fine motor movement on your hands and you do this visual and motor integration. Another thing that we were expecting when we were going through, given the emphasis on the social and group aspect, was to find out whether music actually does something for you in terms of your social behavior, your emotional behavior, your ability to connect with another person. Because, to me, the question was, okay, there's been a lot of evidence showing that music training is good for language development, it's good for mathematical skills. If it does help with all of these cognitive elements but it doesn't help you become a better citizen in the world, like you cannot relate with your peers or friends, it would be nice if it had this more holistic impact. So when we started, these were kind of our hypotheses.
Now, child development is a process that is very strong. When we compare children, we always have to exclude any effect that is related to development, and children during those years really go through this very massive development of the frontal areas of their brain, decision-making, emotion processing, and even language. When we test them from year one to year three, you can just really see this massive change in their language abilities, regardless if they're from the music, sports, or control program. So after controlling for all these values, a general picture that we have observed, the very beginning things that we started to see after two years of training was changed in the perception of sound. So, we started to see that children who were in the music group, they were showing signs that they process music and sound, whether that was speech or sound from nature, different from the two other groups. So they perceive pitch differently, like they were more accurate in detecting changes in the pitch environment, in the rhythm environment, and they were also better in coordinating like if they had to keep a beat on a drum. So both pitch production and pitch perception, and rhythm perception and rhythm production, after about two years of training, started to change and we started to see differences.
As they moved along, after looking at some of the brain data, some of the electrophysiology data we observed—this is a paper that we put out last year looking at a development of the auditory pathway… So this is a pathway that connects the ear, so when the sound, the stimulus hits the ear and it takes the information all the way to the thalamus, the center executive part of the brain, and from there to the auditory sensory areas, and we saw a faster maturation of this pathway in children who have had music training compared to the two other groups. By that, meaning that this pathway had the function that it was more adult-like in the children who had music training compared to the other groups. It was very promising, you could see this is the pathway to the system of the brain that is stimulated by sound, and so they were getting this music stimulation, and the fact that it has impacted this was evidence that the music program was working and children were training. We also observed that their level of expertise, the better they played, showed these differences more clearly.
Now, even though this pathway is engaged in music, it also is engaged in any other domain that relies on sound, whether that is language or successful communication. So as the years have gone by, we're working on a paper to put out, after three years of training we have seen advantages in language domain. So, for example, in verbal memory, the children who have had music training are better in holding some verbal information in their memory and recalling it later in executive function, meaning that they're able to use working memory and inhibitory skills to perform on executive function tasks better. So, really the change seems to have started with the auditory pathway and the sensory system, and now as they train more and they become more advanced in their training, it's expanding to more cognitive and language areas, and memory and attention compared to the two other groups. Now, the result after five years remains to be seen as we collect data, but it seems that this is the direction that we are moving towards.
Dr. Robert Zatorre: Because we have a very complex brain, we are able to derive pleasure from many complicated abstract patterns that have this property of engaging your reward system by virtue of making predictions and then checking whether the outcome is in line with your prediction or not. Music happens to really engage that system particularly well, possibly because it extends over time, so it's a constant sequence of events, and possibly because it's like a linked sequence of events. In other words, each sound kind of predicts the next sound, which predicts the next sound, which predicts the next sound. A constant flow of information coming at you. So, I think that's an extremely powerful way to engage this sensory prediction system, and that's why we get intense pleasure much of the time from musical patterns.
Jesse: What do we know, if anything, about the general differences between the brains of people that are big music fans, the people that are kind of so-so/ho hum, the people that are musicians versus people who are merely music enjoyers?
Dr. Robert Zatorre: So, I think this brings me to this other topic that I wanted to touch on, which is that when we first started doing this research, we sort of assumed, "Well, everyone loves music. " And indeed, it's not hard to find people who love music. Almost everyone seems to really enjoy it. " And we know music is a huge business in the modern world, and that's because it's so widespread. But a few years ago actually I took a sabbatical year and I decided to go to Barcelona because it's a beautiful city, I wanted to be on the shores of the Mediterranean. So while I was there, I met up with a group of scientists who were studying what is known as anhedonia. Anhedonia is a feature of depression where people don't get enjoyment, so they don't enjoy normal things that everyone else enjoys. They were already experts in this area, and so in talking to them, we came around to the idea that, hey, maybe we should look at whether everyone gets enjoyment from music. Is there such a thing as musical anhedonia? So, are there people who don't enjoy music? Or conversely, are there people who are hyper hedonic, who are just absolute music lovers?
To make a long story short, we developed various techniques to examine this and we found that, indeed, there is a small but significant group of people, about 2% of the population roughly, depending on exactly how you measure it, who are perfectly normal and average in every way except that they do not derive enjoyment from music. Importantly, they derive enjoyment from everything else that everyone else enjoys—so all those things we talked about: food, sex, social interactions, family ties, movies, books. Whatever most people like, these people like as well. So they're not depressed, they don't have overwhelming psychiatric symptoms or anything like that. And furthermore, their ability to perceive the music is perfectly normal, because there's a separate condition known as amusia, which is where people have a perceptual disorder, music sounds sort of weird to them, it sounds meaningless, like a meaningless jumble of noise, and so those people, of course, don't derive enjoyment from music.
Jesse: Sort of like the musical equivalent of dyslexia.
Dr. Robert Zatorre: Yeah, I think that's a good analogy. So, music for them is perceptually meaningless, so therefore they don't have the capacity to enjoy it. But these people with musical anhedonia can perceive music perfectly well—in fact, they would be able to say things like, "Well, this was meant to be a sad piece of music. This was meant to be happy. This one's a march, this one's a waltz. " They can describe it in any way that everyone else can, but when you ask them do you actually feel that pleasure, that sadness or whatever, they say, "No, it just leaves me cold. " When we started studying them, some of them said to us, "I'm so glad that you are identifying this situation, and I'm really glad to know there are other people like me, because through all my life people have been telling me, 'What's wrong with you? What do you mean you don't like music? '"
Dr. Assal Habibi: So, executive function is a series of skills that now are known to be really high predictors of success in life, whether that is academic success, job success, and even relationship success. There are three core skills that define executive function: working memory, ability to switch tasks (so, be flexible), and also inhibition (so, inhibiting from having a reward to having it two days later, to understand, oh, I can have a larger reward later). In that executive function domain, we use an fMRI paradigm, and we saw that the music group outperformed the other two groups in that task. However, the sports group is kind of like in the middle. So, it went music, sports, control. So, the sports group was still better than the children with no exposure to any systematic training. So, part of it obviously comes from engagement in a group activity, an engagement in discipline and frequent activity, and then the extra part has come from music.
I always like to clarify that we have never had the intention of saying whether music is better than sports, or one is better, or one should be or one shouldn't be. Both the directors of the study and I are very much in agreement and of the understanding that all of these are necessary for children. We know that physical education is essential in child development. We just chose this because we wanted to have an activity that is comparable to what we were looking at in terms of music.
Jesse: It seems that the level of discipline in a 6 to 10-year-old participating in sports might not be the same level of intense focus and discipline that's expected of a kid learning an instrument. Is there an intentional discipline matching going on? Because if not, that seems like that could be throwing your data out of whack a bit.
Dr. Assal Habibi: Yeah, in terms of discipline, I have asked this question and kind of understand how the two programs are compatible in that sense. So, both of them require regular attendance of their program. Now, what is different between the two is actually the social aspect. So, the social aspect with playing in an orchestra is maybe just, "Oh, let's help each other for the orchestra to sound well," and there is not a specific star in there or somebody who is really good, and they're all helping out. They're not at that age where they have the first violin or the solo player. Whereas in sports, it seems to be more of a sense of competition, of me against the other team, and maybe there's a star who's better or there's a kid who's playing better. So, I think the social relationships are a little bit different between the two programs.
However, I have observed that in both of the sports programs that we're looking at, there is this attention being directed towards this social activity of we all want to help each other, especially with these children who we study, because the communities they come from and a lot of the schools, there's this lack of a sense of belongingness that in the end, when they get a little bit older, through middle school or high school, it really increases the chance of them getting involved with gang activities. But if they have this sense of a belongingness to a community and knowing that, by their participation, they make a difference, so they're told, for example, "If you don't show up today, the team is going to miss a person, so we're not going to do as well, so it's important that you show up and it's important that you follow through. " I feel that that sense is the core of their understanding and connecting with the activity.
Dr. Robert Zatorre: Well, you won't be surprised, of course, that if you take a group of musicians, you will find that the vast majority of them also score very highly in loving music. In other experiments unrelated to these, we have looked at the brains of musicians, and we certainly do find interesting effects going on there. Basically they have better interactions between the part of their brains that process sound and the parts of their brains that execute movements. Which makes sense, because when you play an instrument, you have exquisite motor control over the instrument, and at the same time you have a very finely-developed ear. People say it's the ear, but of course it's not the ear, it's the brain, and importantly it's the communication between those two. So, to play an instrument, you have to not only execute a series of movements in a very skilled fashion, you have to be sure to monitor the sound produced by those movements in order to make extremely fine adjustments. We're currently doing some very cool experiments; we have a cello that was designed by us, and this is a strange cello that is very narrow and small and can fit into an MRI scanner, and so we're actually getting people to play inside the scanner and looking at what's going on in the brains of highly skilled cellists as they execute certain movements. That is, indeed, what we're seeing, is that there's this much more developed interplay between the motor system and the auditory system.
Jesse: What studies would you like to do next?
Dr. Robert Zatorre: So, we're doing some interesting studies. We're doing things like training studies, we're looking at what happens if you take someone who, let's say, doesn't know how to play the cello and you give them lessons, and you monitor what goes on in their brain. We want to see how does this change, and also how is it that some individuals will learn fairly well and others won't be so good. Why is it that there are these discrepancies, that any music teacher will tell you that some of their students are "gifted" and others are just not cut out to be musicians? We'd like to understand why that might be the case.
In terms of the musical pleasure kind of idea, we're currently doing some experiments that I think may turn out to be quite exciting, where we're using a totally different technique, which is a brain stimulation technique. So, this is a way to modulate brain activity, so you can actually change the excitability of the brain tissue either to kind of boost it or to suppress it.
Jesse: Is this like transcranial direct-current stimulation or is it actually something internal?
Dr. Robert Zatorre: It's actually transcranial magnetic stimulation. So, it's basically a coil and you pass a current through the coil, which produces a magnetic pulse, the pulse goes through the skull and causes depolarization of the neurons. So, just brain activity. And like I said, you can either inhibit ongoing activity or you can suppress it by a certain percentage, or you can boost it.
Jesse: I'm wondering about deaf children. I imagine that a deaf child might be able to actually do percussion because they can still get tactile feedback rather than auditory feedback. Is that something that's done? Is there any sort of music training for deaf children?
Dr. Assal Habibi: Yeah, that's a really good question. I don't know, actually, of any program. But what you're saying totally makes a lot of sense, especially with drums and coordination of drumming. I'm aware of programs for children who are blind and music training, and actually there is some evidence, we actually have studied in an adult musician who was blind, an opera singer that, in a very fascinating way, she has this extremely exceptional music skill and when you look at her brain in the scanner when she processes music, not only does she engage her auditory cortex, but also her visual cortex. So, the cortex that doesn't engage in doing the visual everyday activities is now being served as processing auditory information that is crucial to her life, and she uses that as a primary way of navigating the world. So yeah, I'm aware of programs for blind children but not for deaf children. But that seems really intuitive in terms of especially coordination training across drumming.
Jesse: Did you see anything in your study, almost like a refractory period for the enjoyment of music? Like, you could play me my favorite song and I'm sure I'll get a big spike of enjoyment the first time, but if I listen to the same song ten times in a row, even if it is my favorite song, the enjoyment will diminish. What's going on there? Does that play into the idea of anticipation, expectation at this point, when I know exactly what's going to happen and it just doesn't have the same tickle for me?
Dr. Robert Zatorre: Yeah, exactly. So, that phenomenon you described has, of course, been studied and I think that's exactly what's going on, is that if this model of anticipating the outcome is valid, once you know exactly what the outcome will be, there's no longer any anticipation. You know exactly what will happen, so the reward value falls off. This is also related to the concept that people like to listen to music that has the right level of predictability and unpredictability. If you take music that's extremely repetitive, for instance kid's music, because children don't have the mental capacity to appreciate too much complexity, so kid's music tends to be extremely repetitive. Any adult who's had a toddler knows how annoying that music can be after a while, and that's because it's very, very predictable and very, very simple.
Conversely, if you are very musically experienced and sophisticated, if you have a lot of musical training for example, or if you have listened to a lot of music of a particular genre, you probably will be tending towards the more complex end. So, a good example of this is jazz, where if you're not a jazz lover and you listen to John Coltrane, you have no idea what's going on because it's extremely complex. So, your ability to make predictions and understand the outcomes of those predictions is very limited. But if you have enough experience and possibly training in jazz, you will understand at least some of what he's doing and you'll get a lot more appreciation out of it for that reason. So, there has to be kind of a match between your ability to make those predictions and the complexity of the music. So if it becomes too predictable, then it's boring. If it becomes too complex and you can no longer make any predictions, it's also boring because it seems random to you.
Dr. Assal Habibi: There are two parallel studies to our study that are happening in the country. We always compare results; we often give conferences together to just bring our results together. We study a group of 75 children and they have another 100, and the other group has another 50, so it's always nice to see it on a larger scale. So, one of these studies is actually at UC San Diego, and the Youth Orchestra of San Diego. They actually started around the same time that we started, so they're also in their year four, and they are comparing children in music training with typically developing children who do not have any training, and also children who are engaged in martial arts activities. They have had similar interesting findings to us in terms of the processing of kids and their development of their auditory system. Then there's another study, I think it had ended about two years ago, at Northwestern, professor Nina Kraus, who also looked at the community music program and the impact of that on child development and language and speech perception, and had found similar findings in terms of physiology and also the benefits in the language aspect and learning of languages.
There is a lot of work that's been done in adults, looking at adults who have had long-term music training compared to non-musicians, and then there's been some work looking at, let's say, bringing music at an intervention, cross-sectionally, for a year into a school program both in children and adolescents, collecting pre and post-training data. I think the general consensus is there are benefits of music training in the language and cognitive domain, there are benefits in terms of the motor development. And then there are some benefits in the social domain that are still not clear because I think the cohorts are different, the assessments are different, so there is also a lot of meetings and discussions around standardized measurements so we all kind of use the same sets of measures so we can compare our results.
But it's a growing and exciting field. There are two annual conferences, Society for Music Perception and Cognition, and Neuromusic, that brings everybody who does this type of work together so we have an opportunity to discuss and compare results.
Jesse: I'm sure one of the nice things about the study of music is that everybody's rooting for music. Except for the 2% of people that you've identified that it doesn't really do anything for, most of us would love to hear good things about music and the brain and how we can use music therapeutically and stuff like that. So, it's kind of like you've got the whole world at your back.
Dr. Robert Zatorre: Yeah, well that's right, and there is, of course, the whole field of music therapy, and increasingly there's more contact between neuroscientists like myself and people who are actually working in the clinic, using music therapeutically. They used to be sort of two separate communities, and I think now there's a lot more interaction between them, and I think it's quite beneficial to have that interaction.