In the brain of the beholder: Music across cultures
Kicking off a new series of Naked Neuroscience, James Tytko serves up the latest research making waves in the study of the brain with the help of Stephanie Brown and Francis Madden. This month, an analysis of brain networks shows promise for those living with addiction. And a counterinuitive claim that suppressing negative thoughts might in fact be the best way to look after your mental health. Then, with Malinda McPherson and Alexander Jensenius, we dive deep into the rhythms and melodies from music of eclectic origins...
In this episode
01:14 - Researchers identify brain network linked with addiction
Researchers identify brain network linked with addiction
Stephanie Brown, University of Cambridge
First up in the news this month, could this common brain network associated with addiction prove key to helping people overcome it? Time to introduce our first contributor, Stephanie Brown from the University of Cambridge’s Department of Psychiatry...
James - How are you doing, Stephanie?
Stephanie - Yes, I'm very good. Thank you.
James - Delighted to have you with us. So psychiatry, the medical specialty dealing with the treatment and prevention of mental health conditions. Before we get into the research you'd like to share with us today, I wonder if I could start by asking you to tell me about your particular research interests day to day. What are the conditions you study in the most depth?
Stephanie - So my specialty overall is brain imaging, but in particular MRI. We look at Alzheimer's disease, we have an avenue of research also to look at the behavioural difficulties in Prader-Willi syndrome, and there's also an avenue of research into appetite and obesity as well. So it's really a broad church, brought under the umbrella of brain imaging.
James - MRIs, brain scans - psychiatry is different from other branches of medicine, isn't it, in that diagnosis is made more difficult by the fact there are often no or very few independent markers to help with that process. We can't always run a test or do a brain scan to categorically say that our opinion of your condition is validated. Is that a fair assessment?
Stephanie - Yes, that's very true. So the difficulty that we have is that the brain is very complicated and brains differ between people and differ in various different disorders. Brain imaging has taken us a long way forward in understanding what can change in the brain in certain mood disorders and a whole range of things. MRI is a broad field, there's lots of different techniques. You can look at brain structure, brain function, the metabolites in the brain, and we can look at these in a variety of different ways, and that's what makes it such a interesting field to try and drive forward.
James - Very well put. Let's move on to the study you're bringing to the table today. It was conducted at the Brigham and Women's Hospital in Boston in America, published in Nature Mental Health. If you can, Stephanie, could you start by summing it up for us in a sentence?
Stephanie - So the researchers have analysed data from 144 studies across different forms of brain imaging and substance abuse disorders and they've found a common brain network that's linked to addiction.
James - Okay. So we're talking about addiction, substance use disorder. We probably better start by outlining from the scientific standpoint what we know about it as a condition.
Stephanie - So we know that addiction is a condition that involves compulsive seeking and taking of a substance or performing an activity despite negative or harmful consequences. And it can really impact on health, relationships, and overall quality of life. But addiction doesn't happen from having a lack of willpower or as a result of making bad decisions. We know that the brain chemistry changes. This research is specifically focused on substance use disorder, as we mentioned, and that includes addiction to alcohol, nicotine, heroin, and cocaine. So these substances are all very different from each other, but they all strongly activate the reward centre of the brain and produce feelings of pleasure. Substances also send massive surges of dopamine through your brain too. So instead of motivating you to do the things that you need to do to survive, such as eating, working, and spending time with loved ones, massive dopamine levels can have really damaging effects on your thoughts and feelings and behaviours as well.
James - This study's looking more into the particular brain patterns that people with addiction share, and I suppose therefore what we can do to help them.
Stephanie - Yes, that's right. So when we look at a brain scan or a number of brain scans like this, we can look at brain function. And what this paper has been really quite groundbreaking in identifying is this common network between people who have different substance abuse disorders. And that gives us the opportunity to 1) understand more about addiction, and 2) potentially target treatments to it.
James - And what would those treatments look like?
Stephanie - So one of the things that have been put forward by these researchers is the potential for neurostimulation therapies. Neurostimulation is basically the purposeful modulation of the nervous systems' activity using invasive or non-invasive means. So examples of these brain stimulation devices can include vagus nerve stimulation or deep brain stimulation, which you might have heard of.
James - It's a way of encouraging the brain to form new pathways and to rectify, I suppose, the changes that have caused this harmful behaviour?
Stephanie - Yes, potentially. So essentially it might be seen as rewiring or encouraging rewiring of the brain that might rectify some of this behaviour. And they are seen to be effective in treating some cases of epilepsy, neuropathic pain and other medical problems, but there is still really ongoing investigation into using neurostimulation to treat a wide range of disorders. Results are appearing very promising, but there's still much more research to be done in this field.
James - But the thinking is, through this research, narrowing down the brain networks we think are correlated with substance use disorder, we can improve the efficacy of these treatments perhaps?
Stephanie - Yes. So this paper specifically looked at functional connectivity, which is essentially coupling of brain regions in their activity. So instead of focusing on an isolated brain region, this takes a fuller view of the brain and considers how the brain acts essentially as a series of networks and interconnected circuits. There is a lot of variation in the literature about identification of these networks, but this common network tells us more about how the brain functions during addiction and may provide a target for neurostimulation.
James - The phrase that's coming to mind is correlation not being causation here, and that's kind of where we're at.
Stephanie - That's very key, yes. Correlation does not equal causation, and this is one of the challenges in this kind of research. It's very difficult to establish causation. So, as I say, we would need to look further into this common network to see if it really is a cause or an effect of substance use disorder.
James - Interesting stuff. Let's hope neurostimulation develops as we hope it will. Thank you for that, Stephanie.
08:41 - Suppressing negative thoughts may improve mental health
Suppressing negative thoughts may improve mental health
Also this month, a paper detailing that our mental health might in fact be improved by suppressing negative thoughts...
James - Time now to introduce our second neuro news guest. Francis Madden is a trainee clinical psychologist, currently learning his trade at the University of Oxford. How are you doing today, Francis?
Francis - I'm very good, thank you. How are you?
James - I'm very well. You're going to be telling us about an interesting emerging theory on how we might stay on top of our mental health, but as you're going to be dropping into Naked Neuroscience as a regular guest, we hope, let's help our listeners get to know you a little bit better. I mentioned you are going to be sharing your insights with us as you continue studying towards your goal of becoming a fully fledged clinical psychologist. What is one of those, what do they do, and what made you want to be one?
Francis - So a clinical psychologist is a very varied role. So first and foremost, it involves being a therapist, giving psychotherapy to clients of all different ages and psychological difficulties. And for that we primarily use cognitive behavioural therapy or CBT.
James - Just so we are clear, what kind of conditions might people have that you are trying to help them deal with?
Francis - All sorts. So I've worked in training so far in anxiety, which could be general or specific. It could be about social situations, it could be about specific phobias, fear of spiders being classic, but also if you have panic attacks on a regular occasion. Depression, obsessive compulsive disorder, OCD, I could go on. But essentially a very wide range of different presentations. And then beyond a therapeutic role, a clinical psychologist will also work as a scientist practitioner, contributing to new research that's developing.
James - We're talking in a month where we've had World Mental Health Day. In a sentence, could you boil down the research you've chosen to bring to the table?
Francis - So this study is from the Cognition and Brain Sciences Unit at Cambridge University, and it found that the mental health of its participants was improved by training people to suppress their unwanted thoughts.
James - So right off the bat, this seems to contradict a lot of what I thought I knew about mental health. Perhaps we start there with the perceived wisdom on this topic. You'll often hear mental health campaigners or medical professionals urging us to get our worries, our anxieties out in the open, to talk about them, whether it be with our families or our friends or health professionals. What's the reasoning behind that messaging? Getting us not to shy away from negative thoughts, but to confront them?
Francis - I wonder if I could ask you to do something for me now, James, and also the people listening. I wonder if we could just take 10 seconds to think about anything that you like, and I want you to think about anything at all, I just want you to not think about a white bear.
James - It's not going so well.
Francis - Yeah. How are you finding it?
James - Very difficult.
Francis - So this is what Daniel Wegner and his colleagues found in a paper from 1987. They found that people who had to suppress the thought of a white bear ended up thinking about it more often than people who were asked to express the thought of a white bear whenever it crossed their mind. And this is because when we try to suppress a thought, our mind ends up monitoring whether we are thinking about it, which ironically can make it more likely to happen, so this theory goes. And the white bear is obviously a trivial example, but this idea applies to anxious thoughts or depressive thoughts and so on. But there's been evidence since the late eighties about this sort of idea of thought suppression, ironically, leading to the exact thing that it tries to avoid.
James - You've made me think about, at primary school, 'the game,' the rules of that particular game being if you think about 'the game', you lose.
Francis - I didn't want to ruin that for everyone.
James - We get onto this new study, reversing this perceived wisdom in a way. My first question related to it though is how can someone even be trained in the first place to suppress negative thoughts at all? Like you explained, ask me not to think of a white bear and that's the last thing that I'm able to do.
Francis - So what they asked the participants to do was to think of fears that were personal to them, things that might happen within the next couple of years. So this was done during the height of the Covid 19 pandemic, so one of the fears that people generated was that they would get Covid or their parents would get Covid. They were asked to take this fear and then think of a cue word that might cue in that fear. So, for example, with Covid, the cue word might be 'hospital.' And then, later on, in the training phase of the study, the participants were shown their cue words that they created. They might be shown the word 'hospital', and when they were shown the word hospital, they were made to recognise the event to which that referred. But, after that, they were asked to just immediately stop any future imagination of the event, try to block it and keep it out of mind. Not even to replace that with the thought of something else. It was actually just being asked to keep the mind blank, which is obviously quite a challenge.
James - What were the results?
Francis - 120 participants across 16 different countries went under three days of this training, and each day they tried to suppress the thoughts of their fears 12 times, 36 repetitions in total. And what this led to, there was no ironic increase in the amount of times that this fear occurred. So they asked the participants whether they could remember the suppressed fear, how clearly or strongly they felt about them, and then how they felt in general as well. And they also asked them again three months after the training phase took place. And essentially the participants who were asked to suppress their negative thoughts actually ended up better off than the participants who weren't asked to suppress their negative thoughts on these indexes of memory and emotions and sort of mental health in general.
James - Interesting. How does this square with the training that people like you go through when they're studying to become clinical psychologists? Is this something of a watershed moment for our understanding of how to better our mental health? Do we have to start thinking about psychotherapy in different ways now?
Francis - I was definitely surprised to see these findings given that my training has almost entirely given me the opposite impression. When I deliver cognitive behavioural therapy, for example, I'm asking clients to put their thoughts on the table and then we're going to examine the evidence for them and against them. But I think in terms of a watershed moment, often in psychology especially, the literature ends up being quite messy. And I think the conclusion I draw from this is that, as we hear a lot as trainee clinical psychologists, different therapeutic approaches work for different people. And even within the same person, different approaches might work at different times. So while in cognitive behavioural therapy, traditionally, we might ask someone to challenge and confront their negative thoughts. There might be a time where that is too difficult, for example, in PTSD, post-traumatic stress disorder, that's a real challenge to ask someone to bring up their thoughts about a traumatic event from their lives. And so thought suppression might form a kind of strategy. I don't want to speak to give any clinical advice to anyone from this podcast, but I think, speaking hypothetically, something like thought suppression as described in this study could be used as a kind of technique maybe for when someone doesn't feel ready to get those thoughts out onto the table, just a way to manage it day-to-day that doesn't require that incredible bravery and vulnerability of going to therapy and doing the detailed in-depth thought challenging. So I wonder whether this can sit alongside the literature that does exist about challenging thoughts and what we'd call cognitive restructuring. So I think it's really exciting to see such a different, distinct finding to what I've been accustomed to.
James - Spoken like a true professional. Thank you so much for your insights, Francis. That was really helpful.
Francis - Thank you.
17:42 - The indigenous tribe helping scientists study singing
The indigenous tribe helping scientists study singing
Malinda McPherson, UC San Diego
We’re thinking about the variety of ways our brains interpret and respond to music. To start us off, we need to know what the term music actually describes, something that proves more difficult than you might have assumed. To help, James Tytko caught up with Malinda McPherson of the University of California, San Diego, while she was paying Cambridge a visit...
James - We're here at Churchill College, and I'm delighted to be joined by Malinda McPherson who studies auditory cognition. So you're a scientist, Malinda, but you came at this discipline from a background in music. Can you tell me a bit about that?
Malinda - Thank you so much for having me. I started playing piano when I was around six years old and, when I was eight, I picked up the violin and the viola. And my entire life since then I have been a musician; I still play regularly. I think it inspired me, when I was starting out in university, to have this broader interest in just how we hear and how we make sense of the sonic world around us. And so while I don't play professionally (I just play for fun, now) it definitely does inspire some of my scientific questions and keeps me in wonder at how we actually can hear this complicated world around us.
James - We're gathered here to talk broadly about the mind and music and how the two relate. Physiologically, people might be aware that sound travels in waves, it hits our ears, vibrates through the various anatomy in there, reaches our brains. But what I'm interested in for this conversation is how our brain interprets certain sounds as musical. What can you tell me about that?
Malinda - That's really where the most interesting questions lie: how our brains make sense of this pretty chaotic world around us most of the time. And one of the really interesting things about music is we often feel like we know it when we hear it. There has been some recent neuroscientific evidence suggesting that there are actually separate neural pathways in our brain that process sounds like speech and sounds like music, but when we try to define music, we actually run into some really interesting problems. Most definitions of music are along the lines of 'organised sound' or 'sound organised in time.' If you think about that definition just a little bit harder, that can describe speech, it can describe almost any other sort of sound that's made by humans. Even tapping your fingers on a table: that's organised sound, but would we consider that music? Maybe not. There's some really beautiful auditory illusions that can also demonstrate that we can hear the same exact sound and in some cases perceive it as speech and in other cases perceive it as music.
James - You mentioned an illusion and it strikes me as one I might like to demonstrate on our audience. Can you explain how it works?
Malinda - So this illusion is called the speech to song illusion, and it was discovered by Diana Deutsch who's a professor emerita at UC San Diego in the US and what actually happened, the story behind this, which she tells quite delightfully in some places, is she was actually recording some audio for a book and she had it on loop. She walked away to the kitchen to grab some tea and all of a sudden she started hearing somebody singing, and it was her own audio. What happens is, if you listen to this sentence that she says multiple times, eventually it starts to sound like she's singing. What's amazing is that the first time you hear it, it sounds like she's speaking, and then at some point after repetitions, almost everybody, it doesn't work on absolutely everybody but it works on many people, a couple repetitions in, 5, 10 repetitions, you start to hear her as singing.
Diana - The sounds as they appear to you are not only different from those that are really present, but they sometimes behave so strangely as to seem quite impossible. But they sometimes behave so strangely. They sometimes behave so strangely. Sometimes behave so strangely. Sometimes behave so strangely. Sometimes behave so strangely. Sometimes behave so strangely…
Malinda - And then if you listen to the full sentence back, it'll sound like she's speaking. And halfway through the sentence, she just breaks out into song as she reaches this passage that you've heard on repeat.
Diana - The sounds as they appear to you are not only different from those that are really present, but they sometimes behave so strangely as to seem quite impossible.
Malinda - And so it's a beautiful example of the fact that even the exact same sound wave, the exact same sound, hitting your ear and hitting your brain, will sound like speech in one context and music in another. And it really beautifully demonstrates that music is in the ear of the beholder. The amazing thing about this illusion is, once you hear it, you will never unhear it. Anytime you hear this sentence again, you'll hear her singing.
James - That was my question. Once I listen to this, are my ears contaminated forever? Or perhaps after a span of time I would go back to hearing the speech?
Malinda - I'll tell you, I think I first heard this illusion about 10 years ago and every time I hear the sentence it sounds like she's bursting into song. So I wouldn't call it a contamination, I'd call this a pretty good illusion..
James - Fair enough. It's interesting you mention that it is such a universal and fundamental part of being human. Why is that? What is the evolutionary function of music?
Malinda - You know, this is an area of active debate in the field and it's an area of active study as well. There are many theories for why we have music. Because we find it in every culture, it does seem like it's something that has had evolutionary pressures on it, that it's an evolved part of human behaviour. Most of the theories revolve around the idea that it's used for social cohesion. Think about if you're in a crowded room and everyone is speaking at the same time: speech loses its meaning if everyone's talking over each other. You have to have this conversation back and forth when you're speaking. Music on the other hand often gains by the participation of more people. You can have a group all doing the same thing together in a coordinated fashion in music, and you can't really do that in the same way in speech. So many of the theories about why we have music and why it's so important and why it's found in every culture have to do with the fact that it seems to have this social function. So whether it's the function of a mother communicating with their baby and trying to sing a song to get them to feel a certain way, or if you're at a social function like a wedding or a funeral or these sort of key moments in our lives, there's always music that brings us together. And that seems to be maybe not fully universal, but pretty close to a universal function of music. So we can think of it in this sort of functional capacity.
James - You're someone who's obviously deeply appreciative of the western classical music tradition. Would a different human race have developed a musical tradition that sounds just so utterly removed from what we've come to appreciate as music today?
Malinda - So anyone who's listened to music from around the world just knows how strikingly different music sounds depending on where it's from. But the amazing thing is that there actually are some seeming universals. There is some structure in music around the world that seems to be shared. I actually study musical harmony, and I do a little bit of work cross-culturally examining how harmony is perceived. And we find that there actually is a little bit of similarity in music and music perception around the world. People do seem to perceive musical intervals in similar ways and people do seem to default to musical ratios. So the ratios between intervals are low integers. In our music we'll have an octave relationship and that's a one to two integer ratio and frequency, or a perfect fifth. So that's the beginning of the melody, twinkle, twinkle little star. That's a two to three integer ratio. And that actually relates to the structure of many natural sounds we hear. Those integer ratios are actually found within the structure of my voice as I speak. And so it does seem that there are these potential universals of perception and perceptual biases that all humans will share. And it seems like that can bias the production and music around the world to make music not similar necessarily, but built on some of the same building blocks because we're all biased in the same ways because we all have the same auditory systems, we all have the same types of brains to process that sound and that leads many musical systems around the world to actually have the same sorts of biases and structure, even though that can then end up sounding quite different and people can have very different preferences for music.
James - And that was the subject of your research recently in Bolivia to try and drill down into those universal qualities. What was that like? What did you learn?
Malinda - So I've been working in Bolivia for the past about five years. I worked with an indigenous population called The Tsimane' who live in a rural area of the Amazon. They are a really wonderful group to work with for many reasons, but one of the reasons that makes them so fascinating to us from a musical perception perspective is that, as far as we can tell, they don't have group musical performance. So I've talked about music as this social cohesion, the possibility that that's why we have it, but for them music is more individual. People sing alone, they don't necessarily sing in groups. People won't just sing by themselves off lonely, they will sing in front of other people, but they don't have what we would consider musical harmony as part of their music. And so we've been looking at the phenomenon of musical harmony, specifically consonance and dissonance, where in Western music we have these intervals that sound really pleasant. And then other intervals that sound unpleasant or dissonant, we can just measure preferences in people, anyone off the street in the UK and the US where I've done work, and they'll show this preference. But if we test Tsimane' with the same type of experiment and ask them whether they like these consonate versus dissonant intervals, they don't show a preference. They don't prefer one to the other. But we've done some experiments to suggest they do hear the difference. They know that these two types of intervals are different and, mathematically, consonate intervals are related by lower integer ratios compared to dissonant intervals, but it seems like they have the same perceptual system that we do as you would expect, they hear these sounds in the same way, but their musical culture is different. And so they don't have the aesthetic connotations that we have from listening to the music that we've listened to.
James - Thank you to Malinda McPherson from the University of California San Diego for sharing that illusion along with the rest of her insights.
29:00 - Emerging tech creates music from dance movements
Emerging tech creates music from dance movements
Alexander Jensenius, University of Oslo
For the second part of this month’s exploration of music and the brain, James Tytko spoke with Alexander Jensenius from the University of Oslo’s Department of Musicology…
James - Thank you so much for joining me, Alexander. We're exploring music in this episode of Naked Neuroscience, looking at some of the emerging technologies being developed to compose songs. We're going to talk about how this relates to your work a bit later. Specifically, you use motion capture technology, as I understand, to help compose music, a really interesting idea. But first, I think before we get there, we have to start by talking about dance, something we haven't talked about thus far in the podcast. When we were speaking earlier about music, we spoke about its evolutionary function in social cohesion. Is it right to look at dance as an extension of that social function?
Alexander - Absolutely, I would say so. So dance has a social function in terms of social bonding and relating to other people, and it's also highly connected to music. In many cultures, you wouldn't even be able to separate music and dance. In Norway where I live, in most folk music and dance, you would see that it's quite difficult to dance without the music. But also I think if you ask the musicians, a fiddler for example, to play without people dancing, it would be very difficult for them because it's really about the interaction between the musician and the dancers as they go.
James - Interesting. So there's a kind of two-way relationship between music and dance, and you've been cultivating some pretty interesting tools to help you learn more about their relationship, haven't you?
Alexander -Well, it started out for me when I was doing my PhD, I was interested in trying to understand more about how people move to music in different ways, including dancing, and I tried to understand more about music through the body. And that eventually turned into using different types of motion capture methods, including those type of full body motion capture systems that you can put on the body that you use for making animation movies, but also all the types of video analysis and sensor-based systems. So when you have these types of systems, you get a lot of data. And then when you have lots of data coming in, in real time, you can also turn that back again into sound and music. So in a sense, I went from an analytic approach to understanding more about dance and movement to actually creating music through movement.
James - Kind of reversing the prevailing direction of travel from dance to music rather than the other way round. I'm not a professional dancer myself, but I imagine they start with the music and think how they might interpret that into a dance. You've flipped that on its head using body movements as the instrument for composition. How would you characterise it apart from the way it's composed? What makes it different to music produced with more traditional instruments? What does it sound like?
Alexander - Most of these examples are made with computers. So you will get more synthetic sounds and more synthesiser types of sounds, electronic sounds. And we've even tested this with our set of self playing acoustic guitars, which is a collection of physical guitars that resonate and so we can actually set the guitar bodies in motion using human bodies as the starting point.
James - And other than just being an interesting new method of expression, could this have applications for people who, for whatever reason, don't learn to play an instrument or don't feel like they can sing to make music of their own?
Alexander - Absolutely. So one of the ideas I have I think is interesting is to exactly explore how you can make people become more actively engaged with musicing, making music of various kinds, even though they haven't played the piano or the violin for tens of years, they can still create some kind of music on the fly using their own bodies.