#152 - The Brain on Music

0:02Matt Walker: Hi there, it's Matt here and welcome back to the podcast. Today, I'm going to take us beyond the edges of the sleeping brain. Let's talk about what the awake brain does everywhere in the world without ever being invited. I'll begin by showing you an object. It is a piece of bone. It's the hollow wing bone of a griffin vulture, a little longer than your hand. Someone has drilled five small holes along one edge. It was discovered in the floor of a cave in southern Germany, under tens of thousands of years of dirt and debris. It's a flute, a proper musical instrument. It was radiocarbon dated to 35 ,000 years ago, or perhaps earlier.

0:47Matt Walker: The full archaeological timeline of the cave layers puts the earliest music making in that part of the world at roughly 40 ,000 years ago. This bone flute is older than agriculture and older than the wheel. So here's the question I want to consider tonight, and it's a deceptively simple one. What is music for? Every activity that takes time, every expenditure of energy needs to cover its costs, and anything that can't is jettisoned. But music, a costly, time-consuming, seemingly pointless activity, has made the cut for 40 ,000 years across all human groups. Tonight, I'd like to explore what it might be covering.

1:30Matt Walker: First, let's think about the extent of the data. Make a list of 315 different human cultures and look through the literature for evidence of music. You won't find a single culture that doesn't make music. A song that serves the same function, A lullaby, a dance song, a healing song, a courtship song will tend to have the same characteristics in many different cultures. A lullaby sounds like a lullaby almost anywhere on the planet. Within any given culture, there's more musical diversity than between cultures. No matter where humans travel, music goes with them, wearing the same clothes. It appears to be a hardwired capacity.

2:15Matt Walker: If you play lullabies to infants from cultures they have never heard of, from different languages, different tonalities, their heart rate drops, their eyes relax, their sweat decreases, more than when they hear other songs from other cultures. They can hardly have learned this. Even in the first year of life, the ability is present. So why evolution built all this, and here's where it gets interesting, is a matter of intense debate. Two competing groups released opposing manifestos a few years ago in the same issue of the same academic journal, which is the closest thing there is in academia to a fistfight.

2:56Matt Walker: The first group says music evolved as a kind of social glue, a bonding technology that helped humans form groups too large to be maintained by mere grooming and individual friendships. The second group say it started out as a credible signal, an honest advertisement to enemies of how unified a group was, or to an infant of a parent's undivided attention. Hold both ideas in your mind. The next bit is true for both of them. But there is one thing on which both camps agree. Music's natural environment is not headphones. For most of those 40 ,000 years, music was mostly something done by groups. And when you look at what groups doing music together do to them, the effects are not vague and woo-woo.

3:44Matt Walker: They're measurable. Take the experiments on silent discos. Get a bunch of strangers to learn some dance moves and give them headphones. Then change one variable, whether they move in time with each other, move in sync, and people's pain thresholds go up. This being the telltale sign that the body has produced endorphins, its own homemade opiates, and they report feeling closer to their fellow dancers. Fail to move in sync and the pain-killing effect doesn't happen. Physical exertion does help, but specifically moving together in time has its own unique power. And singing does much the same thing, but very quickly.

4:24Matt Walker: Watch the development of groups of newly formed adults doing an education class over seven months, comparing singing classes to craft and creative writing classes. and what you find is the singers bonding much faster and getting closer. It's like an icebreaker and it works on scale. Check the closeness of members of choirs when they sing in their small groups locally and then check again when they join a big 232-person choir for a joint rehearsal. In both cases, the session increases pain thresholds and feelings of closeness. You can see it happening even when people are doing nothing more than sitting in an audience.

5:08Matt Walker: Hook people up to electrodes while they sit at live classical concerts and record heart rate, breathing, and the sweat response of the skin. And as the music plays, these individual bodily rhythms begin to synchronize in the room. And the greater the synchronization, the more people report being moved and absorbed by the piece. Multiple experiments with live music have confirmed this. That feeling you get at a gig that the whole room has become one body, you can measure it. And so we come inevitably to the war drum. And if moving in time makes us more unified, then coordinated music is a kind of public statement of our unity.

5:48Matt Walker: An audible reference check. a crowd that can drum, sing, and move together as one is performing a costly, credible signal of its coordination. Knock the players in a recording 60 milliseconds out of step with each other. And not only does the music receive lower ratings, people's ratings of the music move together with their ratings of the group making the music, not in lockstep, but a solid, consistent correlation. It is not only the crowd that is impressed. Marching in time changes the marches. Tell men to walk in sync with a partner and then ask them to evaluate a supposed criminal and they see him as smaller.

6:32Matt Walker: Men who have been walking in sync think he is less of a physical threat than men who have not. Synchronized groups cooperate more in economic games even when cooperation hurts the individual, and you need not make the group particularly happy for the effect to occur. All the armies in history that have marched to the beat of a drum, all the battle cries before they clashed, those were experiments in neuroscience done thousands of years before any lab existed. But none of this would work unless music also felt good, and the pleasure element is written in remarkably hard chemistry. Start with the chills, the tingling sensation you get with a single chord.

7:17Matt Walker: Study the literature and chills turn out to be a very real event in the nervous system. Most people get them sometimes, in some studies more than 8 in 10, though the precise number depends on how you measure it. With the chills, the skin conducts electricity more strongly, the breathing deepens, and the heart rate shifts. Where is this pleasure coming from? Inside your brain, there is an ancient mechanism, the reward system, a vault set aside by evolution to disperse when we obtain vital things like food, warmth, or sex. Somehow, an entirely abstract pattern of vibrating air has secured a key to this vault.

7:57Matt Walker: Scan subjects with the piece of music that reliably triggers their chills. And as the chills intensify, blood flow increases precisely in that vault. In the ventral striatum, the midbrain, the orbitofrontal cortex, while activity in the amygdala actually drops. The same circuitry that fires for food, for sex, for drugs. The money being handed out is dopamine. And with exquisite clarity, consider a drumroll and a cymbal crash, paying out from different registers. Just before your favorite passage, as the tension mounts, the dopamine comes from one register, the chordate, the brain's wait and see machine.

8:39Matt Walker: On the top, the money changes hands to the nucleus accumbens, the machinery of reward. Both the wanting and the getting are anatomically separate, but they run to music. And better yet, this is causal. Take 27 healthy people. At one session, give them a drug that increases dopamine availability. At another, a drug that decreases it. And at a third, a placebo. Same people, same music. As the dopamine rises, so does the pleasure. As the dopamine falls, the pleasure wanes and the chills diminish. Turn the dial and the joy turns with it. The mechanism is caught in the act. Nature has been doing the opposite experiment too.

9:23Matt Walker: A tiny minority of perfectly well-adjusted people have a thing called specific musical anhedonia. Perfect hearing, perfect sense of melody. Perfect pleasure from money, the reward the researchers tested against. But music does nothing. No chills, no lump in the throat, no change in heart rate or skin conductance whatsoever. Scan them and the reward center lights up normally for a gambling task, but not for music. What goes with it is a weaker link between the auditory cortex and the reward system. The pleasure of music exists in the conversation between the part of the brain that hears and the part that wants.

10:07Longstanding partner of today's podcast is Element, spelled L-M-N-T. Element is a sugar-free electrolyte drink mix. And for me, it was the sugar-free part that made me start using it a while back. And again, I buy my own supply just to stay objective. Beyond having the electrolytes in the right balance, the other reason I'm a fan of Element is that it's scientific. If you look up the people who created the company, you'll find some pretty heavy-hitting physiology, biochemistry, and pharmacology knowledge baked into the product. And again, And all of that comes without any sugar. Now, here's the update.

10:48Element's lemonade salt flavor, which used to be seasonal, was so popular that it's now permanent. You can get it year round. Happily, I badgered them and they have agreed to give you, find folks a free eight count sample pack with any purchase of Element. If you use the link drinklmnt.com slash Matt Walker. So for free product with your purchase, just visit drinklmnt.com slash mattwalker. And as I said, you'll get some free product.

11:26Matt Walker: Now, if you're expecting me to point to the music center of the brain, you're in for a surprise. There isn't one. Music is not stored in one box. It is distributed across the whole organ, an unusual property that happens to be the most important one of all. Play people an actual musical piece in an FMRI machine and map the parts of the brain that respond to the key and the tempo. The response is ubiquitous. The auditory cortex lights up, of course, but also the motor regions, the cerebellum, and the limbic system. A survey of the entire fMRI literature reveals the same players, the amygdala, the hippocampus, the reward circuitry, the neuroendocrine hubs.

12:11Matt Walker: It's even stranger in the case of EEG recordings. Put a person in front of a computer with an array of electrodes on his head while he listens to a beat, and you can see his brainwaves resonating at the very same frequency, the physical manifestation of musical rhythm in the rhythm of the neurons themselves. Now ask them only to imagine that beat as a march, one, two, or a waltz, one, two, three. A fresh electrical spike emerges at the rate of the imagined rhythm, a rhythm that's not present in the sound at all, but only in their mind, and you can measure it on the scalp. Magnetic recordings go even further.

12:55Matt Walker: Musicians' brains track the music more precisely than non-musicians. And among ordinary listeners, the more precisely the brain tracks it, the better they do at subtle listening tasks. What makes the groove feel so good leads to the leading modern account of musical pleasure. Music is a game the brain plays with its own expectations. Think of a great song as like a great joke. You know where the setup is heading. You aren't quite sure about the punchline. Train a computer model on 80 ,000 chords from a generation of pop hits until it understands the predictability of every musical event. Then play those songs for people.

13:38Matt Walker: Pleasure peaks when expectations are sharply and confidently broken and when uncertainty is sweetly resolved. Our emotional and auditory systems move together in the dance of expectation and surprise. This prompts the question you're probably already yelling. Does the brain have an opinion on the genre? The answer has two parts. Part one, yes, there is enough difference between genres in the cortex that pattern recognition algorithms can accurately identify the genre being listened to using only brain data, significantly above chance. Two separate FMRI studies were able to do this, and the genres the computer mixed up.

14:21Matt Walker: Ambient with symphonic, country with rock and roll were largely the same ones humans mixed up. Part two, and this is my favorite part, when you scan people listening to music that ranges from Beethoven to Eminem, the key brain networks don't group by genre, they group by whether you like the music. The music that you like most, regardless of genre, activates the brain's default mode network, an introspective, self-reflective system. Your favorite song changes the communication between the auditory cortex and the hippocampus, the brain's memory center. The brain doesn't store music by genre. It stores it by taste.

15:03Matt Walker: And this, inevitably, brings us to Mozart. Some 30 years ago, an article in one of the world's top science journals claimed that college students had slightly higher scores on a test of spatial reasoning after listening to a Mozart sonata for 10 minutes, an effect that faded within about 15 minutes. This is the whole claim. Out of this tiny seed sprouted a cottage industry. Mozart for babies, Mozart for exams, Mozart no doubt for the family dog. However, when we examine the claim closely, it simply doesn't hold up. Take together around 40 studies involving more than 3 ,000 subjects, and the effect size is small even when you compare Mozart to silence, shrinks to almost nothing when you compare Mozart to any other music, and shrinks further when you take into account the fact that many of the studies failed to find any effect, so they didn't get published.

16:01Matt Walker: Now, the giveaway, the labs connected to the first author kept finding effect sizes three times larger than anyone else in the world. But it was never Mozart truly. It was feeling nice and refreshed. Even the clinical version of the myth, using Mozart to calm the epileptic brain, falls apart in modern analyses as too few small-scale studies. But let me give you the real trade-off, because the truth is that music does something to the brain. Listening won't improve you. Playing will, however. Musicians have been shown to have significantly more gray matter than non-musicians. In motor, auditory, and spatial areas of the brain, with non-professional musicians in between.

16:44Matt Walker: A classic dose-response relationship, although these data cannot rule out that musicians have brains that want to be musicians. A better study took 144 six-year-olds and randomly assigned them to a year of either singing or keyboard instruction versus drama lessons versus no lessons. Those who learned music had a modest increase in IQ across different subtests. And, to my great delight, the drama students did better at social skills than the others. Small effects, but true effects. And now I return to the point I made above. Music exists in multiple parts of the brain, auditory, motor, memory, and emotional.

17:27Matt Walker: This distributional nature has a very important implication. As the brain begins to break down, as region by region fails, music always has somewhere to live. Take Parkinson's disease, which affects, among other things, the brain's deep system that times each step you take without you even having to think about it. Your steps become shorter, you can get stuck in place, you can even freeze in place. However, the auditory and motor systems are closely linked. If you hear a beat, your motor systems activate even if you're lying still, and this link provides an escape hatch. If you provide a person with Parkinson's with an outside beat with a tempo that matches their gait speed, then the borrowed clock can stand in for the broken one.

18:14Matt Walker: Across the studies, walking ability tends to improve. In the classic three-week program, the patients increase their walking speed by around 25%, their stride length by 12%, their cadence by 10%. Not all patients are responsive. A beat is a walking aid rather than a treatment of the condition. But the rhythm works by reaching a motor system that has its front door broken by coming in through the ears. Then there's the stroke. Some people who lose fluent speech after a stroke, who can't even speak a sentence, can still sing it all the way through. Melody and rhythm go down somewhat different neural paths than everyday language does.

18:58Matt Walker: And therapists have figured out how to lay language onto those pathways. The therapist teaches the patient to semi-sing their sentences and eventually fades the melody away. evaluated fairly in its trials the method yields significant improvements in daily communication and in speech repetition no clear effect on word finding and no improvement in comprehension and the trials themselves are small a larger more skeptical analysis finds that most of the measured gain comes on repetition tasks and doubts how far it carries into everyday conversation It's a moderate intervention, but for someone who is shut out of their own language, a moderate intervention composed of music is anything but trivial.

19:45Matt Walker: And then there's Alzheimer's. Maybe you've seen videos or experienced it firsthand. A person is in late-stage dementia until a song from their earlier years starts playing and they come back. Their eyes open, they move their lips, and can pronounce each word correctly and in the right order. Picture Alzheimer's as a slow-moving fire going through a building, and the question becomes, where in this building are the songs stored? Pinpoint where the memory for well-known music resides in a healthy brain, and it turns out to be in two particular areas on the midline of the brain. Map those two areas onto the maps of Alzheimer's, the reduced glucose metabolism, the cortical thinning, and those areas are among the last and most spared areas in the whole cortex.

20:36Matt Walker: The plaques do reach them, but the damage that follows the plaques arrives late. Basically, the shelf that stores the songs ends up on the other side of the fire. The reality is a dissociation, and I'd argue that it's more interesting than the myth. Musical memory isn't airtight in Alzheimer's. A musician's hands can remarkably preserve their skill even late into the illness. But musical recognition tends to decline in groups overall. And yet there are individual cases of severe Alzheimer's that retain musical recognition remarkably intact. As for the moments of clarity, those also have data behind them.

21:18Matt Walker: Familiar music is a remarkably strong memory cue. In the healthy brain, there's a spot at the front of the midline that handles self-representation, and its response is directly proportional to the strength with which the song has been woven into your personal narrative. This explains how a mere three bars of the perfect song can conjure up a whole summer, complete with its own weather. And in people with Alzheimer's, memories recalled via music as opposed to silence come faster, more precisely, more emotionally, and require less mental effort. The music does the remembering that the brain cannot.

21:59Matt Walker: The families claim the song brings something back, and the small studies we have point the same way. To avoid overstating what is achievable, I must mention limitations. Take all the proper randomized controlled trials of music therapy in dementia care, assess them according to medicine's most rigorous standards, and what emerges is this. Musical sessions can probably ease depressive symptoms a little, may improve overall behavior, but show no clear benefit for agitation, aggression, anxiety, emotional well-being, or cognition. In other words, music in dementia care is a tool for caregiving, not treatment.

22:42Matt Walker: It does not slow the disease. What it does do is open windows on mood, on memory, on connectedness in a condition that tends to slam them shut. Here then is the toolkit. One, turn on the music as you turn on the machine. Pool 139 studies of music and physical activity. And the finding is clear. Physical exertion feels subjectively less difficult, mood improves, and objective performance increases modestly but reliably. The cheapest legal doping agent on the planet. Two, music for the worst parts of medical care. Combine 73 randomized trials in surgical patients. and the results show that pre-intra and post-operative music leads to lower pain scores, lower anxiety, reduced analgesic requirement, and higher patient satisfaction.

23:38Matt Walker: If you're about to undergo surgery, a pair of headphones might be a good thing to request. Three, music to signal the end of the day with reasonable expectations. pool 13 randomized trials involving 1 ,000 patients on the effect of listening to pre-recorded music for 25 to 60 minutes daily on quality of sleep, and you find a robust, moderate certainty improvement in how people perceive the quality of their own sleep. How effective this is for treating insomnia per se remains uncertain. Think of it as a sleep aid rather than treatment, And I'd argue a pleasant, safe, free treatment is better than no treatment at all.

24:22Matt Walker: Four, if you want to build community, don't sweat genre. There is no reliable hierarchy of genres ranked by sociality. What the evidence does tell us is that medium levels of syncopation, the quality that creates groove, are the most likely to trigger body movement. And moving together, as the silent disco demonstrated, is where the neurochemical magic happens. Furthermore, songs containing generous and pro-social lyrics were found to increase empathy and helping behavior. Genre is less important than groove, lyrics, and togetherness. Fifth, guard the gateway through which all of this passes. Research with young people across many studies finds that around a quarter of young people listen beyond safe levels via headphones alone, and almost half at loud venues.

25:15Matt Walker: Globally, an estimated 670 million to 1.35 billion young people are at risk of hearing damage. Lowering the volume is one of the smallest but most important gifts you can give your future self. Sixth, treat hearing as a part of brain health. The Lancet Commission on Dementia Prevention now lists hearing loss as one of the two biggest modifiable risk factors in midlife tied with high cholesterol, each accounting for some 7 % of the preventable proportion out of the 14 risk factors that together account for close to half the risk for dementia. Note that this is association and not necessarily causality, and that science should be transparent about its limits.

26:06Matt Walker: However, that same commission finds that the evidence for intervention, namely the use of hearing aids, continues to strengthen. Everything featured in this episode, the goosebumps, the choir, the song that transports a parent back, passes through the ears. It's worth protecting. One final thought, back to the vulture bone with the five holes in it. Someone sat in a cold cave tens of thousands of years ago and spent hours of precious firelight working this into a musical instrument. I hope you can now hear what this object really is. It is one of our oldest surviving examples of a social tool, an invention for connecting strangers, for calming bodies, for transferring emotion from one mind into another, so effective that it's become hardwired into infants and so embedded in our neural architecture that when illness destroys the house brick by brick, the music remains.

27:05Matt Walker: The music is so often left standing in the wreckage, keeping a door ajar. That flute was never a toy. It is a prototype for what we value most. Thank you so much for listening. I'm truly grateful you gave me your time and your attention. Take good care of yourself and enjoy every hour of your day, preferably with something brilliant going on in it. And may you sleep a deep, restorative sleep tonight. Bye for now.