How Your Thoughts Are Built & How You Can Shape Them | Dr. Jennifer Groh

What goes on in our brains when we think might be that we're running simulations related to the thought using that sensory sensory motor infrastructure of the brain. >> Could you elaborate? So the theory is that like maybe when you think about a cat for example or you think the concept of a cat that the mental instantiation of that or the the brain mechanism instantiation of having that thought is to run a little simulation and visual cortex that kind of includes what a cat looks like a simulation in auditory cortex that what does a cat sound like and as I'm telling you this I'm you know if you use the word cat um what color cat are you thinking I'm thinking of a a gray cat, but I keep smelling kitty litter cuz my sister had cats and it drove me. The smell of kitty litter is just so aversive to me. >> Right. And so so you had no hesitation in telling me the color and adding an additional sensory quality. It provides an explanation for why you might, you know, be driving on the freeway and having to merge into difficult traffic and telling your your passenger, "Okay, be quiet. I've got to I got to pay attention now." Like why would speech impair you from visual motor >> if it wasn't all part of a kind of cognitive system that's that's in operation? And maybe you need to shift some resources away from processing the conversation and toward some, you know, actually dealing with the here and now sensory motor task. >> Welcome to the Huberman Lab podcast where we discuss science and science-based [music] tools for everyday life. I'm Andrew Huberman and I'm a professor of neurobiology and opthalmology at Stanford School of Medicine. My guest today is Dr. Jennifer Gro. Dr. Jennifer Gro is a professor of psychology and neuroscience at Duke University. Her laboratory studies how our brain represents the world around us. In particular, how our different senses are merged in the brain so that we can focus and learn more effectively, including how our eye movements fundamentally shape not just what we pay attention to, but how they dynamically control what our brain is capable of. What she shares is fundamental to understanding how your brain works and also how best to focus on and learn different types of information. Not just information that you might read on a page, although including that, but also what you hear, what you remember, and the very thoughts you have about your life experiences. We also discuss thinking itself. In fact, we discuss what thoughts really are. And there, Dr. Gro shares with us what is perhaps the clearest and most useful definition of what thoughts are and how you can control them. As someone who has been in the field of neuroscience for nearly three decades, I must say that her explanation of what thinking is at the neural level, at the psychological level, and at the experiential level is the most compelling and useful one I've ever come across. Today, Dr. Gro explains how to use your experiences, the information you encounter, and knowledge of how thoughts are built up in the brain to become a better thinker and indeed smarter. I'm certain that the information you'll learn from Dr. Grow today is not like any other discussion you've heard about the brain or psychology. I'm also certain that it will be extremely useful for anyone wishing to better understand how the brain works, how their thoughts and emotions arise, and anyone who wants to get better at learning, thinking more deeply, or simply experiencing life with more richness. Before we begin, I'd like to emphasize that this podcast is separate from my teaching and research roles at Stanford. It is, however, part of my desire and effort to bring zero cost to consumer information about science and science related tools to the general public. In keeping with that theme, today's episode does include sponsors. And now for my discussion with Dr. Jennifer Grow. Dr. Jennifer Grow, welcome. >> Thank you. It's great to be here. >> We've never had a proper conversation on this podcast about sensory integration. We've talked about vision, talked a little bit about hearing, a little bit about touch, smell, taste, but we've never talked about how the senses come together. And that's critical to everyday life, critical to perception. >> Absolutely. I know you focused perhaps mainly on the auditory system, but you really are a auditory visual integration person. I know this because I've followed your work for a number of years. So where in the brain do our eyes and our our ears first come together to impact our perception of life? Like we you know the tea kettle is whistling or you know we hear a knock on the door. We know where the door is. We know where the tea kettle ought to be. But where do these things first collide? >> The story that is triggered by that question is a little bit long. So, uh maybe I can start at the beginning of when I first got interested in this question. And so, I was a college student. I was interested in neuroscience, but we didn't have a neuroscience um um major. So, um, a couple of us talked, uh, a professor into offering a a seminar in in neuroethology and and kind of like what he thought were sort of the coolest findings in neuroscience. Uh, and in that class, I learned about a uh, study showing that, and I'm going to I'm going to begin with the neuroscience nerdy lingo, and then we'll unpack it. um that uh there's a brain structure called the superior caliculus um that's responsive to both visual and auditory stimuli and that the responses to auditory stimula depended on where the eyes were looking. Um if you move the eyes the neurons receptive field, the region in space where they were responsive to would shift um as the eyes moved. And that blew my mind. I could not get that out of my head. Um, and it kind of set me on the track that that I've been on ever since then. >> One of the things that was really interesting to me about it is that figuring out where a sound is with respect to where the eyes are looking is something that would be easy for us to do with a pencil and paper. You know, it's very simple math. If you know that um the sound is located say uh you know 10 degrees to the right and your eyes are looking 10 degrees to the left and that tells you that the sound is 20° to the right of where your eyes are. Really not that hard to do. But from what I knew at that point um about how the brain represents this kind of spatial information, it seemed a big puzzle for how the brain might actually create these kind of moving representations of where the sound is located. >> Yeah. Because what you're talking about are dynamic maps. Like we have a I think most people probably appreciate that we have a a map of our body surface, the so-called homunculus. Y >> and so if one were to stimulate in a given region of the brain, you'd uh have the illusion of uh being touched at that location on the body. People perhaps have seen that um the more sensitive an area of the body like the fingertips or lips or face uh or feet, the larger the representation in the brain. But what you're talking about is is shifting maps depending on where the eyes move. And the eyes move quite a lot. >> They move quite a lot. Exactly. and and uh mostly we're not aware of this, >> right? But if you think about it, every time your eyes move, the visual scene is shifting massively on the retina, >> but we don't even notice this. >> Um, and this is an indication that the brain is doing a ton of computation under the hood to give us that perceptual experience because if we were just representing reality, the reality would be these massively shifting, smeared visual scenes. One thing that so intriguing to me about the auditory system is and the visual system is the extent to which they can contract and dilate so fast. >> So for instance, if I'm uh like walking to get on public transportation of some sort, like a light rail or a subway, um I'm walking, you know, there's sound going by me, may or may not be relevant, but at some point I sit down. Chances are I open up a book or a computer. These days, people go into their phone and we say into the phone because there's a lot of sensory information there, but that our visual world and our auditory world just goes into, you know, uh, a small box and we expect whatever we're looking at to relate to the sounds that we're hearing in that small box, right? >> But if somebody says, "Excuse me, do you have a ticket?" You, you know, to look up, >> right? >> We take this for granted. Like most people might think of course you look up like the sound is coming from over there it's now a person but we all of a sudden we can remap our visual auditory world and all the context in like milliseconds >> right >> so is that all happening um and we've been talking about superior caliculus the in this structure the superior caliculus below our neoortex meaning is it below our kind of conscious awareness >> you know gosh I wish we knew where conscious awareness was I think That's an open question. Um, and it, you know, the superior caliculus is important in this story because that's where the research began. It's not that that's where the binding of visual and auditory space, you know, is necessarily fully contained there and only there. I think it's a much bigger problem. And I think what you're describing is kind of um you know another version of this kind of um capturing of um or integrating or connecting the information from one sensory system to another. That kind of shifting your resources around is something that happens in in a few different contexts like what you're describing. And I think one of the things that's really interesting about the phone or really any screen where you're watching a video is that the sound was never coming directly from the screen where you're looking at the visual image. >> You know, it's coming from somewhere else. Maybe you've got earbuds in and it's coming from the earbuds. Maybe the earbud signal is simulating what the location should be um if it was really coming from the screen, but it's a simulation. It's not not actually reality. >> That's so interesting. So yeah, let's unpack this a bit. So we merge what we see with what we hear. Y >> if it makes sense to merge them like lips are moving. >> Lips are moving >> and that's in our hand about a foot in front of us >> but the sounds are coming in elsewhere, >> right? This is very different um than say like if somebody's mouth were moving and the sounds coming out of it were offset by even the tiniest bit of time. It looks weird. >> It looks totally weird. >> It looks totally weird like like this video. Yeah. Somebody somebody grabbed this like like ripped this video from the internet and there's a time delay, right? >> But we easily merge what we see with sounds. That's right. Maybe talk about this because I I now I'm realizing like if I sit and watch >> a movie >> Yeah. >> or movie theater or on a big screen or my computer, >> the sound is not coming from the screen. It's coming from a speaker which is like projecting vertically. >> Yes. >> How does that work? >> Well, not only that, but like the sound is jumping around in your perception as different people on the screen from different locations on the screen are are speaking, >> right? and they're both coming in through your ears or through the speak well >> whatever means the sound is being delivered to you is not changing as the different people are are speaking >> right so let's say a dialogue on a screen between two characters and then maybe there's an explosion in the background or another character walks in the room >> that the source of the sound for us whether it's computer or speakers in the room or movie theater or or earbuds >> is always constant but we can quickly move the sound with our eyes or our eyes moving the sound with our >> ears. Let me let me amend a little bit here because um you know it depends a lot on like how the sound is mixed. They can put in some spatial cues but if they haven't done that then it then what we just said applies. And I think one of some of my favorite videos for, you know, for really appreciating this is a are videos of actual ventriloquists working with their puppets because there they are, you know, the the puppeteer is speaking and they're making it seem like the puppet is speaking and they're making our perception switch back and forth from their own face to the puppet face, back and forth depending on what what they're actually saying. So this is a ventriloquist that says like hey Cornelius how are you and then Cornelius says but the same person says I'm doing great you know and they probably they probably move their lips a little less when they do that. >> Yeah they they try to speak like this without moving their lips too much. Um and they sometimes will do a trick of like there are certain sounds that you just cannot make without closing your lips uh in front and that's really >> hard to fool people about. So, for example, if it's a word that begins with a B or has a B in it, they might subtly just cover their mouth a little bit while they're making that B sound so that it's a kind of misdirection like a magician would do to sort of keep you from attending too much to to the ventriloquist and throw your attention over to the puppet. So, our perception can switch back and forth between where um our brains are telling us this is the most likely candidate for the source of this sound. So, I'm going to override what my ears are telling me to perceive the sound is coming from here versus here. >> Is this something we learn during development? Like, do kids come into the world understanding how to merge sight and sound or >> um or is that a learned phenomenon? It has to be learned and it has to be continuously updated during the course of development until you reach your adult body size. So, let me back up a little bit and talk about how do we localize sound, especially when we're not talking about, you know, screens and video and movies and what whatnot, but just like out there in the in the real world. The way we tell where a sound is coming from is by the physics of the world causing differential delays for the sound to arrive at one ear versus the other. So sound takes a certain amount of time. You know, a sound coming from over here will get to this ear before it gets to this ear. And it'll be slightly louder in this ear than in this one >> because it's just closer to that ear. >> It's closer, but also there's a a kind of acoustic shadow cast by the head. So the soundwave has to kind of come and then go around and there's a little, you know, there's a little sort of dip in the sound intensity cast by the shadow of the head. I like to think about the timing cues because they're really easy to calculate. So if you know how far apart your ears are and you know what the speed of sound is, then you can figure out what's the delay for the sound for sound to get um to reach this ear after this ear. I often take off my glasses to measure the distance between my two ears that way. And it's something like about a half a millisecond is the largest delay you can experience. >> Half a millisecond. >> So this is tiny. And that is for the difference between a sound here versus a sound here. >> So something from your right versus from your left. >> Exactly. we can obviously detect much smaller sound separations than just totally left versus totally right. So there's, you know, it's an incredible feat of computational power by the brain. I think maybe we should tell the audience um why, you know, your brow is f is furrowed and I'm excited about this because half a millisecond is less than the duration of a single action potential, >> right? And we should just remind people action potentials are the electrical signals that neurons use to communicate with one another. These are the the uh the fundamental um way in which our brain works. Without these, we're dead. >> It's the fundamental medium of communication um in the nervous system as you say. So, it would seem totally weird for us to be able to process sensory information that is faster than the duration of that minimum increment of of firing. You know, there's some research about how exactly this can be done and it involves things like lots of neurons firing together and really precise uh synapses that um cause minimal delay and very high temporal precision as the signals are going from one neuron to the next. 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That's wealthfront.com/huberman to get started. This is a paid testimonial of Wealthfront. Client experiences will vary. Wealthfront brokerage is not a bank. The base APY is as of November 7th, 2025 and is subject to change. For more information, please see the episode description. So, you know, if my finger snaps up with my right hand, which is what I just did, you know, intuitively I know that the it's my right hand because I did it. But my brain expects that sound to arrive more quickly to my right ear than my left ear, >> right? >> And yet for things directly in front of me, >> right at my nose, the idea that it's right in front of me, let's say with my eyes closed, I I know to look in front of me. I know to expect it in front of me once I open my eyes. Right. >> Are there conditions where we think we hear something from one location but it's actually arising from another location that's outside an experimental context? >> Absolutely. So if you have hearing loss in one ear >> uh and one ear only then um it it's very difficult to localize sound. >> It's not completely impossible. You would imagine that it would be completely impossible if the hearing loss was complete and if this timing difference and level difference were the only cues that we use. >> But actually the ear has these little folds in them and the folds filter the sound as it comes in. Uh and in particular it alters the frequency content of the sound >> really. So these little dimples inside my ears are are useful for something. >> They're useful and your ears are different than my ears. Um, and so you are going to be expecting a slightly different kind of fingerprint of what the sound sounds like >> as a function of location than I would be. >> Do people with damage to their ears >> have issues hearing? I mean, it sounds like sort of a they must. Um, but like the people I know that roll jiu-jitsu, the wrestlers, their ears are always beat up. Okay. >> They basically don't have these folds. It's just kind of Yeah. interesting. Um I don't know of any studies but I think we can predict from first principles that they would have an initial deficit >> uh and that very likely they would learn to adapt um and they would kind of learn their new new set of ears and what particular frequency pattern to expect from that. >> If if the auditory system is so sensitive, why is it that I don't really hear my own voice? Um, or if I talk out one side of my mouth, I sort of know I'm doing, but it doesn't doesn't throw me off. Doesn't throw me off. And yet, >> most people have the experience of >> watching themselves or hearing themselves speak and it feels awkward. >> Yeah. >> We don't really like I suppose there are some people on the planet that like to hear themselves speak, but most people don't. >> Yeah. >> Most people are not it. It sound It's like we cancel ourselves out while we speak. Yeah. >> But then when it's coming at us from the front, it's like it's >> Do you like listening to this podcast or do you >> Well, I listen to all the podcasts to see ways that I can improve. >> Yeah. >> Um and I like the content that my guests bring on and I like the the topics. >> But it's an awkward feeling, isn't it? To listen to yourself is very awkward. >> Yeah, it's it's uncomfortable. It's uncomfortable. >> Before I answer that question, which is a really interesting question, I want to loop back to the uh do we have to learn this? The the other thing um to say about learning uh learning how to interpret these the timing difference cues and the level difference cues is that a baby's head is about half the width of an adult's head. >> So that means that that you know half millisecond for me is you know a quarter of a millisecond for for a baby and it's going to change as they grow. So that's why you have to do all this learning. >> With respect to the question you just asked about like why our voices sound weird, I can say more about why they sound weird and less about why we experience it is kind of unpleasant. Maybe that the weird and unpleasant connection is because um we're just so used to the way it actually the way it's the way we experience it that to hear it recorded is going to be unfamiliar and strange. I think there's going to be three things. Number one, the recording is not going to capture the full spectrum of frequency content of your voice. >> Number two, your brain has an active mechanism for manipulating the transduction of sound in your ears. That is to say, the conversion of sound into a neur neural signal that's going to go into the brain. So, your brain actually controls that process. Um, and there's some thinking that it's, you know, turning down the volume just before you speak so that you don't get blasted by the sound of your own voice. >> If you think about it, like if I were speaking at this volume with my mouth this far away from my ear, like if I was speaking at this volume from here or somebody else was speaking at this volume from here, it'd be too loud. >> Got it. So for those just listening, so uh Jenny's, uh referring to So the distance between your mouth and your ear is a very short one. And if someone were to speak into your ear at that distance, I suppose unless they were telling you something you really wanted to hear, you'd probably feel like, "Hey, get out of my personal space." >> You'd want somebody to to speak a little more softly. >> Yeah. And yet we're doing it all the time. >> All the time. >> It's just that we're projecting it outward. Well, we're projecting it outward and our brain is turning down the volume um in anticipation of what we're what we're saying. >> So, it's a very, you know, potentially it could be a very precisely timed volume knob that is going with each little word that I say. >> So, when the psychologists say that we can't speak and hear at the same time, they're 100% accurate. >> Probably >> we can't speak and hear correctly. >> We cannot. And then the third thing is that this maybe goes back to the first point about the recording doesn't capture all of it is that some of what um we are picking up is actually through bone conduction. You may have bone conduction uh headphones. I certainly do. These are headphones that um they're they don't go over the ears. They don't go in the ears. They're usually positioned right in front of the ears delivering the vibration signals to the bone right in front of your ear. And that can get transmitted into your ears as well. >> You have these headphones. >> I have these. I have these. >> Why do you use these instead of in ear ear? >> Yeah. >> Cuz it leaves my ears open so I can hear something else. So that's safer if you're out exercising somewhere where there might be traffic or something like that. >> I get a lot of questions about headphones and safety. And uh one thing that uh we resolved recently on the podcast, we had a guest on who's a our chair of autoangology at Stanford and >> she said that if your headphones are loud enough that somebody besides you can hear >> that there is a sound, not even the specific sounds. >> Yeah. >> Uh you are inflicting hearing damage, >> right? >> Probably permanent hearing loss at some level. that that yeah that she sets a pretty low threshold for um kind of like be careful but it seems important given that >> we now know hearing loss is correlated with dementia >> right >> it makes sense less sensory information comes in the brain probably says well there's less stuff coming in and starts turning off circuits >> and then memory goes and attention goes and there are other things obviously that can impact dementia but um so it's interesting um the other question I get a lot um is uh about the Bluetooth >> earphones. People want to know are they safe? Is it safe to have this like Bluetooth arc, you know, in your ears and uh we had a guest on here uh Matt McDougall who's the >> neurosurgeon at Neurolink, >> they're big on Bluetooth, Neurolink, but he said that the amount of uh radiation coming from those Bluetooth headphones >> is considerably lower than >> the sort of radiation that you're exposed to all day every day. So he wasn't concerned. Are you aware of any impact of heat? >> I'm not look looking to go after EMF here if there isn't anything there, but but of heat or of just having um EMF around your given the sensitivity of the bone. I mean, I'm just amazed that you can pick up sound from the bone vibrations. I mean, this is a very sensitive >> neural uh sensory space is what I'm realizing. >> Right. I do think that there's um concerns about just how much sound exposure people are accumulating. >> If we live long enough, 80% of us will get hearing loss at some point in our lives. >> Bummer. >> So, it's a big problem. Mhm. >> There's certainly concerns that young people are farther along on that trajectory to hearing loss than people from older generations were at a comparable age. >> Um just because there's, you know, the earbuds are in from morning to night and volume turned up loud enough to block out surrounding sound. You know, if you're in a >> a loud environment, I would encourage people to give some consideration to noise cancelling headphones and to not having the volume be turned up too loud. >> Like to talk about the experience of listening to something, >> music, let's say, through headphones versus in the room. >> Mhm. >> We don't think about it too often, but it's a totally different experience. In one case, you're hearing the sound in your head. >> Yeah. Right. or even listen, you know, like your phone on speaker versus wearing earphones, >> right? >> The person's voice or the music is in in your head as opposed to in the room, >> right? >> And once you think about this difference, I I simply can't go back. It's like a >> you like the full actual speakers. >> Well, you now I try to listen to music in the room. >> Yeah. >> I find that to be a >> better experience for me. But when I hear things with headphones, I now feel like, oh, like the sound is coming from inside my head. And it it's a little weird. I don't like it so much. >> Yeah. Right. It is possible to make sound that is coming from headphones sound like it is coming from outside. But to do that, you have to use all three of these sound localization cues. um things have to be, you know, to have a a an appropriate timing difference, an appropriate level difference across the two ears, uh and to use the the frequency filtering properties of of the ear. And since everybody's ears are a little bit different, that last step is really hard. >> But there is 3D sound, right? >> Yeah. >> Like we think about like three-dimensional vision is simple for people to think about. As long as they're cited, you understand that, you know, you expect things that are closer to you to be larger. >> Mhm. >> Than if they were far away that we we learn this without >> so many wonderful cues to distance in vision, right? >> Yeah. Things in the distance are harder to resolve as opposed to things up close which you can see all the detail. And there are all these cues, right, that we could talk about. But since we're talking about hearing, >> the >> sounds that we hear at a given level, we know are close are coming from objects that are actually close or far away, >> usually based on what we see. >> Mhm. Yeah. >> Right. So, what is 3D sound? How how do I know the difference between a sound that's right in front of my face with versus far away with my eyes closed? How do I know? This is a computational process in the brain that we don't fully understand. And it's worth thinking about what are what are the available pieces of information that you can use. Sound is much more bendy than light is >> bendy. >> Bendy like it bends, right? It goes around things. Whereas light is just kind of like a straight straight shot. You know, >> you don't have the opportunity to use the same kind of information for sound depth that you do for vision. Um, even though you have two ears, you can't form an image and check to see whether or not the images line up, which is what stereo vision is. >> You don't have occlusion cues. That is to say, one thing being in front of the other blocks your your ability to see the thing that's behind. >> So, you know, the sound can go around objects. >> So, there's a few different cues that we can use. Uh, one is simply how loud is the sound. Mhm. >> Um, things that are farther away are going to sound quieter. But you have to know what the sound volume was out there in the world in order to interpret whether or not that is quiet or loud. >> Let's use thunder as an example because thunder sounding very loud predicts lightning that might hit you. Thunder that sounds way off in the distance. If you have an understanding of thunder and lightning predicts a lower probability of you getting hit by lightning. I had this experience recently. I got caught in a sudden uh lightning storm thunder lightning storm in Austin, Texas and it was coming down in sheets and then you know and the thunder gets louder and louder and you're like wow and and then the lightning gets brighter and brighter and you think I could get electrocuted >> and uh seems like a low probability event, >> right? Depending on where you grew up. Um, you might have learned as a child like some basics of how to tell like when it's good idea to, you know, get to shelter. Um, so, you know, for example, I was taught growing up, you know, you count 1 1,00 2 1,00 whatever. As long as you can count to like 5 seconds, you're probably okay. But once you're getting to that level, you should, you know, maybe go inside >> there. Let take that. Take that one in, folks. from somebody who grew up with them. [laughter] You see the flash of lightning. >> 1 2 100 3 100 4 100 5 100. And if it takes longer than that before you hear the thunder, you're okay. But at that point, I would go inside. >> You may have saved some lives. [laughter] >> Yeah. Growing up in California, we didn't learn anything about it. >> You didn't get that. And people who grew up in cities wouldn't have gotten this. I think in cities, it's actually very hard to see the connection between the light lightning and the thunder. Mhm. >> Um, but I grew up in rural Vermont and it was like very obvious. >> I grew up in the San Francisco Bay area and I've been through so many earthquakes. And one of the things that >> uh people don't realize if they've never been in a major earthquake is that >> it's extremely loud. It starts with sound, not shaking. You don't you don't sure. So this is people always think California earthquakes and you know with the A9 quake and the area freeway pancake and the the Bay Bridge actually a segment fell out. People forget this during the World Series >> that happened now there would be so many casualties but it was a lot less >> busy in the Bay Area back then. >> Yeah. >> The first thing that happens in an earthquake is it sounds like a train is about to come through the room. >> Yeah. Sure. >> And then the shaking starts shortly thereafter. Uh-huh. >> But the sound always comes first. >> I always tell people this when they're afraid of earthquakes. Like you'll hear it before you'll feel it before you see it. >> So if it sounds like a train is going to come through the the room, >> you're probably about to have an earthquake, >> right? I think elephants use um sound to communicate over long distances. I So >> that's cool. They stomp. >> Yeah, I think so. Or they can hear Yeah, they can hear things. I think they have sensors in their feet that can pick up these vibrations that we might call sound. >> Oh, that's cool. Yeah. That's like that scene in Stand by Me. Yeah. >> Where they're crossing the train tracks on a bridge. >> Yeah. >> And all the >> kids are just kind of moving along and then uh Gordy, who's the >> arguably one of the smarter in the bunch, he he's like >> he's reaching down and holding the tracks and he feels the track shakes before he >> hears the the the um the horn. And then of course the smoke rounds the corner, train rounds the corner. >> Interesting. Interesting. Yeah. And with the elephants, I'm not sure. I think maybe it's not sensors in the feet, but bone conduction from the feet to the ear. >> Um, and that's where it's where it's being picked up. >> So, okay. So, your question was, if I can go back to your question, it was about distance and how do we know how far away a sound is coming from? So [snorts] the the loudness cue requires you to know something about how loud the original stimulus at the source is. And so thunder is a wonderful example of this because we do have quite a bit of experience with thunder. So we can kind of use how loud it is as a good cue. And it also works great because we're talking about really long distances, right? There's another pretty cool cue that you and I are probably using right now, and that is that the sound in this room is bouncing off of all the different surfaces. So, the shortest path copy of the sound is coming straight from your mouth to my ears, but in addition, there's a copy that's bouncing off of the table that's between us. That will have a has a longer path length, so it'll be slightly delayed. There'll be another copy that's, you know, hitting the ceiling and and coming down to my ears. Oh, this is weird. >> And that is going to have an even longer delay. I'm completely unaware of this, but my brain is probably using the slight differences and the kind of pattern of slight differences to figure out, you know, that you're about 7 ft away from me. If we were closer to to each other, the difference between that straight path copy and the copy bouncing off of the table would be greater than it is right now. Because at this angle with this, you know, geometry, there's really not that much difference. So the bounced off copy and the straight path copy are are pretty similar. >> I never thought about this. >> It's incredible. Right. >> This is a way that vision is so different. >> Yeah. >> I came up through vision science mostly. >> Yeah. So did I. >> And Right. I mean, there are certain wavelengths of light that can pass through our body like long wavelength light. That's relatively new findings. I think it's really interesting and it's very healthy for us. turns out, you know, mitochondrial health, etc. But >> like in general, we're not used to thinking about light and wavelengths of light going through things unless they're translucent or transparent like a window. Sound is constantly bouncing off everything. >> We're in a hall of mirrors for sound all the time. >> But you experience me and I experience you during this conversation as one coherent sound. Even though we are biologically poised to detect half a millisecond differences in the arrival time of the two ears, they're much greater differences in the arrival time of my voice bouncing off the table versus the walls versus the ceiling versus direct path. But you integrate them >> and I don't hear you as saying the same thing, you know, five different times, right? You know, it's one integrated hole. >> And closing one's eyes doesn't change that. If I close my eyes and you speak, I can register to the direct path, >> I infer that you're right in front of me. Of course, I know that because my eyes were open a second ago, but all the versions of your voice arriving bouncing off the different surfaces are arriving at my ears and I don't it doesn't it's not confusing and it's not jarring, >> right? >> Like if somebody came over and touched my arm and I felt it on my arm but also a little bit on the back of my neck and a little bit on my knee, that would be weird. That would that would be odd, you know, and we can get these sensations. There are certain places on the back, for instance, that you can feel a subtle kind of phantom touch in your foot because of the way the neural circuits are organized. And with pain, we talk about this as like referenced pain. You know, for internal organs, there's they're branches of uh of nerves such that, you know, uh and this shows up in you know, eastern medicine, but also western medicine. Like someone with a with like liver pain will register that in their shoulder, you know, and and we think, oh, this is crazy. You know, it's not crazy that there's actually branches that that support that referenced pain. >> But we don't do this with hearing. >> Yeah. >> We shut it all down and we just collect the the we we make we draw a conclusion, >> right? >> Wild. >> It's wild, isn't it? >> It's totally wild. Uh, are you about to tell me that our voices are also causing vibrations in the objects around us and that we just can't detect them? Why are we not like the elephants? How come we >> Maybe we are like the elephants. I don't know >> is it the case that low frequency sounds can travel further with respect to our ability to detect them. >> So I you know I don't want to get into a conversation about frequency of sound and and intensity and high versus low frequency because that's that's really about the physics of sound. >> Right. Right. >> But ultimately we filter the physics of sound through our nervous system. So, if I want to signal to somebody far away, I would probably want like a big bass drum or a gong. I would not try to whistle to them far away. Or if I could pick a horn that was a a deep like >> versus like I'd want bass. >> So, there's a few things wrapped up here. One is that the lower frequencies bend more bend more easily. So they they can go around these objects better. So if you're talking really long distances, you know, the odds that there's something in the path that you want to >> the sound to go around or are are go up. Uh, another thing that's wrapped up here is that we tend to lose high frequency hearing before we lose low frequency hearing. Mhm. >> And [clears throat] so the lower frequencies are audible to more people and and are louder to people than the higher frequencies. >> So you're saying it's because it can bend around objects. >> Well, I don't really know what the choices that are being made are by the people whose job it is to figure these kinds of things out. But I'm sure that there's some thought being given to the receiver, you know, the the people and what they can what they can perceive. So, let's take a couple other examples of warning systems that that humans use. The gas in a gas stove doesn't have an intrinsic odor to it. >> There's an odorant that's been added. >> That rotten egg sulfur smell. >> That rotten egg. Yeah. Exactly. And so, you know, that was chosen a long time ago to be added. And, you know, it turns out to be a good thing because it doesn't doesn't really smell like anything else. It's not pleasant, but everybody can detect it. I don't know of any cases of people that can't smell that unless they have a generalized uh anosmia where they can't smell anything. Traffic lights are maybe a little bit of a less of a win because you got red versus green and 6% of the population is red green colorblind which operationally means not that you can't see a red stimulus or a green stimulus but that you can't tell the difference um you know whether or not something is red or green. Yeah, I should just say that um that most red green colorblind people tend to be males just because of where the the gene mutation is in the >> in the genome and they don't see people always want to know like what what does red look like to them. >> Red and green look kind of more orang-ish burnt brown orange color and dogs see the world that way all the time, >> right? So if you do a color matching experiment, I my understanding is something along the lines of people with red green color blindness will map both red and green onto yellow >> and not and not be able [clears throat] to tell the difference. It's not the kind of u cartoon view of like it looks black and white. >> There are people who are completely monochromatic, but it's very rare, >> very rare, >> very very rare. And there are other forms of color blindness that are more subtle and color blindness people should we'll put a link to this Jay and Morin Knights up at the University of Washington. a terrific um they run a color vision lab. She's a molecular biologist. He's more of a psychophysicist >> and they have some really great color vision tests there that people can take >> and many people find that they have subtle color vision deficits. >> Yeah. Yeah. Exactly. >> But but they don't consider themselves fully color blind. But every once in a while >> monochromats usually know that they're seeing the world. They're black and white. And a lot of what you know is under this heading is is really more an anomaly than a complete absence of an ability to distinguish red from green. But back to our traffic lights. So you got your red versus green signaling something very different. And most places have those lights oriented vertically which gives you a second cue to what's what needs to be conveyed here. So >> not the same light switching, >> right? It's not the same light switching. um and one is on top and the other's on the bottom. It's more of a problem when uh in some intersections the the the set of three lights is oriented horizontally. >> We've known for a long time that there are things that we can do to improve our sleep. And that includes things that we can take things like magnesium thrienate, theanine, chamomile extract, and glycine along with lesserk known things like saffron and valyan root. 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Again, that's from ourplace.com/huberman to get up to 35% off. So really what we're talking about that I'd like to drill into even deeper across senses but primarily with sound is you know how space how the physical environment shapes our our perception of things. >> Yeah. Yeah. Um, and I'm also very interested in the vi the relationship between vibration and sound given that our ears contain the apparatus to detect sound frequency but also uh have to do with you know balance and and vibration. >> Most of us have had the experience of someone pulling up next to us in a car blasting bass really loud and our windows start shaking and their windows start shaking. Can we talk just about how objects have a a resonant frequency? Right. >> I think this is pretty interesting. And then people will inevitably want to know about how humans have a resonant frequency. And we do. I believe that certain frequencies of sound can shape our emotional state. >> Oh, sure. I mean, that's music, right? >> For example, it just for some reason when we break it down to one frequency and it's not um packaged in music, >> people somehow think it's like woo or mysticism and it's it's not. I mean the I'm fascinated by this like the g like gongs as an ancient tool for trying to orient people's emotional state >> or signal like if we hear boom [clears throat] >> it sounds ominous right if we hear chirping of birds >> we know they're birds but if we hear light um you know in the Disney movies that you know it's been a long time since I've seen a Disney movie but the the kind of the the the stuff of fluttering is high frequency high frequency movement tends to be high frequency sound. So, how do you think about the relationship between frequency and emotion and resonant frequency? I mean, it's a vast landscape, but I'd love your thoughts on this. >> So, can we can we go into the music realm to talk about this, >> please? I think that's intuitive for many people. >> Okay, good. So, one of the things that I think is fascinating about music is that it's universal and nobody really knows what it's for. Like it's pretty clear that language is useful to us, right? It, you know, helps us exchange information. >> So pretty obvious that language is is a benefit, a survival benefit for individuals and for the species as a whole. We don't really have as clear a view of why music, you know, what role did music play in our um success uh in evolution, natural selection. >> You know, music is it really is universal. Um every human culture has it. Um there is some variation as to whether or not um a culture embraces melody, embraces harmony, but every culture has rhythm. You can't have melody or harmony without rhythm. It doesn't make any sense, right? Like imagine imagine a familiar tune like Happy Birthday, but the duration of the notes was completely arbitrary. >> It would sound crazy. >> It would sound crazy. It would not be recognizable to us as happy birthday, but you can um you can play it fast, you can play it slow, you can play it, you know, pitch shifted up or pitch shifted down, musical terms in a different key, and we would recognize that as like a particular, you know, song. Um, so that's what I mean about rhythm being uh really critical. Um, and the criticality of rhythm offers up the following kind of wild uh theory. This is not my theory. Um, I wish I could quote whoseever theory it is, but it is that perhaps what rhythm, what music and rhythm is for, is to help us act in concert with one another and be louder than any of us could be by ourselves. um and to scare off predators and competitors. So, for example, imagine a pack of hyenas are surrounding a kill from, you know, a a lion. The lion is long since sated and has gone away, but now a bunch of scrawny humans want to scare off uh the hyenas. If they go after the hyenas all stomping their feet together and shouting together, it's going to be a lot louder than any one person could do by themselves. >> Well, I like this theory. >> It's kind of nice, right? >> I'll tell you why in a moment, but please continue. And then that kind of concerted working together as a group. And you could sort of see that like once you had the the basics of like and here I'm talking when I say once you have I'm really imagining on an evolutionary scale that any for anything to come about and endure requires that it increase our fitness at every stage of the way. So, initially you might get that rhythm thing going on. Um, but then that would be satisfying to people like if you had a mutation that made acting together feel good for some reason. And then it would come along with this benefit of of competing with the hyenas for the lion kill. And then it would kind of potentially feed on itself of like, well, even more cooperative action, feeling good together allows us to then do other things together that we can't do individually. >> Have you ever seen the uh it's a a song and a um I don't exactly know what to call it. Uh the chanting and the song of of Mauy in New Zealand. Yeah, >> they'll do this before rugby games, >> right? >> Because the All Blacks are one of the best rugby teams in the world. There's an incredible video um that a friend of mine, she always sends this to me when um >> uh when I'll say something like, you know, what do you think of something that was on the news or something and she'll and she'll send there's a incredible case of in the government in New Zealand. I think it's a I don't know if they use parliament or what or what there's an example of um okay I'll just say how it is there some white politician reads out some you know proclamation maybe like that's up for a vote and then all of a sudden it will start in one corner of this uh very majestic like government building >> um >> looks sort of like our congress but it's it's different and she'll start chanting and then and it's like wide eyes there's no blinking it's very interesting and they're stomping and is clapping and then all of a sudden it starts other people start joining in with her, >> right? >> And and it gets really loud when they're together. >> A you know, you know a number of things immediately. A they're pissed. >> Two, they're not going to stand for this. Three, they're a lot of them. And four, like they're not to be messed with. >> They're united. >> They're united. Yeah. >> Admittedly, I had to have someone look this up. It's called Hakka. Uh, and it's incredible because you immediately understand how these people feel and it's a no, we're not going to take that kind of stance. At least in the context of this government example. >> In terms of pre- rugby match, it's really a display of vigor. Uh, and we are primates after all. All we are old world primates. Um, and vigor displays uh run through all the old world primate species, including us. >> Yeah. >> Um, and >> I think it's definitely a vigor display, >> like stomping, making one's big and the lack of blinking is something that, you know, as a vision scientist, I caught on to ear like no one's doing this and and blinking a lot. They're they're showing that they will not break their attention >> until this is complete. And somebody not blinking while staring directly at you is a command for your attention. as well. >> And it's even in our language, isn't it? So and so didn't blink. >> That's right. They don't blink. They're not afraid. They're, you know, these days because of the craziness of the political socio landscape with assassinations and very strong personalities and government and online and because I'm, you know, in media now to at least some extent, different form of media, not politics. But, you know, I'm so um intrigued by the idea that some people are capturing people's attention and loyalty, not just by virtue of what they say, but the certainty with which they say it. Now, that's not a new theme, but also the tamber of their voice. Yeah. >> The refusal >> to entertain dissenting voices, but also how a lot of voices are just >> not the right tamber and frequency and delivered in the way that these people have obviously mastered their ability to command other people's attention. Like, it's it's a because this stuff hits at a primitive level, >> right? People aren't necessarily just voting on issues. They're voting on feeling. we've known this, right? >> So, in any case, the the haka is a is a beautiful example of what you're describing. >> Well, and the other thing is that music plays a role in um in say the military and in war. I read somewhere that the military is the largest employer of musicians in this country. >> Interesting. >> Yeah. >> Makes sense. >> Well, you know, I thought it was a surprise to me when I first first heard it. >> Yeah. Surprising to me, but it it makes I mean, somebody's got to play taps usually. That's one that's one horn. >> You get one, right? So, and I think the other, you know, possible angle for all of this is, you know, there are things in many species that are not obviously beneficial. Take the peacock for example. That that enormous investment in plumage in very colorful tail feathers is not something that is directly adding to the survival skills of the male peacock, but rather it's something the female peacocks like. Um, and so that tends to feed on itself too. So that's another way that music could get into our, you know, paniply of human characteristics without necessarily directly leading to something like being able to get more food. Like the rhythm thing gives us more food. >> People who are good at music might end up um with more offspring than people who um weren't good at music. That would be that would be the sort of uh general idea behind that that part of the theory. >> In many now older movies um typically it was a man singing to a woman or in the movie Say anything. >> John Cusack simply used a boom box, right? um uh or um poetry, >> creative works, but expressed out loud >> were the way that um courtship took place. >> Um >> Eric Jarvis was on this podcast. I don't know if you know Eric at the Rockefeller and he's a very um >> accomplished dancer. I don't know if you know this, but he was supposed to be in the Alvin Dance Company. He decided to become a neuroscientist instead, but as I understand, he's still a good dancer. Um and he was saying that he thought that perhaps primitive vocalizations evolved first. So vocalizations of disgust or pleasure or fear or excitement. >> Then he thought perhaps came song and dance. So song and body movement to signal what one was feeling or what their intention was. >> And then perhaps spoken language came after that. >> Makes sense. I just think we don't know. >> Yeah, we don't know. And I think it's kind of interesting there are maybe sort of two um like I think with the song bird they are signaling things like vigor and fitness and territoriality um and things like that they're not conveying something symbolic whereas the you know vocalizations in the primate tend to mean something specific. You know, sometimes I wish I, you know, could have a time machine and I could go back and, you know, look at what happened >> in earlier stages of of evolution and just kind of see, well, what is the lineage that what is the sequence of events that led us to to have language that led us to have music? Did it come from the same process as birds, you know, song birds or did it come from a completely parallel process? I I mean I think we do see that evolution can arrive at similar characteristics through different means in different places in different times. So you know could be you know kind of convergent parallel process or it could be something different. >> I feel like music um conveys intention. Music can tell a story and music because of the way that it organizes language provided there's lyrics um into like riffs and motifs and melodies and choruses that >> it makes it very easy to remember things. I'd like to talk a little bit about the possible neural underpinnings of this. Uh two things come to mind. First of all, you mentioned uh the ABCs, >> you know, ABC D. Almost everybody knows that um that melody and it's probably easier to remember all those letters in that form as opposed to A B CDE E F G H I Sure, you know, because you break it up and and and I I'm almost certain this is true because I have a good friend and he's a very accomplished musician and he's an incredible >> songwriter and lyricist. He's written lyrics for a number of other artists, not just himself. And he has like several bands. He writes a song a day. >> It's crazy. He writes a He released a song a day during the pandemic. >> Whoa. >> Great songs. And occasionally, because I'm such a fan of his music, I'll say, >> "There's that one song like what's that? What's the lyric?" You know, and and he'll say, "Oh, yeah. No, I I don't remember." He go and then he'll start and then he'll remember it. And I He's got thousands of songs in his in his library of songs he's written and sings. I said, "So, when you're on stage, how does it work?" You said, "As long as I can remember the first two words or three words, >> yeah, >> uh of a verse, the rest just kind of spills out of me." [clears throat] >> I think that's how song organizes language. >> Uh because it's very hard to memorize like a a speech, but you can memorize a song, no problem. >> Yeah. And that's my experience, too, that if I know the first couple of words of a verse, I've got the rest of the verse. >> Yeah. It It's so interesting. So in the brain, >> uh we haven't talked too much about brain structures yet, but maybe we do that. Um and not to fill people's minds with names of things because I always say like it doesn't matter if it's called the superior caliculus or the superiorulus. It doesn't matter unless but what's interesting are the properties of these different brain structures. So I think about the ears as you know separating different frequencies of sound and then there's a bunch of other important stuff. No disrespect to the auditory neuroscientist but but as you said in the superior caliculus is where hearing and vision and the other senses come together. They're mapped onto one another. >> It turns out that the story is more complicated and more interesting than that. I got hooked on that particular study that I mentioned at the beginning. So this was auditory signals in the superior caliculus being affected by the position of the eyes at the time the sound was presented. And now our audience knows about how sound is localized. We haven't talked that much about how visual information is localized. I think because mostly that's fairly obvious that your your eye is kind of a little camera and light hits a particular uh location on the retina and that retinal location tells us what the location of the visual stimulus is. >> But it tells us the location of the visual stimulus with respect to the direction the eyes are pointing. But our sound localization cues are with respect to um where's the sound with respect to the head. So this finding that neurons were responsive to sound but cared very much about the position of the eyes was really you know a startling finding when it first came about. When I set up my own lab I basically set out to find out well where's where does this computation happen? Where is the brain um incorporating information about eye movements into the processing of of sound? You know, we we knew from the literature was okay, the superior caliculus is one of the places, but you know, does it does it happen in the superior caliculus or does it happen in a different brain area? And so we kind of marched along the auditory pathway in brain areas that I call them part of the auditory pathway because they're much more closely connected to the ear than to anything else. Um, and because at the time nobody thought there were visual signals in these areas. We thought it was just auditory. That too turned out not to be true, but they're definitely much more auditory than visual. And what we found was that in each of these areas, eye movements affect the auditory signals there too, even though they weren't in this convergent structure of the superior caliculus. So we we decided that it would take a long time to march through every brain area and that it might be worth sort of jumping over a few brain areas and looking in the ear itself. So I need to give the audience a little bit more information about what you know what is possible in the ear and why that seemed like a reasonable thing to do. It has some little muscles in it. There are two muscles that control the bones of the middle ear. Uh and then inside the cookia there are uh cells called outer hair cells that can actually expand and contract just the way a little muscle could. >> We should explain the cookia is this snail-shaped structure that has the essentially the we call them neurons but these sensory cells that that vibrate according to the frequency of the sound and this is >> critical for our perception of sound. Exactly. And you have one on each side. >> You have one on each side. It's snail-shaped and it's connected uh the vestibular. Um your balance structures are also connected to this as well. And to just describe the flow of information, you have you got your outer ear, you've got your ear canal, you have your eard drum, you've got these little bones that connect the eardrum to the cookia. And so there's muscles that um that affect the motion of those little bones. And then there's cells inside the cookia that can also act like muscles. these structures um get input from the brain. So we thought well if they're getting topdown input from the brain are they getting a top- down input from the brain that carries information about about the position of the eyes? You know that it seemed like it seemed kind of like a wild possibility but not completely out of left field like there was a a possible mechanism here that we could imagine. And the neat thing about this is that um we didn't have to do something like stick an electrode into these muscles because they're attached to the bones and attached to the eardrum. And so if they were being manipulated by a top down signal from the brain, they would tug these bones and that that would tug the eardrum. And when the eardrum moves, normally it moves in response to sound, but if it moves in the absence of sound, it's going to make a sound. >> Mhm. >> So you could put a microphone in the ear canal to see whether or not anything was happening in connection with eye movements. And this too wasn't out in left field to do this because um there's already kind of known signals generated by these kinds of structures that are measured by clinicians by aiologists and and otoarangologists. Um you can put a microphone in the ear and you can measure things called oto acoustic emissions. >> Basically your ears are making sounds folks. >> Your ears are making sounds folks. I know it's weird. It's kind of wild. >> Some people make more of them than others. >> Some people make more of them than others. Exactly. So, we wanted to know if any of these little sounds were being generated with eye movements. And I wouldn't be here telling you this story if it didn't turn out that yes, they do. So, we were able to measure that the eardrum is is basically moving in connection with with every eye movement, every psychic eye movement. These are the fast jerky eye movements. There's other kinds of eye movements and we haven't yet tested them. The signal is very precisely time locked to the onset of the eye movement and the effect um is different in the two ears. So that if your eyes are moving to the left, the eardrum on the right is going to kind of uh bulge inward then outward then inward. I might have this backwards um but whatever the right ear is doing the left ear is doing the opposite so that the eardrums are going to be moving in the same direction. One is going to be inward when the other is going outward >> like a wave. >> Like a wave. Exactly. Like a wave. Not like a a >> not flapping. >> Not like flapping. [clears throat] >> Exactly. You know, we're still actually at pretty early days and understanding this process and and u what it's for, but it's very precise signal. It turns out to carry information uh about how far the eyes are moving to the left or to the right as well as a bit less but some information about vertical movements as well. M >> and we think that this may be kind of the first step in that integration of visual and auditory information >> which would be the critical first step if the major goal of this integration of visual and auditory is for localization of sounds right >> because the you know in um as a neuroscientist you know there's so many different areas of neuroscience like I used to marvel at you you go to a meeting you got people saying consciousness and working on consciousness. You have people trying to figure out how a single photo receptor works or a single hair cell works. And so when I think about a sensory system, I think about layers of sophistication and how they likely evolved >> like very briefly. I mean the visual system first evolved to detect light and dark on the order of 24 hours. So you know the difference between nighttime and daytime which means even with the total inability to see objects, you are safer if you know when to stay in and when to go out. >> And then at some point we evolve the ability to um probably motion detection came before the ability to send to see detail because it's way more important to know if something's big and coming at you big and moving away, >> right? or help you stay oriented like with respect to like knowing what's up and what's down and staying upright. >> That's right. And just like uh the falling uh reflex is probably the most important reflex in the vestibular system to brace yourself so you don't >> you have a lesser chance of dying if you fall. Right. You know if your visual world suddenly goes up very quick, you know you're falling, >> right? >> And then comes, you know, additional layers of sophistication like like fine detail, color vision. color vision probably evolved last at least >> chromatic color vision but and then so in the auditory system I think like the same thing >> you need to be able to know probably um which direction a sound is coming from is it low or high frequency um and then and on and on right you know and so I think about that like in the motor system that the oldest we know the the evolutionary history of the genes that that are expressed in like the motor neurons that move the trunk are the same ones >> that undulating uh >> fish use. And actually, this will get us back to sound, I promise. And then there's the these additional layers of motor neurons that have been added through evolution, the ones that flap the fins. And then the final addition are the motor neurons that control fine movement of the fingers. M >> so I have this kind of obsession with this because if you look at music that's very um primitive right like you just look historically speaking I'm not casting judgment on music just historically um it's rich in bass tones relative to high frequency tones >> and dance that we assign as primitive tends to involve a lot of movement of the of the trunk >> you're not people aren't just like flap ing their fingers and toes out there right >> now. So the as you go from low to high frequency, there's a body map of low to high frequency. >> And actually if when people are making a very detailed point, they'll often like like point with their fingers. They'll move their fingers. >> But when we want to emphasize a big point, we use our whole body. We put our whole body into it. So I actually believe that all the sensory systems are mapped to one another in a way that goes from low frequency to high frequency. >> Intensity is important and direction is important. me pointing at you, which I even feels funny to do because we're on good terms. As far as I as far as I'm concerned, I we're on good terms, you know, um is very different than than uh me standing back and if I come at you with my whole body, it's very different than if I point a finger for instance, right? So, I feel like these things probably evolved from this in parallel >> and and as you pointed out before, they serve an adaptive role, >> right? So the fact that position of the eyes can change the way I hear seems wild and that's a wild thing. Um is the inverse also true? Is is where I listen affecting um how my eyes Yeah. my where I hear something typically directs my head movement and my eye movement. So this is just the same thing in reverse. >> It's part of I think it's all part of an integrated system. Um, you know, we talked about the top down control over the ear, but there's a lot of top- down control over vision, too. And some of it is a little easier to understand than what I just described because blinking is top- down control over vision. Uh, eye movements, top down control over vision. Focusing the lens of your eye, right? That's also top down control. >> Um, there are descending connections from the brain to the retina itself that nobody understands. Apologies to the people working on this. I really want you to keep working on this, but I feel like there isn't a clear theory yet about what exactly these descending connections might be doing. From what I know about it, they are uh, you know, pretty diffuse connections, the pretty broad branching of of neurons uh, throughout the retina or not throughout the whole retina, but but probably not well suited to manipulating fine spatial detail, but could very well be suited to incorporating some kind of circadian influence to the retina itself or something else that that you want the same signal to be broadly available throughout about the retina. >> I'd like to take a quick break and acknowledge our sponsor, Helix Sleep. Helix Sleep makes mattresses and pillows that are customized to your unique sleep needs. Now, I've spoken many times before on this podcast about the fact that getting a great night's sleep is the foundation of mental health, physical health, and performance. When we aren't doing that on a consistent basis, everything suffers. 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I started sleeping on a Dusk mattress about three and a half years ago, and it's been far and away the best sleep that I've ever had. So, if you'd like to try Helix, you can go to helixleep.com/huberman. Take that 2-minute sleep quiz, and Helix will match you to a mattress that is customized for your unique sleep needs. Right now, Helix is giving a special offer to Hubberman podcast listeners of up to 27% off sitewide. Again, that's helixleep.com/huberman. I want to talk a little bit about physical spaces. >> Yeah. >> Recently, I was in New York and someone took me to Grand Central where there are these incredible um arches >> in one of the hallways there. >> Um people should check this out. It's really, really cool. >> It is beautiful. >> It's beautiful. You have this high ceiling main kind of chamber room of the of Grand Central. Um, and there's also a a hallway off to one side where you can go into a corner. Do you know about this? Uh, >> and you can face into the corner like you were going to, you know, like you're facing the corner in shame, but you're not. >> And whoever you're with can go to the opposite diagonal corner. >> Yeah. >> The ceiling is shaped like a a somewhat of a dome. Uh-huh. >> It's contoured, but it's more or less a small a small dome, >> but you are easily 25 ft away from this person that you're there with. >> Again, diagonal corner. >> And if you speak at a very, very low volume, they can hear you on the opposite side. >> Yeah. >> And if they speak, you can hear them. And what's wild is there's a lot of noise in the environment. This is Grand Central Station. >> Yeah. Yeah. >> And we played with this a little bit like if high frequency sounds do seem to travel a little bit a little bit better in this uh environment because if one person laughs, you can hear it very clearly. >> Um but you can whisper and they'll hear you and they're 25 ft away in a major city with a ton of city noise, >> right? And so obviously the sound waves are traveling along the ceiling >> on that parabola. >> And it's just it's a it's a no pun intended. It's a mind bend to experience sound >> coming from some from a distance far away, >> not through a device that is clearly being spoken at a low level, like a whisper, but you can hear it. In the same way that it always weirds me out when I'm in San Diego in the winter and the days are short, but it's like 80°. Like when days are short, it's supposed to be colder. >> Yes. love San Diego. Great great tacos, great people. But um they're always talking about tacos down there. But um >> it's so strange to be in a short day where it's hot. >> Yes. >> Because even if I go visit my relatives in Argentina who experience Christmas in the summer, the days are long and it's hot and it's Christmas and Santa Claus is supposed to be in a sleigh in the snow, but that's a whole different thing. >> Okay. Yeah. But there's something about the way our nervous system is mapped where we expect soft sounds to not travel very far. >> Sure. Sure. >> The opposite would be like shouting and your voice just disappears even though the person's right in front of you. It is so weird. And I feel like people should experience this natural naturally occurring experiment >> because it it you walk away from that understanding sound >> intensity and frequency and localization completely differently. It changed the way I think about this. And it has nothing to do with being a neuroscientist. You're like, that's crazy. I can hear a whisper from 25 ft away. And I wondered, is this what it's like to be a wolf? >> That would be really cool. It would also be really irritating >> because you don't want to hear all the things that people are saying all the time, >> right? I mean, this is one of the problems with hearing aids. They amplify everything. >> It's not replacing what your brain does. It's not replacing what your ear normally does. >> Yeah. It's such a mindbend. Mhm. >> Um it's so cool and it if you provide you're in New York, it costs nothing to do it. It's just you just have to wait your turn. People are catching on to this or it's been known for a while. I'd like to get your thoughts on the opposite example where if you go into a like a high ceiling cathedral church, >> um what do high ceilings do for our perception of sound given that there's a lot of space for the sound to travel? I'm not sure that I can add something that's really specific to that particular circumstance, but to say more generally that, you know, the sounds that we experience in a particular setting are really the combination of all of the reflective surfaces that are in that setting. And so, like if you have a carpeted room, that's going to absorb sound from the on the floor. And so you're going to it's going to take out one part of what um what you would be hearing in a room that is not carpeted. >> Um and the high ceilings, I would imagine that would kind of depends on what the surfaces are on the ceiling. Um one thing that'll happen in that kind of setting is that the sounds that go up that way, if it's a hard surface, they'll probably bounce off and come back down, but with a long delay. And once the delays get pretty long, then you do start to hear it as a whole separate sound. >> Almost like an echo. >> Not even almost like an echo, but actually an echo. >> Do you think this is used to amplify aspects of the music? >> Yeah, maybe that's why some of the older genres of music can be a little slower and chants. >> Yeah. longer sustained notes because you don't want to have too many transitions from one note to the next. >> Gregorian chant is a wonderful example really kind of long slow sustained um many different voices blending together versus a much faster like Mozart um minuette or something like that like those notes would just jumble together with the kind of delay that we're talking about. Yeah, it's I I mean I think that um the ability to to um localize sound. We talked about we talked about quality of sound based on high and low frequency. And I I I confess I'm I'm a little fixated um on this idea that >> when people join together in sound that you're communicating something very important that that that's the most effective way to communicate a feeling. And people say, "Well, of course you go to a concert and you feel something, but in the concert, right, you have the performers, but the audience is often singing with them, >> right? I know." Which is one of the most wonderful things. >> I recently wondered if uh I was trying to think back to like the '9s and what what created effective movements. Um and I thought maybe what we need in America right now is we need um like music that actually brings people together. Sounds really corny, >> but I really believe this. No, I do think that would be helpful. >> Maybe there just too many different musical tastes now. >> I I >> So, we should start by telling people you can't have that taste. >> Well, there should be a new [laughter] one, >> right? And maybe it should be very very uh very primitive. I mean, the the haka thing that we talked about earlier is is a kind it's an angry intention, >> right? But um and this is I guess where people will think like like my East Coast relatives will be like, "Oh, you want us all the kumbaya? I I have relatives from Jersey. So they're like, we're I know out there in California, you're all kumbaya, but I think that the we're sort of half joking here. >> So given the links between the emotion system and sound and and joining in in in sound, >> I mean, maybe this isn't too crazy an idea. Maybe it's crazy, but who cares? >> We have some advantages in science that we have a comfort with have with argumentation, you know, with disagreeing about things. but agreeing fundamentally that that we're gonna go where the facts lead us. Do you know what I mean? So the disagreement is about what the facts are, but we agree that if we can come to agreement about facts, then we can proceed from there. But there's a feeling that I have come to appreciate maybe isn't present in other domains, other kind of you know academic domains or areas of the occupations that people have that you know may be a little different from what um what we have in science you know and I don't want to make science seem all perfect in all regards but I think there's a there's a sense of like, well, you may not want to hear that I think you're wrong, but we know that, you know, those kinds of things have to be said that that you're going to have to defend your work in a peer review when you try to get your your work published. You're going to have to deal with, you know, peerreview comments that you may not, you know, I certainly have had my moments where I've been like, [snorts] I cannot believe somebody thought that when I wrote this, you know what I mean? you know, but you go through that emotional period of of time and you're like, "Oh, well, actually, it's kind of I can see how it's actually my fault for how I wrote it." You know, that it didn't actually say what I wanted or it didn't say didn't set up the reader to understand the point I was making. So, I need to fix this. And yes, you're right that there is a hole in the in the data here that it doesn't fully support the hypothesis the way I thought it did. And it's and that's okay. Like it's okay not to have the story complete. It's okay not to have every detail of it right. Just acknowledge that you don't, you know, acknowledge what you think the weaknesses are. And I I kind of don't see people acknowledging weakness in let's say the political domain >> right now. like to acknowledge well you know I'd like I'd like [snorts] such and such a thing but I can see that there's that there's a counterargument to that how can I address that or should I change my mind >> yeah I think in science we have agreements on how to evaluate strength of evidence >> and um like we can't just have one data point and draw a conclusion from that um we won't convince anyone even if we're convinced and if we are we should check ourselves I do have a question about the auditory system which is a number of people including myself are obsessed with trying to find what is the optimal thing to listen to perhaps it's nothing >> in order to be able to focus >> and the data as I see them are basically pointing to silence >> is best and so I have a question about silence and the voice in our head >> I have a question about that Yeah, >> it's very clear that certain frequencies of sound actually sometimes listen to white noise. There are a number of companies now that put out free content um of it's not necessarily binaural beats, but different frequencies that oscillate >> could be totally placebo, >> but I don't think so because they referenced a number of studies. It looks like you can get some cognitive enhancement or focus enhancement and I use these. There's some great, you know, study with me >> uh channels online where you sit there and you you work while they work. What are your thoughts on how on the use of sound as a way to change brain state? >> Okay. So, I want to back up on this question because I think you're asking a pretty deep question. One might wonder why would that matter? Like what is our what what is actually going on in our brain that that kind of pairing would have an effect? regardless of what might turn out to be sort of the best option. And so one theory that I like to think about a lot is a theory of thought and what is actually going on in our brains when we think. >> And this theory is that what goes on in our brains when we think might be that we're running simulations related to the thought using that sensory sensory motor infrastructure of the brain. >> Could you elaborate? So the theory is that like maybe when you think about a cat for example or you think the concept of a cat that the mental instantiation of that or the the brain mechanism instantiation of having that thought is to run a little simulation and visual cortex that kind of includes what a cat looks like a simulation in auditory cortex that what does a cat sound like and as I'm telling you this I'm you know if you use the word cat um what color cat are you thinking I'm thinking of a a gray cat, but I keep smelling kitty litter cuz my sister had cats and it drove me the smell of kitty litter is just so aversive to me. >> Right. And so so you had no hesitation in telling me the color and adding an additional sensory quality. Mhm. >> So that's a, you know, it's a bit of a just so story, but I think that it's a plausible possibility that that's in fact what's happening when we think. And, you know, some of what um kind of u tangentially supports this is that we have many more sensory sensory areas of the brain than than monkeys do, than you know, more distant mamalian uh relatives do. as if what might have happened to allow us to become so smart is to, you know, make extra copies of some of these sensory areas of the brain. And then when you have an extra copy, you're no longer so constrained, right? We don't really see or hear any better than monkeys do. So what's this extra tissue doing for us? possibility is that that we're using it to to generate these simulations and that that running these simulations is kind of what thought is >> interesting. Is it um helpful? Is it adaptive? >> Well, it might just be the only game in town. It provides an explanation for why you might, you know, be driving on the freeway and having to merge into difficult traffic and telling your your passenger, "Okay, be quiet. I've gotta I gotta pay attention now. Like, why would speech impair you from visual motor >> if it wasn't all part of a kind of cognitive system that's that's in operation? And maybe you need to shift some resources away from processing the conversation and towards some, you know, actually dealing with the here and now sensory motor task. I like this a lot and I want to continue down this thread because we've never talked about what thought is on this podcast and I've wondered like why is it that so many of our thoughts are incomplete sentences? They're so fractured. >> And if you really just track your thoughts for a moment, you realize they jump around >> even if they're around some coherent >> framework or subject. >> It's predictable. Like you can see the train of thought sometimes like they rarely jump completely in some totally new. >> Sorry I'm laughing. For some people they really do. >> Do they really? >> They do. They do. Sort of like the liinal state between awake and sleep. I like to lie there right as I'm waking up >> and think >> and and try and stay on a thought thread and then I'll just chuckle to myself like 30 seconds later. It's some place completely because in that liinal state you're still in a pseudo dream uh state. One time in my class, one of my undergraduate classes, I um I asked people to try to um without thinking too much, come up with a word that was totally and completely unrelated to anything that we had just been talking about. >> I'm going to give you a moment, but not too long. >> Okay. >> It's really tough, >> isn't it? Hard. >> The first word that leapt to mind was cacophony. And it's like, no, that's directly in in the framework of what we're talking about. I'm like, damn it. I And I looked at the the paneling on the wall and I thought maybe it's something about and like now I could do it like I'd say like lacquer or something like that. >> Yeah. But again, it's going to be related, right? >> Yeah. It's really really tough. >> And and you know, these are these are uh kids that probably have a 30,000word vocabulary, right? That's a typical vocabulary. Young brains. And I had like 15 students in the class. >> Interesting. I think two of them came up with the word elephant and three of them came up with the word banana, you know, like they were clearly not random words. >> So, I think uh we're talking about something extremely important now that I like your thoughts on because this is really about how the brain works, right? And I love the auditory system and and we'll get back to it, but it's part of this larger question of how our brains work. I'm asking about binaural beats or white noise or pink noise or brown noise. um in order to enhance focus. There's a lot of interest in that, but what we're really talking about is how what our thoughts, how we think, and how to anchor our thinking and align it with action. >> And so, I'm obsessed with this notion of attractor states. And the way I think about this, tell me, tell me if I have this wrong, is I think about brain states as very context dependent, especially nowadays with the amount of information we're being bombarded with through our phones. And because a walk to the from the car to your desk or a walk from the car to your first meeting is a very different experience with a phone than it was like 20 years ago. >> Oh, totally. >> And people who are younger than me won't know what we're talking about. They're like, "What are you talking about? The you were always in comm." No, that's not how it was. >> But the the way I think about >> the brain is that >> my thinking is more or less like a ball bearing on a flat surface. Mhm. >> And the more fatigued I am, the more unbalanced [clears throat] that surface is. But assuming I've slept well, and I'm hydrated, caffeinated, and satisfied, I don't have some like basic need like having to go to the bathroom or or gnawing hunger or need for a coffee. I'm like a ball bearing on a flat surface >> and that flat surface is relatively stable. Now, as I move into something like a discussion of this podcast or um or I'm reading something, the the dimples start to form on that surface. And so that ball bearing can rest, >> but you can still nudge it out pretty easily, >> but that as I go further and further into an activity, it becomes a a trench and that ball bearing sinks to the bottom of that trench. Mh. >> And um Kristoff Caul who was here recently said, you know, the flow state that we that we all want so badly is where we actually forget about ourselves because we're so deeply in that state of doing. I think he's right. And I think that many people think that they have ADHD. Many people think that they can't concentrate. I actually believe there are some people with clinically diagnosible ADHD, but that most people are just not allowing themselves a narrow enough set of sensory inputs and context to drop into that trench. >> And yet it's the thing that feels so good >> when we're in it and when we emerge from it, we're like >> like that's what we're supposed to do. So what you described in the classroom where where your students can't even come up with a word unrelated to the conversation is one of these attractor states. >> Is that is I mean where does that sit with you? Yeah, I think that I think that sounds good to me. And I think um I too share an interest in like how to get myself into that flow state >> and what to do when I have sort of bottomed out in like one particular like I get I might be in flow and making good progress on something and then I get stuck and I stop >> and I find that changing my immediate environment is a good way to get out of that little rut. Um, so for example, if I'm working on a difficult piece of writing, I might get to the end of what I can achieve in one particular cafe, but if I go to another cafe, >> you know, >> now this is a very smart strategy. Actually, uh, a neuroscientist whose work I I really admire and uh, and I also really enjoy as a person is Mara Feller at at at UC Berkeley. And >> I think she was the one that told me that at scientific conferences which can go on for 2 or 3 days and sometimes the sessions are very long. You have morning, afternoon, evening sessions. It's like a it's a lot lot to pay attention to, lot of sitting. She would move seats >> around the the um around the auditorium because she swore that it I think it was Mara. Mara, if it wasn't you, forgive me. um but I think it was Mara could she would move seats so that she could always anchor her attention >> uh for each talk or set of talks not necessarily >> you know moving every moment but every every hour or so. Um I think this is absolutely right and so I wonder whether or not some of these effects of binaural beats or other frequencies improving focus >> has to do with just needing to fill the auditory sensory space. >> That could be >> like if I go I have this I work in my basement now. I've set up my basement as like the ideal work environment. No phones, no internet. >> Don't allow it. When I go down there, >> it's just me and my thoughts. >> I do allow some music, but when I get down there, the first 10, 15 minutes are excruciating. >> Like, you can hear every distracting thought. I can think of a million things that I would just pop to mind. But after about 10 15 minutes that all fades away and I can work down there for hours. Like no one can find me down there. I love it. Like I it it I've had to create this physical space because nowadays there's just so much infiltration through through devices. >> So I wonder, you know, for some people they they think they can't focus, >> but that there's a there's a sensory space that needs filling. >> Yeah. They haven't maybe haven't figured out how how they need to hack themselves. Like I and I think that the re one reason why I haven't specifically answered your question yet is because I think the answer may be specific to the individual. So for me for music, I like to listen to music while I work, but I I do it sometimes but not other times. But as a musician myself, the music can't be too interesting to me. Like it has to be either stuff I know really well already so that it's not like grabbing my attention to actually listen to the song or it should be classical music or something that doesn't have lyrics >> so I don't have that language intrusion to my thoughts. >> Sometimes I find it useful to make a playlist for a particular project >> so that those songs start to become a cue >> mh >> for working on that project. Um, so I don't think there's going to be one answer that fits all circumstances, but to maybe have an understanding of what works for the particular person, the particular project. >> There's some very interesting data coming out of Mark Despazito's lab. We've had him on the podcast before about about >> u dementia and ways to um improve working memory. >> Um, which seems to be more of a dopamine thing. Um, but [clears throat] if you can augment acetylcholine, you can improve attention. It's just it's just so clear like that these forbrain structures like nucleus basalis that are releasing acetylcholine they're necessary but not sufficient to to establish an attentional spotlight. Um uh the reason I was going to you know mention in this context is you know that the cortex is you know rich with the the nerve endings of these acetylcholine releasing neurons. The caliculus has acetylcholine input and it seems like any sensor multi-ensory area of the brain where you need to integrate vision and sound and context and thinking and all this stuff and intention and action. You have norepinephrine to raise overall alertness in the brain and body. That seems to be its general function. Dopamine does many different things in different areas as you know. But it seems like acetylcholine is the thing that really creates this this ability for attentional spotlighting that being able to anchor one's thoughts and actions towards a specific set of sensory combinations. And so when we talk about listening to music or not listening to music or um >> one particular space or another space that one works in I I think um so much of it is trying to uh you know we're trying to create these these spheres of attention that are very compact. Um, and I don't think that people really appreciate just how hard that problem becomes when you take a device. I'm not anti-phones. And and you're you're bringing in another sphere of what 25,000 different spheres of attention that you can scroll through. It makes perfect sense why we wouldn't be able to focus because acetylcholine is like a resource that we spend out and it can be replenished in sleep. >> Mhm. You said you'll hit a flow state or a focus state and then we have to switch >> or you hit a wall and it's it I feel like it's a currency. >> It's not something that we should be able to just use, you know, infinitum. >> So I think a theme of some of your podcast episodes involves you know um physical exercise and workouts and you know what's the best routine for this that or the other aspect of of the workout. Um, and generally interval training I think comes up as a pretty [clears throat] effective strategy. I sometimes think about that in the context of of more mental work >> because I have not had good luck screening out all the distractions to get going on deep writing. For me, it's more like I can push out a sentence and that's so effortful that then I need to take a break. Oh, well, I feel much better now because um well, it I think this is where you're going. You may find comfort in the fact that we've had some just phenomenal uh physical coaches on here. I mean people are degreed in um physiology and and teach super high level athletes >> and more than one of them has said >> that the attention span >> of the athlete in terms of ability to >> focus on cognitive information tutorial and learning even conversation >> directly maps onto the duration of their event >> like the sprinters can pay attention for about the duration >> about 10 seconds Yeah. Well, for the 100 meter, right? You know, um, but they can repeat that. >> Cuz the sprinter will sprint and then walk and then repeat. Right. Exactly. So, it's so it's like I'll write a sentence, then I'll check one new site, then I'll write another sentence, and I'll check another new site. And if I try to just write one sentence, and then another sentence, and then another sentence. I get frustrated with myself. It seems like it's I don't know. I can't I can't necessarily do it. Sometimes I can, but I've let go of working efficiently as a goal in and of itself. >> Was it always the case or do you think the advent of of uh phones has made it such that you have this this sort of um step function? >> I've always had a problem with the internet. [laughter] >> The phone is just the way in. But um uh the phone actually can be helpful to me because I can >> I can close all the tabs on my laptop >> and just have my phone be the way that I access the internet, for example. And that allows for like a kind of a mental and physical separation where I can kind of be like, "Okay, now I'm doing this. Okay, now I'm doing that." Um and keep them keep them kind of separated. I'd like to take a quick break and acknowledge one of our sponsors, Element. Element is an electrolyte drink that has everything you need and nothing you don't. That means the electrolytes, sodium, magnesium, and potassium, all in the correct ratios, but no sugar. Proper hydration is critical for brain and body function. Even a slight degree of dehydration can diminish your cognitive and physical performance. It's also important that you get adequate electrolytes. The electrolytes, sodium, magnesium, and potassium are vital for the functioning of all cells in your body, especially your neurons or your nerve cells. Drinking Element makes it very easy to ensure that you're getting adequate hydration and adequate electrolytes. My days tend to start really fast, meaning I have to jump right into work or right into exercise. So, to make sure that I'm hydrated and I have sufficient electrolytes, when I first wake up in the morning, I drink 16 to 32 ounces of water with an element packet dissolved in it. I also drink Element dissolved in water during any kind of physical exercise that I'm doing, especially on hot days when I'm sweating a lot and losing water and electrolytes. Element has a bunch of great tasting flavors. In fact, I love them all. I love the watermelon, the raspberry, the citrus, and I really love the lemonade flavor. So, if you'd like to try Element, you can go to drinkelement.com/huberman to claim a free element sample pack with any purchase. Again, that's drinkelement.com/huberman to claim a free sample pack. >> I love that you're sharing this. Many people will um find comfort in hearing that. You know, my podcast producer uh Rob Moore, he's done multiple triathlons and he's he's an endurance guy. Um at one point in his past, he was like really he had carried a lot more muscle. He's still very like fit and strong, but he shifted over to endurance events. And this guy can work >> like nobody's business. Can work for hours and hours and hours and hours. And I feel like that's how I was in graduate school and as opposed to doc. I suppose I'm more of an endurance athlete with my mental work. I think maybe we should start thinking about cognition in these terms. Um because after all, we're not just two people talking about work habits. >> Um you're a neuroscientist and you study sensory integration and brain states and I I still consider myself a neuroscientist even though I haven't gotten my hands dirty in the lab in a while. Um, I think this is very important because I think people uh flagagillate themselves over the fact that they couldn't pay attention to write one paragraph. Um, and they think that therefore that means they shouldn't write or that they can't write more than one paragraph, but they need to sounds like they need to create a system. >> I come out of the little the little mini internet break knowing what the next sentence needs to say. >> Interesting. So you're really an like an interval athlete when it comes to mental work >> with the hard stuff. With the easy stuff, I can just, you know, do it right. [clears throat] >> But it's this it's this sense of effortful cognition >> that that takes its own time and it just takes its time >> and I don't control that. I do try to set myself up to allow the mental work to happen when I'm in the shower or in the car or whatever. So, for example, if I'm going to work on a grant application with somebody and we're sharing, you know, the writing and I know I can't start until I've had a conversation with the collaborator about who's doing what and what we think this grant is going to be about, you know, I might let that, you know, set up that meeting when there's going to be downtime afterwards. I did this just yesterday. I had a meeting yesterday morning knowing that then I was going to be on an airplane for quite a while knowing that without my having to do anything about it, the ideas are going to marinate. >> They're going to stuff is going to be happening that I'm not aware of and that when I come out of that, I'll probably know what I want at least the first couple of sentences to say. >> Yeah. you trust the uh the sort of um the process of a brain state shifting back and forth. You don't you don't fight it. You trust it. >> Yeah, I have to. I mean, I don't see any other way to be to do it. But I think it's a little like, you know, you need rest and recovery for physical exercise. And honestly, it's not like the brain and the and muscles are all that different from each other. Right. Well, I always think of all nerve action as motor and uh we could talk about that. I mean Sharington said right the final common path the Nobel Prize winner sharing the final common path is movement. I mean that's what we evolved to do first and >> and thinking is a form of movement. It is hard for people to grasp sometimes but um and people perhaps can grasp it more easily in the context of songs. Certain songs sound like they're moving forward like it feels like a physical progression. They make you want to move, right? they actually inspire movement. Um, actually there are very few sounds that inspire stillness. They're they tend to be the, you know, slow oscilly sounds, ocean waves, things that don't have a structure, right? >> They're very fractal and but like to the point where you you don't see that fractal structure. It just kind of breaks up and then your mind just goes into drift. the the only other person I've ever met who um has described embracing their mental process the same way that you have is uh my good friend and the you know he's this like worldrenowned producer Rick Rubin who um he just trusts that there are certain times a day when things are going to come to him that certain things aren't ready and they just need to marinate in sleep or in dreams and doesn't even really try and assign it to sleep and dreams just understands the the process it eventually is going to emerge he's not like why can't I get this thing out. And so he's very very much in flow with his own, you know, peaks and valleys and attention. >> Being blocked can mean you don't know yet what needs to come next. >> Mhm. Yeah. So important for people to hear because I think most everyone is trying to drop into that deep trench attractor state as quickly as possible, >> right? >> And yet there are ways that we can do that. And maybe we talk about that for a few moments. I um I'd be remiss if I didn't um ask about your experience as a musician. What instrument do you play? >> Well, I started off with flute. Um you know, starting in fifth grade. Uh now I play the banjo and I sing. >> Nice. When you're doing that, do you find that you can your attention is anchored for the duration of the performance or practice? >> Yes. Especially when performing, there's a certain um like I feel that the singing in particular can come out better in performance than it does in practice. >> Not always, unfortunately. The more technically challenging, you know, playing with the banjo is a little harder. You know, that the the adrenaline helps with the singing and hurts with the banjo, let's put it that way. >> Interesting. >> Yeah. >> Because adrenaline it was what this like inverted U-shaped thing. Like at very low levels, we can't focus. At higher levels we can focus and it gets too high we're discombobulated. >> Right. Right. Right. Yeah. Right. I mean it's just the shaking of the fingers that can be problematic. [clears throat] >> But the other problem is, you know, from an attention music performance standpoint, I would much prefer to sing a given song only once in a rehearsal than to go over it more than once because I can't remember the words the second time through. >> Interesting. >> And I think it's this mental checklist of I already did I already sing that? I remember sing I remember singing that but no wait a sec but now I have to sing it again you know and just kind of keeping track of where I'm at um gets harder the second time through. >> Pressure is an interesting um thing to explore in this context of of brain states because uh it sounds like you've embraced this kind of oscilly flow of your attention like in one context it works this way and you're not pressuring yourself to do something. There was a really interesting paper recently about the neural basis of of choking and not uh not physically choking but when um something really critical is on the line what happens. Did you see that paper? I thought >> I have not but like >> it's it's really cool. They they record from motor cortex >> and and a bunch of other areas. But the basic finding is that um >> if there's the potential for a low payoff if you get something right. Let's just say it's like throwing darts, which the analogous experiment would be like throwing darts. You say, "Well, let's say if you get on the dart board, you get a dollar." Um, if you get close within a certain distance of the bullseye, you get, I don't know, $1,000. Pretty good. Um, if you bullseye, >> you get $10 million. What ends up happening is that the performance on the high stakes condition is always worse, but just in terms of just even the basic mechanics. Yeah. >> And so choking turns out to be a recruitment of too many motor units. You basically you overinvest motor effort >> as opposed to staying chill and staying in the zone where you still might not bullseye. This wasn't the exact experiment but again it's analogous to what what they really did it. But you stand a much greater chance if you stay within the your ability. You already know how to do this thing. Um, and subjects choke when the stakes go way up because they just overinvest too much motor activity. >> Perfectionism. >> It's a trap. >> You have to almost mentally convince yourself that the stakes are lower, but you can't really lie to yourself. Anyway, it's pretty interesting. It's pretty interesting. I I I love that we're talking about brain states and sensory inputs. In this case, it's knowledge about outcomes, uh, potential outcomes. I want to talk about chickens. Yes, >> you have chickens. >> I do. >> And so, first I'll ask you about chickens and what you find so interesting about them. And then I I want your thoughts about a really wild wild finding about chickens and vision and attention. >> Okay. >> That anyone who's ever raised chickens on a farm >> probably knows, but only a couple of neuroscientists know. You'll probably know it, but anyway. What kind of chickens do you have? >> I have banttom meal flurs. So, banttom is little guys. >> They're little guys. Yeah. >> Meal flurs. >> Meal flur. >> How big are the eggs? >> Uh, they're half the size of a standard gradea large egg from the supermarket. >> Are they tasty? >> Very tasty. >> Okay. How many does it take to make a decent sized omelette? >> Um, well, double the number that you would normally put in in that. >> Okay. So, for me it would be like eight. >> Yeah. >> Okay. So, when did you start raising chickens? >> So, I had I had bantms when I was a kid. I live in Chapel Hill and around 2012 or so, maybe 2011, the town changed its zoning laws to allow uh chickens in the kind of neighborhood that I live in. So, I'm like, okay, this is this is what we're going to do. My husband's allergic to um dogs and cats and anything with fur. So, you know, chickens were kind of the option. I suppose we could have gotten rabbits and kept them outside. cat. >> You know, I won't say that we didn't have that discussion, but it didn't go [laughter] anywhere. >> They're pretty funny. I got a friend. They're sweet. They're like little monkeys. They're always crawling up people. >> Well, they really I do know have met a hairless cat, and I do think that they have lovely personalities, you know, extrapolating from this and of one. Um, you know, because they don't look so great, so they can't get by on their looks. >> Oh my goodness, this is funny. >> Oh dear. >> No, no, [laughter] no, no. It's I I totally I buy it. >> Yeah. >> Yeah. So they're very, you know, very pleasant personality, I think. Um, and the warmth of them because you can, you really feel the warmth of their skin. >> But anyway, so chickens, chicken, chickens, it was, um, and is. And, um, I like the banttoms because they really have a lot of personality. You know, they haven't been bred to be egg layers. They've been bred to be pets. Um, and say they have a certain, you know, pleasing uh, personality and interest in interacting with people that I think might be different from, uh, standard kind of farm chickens. >> Well, I have a uh, non-invasive experiment for you to try. >> Okay. >> Some years ago, I got very interested in the relationship between vision and brain states. Mhm. >> And there's some interesting literature about the fact that when we view horizons, uh especially from a vista um that it relaxes our autonomic nervous system, we go into more parasympathetic mode. >> And it turns out when we view horizons, our eyes naturally go into panoramic vision. We're not foviating to one. >> That's nerd speak by the way, neuroscience nerd speak to we're not focusing on one particular point. If you track one particular point, you obviously do a smooth pursuit of that point with your eyes. But um that you just go to a vista, you look at a horizon, you just your eyes naturally just dilate um as we say, right? But it's panoramic vision. Whereas when we um do a virgin's eye movement, bring our eyes together in a particular point, there's this really interesting increase in the output of areas like locus ceruius that are involved in attention, norepinephrine. I thought this is really wild and you know I was interested in respiration and brain states and >> like oh cool like maybe we're just staring into little boxes too much and that's why we feel like so attentionally um ex exhausted depleted. >> Makes sense. Attention's a resource. Okay. I think there's some evidence now to support every one of those statements. Although we need more brain recordings from humans to really get to the nitty-gritty. But then [laughter] my graduate adviser who unfortunately is passed away um had told me some time ago she said you know you can hypnotize chickens and I said um really cuz that's a lyric in an Iggy pop song uh hypnotizing chickens and I thought wait what? And she said, 'Yeah, you can hypnotize chickens, but they're not really hypnotized. They're just hyperfocused. And I was like, 'Isn't that what hypnosis is?' And she's like, "Yeah, I guess." I thought we always thought hypnosis was like a dream hypnosis is a state of hyperfocus. I have a colleague who does clinical hypnosis, David Spiegel. It's a pro approved by the American Psychiatric Association. Hyperfocus. Here's what you do, and you can find this. People who grew up on farms do this. They'll, and there videos of this on YouTube. They take a chicken and they'll hold the chicken and they'll draw a line in the dirt and they'll place the chicken's beak on the line and the chicken will just stay there for many many many minutes. You actually have to pick them up and kind of get them to orient to the rest of their visual field. Turns out that any birds that eat off the ground have a very complex like sensory motor challenge that my colleague the late he died of old age. Harvey Carton told me about which is, you know, they got this tiny beak and the seed is small >> and >> they, you know, you and I could pick up things off a table and and and pretty quickly, but they're doing this with this tiny be, but their eyes are on the side of their head. >> So, in order to do that, as their head descends really fast, in order to not smash their beak into the surface and make an accurate >> uh pickup of the seed or whatever it is, >> they or bug, >> their eyes undergo a virgin eye movement. they shift their eyes inward and they get a little cone of attention. So when you draw a line and you focus them down, they're literally >> they're stuck in that cone of attention. >> And then I started looking at the literature on behavioral treatments for ADHD and or just for attention. And not in this country, but in China, many schoolroom classrooms begin before the lesson with the kids literally focusing on a single spot, which seems a little bit like kind of uh military. Um but they have embraced this relationship between visual attention and overall kind of ability to cognitively focus and chickens do it. >> Kids in China are doing it and it actually has been shown to work pretty well for improving attention in you know the the subsequent you know 40 minutes to an hour. >> That's really interesting. >> The so our attention tends to follow our vision not necessarily the other way around. So, I've seen some of these chicken YouTube videos. Um, but I haven't I haven't dug into it yet to um try it with my own chickens. But now you're motivating me to to try it. >> Yeah. Let me know what you find. >> As far as you know, is the drawing of the line an important part of this. >> Yeah, it is. >> You can't just put a line down and then bring the chicken over. >> Yeah. So, I have to look at these videos again. It's been a little while. But what they do is they they place the chicken the kind of beak facing down, but they're not like pushing the the bird down and then they they they draw the line starting from the beak. >> Starting no starting >> I can't remember if it's starting from the beak outward or outward toward the beak. What it does is it Harvey was the one. Okay. But Harvey the the late great Harvey Cardon I should just mention he's uh I'll put a link to an obit I wrote. He was one of the >> history and histories and the world's most incredible comparative neuroscientists. He also was a fire hose of information. He used to walk into my lab and just start talking about diving birds and talk. Yeah, he was one of those. But >> uh he made me seem quiet. >> And >> he explained that they when the birds which have eyes on the side of their head do this virgin's eye movement, >> they get locked there. >> So maybe it has to be away from the beak toward the beak >> probably. Yeah. Um, and it's funny because I mentioned this a few times um, places before I had a podcast and people who grew up on farms were like, "Oh yeah, we would do that." You can actually you can actually then take the bird and flip it over. >> Yeah. >> Aggressive roosters become very calm. >> You can or or m you can work with them manageable. And so the the vision drives our brain states. And I think about this a lot in the context of the phone where our vision is brought into this little box, >> but the number of different contexts within that box is is infinite. >> I mean, do you find I mean diving into the phone thing, um I'm definitely going to try the chicken thing. Um >> yeah, let me know. >> Yeah, maybe I'll make a video. Um >> I mean blinders like they put on horses. >> Yeah. Yeah. Or they put on Yeah. I mean our own fal falconers use these, right? The idea is you you're trying to >> physically make you focus on one thing. >> That's right. And there's some funny pictures um that you can find on X every once in a while of focusing tools from the 1930s where they would literally put kids in these helmets with just two little eye portals and it was supposed to keep the kids that couldn't pay attention focused on their work so they wouldn't see any other kids. We think about it so it seems so silly and so barbaric. Well, I think too it could be helpful to ponder why one's attention is being drawn to other things because I think that um like the most relaxed I can get these days is if I know someone else is monitoring the state of the world and will let me know if there's some major disaster. >> I've had to do some of that outsourcing too, >> right? But having that outsourced is super helpful because it satisfies the need to have a warning system >> going on at all times >> and it allows me to kind of, you know, then focus in on, you know, what's in front of me right at them at the moment. I give you an example that's not really about attention, but it's about like what's the best way for me to achieve a state of relaxation. So, I went on a lovely rafting trip in Idaho this past summer. I have a Zolio satellite communicator. This is basically a thing that interacts with your phone and interacts with a satellite. Um, you can you can't make phone calls, but you can send and receive text messages. And I brought that along because I felt that I would probably be more relaxed knowing that if something really bad happened, people could reach me >> than being completely out of touch. Mhm. >> So for me that sort of middle middle space of like some contact >> otherwise I'm going to be you know a heightened state of arousal when I come back out from the you know from the remote wilderness. >> You know I think about people like my niec's generation. She's you know late teens about to hit her 20s. And to completely remove oneself from uh smartphone technology in that age bracket >> um sets up a a kind of a return to or a return to communication with others that probably involves a lot of stress. >> Yeah. >> Like what are you going to get? It's like opening your email after a two-month vacation. You just can't do that when you're running a lab. And then the the re-entry is so painful >> of that sort of onslaught of >> of things and um you know even emotional messages from people that if you read them in order you know and it's five or six days ago and you're like then you see follow-up messages and things got resolved without you usually fingers crossed usually that's what happens. It so rapidly wipes out that state of calm that you can get from being out in the wilderness. >> Yeah. I I will um periodically go into the wilderness. I did this recently and I I didn't notify enough people. I notified the critical ones >> and people don't like it. >> No. Well, I wish we could set up an auto reply for text messaging. >> That would make me feel more calm. What I'm hearing from you is that you embrace the natural, you know, peaks and valleys in your attention. You've figured out what works for you in different contexts. It's not like it's always one sentence a break. One sentence. It really depends. And I think, >> you know, we we hear a lot about how phones are the problem. We had Jonathan Haye on this podcast. He's the most vocal out there. And I really support his message. >> Um, so I want to be clear about that. But >> for many people, it's just not feasible. people with kids, people with with jobs, people with, you know, um you know, outside the elementary and high school classroom, >> people need to be accessible if something critical comes through. And and I think that's really the thing is it's it's just very unfiltered >> and and that's what is leading to so many challenges with getting real work done. >> I think the movement to get them out of schools is good. Um, you know, we I felt like we as parents, we had no choice that the that our children were being it was a required part of of what they had to do in the classroom was to have access to the internet on something. >> You know, at least recognizing that problem and being a little more thoughtful about it. And, you know, the cases where schools have decided to keep the phones all the way out of the classroom, I think are um certainly that's worth trying and let's see how it goes. So, I try to be aware of what am I getting from the phone at any particular moment in time or for any particular purpose. So, I feel pretty good about texting with my friends and family. >> I feel great about using it to um have access to public transit in a city that I'm not familiar with. >> Love that. >> Love it as a travel tool. Love it for, you know, booking plane flights and things like that. So convenient that I can do that. It frees up time that I would otherwise be at my computer doing some deeper work, you know? Okay, now I can do that on my phone somewhere when I just have a free moment. So, I love that. I think it's useful for me to try to be aware of what do I want to get out of my phone right now and am I just bored? you know, if I'm using it because I'm just bored, that's the thing that, okay, let me see if I can swap it out for something that might be a little healthier, like listening to a podcast or listening to an audio book or reading a book on my phone or reading a book actually a book. Um, that can be good. I've tried to set myself up with some exit paths from being on my phone. like, okay, yes, I will admit it's one of the first things I do in the morning. I know I should go outside and touch grass and get some sunlight. I know. I know. >> Set that circadian rhythm. >> I Well, I often wake up before it's light out, so >> I I have to wait for that anyway. So, for example, I'll do my one or two hits on Dolingo >> and one or two other language apps. I'll do a couple of my favorite games on the, you know, New York Times games site. Um, but those are usually things that like there's a sense of satiety. There's a sense of being finished. >> Like it's not an endless scroll. >> I have completed one lesson, >> so there's a moment to get off the phone. >> I'd love to have an app that limited the endless scroll on social media, like an interface to social media that that sort of served me. Mhm. >> Um maybe some designated number of posts and then I would have to take some explicit action to get more and that might help me get off. >> Yeah. based on the the uh dopamine literature and um everything I know about the brain, I decided that um any activity that has a seamless on-ramp to full attention >> and that has no end point. You mentioned end point >> is the thing to be really careful of. Yeah. Yeah. >> So, the seamless on-ramp to grabbing it, full attention. It's like from flat sur it's like ball bearing from flat surface into the trench. >> There's no work involved, >> right? >> And then you're there and you can stay there as long as you want. >> Yeah. >> Doesn't kick you out. You have to kick yourself out >> or life kicks you out cuz you didn't go do something or something happens. >> So, that's key. Um, so that's the slot the slot machine analogy. Very easy to play a slot machine >> and it's very easy to spend out all your money on a slot machine. And so they created this thing like where you can go get more money out of a machine, right? So you can continue playing on the other machine. And that's the same thing, but it's it's how seamless it is. Like you don't even need to learn the card game to gamble. You just have to know how to pull a lever, press a button. >> Social media is a bit the same. My solution to the social media thing is I took an old phone. >> I put X and Instagram on that phone. Those are the only two social media platforms I use. >> And it's somebody sends me something on my phone like a social media. I don't I can't go to it. So my I I have to segregate social media. I have a social media phone and I only get a certain amount of time with it. >> You can't get into your social media from a browser. >> Uh no. >> Okay. >> No. I I So like if someone sends me an Instagram post, I click on I can't see it. I get that error saying sign in and I I'm not signed in. It's like I don't even know my password. Okay. >> It's written someplace. >> Yeah. >> But I have a password generator. It updates all the time anyway. So yeah. So, so the solution was to create >> to log out and then have a phone that just had those. >> I don't even have the apps on my that phone. I would have to install the apps. I'd have to sign in. I'd have to I'd have to find my password, which my team knows I'm never going to happen. I'd have to >> log in. So, I just >> too many keystrokes. >> I just don't have access to it. I I it unless I'm on that phone. So, >> that's great. I think that's perfect. >> That I mean works for me. >> Works for you. >> Works for me. But I think [clears throat] having systems like this is like going to be required for most people because I I don't I don't think anyone's going to create the app that you're looking for. I hope they do, but I don't think they're going to. >> Yeah. >> So your lab is still super productive. So when you're in the lab presumably and >> interacting with students and writing grants and stuff, all this stuff falls away, right? It's because inside the lab context, it's like your workshop. I'm guessing that makes it much easier. >> That's true. That's true. Yeah. Yeah. When I'm interacting with people at work or I'm in the actual lab, um it does it all falls away. >> Yeah. >> Yeah. The the the cues to stay focused are very strong. >> I knew we were going to talk about the auditory system >> and we did. I knew we were going to talk about the visual system and we did. And I knew we were going to talk about their integration. And what I did not expect, what I'm so delighted happened is that you brought us into the realm of of true multiensory integration and the extent to which our physical environment shapes the way that our brain works. And our brain is also creating its own internal environment and that we have a lot more control over that than perhaps we think unless we just leave it to circumstances, which is really the the takeaway that I I at least I pulled from this last portion of our conversation. So, thank you so much for coming here and explaining this. We've not um talked about multiensory integration before. I started off by saying that and now we have and um I'm so glad that you were the one to introduce it to us because it's a fascinating aspect of how we work. And it's really like the core mechanics of how we work. When we talk about thinking or you know or working or focus, we're not just talking about vision or hearing. We're talking about their verge. So, >> exactly. Thank you. >> It's really wonderful. And let me know how the experiment with the chickens go. [laughter] >> Yeah. >> Thank you so much. This has been great. >> Oh, I really enjoyed it. Thank you. >> Thank you. >> Thank you for joining me for today's discussion with Dr. Jennifer Gro. To learn more about her laboratory's work and to find a link to her excellent book entitled Making Space: How the Brain Knows Where Things Are, please see the show note captions. If you're learning from and or enjoying this podcast, please subscribe to our YouTube channel. That's a terrific zerocost way to support us. 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