How Meditation Works & Science-Based Effective Meditations

Andrew Huberman 0:00 (Music) Welcome to the Huberman Lab Podcast, where we discuss science and science-based tools for everyday life. I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today, we are discussing meditation. We are going to discuss the science of meditation, that is, what happens in the brain and body while we are meditating, and we will talk about the science of meditation as it relates to how the brain and body change as a consequence of meditation, that is, what you export or take from a meditation practice that can impact everything from your sleep to your mood. For instance, meditation has been shown to alleviate symptoms of depression. And we will also talk about how meditation can be used to enhance focus and other states of mind that are useful for work and other aspects of life. Now, of course, most of you have probably heard of meditation, and when we think of meditation, most often we think of somebody either sitting or lying down. If they're sitting, we might imagine them in the so-called lotus position, you know, sitting with legs crossed, very upright with hands on the knees or, you know, crossed in our lap or something of that sort. Typically, we think of somebody who's in a very calm state, eyes closed, focused on their so-called third eye center. The third eye center is the area just behind one's forehead. There's no third eye there, at least, uh, there shouldn't be. But I'll tell you why it's called the third eye center, what the origins of that are, and why it's relevant actually for a meditative practice. With all that said, it turns out that meditation encompasses a huge variety of different practices. Some of those practices indeed are done sitting or lying down with one's eyes closed, focusing on the third eye center. Other of those practices are focused on a body scan, you know, really focusing on one area of the body and its contact with whatever surface you happen to be sitting or lying on. Or can be done walking, in fact, there are walking meditations done with eyes open. So there are many different forms of meditation, but today we are going to focus mainly on how specific types of meditation and specific areas of the brain that are activated during those meditations change our way of being in fundamental ways, not just during the meditation practice but afterwards as well. So if you're somebody who's interested in changing your default state of mood or of thinking, or enhancing your ability to focus, or improving your sleep, or improving performance in some cognitive or physical endeavor, meditation is powerful but you want to make sure that you pick the right meditation practice. So we will talk about picking a meditation practice that isn't just feasible because you'll do it, but is actually directed at the goals specific to you and what you need most. So to give you some sense of the contour of today's episode, first I'm going to talk about some of the underlying biology, the mechanisms and the brain areas and also the areas of the body that are activated during certain forms of meditation, and equally important, which areas of the brain and body are shut down or reduced in their activity during specific types of meditation. Then I'll transition into how to best do a meditation practice, how to get the most out of that meditation practice. And then I will talk about how to change or alter your meditation practices according to your specific goals and as you get better at meditation. And this can get a little bit counterintuitive but in a positive way. What I mean by that is, for instance, a lot of people think that as you meditate and get better at meditating, you need to meditate more and more and more, sort of like if you get better at running endurance races that you need to keep running longer and longer, you know, first a 5K, then a 10K, then a marathon, then ultras. With meditation, it's actually quite the opposite. The better that you get at dropping into a particular brain state and the more your so-called traits of brain state shift, not just states as they're sometimes referred to but traits, this is a theme that I've picked up from a terrific book that I'll refer to later, but the more that you can get into specific neural circuits quickly, actually the less you need to meditate in order to derive the benefits of meditation. So that's a wonderful aspect of meditative practices that's unlike a lot of other forms of mental exercise and cognitive enhancing exercises. So we'll talk about all of that today, and I promise that by the end of today's episode you will have a rich array of meditative practices to select from, you'll know why each of them work and why they can be directed toward particular goals and how to do

Andrew Huberman 4:13 that, and you'll also know how to modify those meditation practices under conditions where you might get busier or where you're suffering from lack of sleep. And I think a lot of people will be excited to know that today we are going to discuss a specific form of meditation that can indeed reduce your need for sleep and still allow you to enhance your cognitive and physical abilities. 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, I'd like to thank the sponsors of today's podcast. Our first sponsor is InsideTracker. InsideTracker is a personalized nutrition platform that analyzes data from your blood and DNA to help you better understand your body and help you meet your health goals. 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Andrew Huberman 8:25 Let's talk about meditation. As I mentioned earlier, we are going to talk about what areas of the brain and body are active during meditation and after meditation, and why that can be so beneficial. We will also talk about when and how best to meditate. Now, this is a topic I've long been interested in. I was first given a book on meditation when I was in high school, 'cause, to make a long story short, I was a bit of a wild one early in my high school years, and as a consequence of a program that I was in, somebody handed me a book on meditation. That book is still available now. That book is called Wherever You Go, There You Are by Jon Kabat-Zinn. He was one of the first, not the only, but one of the first people to really start popularizing meditation mindfulness practices in the United States. So this was in the late 1980s, and it was really only until recently that there were very few studies of meditation, although those really picked up in the '90s. Now, you can find many, many thousands of studies on meditation and their mechanistic basis of brain imaging studies, changes in hormones in the body, but in the late 1980s and in the early 1990s, because functional imaging of the brain, so-called MRI or fMRI, was really just starting to emerge as a popular tool in laboratories and hospitals, there really wasn't that much mechanistic understanding about how meditation worked. But, of course, there was a deep understanding from cultures outside the United States that meditation was extremely useful. I should just mention, as long as we're talking about the history of meditation, any discussion about meditation is going to be a discussion about states of mind, and any discussion about states of mind invokes the word consciousness, a kind of a, a dangerous topic to get into in any format, because a lot of people talk about consciousness, but people use consciousness, the word, to mean different things. It doesn't have one standard operational definition, as scientists call it. However, discussions about consciousness are often part and parcel with conversations about things like psychedelics and kind of alternative therapies. And so in the 1960s and especially in the 1970s, meditation and psychedelics were actually close cousins in the conversation about consciousness and states of mind. That conversation started to split into two different divisions, and I'll explain why in a moment. It gets to a little bit of interesting academic sociology. But what happened was, there were a couple of guys at Harvard, including Timothy Leary and others, who got really interested in psychedelics, in particular LSD, lysergic acid diethylamide, and at that time, that was part of the whole counterculture movement. It was considered very anti-establishment, and they were really encouraging students at Harvard to take LSD. They were also very interested in meditation, but what ended up happening is they essentially got kicked out or fired from Harvard, and there's a book that I'll refer you to in the show note captions if you're interested in learning more about all this. But they got kicked out and fired for their emphasis on psychedelics. Now, nowadays, there's a lot of interest in psychedelics.We've had episodes with Dr. Matthew Johnson from Johns Hopkins University, who's running clinical trials on psychedelics like psilocybin and LSD for the treatment of depression and PTSD. We've also had Dr. Nolan Williams on the podcast, my colleague at Stanford, who's doing incredible studies on some of those compounds as well. So nowadays, the conversation about psychedelics is coming back, and it's somewhat divorced from the conversation about meditation. But in the 1960s and 1970s, the conversation about psychedelics and meditation was sort of one and the same. That changed in the late 1980s and early 1990s when people like Jon Kabat-Zinn started writing books that were purely about meditation and suggesting that people explore meditative practices for the utility to bring calmness, adjust stress, improve sleep, et cetera, divorced from the conversation about psychedelics. Now, that's not to say that the scientific community immediately embraced the conversation about meditation. In fact, it took quite a long while for schools like Harvard and Stanford and other universities around the world to start embracing and funding studies of meditation, asking what sorts of brain areas are involved, how it changes the body, and perhaps most importantly, how a meditation practice can shift the brain and body when somebody is finished meditating and is off in their life doing their everyday things. In the late 1980s and especially within the 1990s, the advent of brain imaging technology like magnetic resonance imaging, MRI, or functional magnetic resonance imaging, was a way to look at the brain while it was active, not just to get a, an image of its structure, but also how it's functioning, the areas that so-called light up. When all of that technology became accessible and popular, well, that allowed a large number of laboratories to start asking how specific patterns of thinking and breathing, maybe people sitting in the lotus position, but more often than that, it would be people inside of an MRI magnet, because it is a magnet, so it would put you into a little tube and push you into the tube, not against your will, of course, but put people into the tube, have them meditate, and then look at how the brain changed, and to do that over time. When those studies were done, what was discovered was really quite miraculous really, and now we don't think of it as surprising, but what was discovered was a huge laundry list of brain changes. And then when people were evaluated in their outside life, so when they would fill out reports of their subjective feelings of happiness, or they would report their sleep, or even if objective measures were taken with changes in hormones or markers of inflammation, et cetera, a large list of information fell out of that, which revealed that indeed there are many, a dozen or more, clear benefits of a regular meditation practice. And some of those meditation practices could be quite short. So nowadays we think of meditation as pretty commonly accepted, and in fact that has a lot to do with the fact that many of the major tech companies in the Bay Area during the s- 2000s, such as Google and Apple and any number of different social media companies and other companies and business ventures, et cetera, investment firms all over the world started hiring people to train meditation or had online courses for meditation. So nowadays we think of meditation as this thing that almost everybody understands can benefit us, but we now sit at an interesting frontier where most people think of meditation as one thing, sort of like the word exercise, which of course could mean weight training, it could mean running, it could mean high intensity interval training, all of which, as you know, will get you different results depending on what you do, how often you do it, and the specifics of what you actually do. So too meditation can give you very specific results. It can give you more focus, it can give you better sleep, it can give you a combination of results, just like exercise can depending on the exercise. So what we are going to talk about next is the specific changes that happen in the brain with specific aspects of meditation. That is, what happens when you close your eyes? What happens when you focus your attention inward versus focusing your attention outward? Because as I mentioned before, there's third eye meditation where you close your eyes and focus on that spot just behind your forehead, and you focus on your breathing. There's also meditation practices where you're focusing on what you're eating with a lot of so-called mindfulness, being very present to whatever's happening, not letting your mind wander or think about yesterday or tomorrow, what's happening next, but really focusing on the present. There are also meditation practices, of course, where you are in a format of interpersonal communication, where you're really listening very intensely. That too is a form of mindfulness. So we're going to parse each of these things, and we are going to ask what's happening in the brain and body during each of these meditation practices so that you can develop specific meditation practices that you can invoke in your real life on a daily basis. Or thankfully, I would say for some who are pretty busy, that you could even do once a week or even once a month that will still clearly benefit you in specific ways.

Andrew Huberman 16:19 I'd like to spend the next ten minutes or so talking about the neuroscience of meditation. And I promise you, I'm not going to just list off a bunch of different brain areas that are active during meditation. That wouldn't be useful to you. In fact, I don't believe in throwing out a lot of nomenclature without also giving some mechanistic explanation as to what different brain areas do. And you could say, "Well, what good is it knowing what different brain areas do and their names if I can't actually manipulate those brain areas?" But the good news is, you actually can manipulate those brain areas. As I'll tell you today, you can turn up the activity in certain brain areas and turn down the activity in specific brain areas with specific elements of a meditation practice. So that's quite exciting and quite different really from other aspects of neuroscience that we might discuss on this podcast. So there are a few different brain areas whose names I'd like to arm you with. And again, the names themselves aren't essential, but if you can grasp even the top contour of what I'm about to say, you'll be in a much better position to parse and use the information that follows. There's an area of your brain that sits right behind your forehead that's called the prefrontal cortex. Basically it's the front bumper of your head just behind the bone, okay? That area just behind your forehead that we call the prefrontal cortex actually encompasses a lot of different things, and actually-You have two of them. You have one on the right side of your brain, and you have one on the left side of your brain. And they're connected to one another, but they actually do different things. The area that I'd like to focus on today for a bit is the so-called left prefrontal cortex, or if we were going to get really specific, we'd say the left dorsolateral prefrontal cortex. Dorsal means up, lateral means to the side. So if you want to touch the left side of your head and move your hand just toward the midline, toward the sort of top of your head a little bit, so that's dorsal, and then lateral. As long as your hand is still on the side of your head, you're in the left dorsolateral prefrontal cortex. Okay? So you got your hand probably right over your d- left dorsolateral prefrontal cortex. That area of the brain we know from lesion studies where it's been damaged in animals or humans, and we know from stimulation studies where it's been selectively stimulated in animals, or yes, indeed, also it's been done in humans, has an incredible ability to control your bodily senses and to make sense, that is to interpret what's going on in terms of your emotions and your bodily sensations. So from now on, unless I say otherwise, if I say prefrontal cortex, I'm specifically referring to the left dorsolateral prefrontal cortex, but I'm going to shorten that up just for sake of simplicity and ease of communication. If I'm going to talk about another area of prefrontal cortex, I'll talk about another area. But if I say prefrontal cortex today, what I mean is left dorsolateral prefrontal cortex. Stimulation of left dorsolateral prefrontal cortex, or I should say more appropriately, when your left dorsolateral prefrontal cortex is active, you are in a great position to interpret what's going on with you emotionally, to interpret your bodily signals of comfort or discomfort, and then to make really good decisions on the basis of that interpretation. And that's because the left dorsolateral prefrontal cortex is in direct communication with and is directly connected to another brain area called the anterior cingulate cortex or ACC. Now, I'm just going to refer to it as the ACC. Okay? The ACC is an area of your brain that is interpreting a lot of different things about bodily signals. For instance, how fast you're breathing, whether or not your heart is beating quickly or slowly, and more importantly, whether or not your heart is beating quickly or slowly for the circumstance that you are in. So for instance, if you're running up a hill and it's a, you're in, even in great shape and your heart is beating very fast, it's unlikely that you're, are going to be concerned about your heart beating fast because that is appropriate for the circumstance. However, if you're just walking along and all of a sudden your heart starts beating very quickly for no apparent reason, well then, you are going to interpret that as either pathologic or d- uncomfortable, inappropriate for the context that you happen to be in. The left dorsolateral prefrontal cortex is the area of the brain that actually has some control over and especially can interpret what's going on in this ACC region. Now, most of you probably haven't heard of the ACC. Most of you probably have heard of a brain area called the amygdala. It's an almond-shaped structure on the two sides of the brain. People talk about as the fear center, et cetera. But your ACC, the anterior cingulate cortex, gets input from areas like the amygdala, your threat detection centers, but e- it also gets input from an enormous number of other areas of your brain and body, including your heart, your gut, so it gets information about how full, that is distended, or how empty your gut is. It gets information about how quickly you're breathing from input from your lungs and related structures. It's an absolutely critical station for making sense of what's going on in your body, and it works very closely along with one other structure, and I promise this is going to be the third structure in this triad, and then I'll stop listing off names. So we have dorsolateral prefrontal cortex. Think of that as sort of the interpreter of what's going on inside of you. You have the ACC or anterior cingulate cortex, which is the area of your brain that's bringing in all this information about what's going on inside your body and e- even on the surface of your body. You know, if you have any pain or an itch or a mosquito bite on the surface of your body, your ACC would definitely register that. And then there's this other absolutely incredible brain structure which is called the insula, I-N-S-U-L-A, insula. The insula has a bunch of different parts to it, but the insula is another area that is interpreting signals of what's going on in your brain and body. So the ACC and the insula are working together to try and figure out, you know, what's going on inside me? And in addition to that, the insula is interpreting information about what's going on outside of you. So your insula is saying, for instance, "Hey, this is a steep hill that I'm running up, and as a consequence, whatever heart rate increase that I'm experiencing or heavy breathing or burning in my lungs, this all makes sense. I don't have to be worried. I don't have to be scared. I might want to slow down, but this makes sense." Whereas it, for instance, in the example I previously gave where if you're sitting in a room and everything is pretty calm and all of a sudden you start feeling really uncomfortable, like your stomach doesn't feel right or you start breathing quickly or you start having a so-called anxiety or panic attack, in large part that's because the shift in your bodily sensations doesn't match or doesn't correspond to something in the outside world. So there's this incredible triad which includes the left dorsolateral prefrontal cortex, the cingulate or anterior cingulate cortex, and the insula. And those three are working together in a kind of conversation. It's a neural conversation, but a conversation nonetheless trying to figure out, okay, what's going on inside me? How do I feel? What am I thinking about? And this could be thoughts about the past or the future or the present. They are also in a conversation as to whether or not the sensations that you're experiencing, meaning how quick your breathing is or how slow your breathing is, how your heart feels, how your skin feels, any sensations of pain or pleasure for that matter, whether or not that makes sense for the situation you're in and trying to determine whether or not you are doing the right things as a consequence of those sensations. Okay. So again, if you can't remember the names of these different neural structures in the brain, don't worry about it. It's really not that critical. What is critical is that you understand that there's a conversation that's constantly occurring...... as long as you are awake, trying to figure out what's going on inside of you, whether or not it makes sense relative to what's going on outside and around you. Now, humans are smart. That is, we are, to some extent, conscious of the fact that we have memories of the past, awareness of the present, and anticipation of the future. So, we do realize, for instance, that we can be sitti- seated at the dinner table, excuse me, and have a thought about something tomorrow, maybe an exam that's stressing us out or something like that, and that will change our bodily state in a way that is not optimal for what we're doing in the moment, but that can still make sense to us because that exam is important. Maybe we're feeling some pressure about a hard conversation we have to have. Or, maybe we are very excited about the next day and we can't eat because we're so excited, and that can make perfect sense to us, because we do have access to this knowledge about self that we can think about the past, the present, or the future. So, that makes the conversation these three structures are in even more interesting and dynamic, because what it means is that we can be doing something, eating, talking, running, any number of different activities, and our bodily state may or may not match what we are doing in a way that's adaptive for that, and yet that can be completely okay or at least understandable for us. Now, a major emphasis of a meditation practice is to make us so-called more mindful. What is mindfulness? Well, again, there isn't one perfect universally accepted operational definition of mindfulness. That's basically nerd speak for saying people can't agree exactly what mindfulness should be, is, and means for everyone. But most people assume, and I think agree, that mindfulness includes something about being present. And when I say present, that doesn't necessarily mean present to one's surroundings, because of course, a lot of meditation practices that are designed to make us more mindful and present are designed to make us more mindful and present to what's happening internally while ignoring everything that's happening externally. But they are designed to make us more present to our bodily sensations, and in particular, our breathing and our thoughts in the

Andrew Huberman 26:07 moment. So, n- let's now explore what a generic meditation practice looks like, and let's evaluate how that tends to change the activity of these neural circuits in the brain and body. And then from there, we can split the conversation into a couple of different bins. That is, meditation practices that are ideal for enhancing focus, meditation practices that are ideal for improving mood, meditation practices that are ideal for improving sleep, and meditation practices that, believe it or not, benefit all of those things in one fell swoop. Okay, so what happens during a meditation practice at the neural level? In order to answer that question, we are going to be scientists. That means you and I are going to be scientists now. We are going to break down a practice into its different component parts and address what we know for sure about the brain activation states that occur with those different component parts. In order to do that, let's use a somewhat generic form of meditation, but it's generic and pretty far-reaching, because I would say that for most people, about 75%, let's say, a meditation practice is going to involve stopping, meaning getting out of motion, sitting or lying down, and in most cases, closing one's eyes. Although, it is absolutely not required to close one's eyes during meditation. There are many forms of meditation that are done eyes open. But for most people, it's going to involve stopping our movement, that is, not ambulating, not walking or running, so se- seated or lying down with eyes closed. When we do that, meaning when we sit or lie down and close our eyes, as trivial as that shift might sound to you, it actually is a profound shift in the way that your brain and other neural circuits in your body function for the following reason. When we close our eyes, we shut down a major avenue of what's called exteroception. What do I mean by exteroception? Well, very briefly, we are sensing things on our body and in our body all the time. We are also sensing things from outside of us all the time. So, these could be sights or sounds, touch on our body, sensations withinside our body, et cetera. Now, sensation is distinct from what we call perception. Perception is, put simply, the sensations that we happen to be paying attention to. So, at any given moment, you are sensing many, many things. There are sound waves hitting your ears. There are pressure receptors on the bottoms of your feet sensing your shoes or your sandals or the floor, et cetera. But you're not perceiving them until you place your attention on them. Now, the way perception works is that you have so-called spotlights of attention. You can't perceive everything all at once, every sound, every sight, every touch. That would be overwhelming. In fact, that would be terrible. Rather, you have spotlights of perception that y- can either be very narrow. So, for instance, you could focus all of your perception right now on your big toe of your right foot and really pour all of your awareness, your attention into what you're perceiving there, what it feels like, if there's tingling or pressure, heat or cold, et cetera. Or you can broaden that spotlight to include both feet or all your toes on both feet, and then your legs and your whole body or the entire room. Perception is like a spotlight, and I should mention, there are very good data that we can split our attention into two, but probably not more than two spotlights, and we can make those spotlights of perception either very broad and diffuse or very narrow. You can practice this now if you like. You can pick a spot on the wall, uh, away from you anywhere, or if you're driving, you can look at some location and you can focus intensely on one small location.... for instance, a tree in the horizon or a person on the street, or any number of different things outside of you. Or you can broaden that spotlight to include the entire scene at once. You can also focus a spotlight of perception on your body, say on the left upper portion of your chest, and, of course, you can focus on the left upper portion of your chest and something outside of you. You can split your attention between those two perceptual spotlights. It's very hard, although not impossible, to have three perceptual spotlights. But most people can split to two points of attention or perception pretty easily. The other thing that most people can do pretty easily is merge those two spotlights, or rather to have just one spotlight of attention. So you don't always have to have two spotlights of attention on. And here I'm using the word attention and perception interchangeably. But you could, for instance, have two points of attention. So you're talking to somebody and you're paying attention to whether or not somebody's walking in the door or not, so that's two. Or you could be completely focused on the person you're talking to, or you could be completely focused on the stomach ache or the great sensation of hunger that you have in your belly while talking to somebody. In fact, you're not even listening to what they're saying at all. Okay. So you have s- two spotlights of perception. You can split them or merge them into one. And this is very important, those spotlights of perception can intensify or dim, and there I'm using analogy. What I mean by that is, your perception of what's happening within those spotlights can be very, very high acuity, that is you can register very fine changes in detail like tingling on one side of your big toe of your right foot versus the other, or it can be somewhat more diffuse. You're just thinking about your whole toe, which in that case seems like a small area. But the point is that you can consciously adjust the acuity, that is the fineness of your perception. All of this is under your power because of the incredible ability of a brain structure whose name you now understand and know, which is the left dorsolateral prefrontal cortex, although there are other areas of your brain involved as well. Your ability to direct your attention to specific things in your environment or within your body, or to split those points of attention, or merge them, or dial up the intensity of how closely you're paying attention to every little shift or ripple and change in sensation there, or to kind of dissociate, if you will, for lack of a better word, to disengage from that perception. All of that is under control because of your ability to engage this area that we call the prefrontal cortex, and in particular, the left dorsolateral prefrontal cortex.

Andrew Huberman 32:27 I'd like to take a quick break and acknowledge one of our sponsors, Athletic Greens. Athletic Greens, now called AG1, is a vitamin mineral probiotic drink that covers all of your foundational nutritional needs. I've been taking Athletic Greens since 2012, so I'm delighted that they're sponsoring the podcast. The reason I started taking Athletic Greens and the reason I still take Athletic Greens once or usually twice a day is that it gets me the probiotics that I need for gut health. Our gut is very important. It's populated by g- uh, gut microbiota that communicate with the brain, the immune system, and basically all the biological systems of our body to strongly impact our immediate and long-term health. And those probiotics in Athletic Greens are optimal and vital for microbiotic health. In addition, Athletic Greens contains a number of adaptogens, vitamins, and minerals that make sure that all of my foundational nutritional needs are met, and it tastes great. If you'd like to try Athletic Greens, you can go to athleticgreens.com/huberman and they'll give you five free travel packs that make it really easy to mix up Athletic Greens while you're on the road, in the car, on the plane, et cetera, and they'll give you a year's supply of vitamin D3 K2. Again, that's athleticgreens.com/huberman to get the five free travel packs and the year's supply of vitamin D3

Andrew Huberman 33:41 K2. Okay. So now if we look at the example of what happens when you sit or lie down and close your eyes and decide to meditate, you should immediately realize that that's a tremendous shift in your perceptual ability. Why? Because that spotlight of attention, while it can be oriented toward, for instance, what you hear in the room, or maybe the feeling of wind moving trees in the environment that you happen to be in, when we close our eyes, we shut down one of the major avenues for sensory input, which is vision. And when we do that, there's a tendency for those perceptual spotlights to be focused more so on what happens at the level of the surface of our skin and inside of our bodies. And that informs us about something very important, which is that there are actually two axes, or two ends of a continuum of perception. Up until now, I've been talking about perception and attention as kind of the same thing, and indeed they are, at least for sake of this conversation. But within that word perception, or within that word attention, there's a continuum and that continuum has on one end something called interoception. Interoception, spelled with an I, is everything that we sense at the level of our skin and inward, so the sensation inside our stomach, the sensation of our heart beating. Some people can sense their heart beating pretty easily, other people have more challenge doing that. What we are feeling on the surface of our skin, how hot or cold we feel, that's interoception. In contrast, at the other end of the continuum is so-called exteroception, spelled with an E. Exteroception is perception of everything that's outside or beyond the confines of our skin. So by shutting our eyes, and in particular, in a meditative practice where we direct our attention toward our so-called third eye center, this area right behind our forehead, which not so incidentally (laughs) is the prefrontal cortex, or in some cases where people will focus on their breathing, so the movement of their stomach, or the movement of their diaphragm, or the lifting of their chest, or the extension of their belly while they breathe, by doing that, we are......taking what ordinarily is a perceptual state that's split between the outside world, exteroception, and usually also toward our inner state. You know, most people are generally in touch with how they are feeling from the skin inward, while they are also paying attention to what's outside of them. You can think about somebody, for instance, at a restaurant or sandwich shop about to order a sandwich and you're reading the menu, so that's exteroception, right? The menu is outside the confines of your skin. And little ideas or maybe big ideas come to mind about what the roast beef sandwich or the vegetarian sandwich will taste like, what it will do for you, what- what's in it, what you like, what you don't like, et cetera. That's splitting interoception and exteroception. But when we close our eyes, we stop, we slow down, we focus on our breathing or that third eye center, the majority of our perception then shifts to interoception. And when we shift down to that end of the continuum of- of interoception, something very important happens. What happens is that those two regions, the ACC, the anterior cingulate cortex, and the insula, really ramp up their levels of neural activity. And that should make perfect sense to you, because those are areas of your brain that are registering and paying attention to the various sensations of how full or empty your stomach feels, whether or not the surface of your skin feels hot or cold, and on and on. So by just sitting down or lying down and closing your eyes, your brain undergoes a massive shift from exteroception to interoception. Now, that's not to say you can't be distracted by external events, and in fact, many people are. But the early stages of transitioning into a meditative state involve this shift down the continuum, or I should say, to one end of the continuum, 'cause there's no down up, there's just the continuum, shift along the continuum to heightened levels of interoception. Now, I mentioned this briefly before, but many people are very interoceptively aware, just naturally, even if they don't do a meditation practice. Other people are not. And there's a pretty good measure of whether or not you have high levels of interoceptive awareness or capability, and that is your ability to count your heartbeats without placing your fingers anywhere with any pressure to take your pulse. You can do this if you like, you can actually try and estimate your number of heartbeats simply by trying to feel your heartbeat. Some people are very good, meaning they're very accurate at doing this, other people are not. It does seem to be an ability that can be trained up quite a bit, and in fact, meditative practices will improve your interoceptive awareness. But, and this is a very important point, heightened levels of interoceptive awareness, while that might sound attractive, oh, to be really in touch with your body, that is not always beneficial. Why? Because many people who, for instance, have excessive levels of anxiety, have excessive levels of- of anxiety because they are very keenly aware of any subtle shift in their heart rate or breathing or change in their- the sensations within their stomach. Whereas other people who are less aware of their bodily state, that can be beneficial, right? It can be adaptive or not, depending on the circumstances. It's probably not adaptive to be very, very aware of your internal state. If, for instance, you're doing public speaking, you don't want to be thinking about what's going on in your stomach or how quickly you're breathing. I'm certainly trying to ignore all those, uh, signals, those sensations now. But for somebody who has no awareness of what's going on, very little interoceptive awareness, that can be problematic too, because these are the very people who can ignore the fact that they're having a heart attack or can ignore the fact that they have high blood pressure and are caring about life, focused on everything external with no awareness of their own body. They're, quote-unquote, "out of touch" with their body. So we want to be very careful about placing valence, which is a sort of value of good or bad, on interoceptive awareness versus exteroceptive awareness. More importantly, we want to emphasize that when you undergo a meditation practice, if it's of the sort where you stop your movement and close your eyes, you are training for interoceptive awareness. This becomes important later. We get into discussions about meditation for reducing anxiety. Some people may opt, in fact, I would say some people ought to opt for a meditative practice which involves more exteroceptive awareness, actually a meditation like a walking meditation or even a seated meditation, where they are bringing their focus to a place outside their body as opposed to inside their body. And in fact, there are examples of people who have meditated quite a lot who develop such a heightened state or awareness of their interoceptive components, that is, just fancy, again, nerd speak for so aware of their breathing and of their heart and of their- the state of their gut, that it actually is intrusive for daily activities. So I will ask you to ask this question of yourself now. Are you somebody who tends to be very in touch with your bodily sensations, so- so for instance, from the skin inwards? Or are you somebody who tends to be less in touch with or aware of your interoceptive state? There is no right or wrong answer, you don't get an A or an F or a D or a C depending on your answer, it's just a good question for each and every one of us to answer, and I think most people will answer that it depends. It depends on whether or not you are in a social setting or whether or not you're alone. But we are going to return to that answer, so keep it in mind, because it will become very beneficial in building an optimal meditation practice f- for you. But for now, just know there's this continuum of perception, interoception and exteroception. Closing your eyes increases interoception. Opening your eyes dramatically increases exteroception, just automatically. Just automatically, because so much of your brain, in fact, 40% or more is dedicated to vision, and this, I should say, for those of you that are low vision or no vision, and those of you that are blind or have poor vision, this entire process is translated to the auditory, to the sound domain. So it's true for people that can see it, it's true for people that can't see. Of course, people that can't see, closing the eyes doesn't have this huge shift towards interoception, but there have been a few studies, not as many as I would have liked to find, but a few studies of, for instance, people f-... who are blind or have low vision, don't see very well. And when they close their ears and they can't hear the external world, or they put headphones on or noise-canceling headphones, then the world inside of them becomes very prominent relative to the world outside of them, for obvious

Andrew Huberman 42:20 reasons. So I asked you to ask yourself whether or not you are somebody who tends to be more interoceptively aware or not, more exteroceptively aware or not. And some of you might not be able to answer that question, and if you can't, chances are that you are effectively sliding along that continuum depending on the activities that you're doing. So you're probably the kind of person where if somebody comes over to you and starts talking to you, you will engage in that conversation, and you don't feel so inside your body that you're thinking about your heart beating and whether or not you're flushing red, et cetera. You're going to pay attention to what they say. Many people, however, when somebody talks to them, if they have social anxiety, or even a slight bit of social anxiety, will s- be thinking about whether or not their cheeks are flushing or whether or not they look right or sound right, or whether or not they have something in their teeth. These are normal responses, but they really speak to this issue of whether or not you tend to shift more towards interoceptive awareness or exteroceptive awareness. And of course, it's context dependent. It will depend on whether or not you're, you know, out on a date with somebody that you know you would loathe to find out later that you had food in your, in your teeth, or whether or not you're with somebody you're more familiar with where that would not really matter much or the other person would tell you this kind of thing. What does it mean to be at one location or another lo- location along this continuum of interoception or exteroception? Well, we know what it means neurally, right? We know that if you are more interoceptively aware, your insulin ACC are active, but that's not very useful. That's not, that's not helpful as a tool. That's just a fact. Now, there have actually been studies of what a meditation practice can do in terms of moving you along this continuum from where you naturally sit in order to help you function not just during the meditation, but at all times. And in order to illustrate this, I want to start with a description of what is now a classic study. It's a very cool study, has a very cool name, talks about something very important that will come up again and again in today's conversation, and that's something called the default mode network. The default mode network is a collection of different brain areas that essentially are active when we're not doing much of anything, and certainly is active when we are not focused on one particular task or conversation or activity. The default mode network can be thought of more or less as the network that generates mind wandering, or our thoughts drifting from the past to the present to the future. Remember earlier I talked about how your perceptual spotlight can either be two spotlights or they can merge? Well, similarly, human beings can think about the past, surely, the present, definitely, and the future. And it turns out we can also split our thoughts, just like we can split our perception into two of those three things. So I can think about the past, a past event, and I can think about the present. I can split my thinking and my memory in that way. I can also think about the present and the future. I can also think about the future and the past, although it's very difficult, although not impossible, to split one's thinking and memory into the past, the present, and future simultaneously. Not easily done, but pretty easy to split one's attention and thinking into two of those three things, either the past, the present, and the future, or any two of those three things. Okay? Just like with attentional spotlighting, you can place your mind, your thinking, and your memory, your cognition onto one of those things and be very, very present, or the past and the present and so on and so forth. The default mode network, while it involves a lot of different brain areas, can be thought of simply as the network of brain areas that are active when your mind is wandering between these different time domains. And the paper I'd like to share with you, as I mentioned before, is now a classic paper, has a- a wonderful title, which is "A Wandering Mind is an Unhappy Mind." Now, that sounds almost like a news article or a- a news article about a scientific paper, but that's actually the title of the scientific paper, which was published in the journal Science, which is one of the three apex journals. You know, scientific publishing is competitive, but it's especially competitive to get manuscripts accepted into Science, into Nature, and into the journal Cell. So it represents kind of the- one of the kind of Super Bowl, uh, NBA Championships, and Stanley Cup, if you will, for you sports aficionados of scientific publishing. This is a paper from Matthew Killingsworth and Dan Gilbert. It was published in 2010, but it's still considered a classic. And this paper, "A Wandering Mind is an Unhappy Mind," has a number of very important points. I'm going to paraphrase certain elements of it for you, because they say essentially what I would like you to know far better than I could, um, than I could say. So first of all, they start out with a statement which I confess I disagree with, which is, "Unlike other animals, human beings spend a lot of time thinking about what is not going on around them, contemplating events that happened in the past, might happen in the future, or will never happen at all." I agree with their assertion that human beings do that. That's certainly my experience, although I must say, I don't think there's any evidence whatsoever that other animals don't do it also. So, uh, my apologies, Killingsworth and Gilbert, but I'd be happy to go toe to toe with you on that. I am not aware of any data that prove one way or the other what other animals are thinking. Uh, so let's set aside other animals and let's focus on the human animal. Now, their point is still a very good one, which is that humans have this, uh, wandering of the mind that they call stimulus-independent thought. That is, there's nothing happening to create these thoughts or anything happening in the immediate environment. These thoughts are just happening on their own internally. That's the default mode network. This study was important. In fact, it was a landmark study because they did it right about the time that smartphones became a- widely available and in use, so again, 2010. So they basically pinged people, they contacted people on their iPhones.... (smacks lips) many times per day, and they did this for well over 2,200 adults. They had a mix of male and female people in this study. The mean age was 34 years, but there was a range, mean, of course, being average, but there were a range of, of, of different ages and so forth. And at any moment, they asked people, "What are you feeling right now?" And they also asked them, "What are you doing right now?" So, they were looking for the match or mismatch between what people were doing and what they were feeling. They were essentially trying to probe what people were thinking about, and they also addressed that. And they came up with a, a kind of a, a bubble chart, if you will, where the bigger the bubble, uh, the more answers came back about one particular thing. And they assessed whether or not people were happy or not in that moment, or sad or not, whether or not they were focused on what they were doing or not. There are a lot of bubbles in this chart, so I'm not going to read them all. But the important points that came from the data, and again, this is a very large data set, was that... And here, again, I'm paraphrasing. First, people's minds wandered frequently regardless of what they were doing. You know, in nearly half of the samples taken, people were generally thinking about something else, except, it turns out, there's just one little bubble sitting way far out on the horizon here. People claimed, and I'm, uh, inclined to believe them, that they tend to be very focused on making love if they were making love in the moment where they were pinged on their iPhone. Now, why their iPhone was there with them at that moment, I don't know. That's, um, wasn't included in this, uh, description of the study. But all the other activities, grooming and self-care, listening to the news, watching television, relaxing, working, et cetera, et cetera, during all those activities, people claim that their mind wandered a lot. And then they also assessed, of course, their mood and how th- those people felt at any given moment, depending on what they were doing and how well their mind and their emotions matched what they were doing. And what they say here is, second, they revealed that people were less happy when their minds were wandering than when they were not, and this was true during all activities. And then third, what people were thinking at a given moment was far better a predictor of their happiness than what they were doing. So, this is interesting, and I think matches a lot of people's experience. In fact, I think as you hear about this study, many of you will probably just say, "Well, duh. I mean, if you're working and you don't like your work and you're thinking about something bad that happened, well, then of course you're not going to be happy." But the key point of this study is that it did not necessarily have to be the case that people were thinking about something unpleasant. In fact, if people were working and they were thinking about something else that was pleasant, that also made them feel unhappy. In other words, the mismatch between being in an activity and having our mind elsewhere led people to report themselves as feeling more unhappy in that moment. And when you total this up, what you find is that people are often not present to what they are doing, and that is a great source of unhappiness even if their thoughts are those of happy, joyful thoughts. So, this is interesting, and I think runs counter to what most of us have heard or have been taught, which is, you know, think good thoughts, you know, try and suppress bad thoughts, have a good internal landscape, he- you know, create a good narrative. That is all true, but equally, if not more important, is to have the ability to be fully engaged in what you are doing at a given moment. That is the strongest predictor of being happy. And there were several other studies that followed up on this, but their conclusion that they put in the final short paragraph of this paper I think really captures it beautifully. They say, and here I'm quoting directly, "In conclusion, a human mind is a wandering mind, and a wandering mind is an unhappy mind. The ability to think about what is not happening in a moment," I added the "in a moment" part, "is a cognitive achievement that comes at an emotional cost." So, I know I'm not alone in believing that this paper, A Wandering Mind is an Unhappy Mind, and we will provide a link to this paper in the show note captions, is absolutely key in understanding why a meditation practice is so important, because a meditation practice is really about adjusting your place along that interoceptive-exteroceptive continuum to what you happen to be experiencing in that moment. And while most people think of a meditative practice as focusing on what's going on internally with your eyes closed, third eye center, focusing on your breathing, et cetera, for any number of minutes or maybe even an hour or longer, there are other forms of meditation in which your exteroception dominates, in which you are actively focusing on things outside or beyond the confines of your skin and internal landscape, and that, too, is meditation. And if we are to take the work of Killingsworth and Gilbert, this, A Wandering Mind is an Unhappy Mind, seriously, and I know a number of other laboratories have, and have supported this research with their findings again and again and again, what this means is that meditating is not necessarily a practice that we do divorced from the rest of life. Meditation and mindfulness in particular, being present to what we are doing in a given moment, is one of the essential keys to happiness and improved mood, even if what we are doing is unpleasant.

Andrew Huberman 53:30 So, that brings us to a tool, and it's a tool that any and all of us can use, whether or not you tend to be interoceptively dominant, right, that you tend to pay more attention to your bodily sensations, or exteroceptively dominant. And again, if you don't know the answer to that question, there's a simple test that you can do. You can just sit down or lie down, close your eyes, and you can ask yourself or assess whether or not your attention tends to fleet to things outside of you, right? Cars honking or going by, people in the room. Or whether or not you tend to be able to focus on your internal landscape to the exclusion of exteroception and attention to things outside the confines of your skin easily. Now, of course, this will depend on context and situation, even how well-rested you are, et cetera, but that's exactly the point. This is the sort of thing you want to do every time you decide to do a meditation practice. In fact-I would suggest that you use this to determine what meditation you do at any given moment. So, let's say you are somebody who is a regular meditator, or let's say you're somebody who's never meditated and you'd like to develop a meditation practice. I suggest that you do a test of whether or not you are more interoceptively dominant or exteroceptively dominant in that moment. Okay? This... Again, this is not a personality trait. This is a question about where you happen to be in a moment. So, let's say you're on a plane or you're in the car. If you're in the car, please don't close your eyes while driving, that's sort of obvious, but do this in a safe way, please. But stop, close your eyes, and assess whether or not you can access and focus your attention primarily on your internal state, or whether or not your attention and perception gets pulled to something external, to exteroception. And again, that will vary depending on circumstance and who you are. Then, I suggest opening your eyes and trying to focus your attention to something external to you, and seeing or evaluating the extent to which you can divorce your perception from sensations that occur at the level of your skin or internally. Now, I should say that there's no technology, at least not that I'm aware of, absence of fMRI machine, in which case you are inside an fMRI machine while you do this. But unless you are in that experiment, and most of us aren't, there's no technology that can tell you, for instance, whether or not you are interoceptively dominant or exteroceptively dominant, and whether or not the ratio is, you know, 75 to 25, or what have you at any given moment. You have to assess this subjectively. However, if you sit down, for instance, and you notice that you can equally split your attention between internal sensations and external sensations, or whether or not you find yourself pulled into external sensations when you're trying to focus inward, or you find yourself pulled inward when you're trying to focus outward, well, that will dictate the sort of meditation that you perhaps ought to perform in that moment. Let me give an example of how you would do this. You would stop in some way, so sit or lie down, close your eyes, and evaluate whether or not you can essentially rule out or eliminate attention to all outside events. Most people won't be able to do that entirely, but try and focus your attention, for instance, on your breathing or the typical third eye center, you know, focusing at a spot right behind your forehead. If you feel you can do that reasonably well to the exclusion of what's happening around you, well, then, an important question arises. Should you meditate in a way to enhance that interoceptive awareness, or rather, should you meditate in a way, for instance, with your eyes open and your attention on a particular portion of the landscape you're in, like a tree or, or maybe even a, um, you know, an object or a plant or something else in your immediate environment, to try and cultivate or enhance your exteroceptive awareness? That's up to you, but my bias would be one in which you work against your default state. Again, the default mode network is where you land on this interoceptive-exteroceptive continuum is going to lead to more mind-wandering. Whereas, when you encourage, or we could even say force yourself a little bit to anchor your attention to either inside your body or outside your body, and you make that decision according to what you are doing less easily, well, then you are actively training up the neural circuits. You are engaging so-called neuroplasticity, the brain's ability to change in response to experience. You are deliberately engaging a shift along that continuum. To make this crystal clear, what I mean is this. Let me give an example. If I were to sit down and I want to do some meditation, let's just say three minutes of meditation. There's good evidence that even three minutes of meditation can be beneficial for a variety of things, including enhanced focus and enhanced anxiety management. Let's say I sit down and I notice that I can really focus inward on what's happening at the level of my skin and my internal organs, and I can rule out everything. Maybe that's 'cause the room is quiet, or maybe it is just because my brain is in a state that I'm particularly good at that at that moment. Or maybe it's just a natural ability. Well, then I would opt for a three-minute meditation practice in which I deliberately exterocept, that I build up the circuitry to focus on something external to me, because I want, and I think most people would like, to have an adaptive mechanism within them so that they can slide along that continuum and they don't default to whatever happens to be easiest for them in that moment. Now, if I were to sit down and try and focus on what's going on internally, and I kept getting distracted by things happening outside of me, opening my eyes or feeling like I needed to reach for my phone or paying attention to the sounds in the room, well, then I would actively engage a meditation practice, in this case, a three-minute example, but it could be longer, where I'm deliberately trying to focus my perception on events at the level of the confines of my skin and internally. Why do I say this? Well, you know, I love to use the phrase, uh, anytime with kids, uh, you know, when they say, "This is really hard," or something's challenging, or adults will say, "That's really tough." Well, as my graduate advisor used to say, "That means you're learning." If something were easy, if you can perform any activity or thought, et cetera, well, then there is absolutely zero reason for your neural circuits to change. It's the friction, it's the feeling that something is hard that turns on the enormous variety of mechanisms at the level of cells, et cetera, that allow you to potentially change your neural circuitry. So, challenge and discomfort is the signal to your brain and body that something needs to change. So, I'm encouraging you to embark on meditative practices that are not your default, okay? To essentially go against the grain of where your interoceptive bias or your exteroceptive bias happens to be at a given moment. And again, this will change. For some of you, this will change across the day, where early in the day you are very, very good at doing an interoceptive-biased meditation, and later in the day you aren't.I actually believe, based on the data that I've covered, and we'll get into a few more papers about this, and my lab is actively working on this as well, that a meditative practice can be made far more effective, that is, it can invoke more neuroplasticity, more shift in brain states and brain circuitry if we do not take the easy path. That is, we go against the grain of what our brain would naturally do in a given moment. So, if you're in a crowded airport and you're finding that everything's very distracting, well, then that would be a great time to do some interoceptive-focused meditation. Whereas if you are really in your head, you know, you're looping thoughts about the past and present, maybe you're even in obsessive thought, well, that would be a terrific time, an ideal time really, to do a short meditation focused on something external to you. In both cases, whether or not you're focused on interoceptive bias or exteroceptive bias, you are going against, or I should say, you're pushing back against your default mode network. I would argue it's going to be far more effective, that is, you're going to reduce or shift the activity of that default mode network far more and in a far more beneficial way if you actively try and suppress your bias toward being more interoceptive or exteroceptive.

Andrew Huberman 1:01:48 Now, I think that's immensely beneficial both for the immediate changes that you experience, what others have called a state change, 'cause that's what it is, and it also can lead to, as we referred to earlier, more neuroplasticity, more changes in the brain circuits that underlie your default mode network and lead to what are called trait changes. And I want to be very clear that I am not the first to make this state versus trait distinction. That's a distinction that was raised in a really wonderful book. In fact, I can't recommend this book highly enough. The book is Altered Traits: Science Reveals How Meditation Changes Your Mind, Brain, and Body. This is a book by Daniel Goleman and, uh, Richard Davidson, who've done, uh, terrific work and many writings and many TED Talks, et cetera, about meditation. I would say that circa 2016, 2017, this book really captured what I believe to be the, the most essential elements of the science of meditation and a lot of the history of it as well. Today, we are focusing on much of what's covered in this book, but also a lot of things that have happer- happened, excuse me, since 2017. In fact, most of the papers that I'm going to talk about are papers that were published after 2017. But again, there's a wonderful book where they very clearly distinguish between state changes and trait changes, trait changes being the more long-lasting ones. My read of this book and the literature that follows is, again, that when you sit down to meditate, it is going to be most effective to do that interoceptive, exteroceptive bias assessment, ask yourself whether or not you are more in your head or outside your head, if you will, and then to do a meditation practice that runs counter to where you happen to be at. That is, that pushes you more externally if you're in your head, and if you're more focused on what's going on around you, that pushes you more internally. Now, I think most people are familiar with how to do an interoceptive-biased meditation. Again, that would be setting a timer. Maybe you don't even set a timer. You just sit or lie down, close your eyes, focus on that third eye center behind your forehead, or focus on your breathing or your bodily sensations. That's typical and often discussed. Exteroceptive-based meditations, you pick a focal point outside or beyond the confines of your skin, so that could be, for instance, a point on the wall if you are indoors. It could be a plant. It could be a point on the horizon far away. What you will find is that your visual system will fatigue a little bit when you concentrate your visual focus at that location. I want to remind you that it is perfectly okay and, in fact, necessary to blink, so you should blink. You can relax your face. You can change your expression. There is no rule that says that you can't do those things. This is not, you know, just beaming, uh, a particular location in space and holding your eyelids open. I've been accused many times of not blinking very often. That's for other reasons. It's part of the way I access, um, memory about what I want to say. I don't use a prompter here, so I'm accessing from a sort of in- internal, um, image in my head. Uh, that's how my memory works. But, in any case, if you're going to do an exteroceptive bias meditation, there is absolutely no reason why you wouldn't look away from that location every once in a while. In the same way that if you're focused on internal thoughts with your eyes closed and focused on your breathing, every once in a while, your thoughts will skip away from that breathing or from your third eye center. In fact, and this is discussed in the book Altered Traits but by many other people as well, one of the key elements of any meditative practice, whether or not it's interoceptively focused or exteroceptively focused, is that it's really a refocusing practice. The more number of times that you have to yank yourself back into attending or perceiving one specific things, in other words, the more times your mind wanders and you bring it back, actually, the more effective that practice is. Again, if you can just focus on one location with laser precision and your mind never darts away from that and you don't have to bring it back, well, then there's no neuroplasticity. Nothing needs to change, because your nervous system will effectively know it's performing perfectly. So, if you're somebody who tries to do meditation and you find that your mind just wanders, just remember, every time you scruff yourself and pull yourself back to focusing on some location externally or focus back on your breath or your third eye center, each one of those aren't just opportunities to do better. They are essential to the improvement process. Think about them as ascending a staircase of refocusing. Every time you refocus, you're going up one more level, another stair, another stair, another stair. And I think that will move you away from the kind of judgmental process of thinking, "Ugh, like, I can't focus on anything." Pretty soon, what you'll notice is that the refocusing process will happen so quickly that you don't even perceive it. And again, this is something that's borne out in the neuroimaging data. A lot of people think that they can focus with laser precision, but actually what they are better at doing is refocusing more quickly and consistently over time. There's a classic study about this in very experienced meditators that was done in Japan, where they had people......with varying levels of meditation ability, so some who had never meditated, others who were really expert meditators with many hundreds, if not thousands, of hours of meditation under their belt. And they had those people listen to 20 tones, repeated over and over, the same tone. And they found that the expert meditators could really focus, when they did this by brain imaging, they could really focus on all 20 tones. Whereas most people kind of attenuate or what's called habituate to the tones, so that by the 10th or 11th tone their mind is really going to something else. Now, that's wonderful, but that really just tells us the expert meditators have better focus. But it turns out that the more modern neuroimaging studies have shown that they don't have better focus, such that they're staying in a very narrow trench of focus. What they're doing is they're exiting focus and going back in more quickly, more quickly, more quickly, over and over again. So rather than think about your ability to focus, think about your ability to refocus. And the more number of times you have to refocus, the better training

Andrew Huberman 1:07:35 you're getting. So earlier I mentioned we're gonna do this interoceptive bias or exteroceptive bias meditation for three minutes. Why did I say three minutes? Well, three minutes seems like a reasonable number for most people to do consistently, you know, once a day. And in fact, there are some studies of one-minute meditations and three-minute meditations and 10 and 60. My laboratory has been studying a five-minute-a-day meditation, and that clearly has benefits. But I think it's also clear that by three minutes, many of the benefits are starting to arrive. And so while I'm not pointing to any one particular data point here, it's very clear that forcing oneself to direct one's perception, that is your attention, to your internal state or to something external to you, is immensely beneficial if you do it consistently. And is, again, especially beneficial if you're focusing your attention on the portion of your experience, either internal or external to you, that is not the one that you would default to in that moment. And some people have taken this to the extreme to say that, you know, you can even just move about your day and then every once in a while just do a one-breath meditation. To be honest, when I look at the whole of the data, it seems as if it doesn't really matter in order to derive most of the benefits of a meditation practice. Now, I'm a big fan of some of the newer meditation apps that are out there. One in particular that I've been using and that, actually I started using because my, my dad is a big fan of it, and he does now fairly long meditations. He's doing about 10 or 20 minutes, uh, at least every other day and often every day. And he convinced me to check out the Waking Up app that Sam Harris has put out. Uh, I looked at it, I think some of it sits behind a paywall, but you can access much of it, um, or at least do a trial and try it out without having to get behind that paywall. They're not a sponsor of this podcast, I should mention. But I decided to use the Waking Up app. I think it's terrific. And I think one of the reasons it's terrific is that Sam includes short descriptions of what meditation is doing and what a specific meditation can do for you, just prior to doing that meditation. So those meditations can be quite brief. Some of them are a minute long, two minutes long. Some are, are longer or even quite a bit longer. That app, I think, includes a variety of meditations that really encompasses, um, the huge range of possibilities that are possible with meditation. And that, at least by my experience of the Waking Up app, has led to my most consistent meditation practice. And of course, I would love to get Sam on the podcast as a guest so we could talk about the sort of underpinnings of the Waking Up app and his views on everything from meditation to, I know he's, um, big in the discussion about free will and consciousness, some of the very deep and somewhat abstract discussions. Really hope to get Sam on the podcast at, at a time not too far from now. Meanwhile, we've never met in person, but I absolutely, uh, love the Waking Up app, Sam, and I know, uh, my father does as well, and I know many of you already use it. If you haven't tried it already, I really do encourage you to check

Andrew Huberman 1:10:30 it out. I want to talk just briefly about this third eye center business, because it (laughs) turns out to be pretty interesting. Uh, the third eye is actually a name that's been given to another neural structure, um, or I should say structure, because it's not strictly neural, and that's the pineal gland. This has an interesting history. I promise I'm not, um, taking off on a tangent here that isn't relevant to meditation. So you have a brain, of course, and on both sides of your brain you tend to have mirror symmetric representations of the same things. What do I mean by that? Well, you have a prefrontal cortex on the right, you have a prefrontal cortex on the left, and they actually do slightly different things. Language is sometimes lateralized to one side. But in general, for every structure that you have on one side of the brain, you have the same structure on the opposite side of the brain. There's one clear exception to that, and that's the pineal gland. The pineal gland is the gland that makes melatonin, which at night when it gets dark secretes melatonin, and that melatonin makes you sleepy, helps you fall asleep but not stay asleep. Descartes, right, the philosopher Descartes asserted that the pineal was the seat of the soul because it was the one structure in the brain that he saw was not on both sides of the brain, it was only one of them and in the middle. Now, I don't know if it's the seat of the soul or not. I'm, uh, not in a position to, um, make assessments like that. But what do we know about the pineal? The pineal, as I mentioned, is involved in releasing melatonin. It does a few other things as well. But it is also considered the third eye for a couple of reasons. One is that it responds to light, although in humans not directly. So in birds and lizards and snakes, they actually either have a thin skull or, believe it or not, two holes in the top of their skull that allow light to go directly in. If you look at the head of a snake, light can go directly into (laughs) their brain through these holes and activate the pineal to suppress melatonin and a- and control their, uh, wakefulness sleep rhythms. In birds, they don't have holes in their skull, but they have very thin skulls, and believe it or not, light can penetrate-... the thinness of those, sc- of the skull in many birds, and communicates information about time of day and even time of year, and that's translating to hormonal signals, such as melatonin released from the pineal. And so, the pineal's been called the third eye because it's a light-sensitive organ inside the brain. In humans, the pineal sits deep, deep, deep to the s- surface, and light cannot get in there. In fact, if light can get into your brain, unless you are part of a specific experiment where that's the intention, or you're having neurosurgery, or something of that sort, then you've got serious issues happening. That pineal sits deep, deep, deep near what's called the fourth ventricle, and i- it absolutely should not see light directly. So, the idea that the pineal is the third eye in humans is not true. It just isn't true. So, any time someone says, "Oh, the pineal is your third eye," that's not the third eye center that people are referring to when they talk about meditation. Now, you'll see a number of different, um, forms of art where somebody will, uh, it will be a picture of a face and the eyes will be closed, or sometimes open, there'll be literally a third eye, like a cyclops eye in the middle of the forehead. That has been proposed for many thousands of years to be, quote unquote, "The seat of our consciousness." Now, that's interesting because that real estate behind the forehead actually turns out to be the prefrontal cortex, which we know from lesion studies and stimulation studies, if you remove that brain area, people become very reflexive. They are not thinking intentionally. They don't become deliberate. In fact, and this is kind of an eerie result, but if you inactivate, you turn off the prefrontal cortex, and you give somebody the opportunity to play a shooting game, for instance, their accuracy goes through the roof. They become essentially like a machine. They see a stimulus, they shoot at it. They see a stimulus, they- they shoot at it. Their accuracy is exceptional, but their ability to distinguish between enemy and friend completely disappears. So, they become a highly effective motor, or I should say sensory motor machine, but their assessment and their judgment about right or wrong completely disappears. This is also true for people that have prefrontal damage. They often will have inappropriate behavior, or a hard time suppressing behaviors, et cetera. So, the third eye center as the seat of consciousness and our intention is something that makes sense generally with what we know about the neuroscience and neurology, but there's something more to it that I think is especially important for all of you that goes beyond anything about ancient traditions, or pineals, or birds, or snakes, and pits in the top of the head. And here's what it is. The brain itself, meaning the brain tissue, does not have any sensory neurons. What do I mean by that? Well, if I touch the top of my hand, I can feel that. If I want to sense my heartbeat, if I work at it, I can feel that. If I want to sense how I feel internally at the level of my stomach, is it full, is it empty, am I hungry, is it acidic, do- does it ache, or does it feel pleasant, et cetera, I can sense that. And that's because we have sensory neurons on our skin and in our body, et cetera. We also have sensory neurons in our eyes that let us perceive things externally. We have no sensory neurons on our brain. This is one of the reasons why you can remove the skull and do brain surgery on somebody who's wide awake and be poking around in there and they don't need any anesthetic on the brain itself. They need anesthetic for the incision site, but they don't need anesthetic on the brain because it has no feeling. You have emotions, but there's no feeling. So, normally, we are perceiving and paying attention to what we are sensing either externally, sights and sounds, again, exteroception, or internally, i- interoception, touch, et cetera. But by focusing our perception, our in- and our attention not on our bodily surface like a body scan, but to a point a couple centimeters or inches behind our forehead, we essentially are bringing that attentional, that perceptual spotlight to a location in which there is no sensation. There's nothing to feel there. And when we do that, by closing our eyes and focusing on that, quote unquote, "Third eye center," which is the prefrontal cortex, to be quite honest, when we do that, something else happens. And what happens is, when we are not thinking about and perceiving our sensations, because there are none there, our thoughts and our emotions and our memories sort of mushroom up. They more... A better way to put it would be that they geyser up and take on more prominence in our perception. What I mean by this is that normally, you know, I'm not thinking about, uh, the contact point between me and this chair, but as I'm speaking, I'm in contact with the chair, and those neurons are firing. But if I focus my energy and attention on them, they're going to fire the same, but more of my perception goes there. Similarly, I'm thinking things all the time. You are too. And I'm perceiving things all the time, and I'm remembering things all the time, and I'm anticipating things all the time about the future. But by focusing my attention on the one organ for which I have no sensation, that is my brain, well then, thoughts, feelings, and memories, feelings meaning emotional feelings, start to grow in their prominence, in my awareness, and in my perception. And so this is why when you sit down to a meditative practice, if it's a meditative practice where you close your eyes or you're focused on that third eye center, or you're focused on your brain as opposed to your bodily surface or something external