The Easy Habit That Sets Your Mood For The Day | Dr. Andrew Huberman

How can people think about the best way they can learn? What are different styles? What are different methods? >> Terrific question. Unfortunately, nowadays we can look to studies done in humans that define some very key principles. The first principle is that the whole process of neuroplasticity and learning is really a two-stage process. First, there must be focus and alertness. That focus and alertness is associated with the release of neurochemicals, so-called neuromodulators, things like acetylcholine in particular, and which sort of acts as a highlighter pen, if you will, for certain connections in the brain to later

be reinforced. And the neurochemical adrenaline, which is also called epinephrine, also depending on if you're in the UK or elsewhere. A long interesting story, not for this time, about why it has multiple names. >> [snorts] >> Epinephrine, also called adrenaline, is associated with an increase in kind of agitation and alertness. Acetylcholine, think of it as kind of a spotlight or a highlighter pen for certain connections in the brain. So, you need alertness and focus. And then the second stage is that it is only during periods of deep rest, in particular sleep and something that I

call non-sleep deep rest, which I've Given an acronym cuz scientists like acronyms, NSDR, non-sleep deep rest. Things like yoga nidra, things like shallow naps, things like forms of meditation that don't involve a lot of focused concentration. You're a far more the experienced meditator than I, so I'm outside my wheelhouse when talking about meditation. But, it is only periods of intense focus and alertness, followed by periods of deep rest, that allow the nervous system to change. And There is an abundance of evidence for that. So, that's the first thing to understand. The brain actually re-wires during

deep sleep and rest, because during deep sleep and rest, naps, yoga nidra, deep sleep, there's a replay of the very same cells in the brain that were active during learning, often times in reverse, for reasons that are still not understood, but at a much higher repetition rate. So, you're actually getting repetitions while you sleep. This is why one will strain to learn a language or a motor skill or maths or something like that over and over and over it doesn't happen. You take a couple of nights sleep, take a break from it all of a

sudden it's there. It's because it happens in rest. Now there's some other things that one can do to enhance this process further that are arrived to us from good data. First of all, there's a so-called ultradian rhythm which is the 90-minute Cycles during which we can focus pretty well for a duration of about 90 minutes. Of course flickering in and out of focus. Nobody really focuses for 90 minutes straight unless they've built up that capacity or they are very interested in what they're learning, right? They're just wrapped with attention. But usually people flicker in and

out. And of course nowadays there's a lot of literature and ideas about ways to maintain focus. Put the phone away, Limit noise. Some people like background noise, some people like music, some don't. It's very contextual, highly individualized. But 90 minutes is sort of the the the batch of time that the brain can focus really hard on one thing before it needs a true rest of of an hour or two before you can go back to learning or working very hard. The other thing is that there's some very interesting data Showing that shallow naps or NSDR

non-sleep deep rest done within 4 hours of one of these 90-minute learning bouts can be very beneficial for accelerating learning. And then there are these incredible data on so-called gap effects. So there have been studies now of of skills that are physical skills, mental skills where people will for instance try to learn scales on the piano or a math problem or a spatial problem or a physical skill and then at Random every so often a buzzer will go off and the person will just be told to do nothing. Sit there eyes closed or eyes open

and do nothing. Just stop the learning process for about 10 seconds and then return to doing what they're doing. These are these little micro rests. Turns out that during those micro rests the hippocampus a brain area as you know that's associated with learning and memory and the neocortex also Associated with learning and memory undergoes replay of the thing that the individual is trying to learn at 20 times the speed also in reverse just as in sleep and that has can lead and has been shown to lead to accelerations in learning. So there these ways I

wouldn't even think of them as hacks because the word hack is a little tricky because when I think of the word hack it seems doing something with an object or a tool that wasn't designed for that purpose, Right? The nervous system already harbors these mechanisms and one can access them through these little micro rests. So whether or not you're a child or an adult every so often when trying to learn something just pause for 10 seconds or so do your best to just clear your mind. Of course it's very hard to clear the mind but

do your best to clear the mind and then go back to the learning task as as it were and that has been shown to very to Significantly accelerate the learning process and the retention of newly learned information. And then the last thing you touched on earlier which is this notion of incremental learning. You said you like to throw yourself into something as kind of a litmus test of whether or not you enjoy it or not. Turns out that from beautiful work done by my colleague at Stanford School of Medicine Eric Knudsen has shown that yes

it's true that early in Development in humans this would be up until the mid-20s we can learn things in larger batches and much more easily than we can later in life. However, if one batches that work into smaller increments and so for instance deciding maybe set a timer turning the phone off otherwise and saying I'm going to spend 3 minutes just 3 minutes in trying to intensely learn this thing even if I feel like I'm failing. If one does that repeatedly those little increments of learning can lead to an outsized amount of learning overall. And

so the nervous system loves incremental learning. It loves to batch things into focused little bouts. And you know if that's already the the tools that you've built up which it sounds like you have wonderful but if somebody is out there trying you know struggling to learn. Really trying to break things down into very brief periods of intense Focus. That is the cue by which during sleep the nervous system will change itself. And this has been shown over and over and over again, even in very late life uh individuals, the people in their, you know, I

we like to think life could go on further than this, but people in their 80s and 90s still have neuroplasticity. There's even evidence that new neurons can be produced in the hippocampus of people in their late 80s And 90s. So, the capacity is there. >> This is why I love what you do, because you would never consider that the answer to learning is deep rest, more sleep. >> Provided the focus comes first. >> yeah. Of course, the focus and the attention as you said. >> But of course, sleep deprivation makes it very hard to learn.

And there's a something else that important that happens in sleep. Nowadays, we I think most people, thanks to the beautiful Work of Matthew Walker at Berkeley and others, really understand the value of sleep for health, immune system function, etc. There is a stage of sleep, rapid eye movement sleep, that we're all familiar with, of course, with and where literally the eyes are moving, um that tends to come later in the night during the second half of sleep, where there's a there's a tendency to have very emotional dreams, or at least dreams that are Laden with

a lot of emotional content of some kind. During rapid eye movement sleep, there's an inability to move the body. We call this atonia. It's a literally a a sleep-induced paralysis that's healthy, and a complete failure of the nervous system to release adrenaline, epinephrine. This is sort of like a trauma therapy in some sense. If you think about it, it's a replay of an emotional event minus the Neurochemical that makes us feel tense and agitated. So, in our mind those dreams can often feel very distressing. It's been shown that if you deprive people of of rapid

eye movement sleep, they fail to to dump the negative emotions of things that happened the day before and the day before. And I think all of us have experienced the shift in emotionality that happens when we are sleep deprived. What ends up happening is that the little things seem like big Things, but after a few nights sleep, we're okay. And there's no mystery to why that is anymore. I think almost every sleep scientist believes it has something to do with this built-in kind of trauma release therapy where you get to experience the thing in your

sleep minus the neurochemicals that make your body feel terrible. And somehow that dissociation allows people to then step back into life with a with a clean slate. >> Wow, yeah, no, I've I've heard those ideas before, but the way you just wove it all together is is really special. What I'm intrigued by then is what's the latest science on dreams? >> Dreams are basically a time in which the ordinary sequence of life events is converted into heuristics, shorthand symbols. And the brain loves symbols in the daytime, too. Right? We don't walk around parsing every angle

of every um object. The way the visual system works Is that the recognition of your face, for instance, there's a brain area that rec- I've seen you many many millions of time billions of times, probably. And I recognize you immediately as Jay Shetty because there literally is a neuron in my brain that's a Jay Shetty neuron. We know this, right? From recording from brains of people that recognize people, right? If I I met some of your staff today, lovely people, for the first time, now those neurons exist for them. But the that representation of you

was built up through basic representation of just the orientations of lines. All right? Just like a a one would sketch your face and then a build in more elaborate representation. The brain represents things in the symbols in a very abstract way. So, without going down too far of a rabbit hole, if I were to, for instance, say, "You know what, Jay, I'm going to play artist today, um of which I'm not, and I'm going to draw your face." And I did my best to draw your face and showed it to you, you'd probably say, "Oh,

that's not great, but but you'd probably recognize some of the features." But, for instance, if I decided that I was going to put your eyes in a different location, eliminate your teeth, put a bunch of tattoos on your face, uh for fun, and and show you this, and I'd say, you'd say, "That doesn't look anything like me." And I say, "Ah, but that's my Abstract representation of you." It turns out that the brain represents everything in the external world as a shorthand abstract representation. And in dreams, the reason that this that we tend to, for

instance, replace people with animals or objects with, um, with different objects, >> Yeah. >> is because the brain is thinking more in terms of the relationships between objects than it is the objects Themselves. And so, this is where dream analysis gets a little bit tricky. So, the analyst would say, uh, you know, the, for instance, I had a dream not that long ago where I was being chased by two animals. It was a bear and a wolf, a very salient dream for me. And turns out that that bear and that wolf, I realized only later

that day, I was walking around, I'd gone for a swim in the ocean, got out of the ocean, and I turned to someone I said, "Oh my Goodness, I know what that was about." That was about these two children that are now in my life that, um, and I thought they're chasing me like they need something for me. And it opened up an entire conscious discussion about that. So, in my mind, these children were represented as animals not because children are always represented as animals, but probably because it was the the feeling that they were

impinging on me. And they're one and they're lovely Children, but nonetheless that they're impinging on me. So, the point is not my dream. The point is that dream analysis always has to take into account that the brain operates in symbols where objects are replaceable, >> Mhm. >> and there is there are only relationships between objects. And so, if one has a very scary dream about a person or sees a monster, it's really in the early waking state of The day that we are in a position to best understand those relationships. So, here's a a tool

I recommend that's actually supported by sleep science, >> Please. >> which is when waking and in the first 30 minutes or so around waking, you're in this liminal state, even if you're somebody who wakes up and feels very alert, you're in this liminal state where that symbolism is still quite fluid. I highly recommend that people try and not bring in too much new sensory experience if they want to understand their dream. Stay lying down with your eyes closed. Maybe tell your partner or someone else you live with if you live with somebody that you just

need a few moments and just try and move about your day in a way where you're not trying to solve the dream, but you're also not bringing in a lot of new sensory experience because in that moment you Actually stand a chance of parsing what that relationship is. And this is something that psychoanalysts understand. This is something that, believe it or not, clinical hypnotists understand. Bring people into a state of deep relaxation and be able to capture that transition between the sleep and waking state. >> Are there certain healthy symbols for the brain to connect

with on a daily basis before sleep, after sleep, that Allow us to program ourselves more effectively because I feel like most of the symbols that we're seeing are unconscious or unintentional or mainly marketing or advertising or propaganda, but we're not really selective around our symbols. >> Yeah, I love that you asked this question because um for years, you know, we hear these things like we you know, you are the sum of the five people you spend the most time with, but nowadays We spend more time with symbols and people on social media than we do

often times with other individuals or at least equal amounts of time in the room, right? Rarely is it just the physical bodies in the room. It's all the the people in our phone, which I don't see as a [clears throat] bad thing. >> Right. >> Actually, for years um when I was working more or less in isolation in my lab, um I had this little list. I don't think I've ever shared this before. I had this little list of people who uh I love and admire. Many of whom I've never met. And I just would

read that list over and over again. I didn't realize at the time, but I was developing what believe the analysts call this a um an interject or an introject, perhaps. Someone should look that up. I forget which one it is. Um Which is actually a subconscious representation of somebody else's ideas and approach to things. That if we um for instance listen to you over and over again, the the nervous system starts to ask questions like what would Jay do in this circumstance? That's a very real thing, and we're not always consciously aware of it. Now,

physical symbols are also very important because the brain likes to make predictions. It loves symbols because symbols are a shorthand way of of eliminating a lot of useless information. But much of the way that we operate and feel really does impact us at a subconscious level. >> Mhm. >> And this has been shown over and over again. I mean, it's and it's always cast in the context of subconscious bias, which has kind of a negative slant anytime we hear bias, of course. But there are positive biases as well. So, I Think that for some people

having order among symbols is very important, equal spacing, everything very aligned. I'm sort of one of those, but uh you know, I'm kind of in the middle. Um other people um they aren't so consumed with the with the relationships between how they arrange things physically, but they enjoy great depth and emotional relationship to things. It could be a pendant. It could be nowadays, you know, people like tattoos Are kind of interesting, right? They're much more prominent than when I was growing up. They are an externalization of how people feel on the inside. >> Yes. >>

Right? So, those are very powerful symbols. And there's something about the process of stamping it into one's skin, etc. Um the slider intense pain involved and who and the are a way in which we create an external Reflection of who we are to ourselves, but also they are operating at a subconscious level to keep us for instance in a place of order. Like to be able to organize one's thoughts in a world filled with statistical information. Every ray of sunshine is statistical information. We can't pay attention to all of it. So, I think that um

to directly answer your question, there are a couple of things that I think from morning till night Make it out sized positive effect on our nervous system both in terms of its ability to feel, think, and act and its ability to learn. The first one isn't so much a symbol unless you adopt it as one and I certainly have which is there are now thousands of quality studies showing that we should all try and get some bright light ideally sunlight in our eyes with within the early hours of waking. This Doesn't necessarily meaning waking with

the sunrise although if you can do that that's great. Some people wake up before the sun comes out getting a lot of bright sunlight in one's eyes early in the day puts a number of neurochemicals and hormones into a state of let's just call it what it is positivity. Mood is enhanced, immune system function is enhanced, sleep is enhanced 16 to you know 20 hours later and so on. Also in the evening. So, the sun as a symbol is very important but it's also anchoring our subconscious physiology because every cell in our body has a

24-hour clock. We need to time it to the rise and fall of the sun each day. When human beings become misaligned with that rising and falling of the sun bad things happens to the nervous system. Now, fortunately it's very easy to fix. There's a study done at University of Colorado taking college Students camping. I wish I'd been a subject in this experiment. What they found is that melatonin rhythms, cortisol rhythms which can be a healthy thing. We all have cortisol protects us, energizes us, dopamine, epinephrine, all these rhythms of the body could be reinstated to

their proper timing by waking up and seeing the sun and going to sleep not too long after sunset depending on time of year for two nights and two mornings. And and this lasted at Least two weeks even though people were getting artificial light. So, I would say the symbol of the sun is not just you know it's not a trivial thing at all. It's the anchor by which our our biology is designed and our psychology follows of course. >> That's a brilliant one by the way. Thank you. I >> you know many people who have

trouble sleeping, many people who have mood issues, this enhances metabolism. I Mean, I could list it on and on and on. People will ask, so I'll just put it out there. Um try and do this without sunglasses if you safely can. You don't stare directly at the sun. Never look at any light so bright that it's painful to look at. You can of course blink. Only takes a few minutes on a cloudless day. If you're in the UK in the depths of winter, you're still going to get more light coming Through cloud cover by going

outside than you would indoors with bright lights on. And it can take anywhere from 2 minutes to 30 minutes depending on how dark or or bright it is outside. Sunglasses and excuse me, eyeglasses and contacts perfectly fine. If you think about it, if anything, that just focuses light onto the retina. Don't try and do this through a window or or a windshield because it filters out a lot of the Light that you want. So, the sun is a key symbol. I think if people could adopt that, their I'm certain their physiology and psychology will benefit.

Then in terms of physical symbols, I find it very useful and that there are good data. If a If you know, if a picture is worth a thousand words, a movie is worth a bazillion pictures. So, having an image of something that makes you feel good and seeing that early in the day tremendously powerful. Having a Mental image of something in your mind is equally powerful because you also carry that with you. And then if you do have a meditative practice or even if you don't, being able to try and bring the mind and the

body into that experience. So, taking a moment to look at a photo of someone that you love or appreciate and or the actual person, right? And being able to actually sense that and feel it at a complete nervous system Level. It might sound like kind of woo science, but it's not. The nervous system extends through the whole body. So, the extent that you can make that a truly whole body somatic experience, that it leads to an outsized effect on the just the ability of the nervous system to function. And then of course, we're we are

bombarded all day with negative symbols. There's just no way around that. But we can buffer ourselves against those negative symbols by very Strongly associating with certain things. And here I'll just defer that great neurologist and writer Oliver Sacks had this obsession with minerals and stones. He felt they had personalities. And he used to say that he had developed such a strong relationship to them, their touch, especially as he started to lose his vision later in life, that the the way they felt and they made him feel safe. They made him feel good. So these could

Be inanimate objects. So find things that you love and associate the with them on a regular basis, and you are literally shifting your nervous system towards this place of buffering yourself against negativity, and you are reinforcing the very circuits that trigger the release of neurochemicals that make you feel better. And some people might say, "Well, then you're just kind of doping yourself up with your own chemicals." But as a last point Here, the neurochemical dopamine is a very important and very misunderstood molecule. First of all, it is the substrate by which epinephrine, neural energy, is

created. And people think of it as dopamine is just feeling good, but dopamine is not about feeling good. Dopamine is the molecule of motivation and the desire to pursue additional things in a particular line of life. So when we positively associate with a Song, a person, a face, an object, the sunrise, we don't just benefit from those activities based on the effects of those activities. It's also what we believe about those activities combined. And the release of dopamine makes you more capable of then leaning into life and going and doing other things. And so it

And these are not small effects, right? The The effect of a small, even, you know, half a percent increase in Dopamine transmission in the brain is the difference between feeling like your life is bleak and you can completely attack the day in the positive sense. So fill your life with symbols. You get What's wonderful is that you get to curate what those are. >> Mhm. >> If you don't have access to them in your physical environment, they can be entirely internal. >> Yeah. >> And when I think about the great stories of the Victor Frankls

and the um >> Yeah. >> You know, uh and people who have just overcome tremendous challenge, they've internalized symbols such that the tiniest of things can actually evoke this this dopamine release system. And dopamine is just a generic neuromodulator. It doesn't know anything about your experience. It only knows What you believe about your experience. And it's deployed according to what you believe about your experience. So, in theory, I I could train my dopamine system to release dopamine every time I raised my right hand if I genuinely thought that that had If that has meaning for

me. And this is the art also of superstitions, right? This is why uh you know, people will engage in superstitions because they've built positive associations with outcomes uh According to a certain behavior. So, what you start to realize is that the brain is making predictions about the external world. Who's Jay? When's he coming back? Um you know, what objects are going to be in the room this time versus next time. If I suddenly walk out and that painting over there, which I happen to love, is now on a different wall, my nervous system would notice

that because it's but it's also making predictions about internal state. >> Mhm. >> And a lot of depression and anxiety is about people feeling like oh, when they feel lousy that that lousy feeling is going to go on forever. >> Yes. >> The way to rewire this is to understand that making and controlling predictions about how you feel internally gives you a sense of agency. And that sense of agency at the end of the day is just purely neurochemical. So, these are Pretty straightforward things to master. >> I mean, that's mind-blowing to me because I've

never heard dopamine be explained that way. >> Well, dopamine Everything about dopamine release is learned. >> Yeah. >> There are a few things like um all the adapt All the ones that evolved uh for us to be here. Uh okay? So, associated with reproduction, food, sugar. There's a very powerful dopamine Pathway in the brain and in the gut to because sugar has a nutritive value, right? We should all probably be ingesting less of it, but you know, you get it's a hardwired system. Um food when we're hungry, warmth when we're cold, those are hardwired. But

the dopamine system is designed to be trained up to associate with anything. >> Yeah. >> And this is how a a guy like uh you can meditate for long periods of time and Feel it I'm guessing there were times in which it felt brutal and there were times in which it felt incredible. >> Absolutely. >> Um this is how a a guy like David Goggins can um you know, punish himself with running it you know, over and over and over and yet somehow he's inverted that dopamine circuit so that it feels like something he either

wants to do or that by overcoming the The resistance to doing it, he he gets a a dopamine >> Yeah. >> release. So, dopamine is an entirely a learned release system. There are a few things that trigger its release no matter what, but and I should highlight drugs of abuse. >> I was just about to say but you anything can become an addiction. >> Cocaine, amphetamine, um excess, you know, pornography, excessive dopamine Release and that the diabolical thing about dopamine under those conditions is that the higher the dopamine release, the big amplitude dopamine, the bigger

the crash, always. It's the way the circuits are designed. >> Yeah. >> Now here we're talking about self-training in healthier amounts of dopamine release, non-addictive amounts of dopamine release or you could say mildly addictive patterns of behavior That serve us and the people around us well. And in that case, I think of that as kind of an adaptive addiction compulsion. >> Yeah. >> Um and not one that we should necessarily avoid. >> Absolutely. I think that for me, the way I differentiate that and I think that's such a good distinction that you're raising there because

what you're basically saying is we could convince Ourselves through the release of dopamine that anything is good for us and hence it can lead to addiction or it can be these aspirational positive habits for us. And I think the way I've been able to at least differentiate is that which is good for me after that which makes me feel good after I do it. Because that's that release of dopamine that I'm experiencing after I do it is more important than that which makes me feel good before I do it. >> I love that. >> So

I don't feel good before I go to the gym or maybe before I meditate or before I eat a healthy bowl of protein and food that's good for me, but I always feel good after it. >> that. >> And when I I feel good before I stay up late at night and hope that we're going to have a great time. Well, I feel good before I eat a pizza or I feel good before I have loads of sugar because I Have a massive sweet tooth, but then afterwards I feel the pangs of it. >> I

love that and it proves that um in your heart you're a neuroscientist because there's something called dopamine reward prediction error. This was defined by a guy named Wolfram Schultz and others and it's an incredible thing and it can be made very simple, which is when we positively anticipate something there is dopamine release. I mean just Tell kids that you're going for ice cream and you're seeing what is I'll now explain as reward prediction error. Now you get to the ice cream shop and it's closed. What happens is their dopamine drops below baseline before they were

told they were going for ice cream. If they're going to the ice cream shop and they have ice cream you might think then they get even more dopamine, but guess what? If the ice cream isn't as good or if one kid the the ice cream cone falls And they don't get another one, what ends up happening is that dopamine is relative to where they were just feeling, it doesn't feel that great. >> Yeah. >> And so this is the the the diabolical nature of addictive drugs. People get a dopamine surge in anticipation of using and

over time they get less and less of a dopamine surge, but the punishment signal as we say that comes afterwards, The trough afterwards goes lower and lower and lower. So it's like a asymmetric seesaw. It's not just back and forth, it goes "Dopamine." But then it goes, "Punishment signal." Now, you figured it out because dopamine reward prediction error says that if you have less dopamine heading into something than you do afterward, that tells the synapses, the brain connections that were involved to reinforce themselves and to engage in That behavior again. And this is also what

happens with surprise. If you go someplace you're not expecting it. Like, you know what? Like, let's let's go this place for dinner. I don't know. Looks good. And it's amazing. You create a much bigger dopamine signal than if I tell you, "Jay, I got to take you this place. This is the best sushi in Los Angeles. It's incredible." That actually sets you up to not enjoy the meal as much. So, we all should learn to kind of Control this dopamine knob. You've done it beautifully by simplifying it into making sure that you get enough happiness,

thrill, excitement in retrospect. That's the way to wire in healthy behaviors. And I'm I I've never actually heard it put as succinctly as you because academics are not trained to be succinct, as you can tell. But, I think if everyone kept that in mind, they would do themselves a great service, which is Try and ask whether or not the ple you had as much or more pleasure in the aftermath of something as you did during. And you will you get two benefits. One is you can avoid addictive type behaviors. And the other, because you avoid

that crash. If there's a dopamine release after, there's no crash. And the other is that you'll have a tendency to return to that behavior over and over again. That's also why I think a lot of people enter new relationships. And there is a well-established dopamine surge with the early phase. Everything feels possible. People feel like people will go out and make purchases. They're kind of manic, right? And it's a very exciting kind of mental illness that we all enjoy from time to time. People start to enter the phase of real challenge or often times real

challenge. And if they can't make that transition Seamlessly and they constantly focus back on how great things were and they look at the differential, it can be a kind of a dark picture. And then people have to start working on trying to reignite, so to speak. So, I think that a wonderful model for relationship is also to temper that dopamine release. Spread it out over time. Try and spread it out over 50 years and you and you're home free. Now, I'm not an expert in relationship, but it is absolutely clear That dopamine is the hallmark

of human bonding. Then, you know, early on anyway, then come the oxytocin and all that the the feel-good warmth molecules because dopamine fundamentally is about accessing things that are outside your immediate experience. It's reaching for things beyond the confines of your skin. A degree, money, a relationship that you're work that's developing and that you're working on. Whereas the serotonin and Oxytocin system, which I think most people have heard of, are feel-good molecules. They're associated with things we already have. Knowledge of how wonderful our partner is. Knowledge of how much we love something or or how

much we appreciate the meal that we had. So, neither it's not that dopamine is bad and and and serotonin is good. These are molecules that have been built up in our system over time to allow us to establish new relationships of all Kinds, to things and people and to ourselves, and then to sustain them. But that those big dopamine peaks early on are very, very dangerous. And you we need to learn to temper them. And just spread that out over time. It's a resource and we need to learn to calibrate that resource. >> As we

all know, shifting and being good with change is so integral. What do we do with that? Like, how do we start opening up and being more Comfortable in the discomfort of change, not just growth, but just change and shifts that we don't expect and predict? >> Yeah, I think two ways. Um one, I'll just go back to this fundamental feature of the nervous system, which is it's trying to make predictions. So, the reason why change is stressful, even positive change, believe it or not, is {quote} "stressful" Um >> uh is because of this then the

release Of adrenaline and and associated molecules with anytime things change. I mean, if you look at the psychologists have worked this out, there's a hierarchy of stressors. Um and of course at the at the top of that hierarchy are awful things that we don't you know, I think at the top, to be honest, I think death of a child is is perhaps the the greatest stressor. Divorce, death of a loved one, um these kinds of horrible things that we Wouldn't wish on anyone. Then, as one goes down, not too far below, you see things like

moving to a new home or apartment. You think, well, that could be a great event, right? Birth of a new child. And you think, wait a second, I thought that's supposed to be one of the greatest joys in life, and indeed it is. But it's stressful to the nervous system because so many things have to be reconfigured to sit not to say anything about the lack of sleep with a newborn And this kind of thing. So, change is always going to force our brain to make more assessments of our environment. One of the things that

we can say about the brain for sure is that once it learns something, it likes to not have to think about it. When you walk, because you already know how to walk, you don't think right, left, right, left, right, left. But when you learn how to dance a new step or something of that sort or a new skill Uh sports skill, you have to think about it, and it's work. And anytime we have to think about behaviors and they aren't simply reflexive, that work, as we call it, is in it's a combination of the release

of things like adrenaline, epinephrine in the brain and body, I should say, from the adrenals in the body, but also in the brain from a little brain area called locus ceruleus that is acts as kind of a sprinkler system for the brain to kind of wake up All brain areas saying, okay, let's pay attention to a lot of stuff here. Very basic system, um but but very fundamental system. It's literally a wake-up system for the brain. Works in parallel with the release of adrenaline into our body. Now, one way to deal with change is to

simply know this, right? To understand that if one feels stressed or agitated around a new move, or you have a partner who's Really stressed about a new move even though it's exciting, it should be exciting, that that's perfectly normal because what they're experiencing is this increase in agitation and alertness, and it also makes it harder to enter deeply relaxed states because the brain is in a mode of predictions, making predictions, what's happening next, thinking, thinking, thinking. And one of the things that's key to falling asleep sleep each night and replenishing Our ability to think and

make predictions is the ability to turn off thinking. This is why I'm such a fan of what traditionally was called yoga nidra, which literally means yoga sleep. Lying down, it's a form of meditation, as you know, and with breathing, etc. Um I certainly I want to point out that I have no desire to rename any of these ancient practices. These are beautiful practices that have been built up over thousands of years. The reason I call Sometimes batch yoga nidra with so-called NSDR, non-sleep deep rest, is that unfortunately both in science and in traditional cultures around

some of these behaviors, the language has become a barrier for people to try them. I'm not trying to to wash away any of the the wonderful culture and tradition around these. I want to be very clear about that. But ultimately it's about accessing a state of mind as for anyone That's listened to a yoga nidra script, and I should say I do nidra every day. I have for almost a decade now. It's without question along with viewing morning light, sunlight, the most powerful practice I think I can recommend anyone. Um it is about, as you

always hear in a classic nidra script, you move away from thinking and doing to being and feeling. Now, what is that? If we take a neuroscience lens, I mean, what is this Thinking and doing, being and feeling? It's about shutting down of the prefrontal cortex, which is making predictions, what's happening next, right? It as you move into sleep, you enter that kind of liminal state where things become disjointed, right? A cat flies through the room, and then you might jerk yourself awake and it's kind of odd, but that's the state of not thinking and doing

and just being and feeling, being in one's pure somatic Experience. So, I would say in order to move through change, designate 20 to 30 minutes each day to put the brain into a state of non-thinking, non-doing and into a state of {quote} being and feeling. So, not making predictions. Now, the tricky thing is when one is stressed, that's especially hard to do. Yeah. And this is why I think what is it Thich Nhat Hanh said, you know, what is it who said, you know, um When stressed, you know, meditate every day, but when stressed, meditate

twice as long or something like that, right? >> When I don't think I have time, like that is almost when I need to make the time. >> It's a skill. And so, this ability to turn off thinking enhances one's ability to enter sleep, which is vital for mental and physical health, obviously. Learning, et cetera, for reasons we discussed. So, develop the ability to Deliberately disengage from thinking and doing and do that during periods of low stress. Right? 20 to 30 minutes a day, even 10 minutes a day of just learning teaching oneself and practicing the

art of turning off prediction is an incredibly valuable skill. >> Wow. >> And then the other one is to just understand that we're being bombarded with contextual change all the time. You know, I love Instagram. I teach science On Instagram. I see you there daily. Um and so, scrolling on Instagram is an interesting experience because in 5 minutes, you can look at a thousand different contexts. The human brain has never dealt with that kind of change before. Even when television, when I was growing up, there were three or four good channels, then it went to

cable, and then now you get onto an airplane or something, you got 240 channels. That's that's a drop in The bucket compared to what we can get in in a social media feed. So, I think we just need to be aware that the brain can work with that. But then, what you're turning on is an ability to walk into a new context and and figure it out the statistics. Imagine if if in an Instagram feed and I'm not demonizing Instagram. I think they're wonderful. I think they provide a wonderful resource, truly. But imagine if we

walked out of this room And it was a completely different landscape. It was a jungle. Then we turn the corner and go into what I would think was the kitchen and it was the kitchen of the some, you know, of what some Thomas Keller restaurant in New York. Turn the corner and all of a sudden we're underwater. That's social media. >> Yeah. >> And we can cope with that. So >> meta verse. >> So if I think about it that way, then I think if we can cope with that, then we can cope with transitions

in so-called real life with with ease. Now, some people have more situational awareness than others. They walk into an environment and they're sensing all the things. Other people walk into an environment and they're very good at narrowing their attentional spotlight. The latter group actually has a bit of an advantage. They probably wouldn't be So good as a special operator in the military that has to develop situational advantage or a police officer or a teacher, but they're going to be immensely good at one-on-one interactions because they can make the room disappear. And so both we need

both kinds of people and we all need to learn how to sort of brighten and broaden these attentional spotlights and narrow them as well. And I'll just briefly say we Are old world primates, as it turns out, and we have the capacity to do what's called covert attention. >> Yeah. >> I can pay attention to you, but I can also notice that in my periphery there's something else going on. So I've got two spotlights now, but I am dividing my attention. We can't do three simultaneously. But what I can also do is decide to merge

those two spotlights and intensify them and narrow the Aperture of my visual window and my auditory window. So we should always think of our as our attention is two spotlights that can be very broad or it can be very narrowly focused and then we can overlap them. >> Yeah. >> And I think >> That's fantastic. >> we should all know how to do both. >> Yes. >> We should learn how to narrow the Aperture of our focus, deeply engage, but also deliberately disengage. And the process of falling asleep that we were talking about before is

the practice of learning how to take that attentional spotlight, move those two apart, and then dip not dim them, but extend the that same luminosity out more broadly, more broadly, and then we're off to sleep. So so it's about deliberate control of the nervous system. And unfortunately, we All know how to focus on something if we're very stressed or excited by it. Most people don't learn how to turn off this focus and learn how to deliberately disengage. And one of my great hopes for humanity is that children and adults will learn how to deliberately disengage.

Because it benefits sleep, which benefits mental and physical health. And also, if you think about it, most of the bad things that we do to ourselves and others and that people do To one another, most, not all, but most are from a heightened state of reactivity where we're just not conscious. >> Yes. >> And that's because our aperture, our window of attention, is too narrow. We're not taking into account the full space and time of what we're thinking about. >> Yeah. >> And as a last point, space and time are Linked in the brain. Uh

if you have a narrow visual focus, you tend to have a narrow time slicing, right? Which makes sense if you think about like a little kid watching ants on the ground and then gets called in to dinner and all of a sudden the way you batch time is different. When you're sleepy, you tend to batch things in big blocks. Okay? Or when you're bored, big blocks of time. When you're very excited, stressed, or happily excited, you're in that fast Frame rate. You've gone from 60 frames per second, which I think is a a typical smartphone,

to 1,000 frames per second. >> Wow. >> So you're catching all the micro nuances, but you're missing everything else. >> Mm. And And what I what I find most interesting about that though is And And I read a study a few years ago, and I I don't know if it I don't know I can't remember where it's from, but it it said Something along the lines of that today in 24 hours, we're exposed to more tragedy through the news or pain or stress, whatever word we want to label that as, than we were in our

entire lifetime 25 years ago. >> I believe it's sadly. I I think I have to agree. >> And And what I found also was that what you're saying, and I love this idea of we have these two points of focus and bringing it together or bringing it up, Which I think is fantastic as as a visual, too. There's an element though that really draws us in of judgment and criticism. Like, I find judgment, I'm using judgment as the overall word. Criticism is very specific word, but what really makes something harder, like when we're processing thousand

posts on Instagram, the most difficult part is when judgment comes in, whether it's positive or negative, because that's what draws you In. And I find that we have more things to judge. And to make that many judgments in a day is quite exhausting. And then to be exhausted by the number of tragic or stressful moments that we experience. And like you said that, you know, it's okay if we're on Instagram, we're seeing multiple things or we're seeing this kitchen into this animation into this world, but when a lot of it is painful to deliberately disengage

but remain Connected to reality, I feel like that's somewhere where people feel like they're in no man's land. >> Yeah. And you know, it's it's a particular challenge now with with the number of images and movies that can come at us. And And you know, I think that uh here I I I'm not one to to usually talk like this, but I think much of a building a good life is about both honoring and Challenging the asymmetries of our nervous system. What I mean by that is, you know, everything we've talked about up until now

are wired into us from birth. We have dopamine, epinephrine, the circuitry we can attentional spotlight. That all we show up in the world with that and we and we have to work with them. We also need to acknowledge that there is an asymmetry to learning. You know, before we talked about the gap effects and That's two-stage process of neuroplasticity. There are exceptions. The exception is learning of negative things. You only have to touch the hot stove once or the meta- metaphorically speaking, the hot stove only has to touch you once before it changes you. So,

there's one-trial learning of negative experiences. Now, once we understand that asymmetry and once we understand that negativity actually has a bit of a stronghold on Our nervous system, then we accept I would hope we'd accept the idea that then we have to work a little harder to counter that or maybe a lot harder in the same way that so-called highly palatable foods >> Yeah. [laughter] Yeah. >> which is now because kind of science geek speak for unhealthy highly processed foods cuz there's some, you know, I do love fruits and vegetables and all that. And there's

some wonderful Baked goods. Let's face it. I mean, I love croissants. So, I don't want to demonize highly palatable >> Yeah, highly palatable foods. But but I think we could all do well to eat healthier foods and they are not as rewarding in the short term as some of these highly palatable foods, right? And especially to the young nervous system, you know, there's you know, a a milkshake or or a um candy just tastes better to these kids Than vegetables >> Yeah. >> for reasons that are hardwired into the nervous system. But we know that

kids need their fruits and vegetables probably more than they need candy. >> Yeah. >> So, we have to all learn to counter these built-in asymmetries in our nervous system. And as adults, we probably thought we had it made, but then now We're bombarded with all this negative imagery. And so, the key is really the symbols that we were talking about earlier. To really build in positive symbols and internal symbolic representations. What I mean by that, not just physical things in our environment and people, but also how we hold those things inside is so important. I

think this is what comes to this notion of intentions. It's work, right? Right life and right action and All these things that we hear about, it's work. It's It's working against the tide that is pulling us toward negativity. That's Um in fact, there's a study that was done in the '60s. It was published in the journal Science. It's an excellent journal that apex journals had people with stimulating electrodes in their brain for reasons related to neurosurgery. These people could stimulate multiple areas of their brain one at a time. And then they reported How they felt.

So that the the human would stimulate and they'd feel drunk. Or they'd stimulate another area and they'd feel happy. They'd stimulate another area they'd feel sad. The fascinating we learned a lot about the human brain from these studies. The brain area that people preferred to stimulate the most, this is really going to upset a few people, was the one that led to anger and frustration. >> Wow. >> And you think to yourself, well, that's just terrible. Are we just doomed, right? >> Yeah. >> No. What turns out that anger and frustration is a signal to

the brain and body that you need to do something in response to that. Usually move away or move forward and and sort of enter an aggressive state. Knowing that >> trained, right? That's uh like habit. Like that's always there. >> comes through in habit. I think this is why people I spend more time um on Instagram than I do on other social media platforms. But listen, I I'm not embarrassed to say you go on Twitter and it's a more combative zone. It's just the nature of the beast there. So more combative zone. In part cuz

there are a lot of academics on there. >> [laughter] >> Uh it's more combative. So I notice if I Log on to Twitter, I already get a little bit of an adrenaline surge. It's like, all right, you're ready to fight. And just knowing that we have this innate bias towards frustration and anger and that kind of friction, hopefully my wish is that it will allow people to relax around that. And to realize, ah, this is sort of like the food that I immediately want to reach for, that's the kind of dopamine signal that you were

talking about early on, But how am I going to feel afterwards? >> Yes. >> How am I going to feel afterwards? And I would say that 99% of online interactions where people end up in these ridiculous battles, later both parties probably think, well, how did I get wrapped up in that? >> Totally. >> That's absolutely crazy. You know, you think you're scoring slam dunks on each other at the time, but it's ridiculous. So, I think the thing to understand is that we have these asymmetries, but that we can learn to work with them. The way

that a really I think a really incredible psychiatrist, he's done a lot of work on trauma, Paul Conti, describes it in a different context, is that um and but and he's like in to my mind the expert on trauma and just has done beautiful work, is that it's like those little kids toys where there's a little Ball bearing moving around in a maze. He described this to me. So, this is all Paul Conti, he's an MD and this is his work, not my his words. You know, there are times in which we are like that

game where just a slight shift and all of a sudden the ball bearing goes down the >> Yeah. >> chute. And what we should all be striving for is for, you know, slightly Concave and for it to kind of maybe move around a bit with the with the with the events of life and what we hear and see. That's what we should be striving toward. And that takes work. Some people are naturally there, but very few people are naturally there. But this is the power of meditation. This is the power of non-sleep deep rest. This

is the power of good sleep or most nights. This is the power of excellent social relationships. This is the power of Mindsets and intentions. That stuff, gratitude practices, none of that stuff is weak. All of that stuff acts as a kind of a a foundation from which we can approach things and go, "Yeah, the impulse is to get pretty upset about that, but I'm going to lean away from that." Very hard to do when we're not tending to that those foundational elements. Actually quite easy to do over time because it gives us the perspective. And

um I think that if we understand that we're being bombarded with this, it's like being at a buffet of junk food. >> Yeah. >> But understanding that somewhere in that buffet is really nutritious food, and that's what we should be aiming for. And learning to kind of override the the natural signals of "Ooh, I really want that, and I really want that." by thinking about exactly what you said earlier, which is how am I going to feel Afterwards? >> Yeah. >> And what what's that? That's dilating our perception of time. We're getting out of that

slave to dopamine mode, and we're starting to think about "No, I'm not going to let dopamine control me. I'm going to control dopamine." And that's powerful. >> Yeah. I I I What that sparks for me is also this idea that I've been in love with for a while is Fragility and strength, and how not being exposed to something doesn't protect you, but it makes you weaker. >> It absolutely does. And you know, nowadays there's a big interest in so-called dopamine fasts. I I think they have their place. You know, if people have been have been

engaging in things that are high dopamine-evoking behaviors, there is a place for this. This is one of the routes to sobriety. Beautiful work by my colleague at Stanford, uh Dr. Anna Lembke. She wrote Dopamine Nation. Incredible book about dopamine in the context of addiction, but all kinds of addiction. Uh she talks about this. There is a role for dopamine fasts. Really moving away from intensely pleasurable activities for about 30 days is necessary for some people to reset. >> Yeah. >> But it's naive for any of us to think that then you go back into the

world and you're not being bombarded with Temptation of different kinds. I've been The whole idea is to bring the system back into balance so that you can notice the subtle inflections, right? I guess the the the meditators and yogis, I always loved the language they use would be that the kind of subtle After meditation, you can notice the kind of subtle ripples in life, right? Whereas, if you're just hard charging all the time, you miss so much. Again, I'm using the wrong language here. >> Yeah, beautiful. >> But I think that um so, dopamine fasts

have their place, but better to have your hands on the steering wheel, accelerator, and brake of all these mechanisms. And to go through It's only when, you know, the car has been wrecked that it needs to go into the repair shop. Most of us don't need a dopamine fast. We need to understand how dopamine works. We need to do exactly what you described earlier, which is to extend The time domain, so that we think about, "Am I getting dopamine later also, or is this just a quick up-and-down kind of event?" Then I think we can

move through life in a much more adaptive way. >> And then you mentioned, obviously, when we talk about my relationships, you know, we talked about how dopamine is there at the beginning, but then we talk about serotonin and oxytocin, these inner feelings, which I love that description also of like how dopamine is This pursuit of external things, and oxytocin and serotonin are more about how we feel what we have. I think that was a another great visual, and I love how you speak in symbols more than you know. Like there, you know, it's I really

Everything you've been sharing today, I can visualize it, and I really enjoy visual learning, and so when you were speaking earlier about how you can visualize a symbol even if you don't have it physically, and even when you Said that to me, I'm like, "Oh, that's really fascinating that dopamine is that, oxytocin and serotonin is this." With oxytocin and serotonin, we know that a lot of the habits you just mentioned, they are what create this balance, right? So, the reason why people are talking about decreasing dopamine, I guess, is because we've noticed that dopamine is

shooting through the roof, and often what we do for oxytocin oxytocin and serotonin are Not really that balanced across the board. Uh what are Let's look at relationships and go, "Is there a need to have dopamine in long-term relationships, or are serotonin and oxytocin enough?" And not just relationships, that applies to career, it applies applies to everything, I feel. >> Yeah, absolutely. Um there's a wonderful book about this, written by a psychoanalyst in a slightly different Context. The book um the title of the book is Can Love Last? And and it's an interesting book. The

It's operates on the premise that when we first meet somebody and we want this in the context of romantic relationship and we desire romantic relationship with them, it's very much about objectification of the other person. And I don't mean objectification in the traditional sense, but we don't rely on them yet. Right? We only rely on the ability to Pursue and get them, right? Or for them to for us to pursue them, however it Or exactly. But we don't rely on them for safety at all. If that evolves to become a romantic relationship, right? With trust,

then what happens is there's a true dependency there. If one person were to leave for any reason, die or leave or cheat or break up, it is truly devastating to the safety mechanisms of the brain and body, right? It's a Reactivation actually of a lot of the machinery that was designed for attachment between infant and parent, right? As it just as an important aside, the all the work on attachment that was done by Bowlby and Main and others in psychology of taking deliberately taking babies away from their mothers and then reuniting them and evaluating the

responses, batching them into different All that circuitry isn't lost as we grow up, it's repurposed for romantic Attachment. There's no question about that. No question about that. We just operate in the different domains of anxiety becomes about waiting for a text message as opposed to, you know, mother to come back in the room or or nursing, etc. So, same circuitry reapplied. As we advance into relationships, we become more dependent on people, but the idea in that it's touched on quite a lot in this book Can Love Last is that There is a need from time

to time in some relationships to bring the dopamine element back in. Now, certain cultures have actually built this in in a very strategic way of actually having men and women not physically contact one another for several weeks out of each month in order to maintain the kind of {quote} excitement of a relationship. Nowadays, we tend to have this model of lover and best friend and sometimes even business partner, right? >> Literally. >> Which for some people can work and for other people can quash all the excitement, right? It really depends. And especially nowadays where people

are working a lot more from home, there isn't a tendency for people to spend much time apart and to miss one another. Missing one another, the yearning for the other person is a beautiful thing. >> Yeah. >> It's a painful but beautiful thing. What Is that yearning? That yearning is the pain of the lack of dopamine and serotonin. I actually just came back from a a trip and we were visiting a couple friends of ours and they said it was very beautiful. They said they've been together a long time. They said that they've had three

nights apart in their entire relationship. >> Wow. >> And one of them got sick during that time apart and I thought, that's Beautiful. Now, for some people, that's a beautiful model. For other people, that would be excessive and it actually could eliminate a a number of the positive neurochemical features of the relationship. >> Yeah. >> And there's a lot of variation around this. So, dopamine is required to quote-unquote re-up >> Yeah. >> the excitement in a relationship. How is That achieved? Well, dopamine is the molecule, as you recall, of reward prediction or of novelty. So,

doing things that are not expected is great. Routine is great for serotonin and oxytocin. Predictability, routine, predictability, same thing. Safety, routine, predictability, serotonin, oxytocin system, no question about it. Dopamine is the neurochemical of novelty and pursuing new things. So, for couples That are very set in their ways and feel very safe and homey together, wonderful, but creating ways in which they miss one another or creating new experiences for them to kind of re-up the dopamine in the relationship can have a a tremendously positive effect. And I look forward to a day where neuroscience is actually

incorporated into relationship design in an intelligent and and respectful way that there are respectful meaning that there are differences. >> Yes. >> But we see a lot that people will just go out and get a new relationship, right? I'm of the mind that unless, you know, it's there it's dangerous situation, better to probably avoid divorce, right? Um certainly for sake of children. Some I've heard, of course, that divorces can rescue relationships, too. I understand there's a lot of nuance, but I think everyone would prefer, emotionally, Financially, etc., to be able to be in a great

relationship for a long period of time. >> Yeah. >> And so, I think that understanding that the the push-pull between dopamine and serotonin is key. And just to remember that missing someone, yearning for someone, is the anticipation of how great it's going to feel when together. >> Absolutely. >> I think that that could that could go a long way. And also for people that get very, very, very excited about the new person, the new thing, just be wary that not everyone's dopamine system works the same way. >> Yeah. >> And so, learn to temper the

excitement if you're an excitable person. >> Yeah. >> And uh and I would say learn to ramp up the Excitement a little bit if you're somebody who's not so easily overwhelmed. >> Andrew, you've been so kind, gracious with your time. Uh I am you know, I I've always known how phenomenally intelligent and and smart and sharp and deeply studied you are, but I'm really grateful I got to experience your heart today in so many ways. And uh to me that That beautiful synergy you have is is is really uh meaningful to me to experience. I'm

I'm so grateful to you for being here, for taking the time, for For me, we've been in touch for a couple of years, maybe even it's been all, you know, through messaging, but to really experience you in full today has been been a treat for me. Uh we end every On Purpose episode with a final five. These have to be answered in one word to one sentence maximum. >> Uh which which for this academic might be a bit of a challenge. >> hard, but we will try. So, Andrew Huberman, these are your final five. Uh

the first question is, what is the best advice you've ever received in any area of life. >> Know thyself. >> Right? >> The oracle said that and it's absolutely true. We have to be good scientists of ourselves And understand where we have talents, competency, and/or challenges and then work with those. >> Beautiful. All right, second question. What is the worst advice you've ever received or had? >> That everything is just experience. You know, the idea that all experiences are equivalent. Um I would love to think that um all our steps lead us to enlightenment Kind

of thing, but we have I do believe that we or at least I need to be far more intentional than that and that we can be. >> Beautiful. Uh question number three. What is something that you didn't value before, but you've learned to value now? >> Almost embarrassed to say it, but um family. You know, I've relied very heavily on friendship as a deep source of uh of uh reinforcement in my life. I've leaned hard into that for many, Many decades. Um I think in recently I've become quite moved by the the supports within my

family that I did hadn't realized that uh really set me up so well to um to do what I want to do in life. >> Beautiful. Love hearing that. Uh question number four. What's the first thing you do in the morning and the last thing you do at night? >> First thing I do in the morning is get outside and get sunlight. And if the sun Isn't up, I flip on all the lights and then I go get sunlight. Also drink a glass of water. Before I go to sleep at night, >> yoga nidra? You

don't do that at night. You do it in the morning. >> I actually I think about those three people I was talking about before. I do. Every night. I just think about them. I don't know. It's been a long time now. That accumulated over several decades and um Yeah, I think about them every night. >> Love that. >> I don't even think to do it. It just I just do it. >> I was just trying to Yeah, I've I've a I lost one of mine mentors. The others are still alive right now. One of them

is stage four brain cancer and just couple of years ago. And I I when you said that I was like, yeah, I I know yeah, know that feels like. So, yeah. All right. Fifth and final question. If you could create one law or set one habit that everyone had to do every day for the rest of their life, what would it be? I think I know what it's going to be, but I'll have to ask you. >> Well, since most people will assume it's sunlight viewing, I'll just I'll just assume they're doing that anyway. I

would die a happy person if people would adopt a practice Of learning to deliberately calm down. Whether or not through non-sleep depressed or a couple deep breaths, um find a tool because I really believe that much of the misfortune and pain of life could be avoided if people learned to calm down. I also know that there's a lot more joy to access when we do.