Dr. Marc Berman on Huberman Lab: How Nature Restores Focus

Andrew Huberman 0:00 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. My guest today is Dr. Mark Berman. Dr. Mark Berman is a professor of psychology at the University of Chicago, where he directs the Environmental Neuroscience Laboratory. His research focuses on how our physical environments, particularly natural environments, impact our brain function, mental health, and cognitive performance. During today's episode, we discuss the fascinating and actionable science of how your physical surroundings indoors, and in particular, your relationship and interactions with nature, can shape your biology and your cognitive abilities. Dr. Berman explains how exposure to very common features in nature, such as fractal patterns, increase your ability to focus, reduce your stress, and improve your mental and physical health metrics, and not just while you're in nature, but after you return indoors for many hours and even days afterwards. During today's episode, you'll learn about something called attention restoration theory, which turns out to be very important for understanding how different types of indoor and outdoor environments either deplete or restore your cognitive resources. We also discuss practical science-based strategies that anyone can implement regardless of where you live. So if you're in an apartment or a house, if you have ready access to nature or if you don't, today's episode explains how to design your indoor space, the optimal duration and timing of nature exposure, and the specific visual and auditory elements that will provide you with the greatest cognitive and health benefits. So whether you're a student or a professional looking to enhance your learning capacity, focus, and reduce your burnout, or you're simply interested in optimizing your mental and physical health through exposure to different elements of nature, today's episode provides clear, actionable protocols based on rigorous scientific research. By the end of today's episode, you'll have a toolkit of evidence-based strategies that will transform your relationship with your indoor environment and outdoor environments, and you'll learn to harness those to improve your brain and body. Before we begin, I'd like to emphasize that this podcast is separate from my teaching and research roles at Stanford. It is however part of my desire and effort to bring zero-cost-to-consumer information about science and science-related tools to the general public. In keeping with that theme, today's episode does include sponsors. And now for my discussion with Dr. Mark Berman.

Andrew Huberman 2:14 Dr. Mark Berman, welcome.

Marc Berman 2:17 Great to be here, Andrew.

Andrew Huberman 2:19 I love being out in nature, so I'm excited about today's conversation, which is taking place indoors-

Marc Berman 2:25 (laughs)

Andrew Huberman 2:25 ... but we're going to talk about the relationship between the mind, the brain, nature, stress, rumination, and this incredible power that interactions with the natural world can have on our brain. As we wade into this, I'd like to start with this issue of recapturing our attentional abilities, because I think nowadays, everybody, whether they're clinically diagnosed with ADHD or they are just a human being on the planet, feels as if their attention is being pulled in different directions, sometimes without our awareness, sometimes with our awareness. What is this notion of recapturing attention?

Marc Berman 3:04 Yeah, I think it's a really fundamental concept. Um, and we think that attention, you know, maybe on the surface of it, people just kind of think about, "Oh, it's kids trying to pay attention in school," or, "Oh, it's trying to pay attention at work," but it's actually deeper than that. We kind of think that, uh, elements of attention are sort of involved in controlling all of our behaviors. Um, and when our attention is depleted, um, we don't have as much impulse control, we might behave more aggressively. Um, you know, we may not be able to achieve our goals. Um, and (laughs) with a lot of things in the modern world, our attention is just being fatigued, and we're depleted. And it's really hard to recharge the battery or know what to do to recharge the battery. And I think that's kind of the entry point why I s- I sort of got into, interested in this, and one of my mentors, Steve Kaplan, would talk about this directed attention fatigue problem, uh, that a lot of us are facing. You know, our ancestors, you know, thousands of thousands of years ago were not bombarded with so much information (laughs) like we are now. Now, the modern human has to sort of pick and choose what to pay attention to, and it's, it's kind of overwhelming. And Steve, uh, Kaplan had this idea that humans kind of have two different kinds of attentions. So, uh, one kind of attention is called directed attention, and that's kind of the attention that I've been talking about, uh, just recently here, and that's the kind of attention where you as an individual person are deciding what to pay attention to. So presumably, Andrew, you're deciding to pay attention to what I'm saying, uh, even though there's many other things you could find that might be more inherently interesting than what I'm saying. And this is kind of a very, you know, unique human capability. There may be other species that can kind of decide what to pay attention to, but we're really good at it. Humans are really, really good at being able to, like, focus on this lecture or focus on reading this paper or focus on trying to, uh, finish this math problem. But we can't do it forever. Uh, and I, I think everybody kind of has had that sensation where, uh, at the end of a long work day, maybe three or four o'clock, you might be just staring at the computer screen, and you can't focus anymore. And we call that a directed attention fatigue state, where you can't really control your attentional focus anymore, and I (laughs) , I, I see this all the time when I'm lecturing at the University of Chicago. Uh, and I think I'm a decent lecturer. First five minutes of class, all the students' eyes are on me. They're engaged, you know? I see they're nodding along with me. And, you know, 45 minutes into my lecture, I kind of see people nodding back (laughs) like this. They're getting tired. It's just hard for people to direct their attention for long periods of time. So that's, that's kind of the special attention, directed attention.We think there's this other kind of attention that we call involuntary attention, and that's the kind of attention that's automatically captured by interesting stimulation in the environment. So bright lights, loud noises, those things automatically capture our attention, and we don't really have much control over it. And we think that kind of attention, this involuntary attention, is less susceptible to fatigue or depletion. So you don't often hear people say, "Oh, I can't look at that beautiful waterfall anymore. It's just too interesting. I, I gotta step away." Or, "Oh, I have to stop watching this movie. It's just too interesting. I'm too tired out." So that's a different kind of, uh, kind of attention, and, and we think what's happening, um, in modern times is that our directed attention is being fatigued, um, but, uh, maybe we can restore directed attention, uh, by going into environments that can softly capture our involuntary attention.

Andrew Huberman 6:59 Do we know the basis of attentional fatigue? I mean, uh, I could imagine it's something in the noradrenergic, uh, dopamine, catecholamine world, listeners to this podcast will recognize those terms, at least crudely. Uh, I could also imagine that it's literally a fatigue of the visual system and/or the auditory system. You know, it's hard to maintain fixation, as we say-

Marc Berman 7:24 Yes.

Andrew Huberman 7:24 ... as visual neuroscientists, to focus on a target.

Marc Berman 7:27 Yes.

Andrew Huberman 7:27 It's challenging. You know, i- um, if we allow our eyes to rest, it actually gets easier to look back at a- and fixate on a target. So what is the basis of the attentional fatigue for this focused attention, or, uh, what you call directed attention?

Marc Berman 7:41 Yeah, it's a really great question. I'm not sure I have a great answer yet. Uh, maybe you'd have some ideas, Andrew. You know, one thing that, that sort of, to me, puzzles me a little bit about the brain is that from my understanding, it's kind of like brain metabolism is 20% of overall metabolism, no matter what people are doing, except for really extreme exercise where brain metabolism goes down a little bit. But if you're asleep or if you're doing a hard calculus problem, I think the brain is still using 20% of metabolism. So it's sort of this puzzle, why do we get this mental fatigue state? I, I'm, it's gotta have some kind of neurological component. At this point, I can't point to it, so I'm gonna talk about it more at this psychological level, it's this sensation that we have that we can't focus anymore. If I was to talk about brain areas, I would say probably this ability to direct attention is most likely in frontal cortex. Um, whereas this involuntary tension, sometimes we call it more bottom-up attention or exogenous attention, where it's activated by external stimulation, I would say that's probably more activated by things in the parietal cortex or even occipital cortex or auditory cortex, depending on what that external stimulation is.

Andrew Huberman 8:55 I'm not gonna lean everything on the visual system, but I've been listening to this book, uh, that unfortunately is only available as an audiobook, called Daily Rituals, which-

Marc Berman 9:03 Mm-hmm.

Andrew Huberman 9:04 ... it's got two-minute chapters, and it describes the daily rituals of writers and artists and creatives. And, um, it's very interesting that across many of those chapters, you find the same thing, which is that almost all of these people had a ritual of taking some stimulant, typically caffeine, sometimes more aggressive stimulants-

Marc Berman 9:24 Yeah.

Andrew Huberman 9:24 ... but caffeine, and then something to restrict their, uh, visual world, make it more tunnel vision. In fact, there are certain, um, painters, I, I forget the, the particular painter that they described, who literally built, uh, cardboard blinders-

Marc Berman 9:37 Ah.

Andrew Huberman 9:37 ... onto his glasses when things weren't going so well.

Marc Berman 9:41 (laughs)

Andrew Huberman 9:41 Um, now, the reason I bring this up is not as a suggestion-

Marc Berman 9:44 (laughs)

Andrew Huberman 9:44 ... although I suppose it could. Um, I actually used to read papers, maybe I need to go back to this, I'd put a, like a baseball cap on, put a hoodie on, and you'd-

Marc Berman 9:51 Yeah.

Andrew Huberman 9:51 ... re- restrict your visual world.

Marc Berman 9:53 Yep.

Andrew Huberman 9:53 And it makes perfect sense if, in fact, involuntary attention, which presumably comes from the periphery-

Marc Berman 9:59 Right.

Andrew Huberman 10:00 ... is inexhaustible.

Marc Berman 10:01 Right.

Andrew Huberman 10:02 So, you know, I think what's interesting about the digital interface-

Marc Berman 10:06 Yeah.

Andrew Huberman 10:07 ... that we exist in now is that the whole world is brought right in front of us.

Marc Berman 10:10 Yes, yes.

Andrew Huberman 10:11 So presumably, we evolved to move through space and direct our attention to particular locations and let the rest of the world fall away.

Marc Berman 10:17 Yes.

Andrew Huberman 10:18 And then involuntary attention could grab us-

Marc Berman 10:20 Yes.

Andrew Huberman 10:20 ... to alert us to people showing up-

Marc Berman 10:22 Yes.

Andrew Huberman 10:22 ... or danger or the smell of something-

Marc Berman 10:24 Yes.

Andrew Huberman 10:24 ... uh, wafting by, calling us for dinner. But now, it's all placed right in our central visual field.

Marc Berman 10:32 Yes.

Andrew Huberman 10:32 So it makes sense that we would all be very challenged with, um, maintaining directed attention-

Marc Berman 10:38 Yes.

Andrew Huberman 10:38 ... within that small-

Marc Berman 10:39 Yes.

Andrew Huberman 10:39 ... tunnel vision.

Marc Berman 10:40 Yes. And I would say something else too, I guess. If you felt like you had to create an isolation kind of chamber sort of thing to focus your directed attention, that's where we would say it's probably time to take a break. That that's when, you know, we might recommend that you go for a walk in nature to recharge this kind of precious directed attention resource. So that might be a signal. If, if you're just having a really hard time focusing, yeah, you can try to power through, but I think that might not be the most productive. That might be a signal to you to say, "Hey, maybe I gotta go take a break," and the break better not be scrolling on social media. We're saying a really good break is actually a walk in nature or some kind of interaction with nature.

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Andrew Huberman 13:51 I want to talk about interaction with nature. I just want to, it- it's not a pushback on what you just said, but maybe just to probe a little bit deeper. I think a lot of people struggle with getting into a focused state at the outset.

Marc Berman 14:06 Yeah.

Andrew Huberman 14:06 And I myself am familiar with, uh, the sitting down to do some work and it taking some time to kind of warm up, and that agitation.

Marc Berman 14:14 Yeah. Yeah.

Andrew Huberman 14:14 I always think about it as literally, um, climbing over or through barbed wire.

Marc Berman 14:19 Yes. (laughs)

Andrew Huberman 14:19 Sometimes it actually feels like that, right?

Marc Berman 14:22 Yes.

Andrew Huberman 14:22 And then e- either side of the barbed wire is a steep slope. On one side is distraction that can come from-

Marc Berman 14:28 Yes.

Andrew Huberman 14:28 ... surfing the web or social media.

Marc Berman 14:29 Right.

Andrew Huberman 14:29 And then on the other side is any sort of drama.

Marc Berman 14:31 Yes.

Andrew Huberman 14:32 And then, of course, our mind starts creating all these things that we think we need to do. And the idea is to get through the barbed wire.

Marc Berman 14:38 Yes.

Andrew Huberman 14:38 And then on the other side of it is that focused state.

Marc Berman 14:40 Yes.

Andrew Huberman 14:41 For most people, I think what I described is not terribly different from that.

Marc Berman 14:47 Yeah.

Andrew Huberman 14:48 I- I'm making a lot of assumptions here, but I don't know many people that can just sit down to work-

Marc Berman 14:51 No, and just ...

Andrew Huberman 14:52 ... and just drop in-

Marc Berman 14:53 Right.

Andrew Huberman 14:53 ... like a s- like a ...

Marc Berman 14:54 Yes.

Andrew Huberman 14:54 You know, like a trench.

Marc Berman 14:55 That's right.

Andrew Huberman 14:56 Um, can you do that?

Marc Berman 14:57 No. But I can do it better after a walk in nature. So, I think almost, like, the walk in nature is sort of like a preparatory-

Andrew Huberman 15:06 Hmm.

Marc Berman 15:06 ... kind of process. Um, just like, you know, think about, like, lifting weights or something like that. You wouldn't start off a workout and say, "Oh, let's put 250 on the bench and start going."

Andrew Huberman 15:15 Correct.

Marc Berman 15:15 You warm up. You gotta wake up your, your nervous system a little bit. And I think, um, that's kind of a little bit what we think interacting with nature is kind of doing. I mean, it's not a passive process. We're not saying, "Go and sit in a dark room (laughs) -"

Andrew Huberman 15:31 Mm-hmm.

Marc Berman 15:31 "... for 30 minutes, and then start to go to work." No, we're saying, "We want you to be interacting with nature. We want you to notice nature. We want your involuntary attention to be automatically captured by the stimulation in nature." And then, after you've kind of been sufficiently recharged, then we think you're gonna be able to go back to your desk and be able to direct attention and be able to focus.

Andrew Huberman 15:53 So let's talk

Andrew Huberman 15:54 about some of the data around what walks in nature and interactions with other components of nature can do for our cognition and our level of focus. Um, I think intuitively people appreciate, okay, a nice walk in nature, not looking at one's phone, it's very pleasant, it's relaxing, and then you get back to your desk and you can really focus. What about the laboratory data that support this? Or out of laboratory data that support this?

Marc Berman 16:20 Yeah.

Andrew Huberman 16:20 Maybe you could describe a few of the incredible studies that you've done, because they are really incredible and they're very pioneering in the way that you've brought real laboratory technology into nature as well. So, pick your favorite study about this, and then I'll ask you about a few others as well.

Marc Berman 16:33 Sure. Thanks. Well, I think the, the kind of the seminal, uh, experiment that we did, um, was back in, you know, 2008. And at that time, um, when people did these sort of nature walk studies, they would ask people, "How do you feel after the walk?" And it was very subjective. And I- I'm not against, uh, subjective accounts. And people reported, "Yeah, I feel much more refreshed after the walk in nature." Um, but I always felt a little bit dissatisfied by that. I, I wanted to see, well, does objective performance change? Just like we would probably be dissatisfied if I gave you a pill and I said, "This pill is gonna, uh, get you stronger. You're gonna be able to lift more weight." And if we just had people say, "Yeah, I feel like I can lift more weight," I don't think that'd be satisfying. We'd actually wanna see, can people actually lift more weight? And so what we did is we designed a study, um, that was experimentally controlled that would have objective measures. Uh, how do people perform cognitively before and after going on a walk in nature? So what we did is we brought people into the laboratory, uh, and then we gave them some challenging working memory and attention tasks. So one of the task- task was called the Backwards Digit Span Task, where you would hear digits, um, out loud at a pace of about one digit per second, and then the participant would need to repeat them back in backwards order. So if I said, uh, "Five, six, seven," the participant would have to repeat back, "Seven, six, five." Pretty easy task at three digits, but we keep increasing the number of digits all the way till about nine digits. At about five digits, you're ready to pull your hair out. It's a challenging task. So we gave participants, uh, this Backwards Digit Span Task. And then, uh, we gave them a map of a walk. Uh, it could be ... The first studies were through, uh, the Ann Arbor Arboretum, which was a nature walk, uh, kind of by the psychology building at the University of Michigan. Or participants went for a walk, uh, on busy Washtenaw-...uh, street in downtown Ann Arbor. Uh, the walks were both, uh, about 2.6 miles, so it took people about 50 minutes to do the walk. Uh, we also took participants' cell phones (laughs) because we didn't want them texting or chit-chatting on the walk. We wanted their attention to be fully focused on the environment. And we also did one other thing. We also gave them a GPS watch. Uh, why did we give them a GPS watch? Well, we did it for two reasons. One, we wanted to make sure they went on the walk, they didn't just go to Starbucks. And two, um, we wanted to see, did people get lost? Because if people got lost on the walk, maybe that wouldn't be restorative. Okay, so people do the backwards digit-span task. We send them on a walk in nature, or we send them on a walk, uh, through an urban environment. They go on this 50-minute walk. They come back to the lab. We give them that same backwards digit-span task again to see if there is any performance change or not, measure that. Then we have people repeat the whole procedure again, and they come back to the lab a week later. So, if they walked in nature the first week, uh, they walked in the urban environment the second week or vice versa. So it was all within subject, very, uh, tight experimental control. And what we found was pretty incredible, that people's working memory capacity and their ability to direct attention improved by about 20% after the walk in nature versus the walk, uh, in the urban environment. And people might be thinking, "Well, maybe it's just because, uh, the nature walk was just more pleasant. They just liked the nature walk more." And people did tend to like the nature walk more, um, and we did measure improvement in mood, how much did mood improve on the walk? We didn't find very strong correlation between improvements in mood and improvements in the working memory and directed attention performance, suggesting that people weren't just getting better because they were getting into good moods. But the even stronger demonstration that this wasn't mood driven is that we had people walk at different times of the year. So some of our participants walked in June when it was, like, 80 degrees Fahrenheit. People said, "Mark, I can't believe you're paying me to go (laughs) for a walk in nature." Really healthy mood benefits, really healthy working memory and attention benefits. We also had participants walk in January, 25 degrees Fahrenheit. People said, "Mark, I was freezing my butt off out there. I did not enjoy that walk." But incredibly, the people that walked in January when it was freezing cold and they didn't enjoy the walk obtained the same working memory and attention benefits as the people that walked in June. So, you didn't even have to like the nature interaction to get this directed attention benefit. So that, I thought, was pretty interesting and counterintuitive, that this isn't just about liking or pleasantness. There's something deep about processing auditory, visual, maybe even tactile stimulation of nature that somehow is good for our brains and restores our ability to direct attention.

Andrew Huberman 21:32 Super interesting findings, and it leads me back to this, um, uh, finite resource of directed attention, whatever the underlying networks and chemicals-

Marc Berman 21:42 Right.

Andrew Huberman 21:42 ... happen to be. Could we speculate what might be occurring in the nature walks that is, um, enhancing or allowing restoration of directed attention? And I guess the neurobiologist in me wants to say, okay, uh, y- I'm walking in nature. That probably means some greenery, um, some dirt, uh, maybe some water. Um, and I could imagine one hypothesis that it's the, uh, kind of irregularity of nature environments, right? I mean, maybe trees are spaced out, you know-

Marc Berman 22:17 Yep.

Andrew Huberman 22:17 ... in perfect spacing, like, on Palm Drive at Stanford.

Marc Berman 22:20 Yep, yep.

Andrew Huberman 22:20 It's like, it looks like a, it- it speaks to the engineering department that they're s-

Marc Berman 22:24 (laughs)

Andrew Huberman 22:24 ... set at such even intervals.

Marc Berman 22:26 Yes. (laughs)

Andrew Huberman 22:26 Right? But, um, typically, when you're in the forest, um, or nature, there, there's also things to break up that regularity.

Marc Berman 22:32 Yep.

Andrew Huberman 22:33 Um, whereas indoor environments and city environments tend to have a lot of right angles, buildings can be different sizes, but city blocks are pretty fixed for a given neighborhood in terms of their size.

Marc Berman 22:45 Yep.

Andrew Huberman 22:45 So that's just one hypothesis-

Marc Berman 22:47 Sure.

Andrew Huberman 22:47 ... I'm coming up with this off the top of my head. Do we have any data, or do you, um, uh, have any preferential speculation as to what it is about nature in terms of its physical structure-

Marc Berman 22:58 Yep.

Andrew Huberman 22:58 ... and as a corollary to that, is it that nature is relaxing people and therefore they're not having to use their directed attention, and therefore directed attention capability comes back or is, uh, set at a higher level? Um, I realize this is two questions kind of, uh, braided together, but that's what I'm curious about.

Marc Berman 23:18 Yeah, and I think, um, I think both elements are placed. So maybe I'll start first with kind of the, the resting directed attention element. So let's, let's pretend we're on these walks in nature or the walk on the urban environment, and I'll start with the walk on the urban environment. The walk in the urban environment, um, required people to cross a lot of streets. So you had to be vigilant, so you still had to use directed attention. Also had a lot of car traffic, so you're hearing the noise of cars whizzing by at probably, you know, 40, 45 miles per hour. There's also advertising. You're going by shops and billboards, and that, that kind of requires some directed attention. So you can't really just mind wander and, and let your mind kind of go in those environments. You still have to be vigilant. You still have to use directed attention. The walk through the Ann Arbor Arboretum, you didn't have a lot of those distractions. So, I think you only had to cross one or two streets, and then you're kind of, uh, getting towards the arboretum. You don't have to cross any more streets. Um, there's no advertising there. And then, and, and this is a thing I wanna talk about too, this idea of soft fascination. There's all the colors, fractalness, curved edges of nature that we think, um, sort of captures our involuntary attention in what we say is softly fascinating ways, and we think that......in combination with not placing a lot of demand on directed attention, is why nature is able to restore our directed attention. So, what do I mean by softly fascinating stimulation? So, let's pretend we're looking at a waterfall and the waterfall is really beautiful. You can hear the rush of the water going down. You can see all the, like the bubbles, and, uh, maybe some of the froth of the water going down. It captures our attention, but we can still kind of mind wander and think about other things at the same time. So, it doesn't really harshly capture all of our attentional resources. If we're in Times Square, also super interesting, lots of interesting stimulation to look at, but it kind of captures all of our attentional resources in an, in an all-consuming way that doesn't allow for any reflection or mind wandering or anything like that. So, while Times Square does capture our involuntary attention, we say it does so in a very harshly fascinating way, whereas the waterfall captures our, uh, involuntary attention in a softly fascinating way. And we think that's the way that's gonna be restful, eventually, of directed attention. So, we think two elements, uh, created why the nature walk was restorative. One, it didn't place as many demands on directed attention. And two, it had this softly fascinating stimulation that activated this involuntary attention, but not in an all-consuming way. So, we think those two things are critical. The other point that you bring up about, okay, well, what, what causes soft fascination to be captured? Or w- or why does something capture involuntary attention in a softly fascinating way? And that gets really interesting, where we think it could be elements of the structure of nature. So, it's interesting, Andrew, that we can get these effects of, um, nature-improving cognitive performance, people just looking at pictures of nature, versus looking at pictures of urban, uh, scenes, listening to nature sounds versus listening to urban sounds, watching nature videos versus watching urban videos. So there, you don't have to worry about getting hit by a car. There's something about the visual aesthetic of nature that we think is producing some of those benefits, that somehow our brain maybe processes that fractal stimulation in more efficient or easier ways than kind of what you were talking about, the 90-degree angled built environment that we've, uh, constructed.

Andrew Huberman 27:12 I have to ask. If you are exposing people to nature images versus, um, urban environment images in the laboratory and seeing some of these same effects, are you presenting that on a typical, you know, small screen right in front of somebody, or is it in panorama? I- I'm headed in a particular direction-

Marc Berman 27:31 Okay.

Andrew Huberman 27:31 ... with this question, um, because I have a head hypothesis as to what nature could be doing, um, to not deplete directed attention.

Marc Berman 27:40 Mm-hmm.

Andrew Huberman 27:40 Uh, but before I ask you about that, I'm just curious what the experimental setup is.

Marc Berman 27:45 Yeah.

Andrew Huberman 27:45 I'm also asking because I'm a little concerned that people are going to hear, "Oh, great. I can just look at a picture of a forest."

Marc Berman 27:50 (laughs)

Andrew Huberman 27:50 "I don't have to get outside," and as you mentioned, there are so many things in a, in an actual nature environment that, uh, provide a rich experience of soundscape, et cetera. But-

Marc Berman 27:59 Yeah.

Andrew Huberman 28:00 ... uh, what's the format?

Marc Berman 28:01 Yeah. So, it's, uh, basically the same format as the walk. Uh, it, the walking study that I described. So, people come into the lab. We give them, uh, the backwards digit-span task, but then we take them into a room in the lab where they just have a computer screen that's flipping through, uh, nature scenes or urban scenes. They look at the scene for a couple seconds. We also have them rate the scene on a scale of one to three for how much they like it, just to make sure that they're awake and they're engaged with the environment. Uh, that whole procedure takes about 10 minutes. Uh, they come out of the laboratory room that had the pictures, and then they take the backwards digit-span task again, um, to see if there are changes in, uh, performance. And then we'd have them come back to the lab a week later, repeat the whole procedure again. If they saw the nature pictures the first week, they see the urban pictures the second week or vice versa. And they're, even just seeing the pictures of nature, we see, um, improvements in working memory and directed attention. However, I would caution that the effects are not as large as they are for the actual walk. Um, so it's harder, uh, y- or I would say, I guess, the, the intervention is not as strong as actually walking in nature, right? Just seeing 10 minutes of nature pictures, it's incredible that it works, you can get some of these benefits, but the benefits are not as strong as they are for the real thing. And the same procedure happens when we test, um, sounds of nature versus urban sounds. We test people, uh, with the backwards digit-span task, then we put headphones on them, play a series of nature sounds or play a series of urban sounds. Then they do the backwards digit-span task again, um, and we find that when people listen to nature sounds, they also show improvements on, um, on working memory performance and directed attention. We don't do anything, uh, special in terms of having it being a panoramic view. It's basically just looking at a, a slideshow of nature pictures or urban pictures on a computer screen.

Andrew Huberman 30:04 So, I'm hearing this. I'm starting to wonder whether we have brain areas and/or circuits that are devoted to nature. Uh, which, you know, first pass, seems like kind of a crazy idea because visual perceptions and auditory perceptions are built up from their sort of elementary units, which is just nerd speak for y- you know, your eye and low level visual system cares about-

Marc Berman 30:29 Yeah.

Andrew Huberman 30:29 ... uh, circles and angles-

Marc Berman 30:30 Yeah.

Andrew Huberman 30:30 ... and then your higher level cortex-

Marc Berman 30:32 Yeah.

Andrew Huberman 30:32 ... puts it into-

Marc Berman 30:33 Yeah.

Andrew Huberman 30:33 ... like, the recognition of a person or a building, et cetera. It's literally built up from, from elementary units. You know, in the sound domain, it's built up from different frequencies-

Marc Berman 30:42 Yep.

Andrew Huberman 30:42 ... et cetera.

Marc Berman 30:44 Yeah.

Andrew Huberman 30:44 But, you know, there's something about-This problem. Uh, here, here's what's on my mind here. If I walk through a neighborhood, an urban neighborhood-

Marc Berman 30:55 Yep.

Andrew Huberman 30:55 ... where it's a bunch of warehouses-

Marc Berman 30:57 Yep.

Andrew Huberman 30:57 ... um, with some cyclone fence-

Marc Berman 30:59 Yep.

Andrew Huberman 31:00 ... and some signs, and it's a weekend, maybe it's a Sunday-

Marc Berman 31:04 Yeah.

Andrew Huberman 31:04 ... and they're all closed. There aren't trucks coming in and out-

Marc Berman 31:06 Yeah, yeah.

Andrew Huberman 31:06 ... and not, not a whole lot's happening.

Marc Berman 31:07 Yep.

Andrew Huberman 31:08 This is, uh, reminds me of, uh, like, West Oakland near the shipyard on a Sunday.

Marc Berman 31:13 Yep.

Andrew Huberman 31:13 Right? Not a place I recommend people go unless you really like kind of bland, urban environments on a Sunday-

Marc Berman 31:19 Yeah.

Andrew Huberman 31:19 ... 'cause not much is happening. It's a shipyard. It's Sunday. It's closed. Versus a trail in Yosemite. I used to work up in Yosemite in the summers. But it's not one of the most magnificent trails. Uh, meaning, it's not Yosemite Falls, Half Dome, or Clouds Rest, my favorite trail. It's a kind of barren environment. But there might be a meadow and there might be a mountain. You would never say, "You know, this trail up in Tuolumne that I'm on right now is... it's kind of boring."

Marc Berman 31:48 Yep.

Andrew Huberman 31:49 "It's not as interesting as the peak of Clouds Rest." And arguably, it's not.

Marc Berman 31:53 Right.

Andrew Huberman 31:53 I mean, when you get to the top of Clouds Rest, it's like, whoa.

Marc Berman 31:56 Yeah.

Andrew Huberman 31:57 Like, it... Uh, I mean, uh, it's a spiritual experience.

Marc Berman 31:59 Yes, yep.

Andrew Huberman 32:00 Okay. But when we are in nature, we don't tend to think, "Oh, this is boring. Uh, there's nothing here."

Marc Berman 32:07 Yep.

Andrew Huberman 32:07 Even if it's fairly sparse, visually.

Marc Berman 32:09 Right, right.

Andrew Huberman 32:10 So, uh, so as we dissect this, it, it can't just be density of visual stuff.

Marc Berman 32:14 No.

Andrew Huberman 32:15 There must be something additional.

Marc Berman 32:17 Right.

Andrew Huberman 32:17 Even... And we could say, well, maybe it's the greenery. But, you know, I was out in the Utah desert not that long ago, and it wasn't arches or, you know, the beautiful, uh, you know, landscapes that definitely exist out there.

Marc Berman 32:27 Yep.

Andrew Huberman 32:27 It was just kind of like horizon, sky-

Marc Berman 32:30 Yeah.

Andrew Huberman 32:30 ... some sand-

Marc Berman 32:31 Yeah.

Andrew Huberman 32:31 ... l- uh, maybe a cactus or two-

Marc Berman 32:34 Yeah.

Andrew Huberman 32:34 ... some rocks. But it's beautiful.

Marc Berman 32:36 You're right.

Andrew Huberman 32:36 And you would never say, "Oh, this is boring because it doesn't have arches."

Marc Berman 32:40 Right.

Andrew Huberman 32:40 When you get to arches, you're like-

Marc Berman 32:41 (laughs)

Andrew Huberman 32:41 ... "It's that much better."

Marc Berman 32:42 Right.

Andrew Huberman 32:42 You get the point here.

Marc Berman 32:43 Yeah.

Andrew Huberman 32:43 So, it can't be density of visual objects.

Marc Berman 32:46 Right.

Andrew Huberman 32:46 Um, and it's pretty quiet out there in the desert-

Marc Berman 32:49 Right.

Andrew Huberman 32:49 ... except at night when it's really quite noisy in the desert, actually-

Marc Berman 32:52 (laughs)

Andrew Huberman 32:52 ... with animals and, and stuff-

Marc Berman 32:54 Right.

Andrew Huberman 32:54 ... uh, if you're lucky. So what's, what's the deal?

Marc Berman 32:57 Part of it could be evolution to some extent. I mean, our brain's evolved in nature, right? So is, is it possible that our neural machinery is just more attuned to that kind of stimulation? I mean, there's no natural right angles in nature. We created right angles. I mean, that's pretty speculative, right? And I'd wanna dig in a little more about that, but I, I can't ignore it, that there's just something maybe fundamental with how our brain's evolved, um, and we evolved in nature that there's just something maybe about we just maybe more fluently process natural stimulation and we... and maybe we like that. But we started to have some ideas. You know, soft fascination, I, I love it, um, as a concept, but it still is a little bit squishy. I kind of wanted to get some kind of quantitative parameters around it. So, one idea that we were thinking about was that maybe nature scenes are actually more compressible than urban scenes. Now, what do I mean by that? So, what I mean by that is that maybe they just... there's... because there's repeated patterns in nature, I don't need to store all of the information. I can kind of smoosh it down into fewer bits. Um, and that might be easier for my brain to process. Whereas, in a lot of urban scenes, it's not very fractal and maybe I have to store all of that information. So we actually... This is one of my students, Nok Wan. We actually did... we ran a JPEG compression algorithm on thousands of nature and urban scenes, and it turns out nature scenes get compressed down into fewer bits.

Andrew Huberman 34:35 Um, so we should, no pun intended, unpack a little bit of what you-

Marc Berman 34:38 Okay.

Andrew Huberman 34:38 ... just said because I think, um, for people that are not familiar with thinking about neural processing-

Marc Berman 34:44 Yes.

Andrew Huberman 34:45 ... and JPEGs versus-

Marc Berman 34:46 Yes.

Andrew Huberman 34:46 ... TIFF files-

Marc Berman 34:46 Yes.

Andrew Huberman 34:47 ... uh, if, if I may, I'm just gonna give my, uh-

Marc Berman 34:49 Yes, yes, sure, sure.

Andrew Huberman 34:49 ... crude rendition of this 'cause I, I was very interested in this and, and did some work related to this years ago. But just to keep it brief, um, people are probably familiar with the idea that some electronic files are larger than others.

Marc Berman 35:03 Yep.

Andrew Huberman 35:03 So, if you have a picture that you take on a camera or your phone and you wanna email it to somebody... Nowadays, you would just text it, but-

Marc Berman 35:09 Right.

Andrew Huberman 35:10 ... you might wanna email it to somebody. You can send them the TIFF version or the Photoshop version and it's going to be a very big image-

Marc Berman 35:18 Right.

Andrew Huberman 35:18 ... or a big movie for that matter.

Marc Berman 35:19 Right, right.

Andrew Huberman 35:20 There's another way to send it, which is at a lower file resolution-

Marc Berman 35:24 Right.

Andrew Huberman 35:25 ... but, um, therefore takes up less memory.

Marc Berman 35:28 Right.

Andrew Huberman 35:28 Doesn't come through as this massive file-

Marc Berman 35:30 Right.

Andrew Huberman 35:30 ... that you need to go to a second-party site to download or something.

Marc Berman 35:32 Right.

Andrew Huberman 35:32 And that's a JPEG.

Marc Berman 35:33 Right.

Andrew Huberman 35:34 The whole basis of JPEG is to take the average of pixels near one another and compress them. Kind of take a best guess as to what-

Marc Berman 35:43 Yes.

Andrew Huberman 35:43 ... a black pixel is probably next to another black pixel, or probably a gray pixel, but probably not a white pixel. It could-

Marc Berman 35:48 Right.

Andrew Huberman 35:49 ... but it... what it does, it takes a local averaging-

Marc Berman 35:51 Yes.

Andrew Huberman 35:51 ... and then it compresses it into a JPEG and you send it to the other side.

Marc Berman 35:55 Yep.

Andrew Huberman 35:56 But on the other side, you can also unpack that image to its original high resolution value. The brain does a similar thing. And the best example that I have from the brain is the olfactory system. In the olfactory system, you're breathing in tons of volatile chemicals-

Marc Berman 36:11 Yeah.

Andrew Huberman 36:11 ... meaning... Volatile makes it sound like they're about to throw a tantrum, but-

Marc Berman 36:14 (laughs)

Andrew Huberman 36:14 ... um, they're, they're moving through the air, you inhale them, and they're activating millions, probably, of different odorant receptors. But your brain compresses those down into coffee. This is coffee. And then you unpack it as coffee. Now, if you're a coffee connoisseur, or in the case of wine or a food connoisseur, you can get into the subtle nuance-

Marc Berman 36:35 Yes.

Andrew Huberman 36:35 ... and say, "Oh, you know, there's a lip... a little bit more of this and a little bit more of that," but you're not thinking about the individual chemical molecules. You'd say, "Oh, it's a little bit of a cherry flavor," or, "This chocolate has a little bit of a citrus..." You know, this is the-

Marc Berman 36:46 Yeah.

Andrew Huberman 36:46 ... sorts of thing. So, that's essentially what the brain does with visual images as well.

Marc Berman 36:50 Yes.

Andrew Huberman 36:51 Okay, so that's my, um, very crude and, um-...certainly not complete, um, description of how bits of information are compressed as they go into the brain and then unpack-

Marc Berman 37:03 Yes.

Andrew Huberman 37:03 ...into what you call a perception.

Marc Berman 37:04 That's right.

Andrew Huberman 37:05 Or an experience. And the same thing is true of a TIFF or a Photoshop file, compressed to a, a JPEG-

Marc Berman 37:10 Yes.

Andrew Huberman 37:11 ...um, and then you can literally uncompress that file-

Marc Berman 37:14 Yes.

Andrew Huberman 37:14 ...uh, if you have the capa- the, the sort of computational capability.

Marc Berman 37:17 So, one thing that I just want to add to it. The, the kind of compression that we were doing with the JPEG compression was, was lossy, meaning that the information was thrown away. You couldn't recover it.

Andrew Huberman 37:26 Mm-hmm.

Marc Berman 37:27 But that didn't really matter. So if you showed people the image at its high resolution versus the image at its compressed or lower resolution, the human eye can't really tell the difference.

Andrew Huberman 37:38 Mm-hmm.

Marc Berman 37:38 And I think, um, but for the urban images, you couldn't get away with that trick.

Andrew Huberman 37:45 Yes.

Marc Berman 37:45 It, you needed to, to keep all of the original pixel values. So that's, kind of, that's what computers and our iPhones are actually doing (laughs) .

Andrew Huberman 37:52 Mm-hmm.

Marc Berman 37:52 They're, um ... and the reason why we think they can get away with that is because nature has a lot of this repeated structure, like you were talking about before, about predicting the pixel's value. And you can use that. You can capitalize that. That, that means there's a lot of redundancy, so you don't need all of that information. Natural images also tend to have, and maybe this is gonna get a little bit technical, too, a lot of high frequency spatial content.

Andrew Huberman 38:17 (laughs)

Marc Berman 38:17 So, a lot of little changes or little contrast changes that we don't really need, whereas in the urban environment, there's more of these big contrast changes that we do need. So, we think maybe the brain is ... like you're saying, there's all this evidence that the brain is basically doing that. And in nature-

Andrew Huberman 38:35 Mm-hmm.

Marc Berman 38:35 ... because you can sma- you know, you're walking through the nature, you can kind of throw away a lot of the information.

Andrew Huberman 38:44 Mm-hmm.

Marc Berman 38:44 And so we think that actually might be why it's sort of more softly fascinating and easier to process versus the urban environment. There's another element here, too, which we haven't got it completely yet, but which I'm very interested in. So that, that's looking at sort of, like, complexity of the images at the very, very low level. But you could also think about semantics, like the language that we use to describe a scene. And when I see a nature scene, you know, I don't have a huge language repertoire. I can say lake, tree, river, shrub, sand, desert. But when (laughs) I'm in the urban environment, I can say Volkswagen Beetle, you know-

Andrew Huberman 39:26 (laughs)

Marc Berman 39:26 ... BMW M3, uh, Gothic architecture. Like, my vocabulary is so much more complex for an urban scene. So, so one thing that we're also thinking about is, like, maybe nature might also be more semantically simple, like from an, a linguistic level, that I can just label it really easily, and then it allows my brain to just not have to store as much information, whereas in the urban environment, maybe I'm forced to sort of label all of these objects, and it just takes up more room in our brain. So, we also do these studies where we show people a bunch of nature scenes and urban scenes and then test their memory for the scenes. And it turns out that people's memory for the nature scenes is worse (laughs) than the urban scenes. So people remember-

Andrew Huberman 40:14 Perfect.

Marc Berman 40:14 Exactly.

Andrew Huberman 40:15 It fits.

Marc Berman 40:15 It fits. And you might think, oh, well, you want to remember stuff. But actually, you know, in some sense, it's, it's measuring how, how just difficult it is to process and, and where if it's so easy to process nature, you're just not gonna remember it. And that, in this case, is a good thing. So, we think that's also part of it, that it's, that that's also saying to us that, yeah, it's just, it's just easier to process this natural stimulation versus this urban stimulation where you just have to attend to more stuff. It's more sticky.

Andrew Huberman 40:43 Do you have

Andrew Huberman 40:44 any data as to whether or not people track time better or worse when they are in natural versus urban environments?

Marc Berman 40:51 So, I don't have direct evidence to this, but I have a, a few other little pieces of evidence that I think will kind of get us there. So, we've done some studies where we send people, uh, this one was actually, uh, sending people to a nature arboretum, an in- indoor nature arboretum, the Garfield Conservatory, a really beautiful conservatory in Chicago, versus the Chicago Water Tower Mall, a very fancy indoor mall in Chicago. And, uh, we actually gave, uh, participants here, uh, cellphones that we had in the lab that would ping them, uh, and ask them questions while they were going on the walk in the conservatory or the walk in the mall. And we asked them, you know, "What are you thinking about?" And it turns out, when people are walking in, uh, nature, they actually think more about the past (laughs) uh, than walking, um, in the mall. So, that was kind of interesting.

Andrew Huberman 41:44 Mm-hmm.

Marc Berman 41:45 (laughs) Um, this is also kinda interesting. People also said that they felt more impulsive in the mall (laughs) -

Andrew Huberman 41:50 (laughs)

Marc Berman 41:50 ... than in the conservatory, which makes sense that, you know, mall designers want people to be buying things. Um, but this idea about thinking about the past, to me, suggested a little bit that time might be going a bit slower. Other people have found in cities, that the larger the city is, people, like, walk faster. Like, the pace of everything is a little bit faster. So, my hunch is that based on those two findings, that I think time does probably slow down in nature, but I don't have direct evidence for that. I, I think that's something that'd be really super interesting to study. But that would be my hypothesis, that in nature, time does slow down a bit.

Andrew Huberman 42:29 If you had to wager a guess, would you assume that going into an art gallery is more similar to taking a walk in nature or an urban environment? I mean, it's so rich with information.

Marc Berman 42:39 Yeah. Yeah.

Andrew Huberman 42:40 You have options.

Marc Berman 42:41 Yeah.

Andrew Huberman 42:41 You have to decline certain things-

Marc Berman 42:43 Yeah.

Andrew Huberman 42:43 ... certain rooms, certain paintings, certain sculptures. There's a lot of decision-making.

Marc Berman 42:47 Yeah.

Andrew Huberman 42:47 And yet most people find galleries-

Marc Berman 42:51 Yeah.

Andrew Huberman 42:51 ... big galleries-

Marc Berman 42:52 Yeah.

Andrew Huberman 42:52 ... to be extremely calming.

Marc Berman 42:53 Yeah.

Andrew Huberman 42:53 Maybe it's also because everyone's quite quiet in them?

Marc Berman 42:56 Yeah (laughs) .I would say the, the gallery is- would have a similar effect to nature, would be my guess. Because, you know, Kaplan's Attention Restoration Theory really is not specific to nature. It basically just says you gotta find an environment that doesn't place a lot of demands on directed attention while simultaneously having softly fascinating stimulation. And an art gallery might meet those two criteria. If you don't have to be tested on the artwork and you can just kind of go there and you don't have an agenda, I think there's gonna be a lot of very softly fascinating stimulation in an art gallery. So, my hunch would be that, yeah, walking through an art gallery might have a similar kind of effect. Um, I would ... This is gonna be a little bit of a jump. There, there are some studies that we did where w- we're looking at the relationship between park visits and crime, and going to a museum (laughs) versus crime. Um, so these were, uh, uh, there's been a lot of actually interesting studies suggesting that interacting with nature can make people less aggressive, and we think it has to do with attention. So we, uh, (laughs) you know, we had this incredible dataset, um, this cellphone trace dataset where, from 100,000 people in Chicago, we knew where they lived, um, and we knew where they went for an entire month. So, what we did is we quantified how many times did people leave their neighborhood and go and visit a park versus leaving their neighborhood and going to a museum or something like that, and we wanted to correlate that with crime. And sure enough, we found that neighborhoods where people leave their neighborhood and go and visit a park, there's ... actually, that predicted less crime in those neighborhoods, but the museum visits didn't predict-

Andrew Huberman 44:53 Ah.

Marc Berman 44:54 ... that.

Andrew Huberman 44:54 And this was controlled for kind of, like, uh, socioeconomic background-

Marc Berman 44:58 Yeah.

Andrew Huberman 44:58 ... this kind of thing?

Marc Berman 44:58 I mean, and more or less. I mean, again, it's a correlational study, so I can't claim causality, but we also controlled for age, education, income-

Andrew Huberman 45:06 Mm-hmm.

Marc Berman 45:06 ... all those demographics. Um, so there, it seemed like there was something special about the park visit versus the museum visit on, at least, aggression. Um, but I do believe that, um, going through a museum might have a similar effect to nature. I'm not sure it'll be as strong, but I think it has ... the, the museum maybe has a lot of the same elements that a, that a nature walk might have.

Andrew Huberman 45:31 I mean, I

Andrew Huberman 45:32 think I'm just obsessively starting to drop into the trench of, you know, what sorts of things are attention depleting and what sorts of things are attentionally restorative, um, because I personally believe that our ability to attend is, like, the hallmark of building a great life.

Marc Berman 45:49 Yes. (laughs)

Andrew Huberman 45:49 And I've ... So much so that, you know, on hikes and walks, I will listen to audiobooks and podcasts-

Marc Berman 45:55 Yeah.

Andrew Huberman 45:56 ... um, but there are times when, for instance, I will exercise with silence-

Marc Berman 46:02 Yep.

Andrew Huberman 46:03 ... and then I'll use music as something to, like, push me through some-

Marc Berman 46:06 Yeah.

Andrew Huberman 46:06 ... particularly hard-

Marc Berman 46:07 Yeah.

Andrew Huberman 46:07 ... moments in the exercise, but then I'll turn it off-

Marc Berman 46:09 Yeah.

Andrew Huberman 46:10 ... and bring it back. I, I don't just kind of, like, head out the whole time-

Marc Berman 46:12 Yeah.

Andrew Huberman 46:12 ... blasting music.

Marc Berman 46:14 Right.

Andrew Huberman 46:14 Sometimes I'll do that-

Marc Berman 46:14 Yeah.

Andrew Huberman 46:15 ... but I'm, I'm starting to become a, kind of a experimentalist with this idea of, you know, attention as this resource that we deplete each day. Sleep, it's restored, mostly. You go back again, uh, you know, looming in the backdrop of this conversation is a conversation about social media, but before-

Marc Berman 46:33 Yeah.

Andrew Huberman 46:33 But before we go there, if you were, at this point, to give a, kind of a best recommendation in terms of how to reset one's attentional abilities, uh, what are the sort of basic requirements?

Marc Berman 46:45 So, I think there's, there's a lot there too. Um, I think you have to be really mindful about directed attention fatigue. So, if you're trying to study or, uh, you're at work and you're having a really hard time concentrating, I would recommend not just trying to power through. If, if you have the ability, uh, and the time to take a break, I recommend that you stop and you take a break. And what kind of break do I recommend you do? I recommend that you go and try to find some nature and walk in nature. And-

Andrew Huberman 47:19 What if you're, wh- you're having a hard time getting into a focused state at all?

Marc Berman 47:23 Yeah.

Andrew Huberman 47:23 It's not that you fatigued it-

Marc Berman 47:24 Okay.

Andrew Huberman 47:24 ... that day.

Marc Berman 47:25 Yeah.

Andrew Huberman 47:25 You, you know, so many people that I hear from-

Marc Berman 47:28 Yeah.

Andrew Huberman 47:28 ... uh, who listen to the podcast and elsewhere, will say, you know, they, they get up, they-

Marc Berman 47:34 Yeah.

Andrew Huberman 47:34 ... did their best to get their sleep, they get their morning sunlight-

Marc Berman 47:36 Yeah.

Andrew Huberman 47:36 ... they hydrate, they drink their caffeine, they sit down to their computer, and they just can't focus.

Marc Berman 47:41 Right.

Andrew Huberman 47:41 And then they start thinking, like, do they have brain fog?

Marc Berman 47:45 Yeah, yeah, yeah, yeah, yeah, yeah.

Andrew Huberman 47:46 Do they have ... Do they need a nootropic, you know? There ... All these questions start to arise. W- what, what are your thoughts?

Marc Berman 47:51 I think in some sense, even though you might be very well slept and very well fed, you could still be in a directed attention fatigue state. So, I think, yeah, if you can't concentrate right in the beginning of the morning, then you should go for a walk right ... That should be the first thing you should do. Or if you don't have access to nature, maybe listen to some nature sounds, or, or watch a nature video or something like that. Uh, we find that all those things can be beneficial. Even looking out the window to nature can be beneficial. Looking at a picture. You've got a picture of nature here. Looking at a picture of nature can be beneficial. So, I would say anytime you're having trouble concentrating, it doesn't have to ... it doesn't matter if it's in the beginning of the day or the end of the day or the middle of the day, we ... I would recommend that you take some kind of break with nature. And it could be simulated nature, like, uh, listening to nature sounds, watching a nature video, looking at nature pictures, or even better is if you can actually get out and, uh, interact with nature because Steve Kaplan used to also talk about these other elements that might be important for a restorative environment. One was that the environment had to have extent, meaning that...It, it had to have enough interesting things t- to look at. Now, it doesn't mean that it has to be Yosemite Valley, which has incredible spatial extent. I mean, it's huge. It's enormous. But, you know, like, near my office, um, at the University of Chicago, we have this, uh, Japanese garden, the Garden of the Phoenix. It might be only, like, 100 square meters. It's pretty small. But man, it's still got a lot of extent. You know? It's got a pa- a walking path. It's got a little waterfall. You can see Lake Michigan. Um, so that's one element. Another thing, uh, about the, the nature is that you want it to be compatible with your goal. So, so what do I mean by that? If you've got a big exam and you haven't studied, I'm not sure going for the walk in nature is gonna work (laughs) -

Andrew Huberman 49:53 Mm-hmm.

Marc Berman 49:53 ... you better use that time to, to study. But if you can't concentrate, you know, trying to power through, I don't think it's gonna be compatible with your goals. I think going in- for the nature walk is compatible with your goals, so that's another thing that's gonna be really important. And the other concept, uh, that Steve used to talk about being important is this, is that the environment needs to give you the sense of being away, that you're kind of removed, um, from your current environment, almost like a change of mindset. Um, and again, that doesn't mean you have to go really, really far away. But you might wanna go to a location that's not at your desk. So, maybe don't sit at your desk and look at the nature pictures. Maybe you wanna go somewhere else and look at the nature pictures. And this kind of distance, I think, could be helpful. I don't know if Cal Newport talks about this in his deep work, but you know, I've heard people talking about, in an office, you might wanna have, like, a separate area of your office for deep work. And I think this kind of sense of being away is related to that. You kinda wanna get out of your current state and go into this other environment that might be able to replenish those resources.

Andrew Huberman 51:00 Mm-hmm. So, I'm hearing that there are two sides of the coin. One is to designate an area for work that's truly for deep work.

Marc Berman 51:06 Yes.

Andrew Huberman 51:07 I followed Cal's recommendation, and, and now I have an area in my basement, believe it or not-

Marc Berman 51:11 Mm-hmm.

Andrew Huberman 51:11 ... and there has never been a phone in that basement.

Marc Berman 51:15 Right. (laughs)

Andrew Huberman 51:15 There's no phones allowed in that basement.

Marc Berman 51:17 Right, right.

Andrew Huberman 51:17 That's a, that's not a rule.

Marc Berman 51:18 Yeah.

Andrew Huberman 51:18 It's not a protocol. It's a policy.

Marc Berman 51:19 Right. And I remember he talked-

Andrew Huberman 51:20 Yeah.

Marc Berman 51:20 ... about in his, he has this library-

Andrew Huberman 51:22 Yeah.

Marc Berman 51:22 ... office that he goes to.

Andrew Huberman 51:23 Yeah, yeah.

Marc Berman 51:24 And I, I very much-

Andrew Huberman 51:25 Yeah.

Marc Berman 51:25 ... agree with that.

Andrew Huberman 51:26 Yeah. Now, I do get internet access down there a little bit if I need to look for papers.

Marc Berman 51:31 Yeah.

Andrew Huberman 51:31 But, um, I've been turning off wifi on my computer when I go down there to work.

Marc Berman 51:35 Yeah.

Andrew Huberman 51:35 And I get more done in three hours down there-

Marc Berman 51:38 Yeah.

Andrew Huberman 51:38 ... than I would in three weeks-

Marc Berman 51:40 Yeah.

Andrew Huberman 51:40 ... above ground.

Marc Berman 51:41 Yeah.

Andrew Huberman 51:41 I swear. It's a, it's a huge effect.

Marc Berman 51:43 Yeah. Yep.

Andrew Huberman 51:44 Um, the other side of the coin is this business of getting out into a different environment. And it sounds like these walks, or, uh, or these ventures into nature don't take terribly long. How, how long does one need to do this in order to get the enhancement in focus and working memory? Like, what do the data say?

Marc Berman 51:59 Yeah. I mean, when we did the... W- our walking study was 50 minutes, but I've seen other studies with as little as 20 minutes, you can get the effects and-

Andrew Huberman 52:08 For cognitive enhancement?

Marc Berman 52:08 For cognitive enhancement.

Andrew Huberman 52:10 Mm-hmm.

Marc Berman 52:10 Um, and there've actually been some interesting studies with kids with ADHD, and they find attention benefits, uh, for these kids with ADHD after just a 20-minute walk in nature that (laughs) actually was similar, um, to, like, a dose of Ritalin. So, that was pretty, uh, incredible. So, it doesn't have to be super long. Uh, and when we were doing the, the slideshow of nature pictures, that was only for about 10 minutes, so it doesn't have to be a really, really long immersion. There have been other studies that have suggested, like, overall, uh, you might wanna get about two hours a week in nature.

Andrew Huberman 52:47 I'd like to take a quick break and acknowledge our sponsor, AG1. AG1 is a vitamin mineral probiotic drink that also includes prebiotics and adaptogens. As somebody who's been involved in research science for almost three decades and in health and fitness for equally as long, I'm constantly looking for the best tools to improve my mental health, physical health, and performance. I discovered AG1 back in 2012, long before I ever had a podcast, and I've been taking it every day since. I find it improves all aspects of my health, my energy, my focus, and I simply feel much better when I take it. AG1 uses the highest quality ingredients in the right combinations, and they're constantly improving their formulas without increasing the cost. In fact, AG1 just launched their latest formula upgrade. This next gen formula is based on exciting new research on the effects of probiotics on the gut microbiome, and it now includes several clinically studied probiotic strains shown to support both digestive health and immune system health, as well as to improve bowel regularity and to reduce bloating. Whenever I'm asked if I could take just one supplement, what that supplement would be, I always say, "AG1." If you'd like to try AG1, you can go to drinkag1.com/huberman. For a limited time, AG1 is giving away a free one-month supply of omega-3 fish oil along with a bottle of vitamin D3 plus K2. As I've highlighted before on this podcast, omega-3 fish oil and vitamin D3-K2 have been shown to help with everything from mood and brain health to heart health to healthy hormone status and much more. Again, that's drinkag1.com/huberman to get a free one-month supply of omega-3 fish oil plus a bottle of vitamin D3 plus K2 with your subscription. Today's episode is also brought to us by Our Place. Our Place makes my favorite pots, pans, and other cookware. Surprisingly, toxic compounds such as PFASs or forever chemicals are still found in 80% of non-stick pans, as well as utensils, appliances, and countless other kitchen products. As I've discussed before in this podcast, these PFASs or forever chemicals like Teflon have been linked to major health issues such as hormone disruption, gut microbiome disruption, fertility issues, and many other health problems. So, it's really important to try and avoid them.This is why I'm a huge fan of Our Place. Our Place products are made with the highest quality materials and are all completely PFAS and toxin free. I especially love their Titanium Always Pan Pro. It's the first non-stick pan made with zero chemicals and zero coating. Instead, it uses pure titanium. This means it has no harmful forever chemicals and does not degrade or lose its non-stick effect over time. It's also beautiful to look at. I cook eggs in my Titanium Always Pan Pro almost every morning. The design allows for the eggs to cook perfectly without sticking to the pan. I also cook burgers and steaks in it, and it puts a really nice sear on the meat. But again, nothing sticks to it, so it's really easy to clean and it's even dishwasher-safe. I love it, and I basically use it constantly. Our Place now has a full line of Titanium Pro cookware that uses its first of its kind titanium non-stick technology. So if you're looking for non-toxic, long-lasting pots and pans, go to fromourplace.com/huberman and use the code Huberman at checkout. With 100-day risk-free trial, free shipping, and free returns, you can experience this terrific cookware with zero risk.

Andrew Huberman 56:00 You know, I've been long obsessed with this, um, difference between what happens in our brain stem, you know, the areas involved, as you know, um, with levels of arousal and stress versus calm, um, when we look at a fixation point versus a, a horizon or when we go into-

Marc Berman 56:18 Mm-hmm. Mm-hmm.

Andrew Huberman 56:18 ... panoramic vision. And there are now ample data to support the idea that when we fixate on a small box-

Marc Berman 56:24 Yeah.

Andrew Huberman 56:24 ... like a phone or a computer-

Marc Berman 56:26 Yeah.

Andrew Huberman 56:26 ... or we, you know, w- we're fixated on something we're reading or paying attention to it, that our level of autonomic arousal creeps up. Doesn't creep up indefinitely, but this makes sense, right?

Marc Berman 56:36 Yeah. Yeah. Yes.

Andrew Huberman 56:36 Visual attention matches a cognitive attention.

Marc Berman 56:38 Yeah.

Andrew Huberman 56:38 You need arousal-

Marc Berman 56:39 Yeah.

Andrew Huberman 56:39 ... AKA alertness to get cognitive attention.

Marc Berman 56:41 Yeah.

Andrew Huberman 56:41 But that when we go into panoramic vision, which is, you know, for these aficionados, you can look up magnocellular vision, what you're essentially doing-

Marc Berman 56:48 Yeah.

Andrew Huberman 56:48 ... is you're taking bigger pixels of the-

Marc Berman 56:49 Yes.

Andrew Huberman 56:49 ... of the visual environment.

Marc Berman 56:50 Yes.

Andrew Huberman 56:51 And when we look at a horizon-

Marc Berman 56:53 Yep.

Andrew Huberman 56:53 ... we naturally go into panoramic vision, unless we're looking at our phone (laughs) -

Marc Berman 56:57 Yes. Yes. Yes.

Andrew Huberman 56:57 ... taking a picture of the horizon. So take note. It's interesting to me to think about visual environments such as nature that, that have us taking larger bins, pic- pixels if we're talking about visual space, but that we're also perhaps, this is a question I'm obsessed with, perhaps taking larger time bins.

Marc Berman 57:18 Mm-hmm.

Andrew Huberman 57:19 What do you think about a, a kind of a general idea that what we need to do in order to be focused-

Marc Berman 57:24 Yeah.

Andrew Huberman 57:25 ... is to allow our mind to go into these kind of, like, time drift states?

Marc Berman 57:29 Yeah, and I kind of think, you know, you're talking about it from a, a visual perspective, but I think it's also from a cognitive mental perspective. So I think also too, being in nature kind of widens your cognitive, you know, landscape. You... And that's why I think people sometimes, you know, you hear all these anecdotes where people are struggling to solve a problem, they can't figure it out, they go for a walk in nature, and then boom, they, they solve the problem, 'cause the brain is still churning on that, right? But maybe being out in nature sort of inspires this widening of attentional space internally.

Andrew Huberman 58:07 We had a guest on this podcast, Michael Platt from the University of Pennsylvania.

Marc Berman 58:10 Yeah.

Andrew Huberman 58:10 He's a neuroscientist, and he told us about this experiment, it's pretty wild. I'm s- this still blows me away. You're probably familiar with it, but I wasn't, which is that if you have sub- uh, human subjects in a lab do a connect-the-dots task where the dots are placed very close together-

Marc Berman 58:22 Yeah.

Andrew Huberman 58:23 ... versus a connect-the-dots task where there, uh, the dots are placed much further apart, and then you give them a creativity task, the people who do the task, and it's well-controlled for, folks-

Marc Berman 58:35 Yep.

Andrew Huberman 58:35 ... um, connecting dots that are further apart in physical space show significantly elevated levels of, of-

Marc Berman 58:41 Creativity.

Andrew Huberman 58:42 ... of creative insight to solving problems. And so there's something about-

Marc Berman 58:45 Yes.

Andrew Huberman 58:45 ... visual space-

Marc Berman 58:46 Yes.

Andrew Huberman 58:46 ... and time-

Marc Berman 58:47 Yes.

Andrew Huberman 58:47 ... and our ability to link, um, things in cognitive space-

Marc Berman 58:51 Yes.

Andrew Huberman 58:51 ... and time. This is why, uh, when you said earlier that when you're, uh, out in nature there, there aren't as many words to describe things.

Marc Berman 58:59 Right. Yes.

Andrew Huberman 58:59 What that means to me, if I think about the results that Platt was talking about, is that perhaps it isn't just that, that, um, there's a dearth of language, but perhaps then your brain starts to drop into other, m- like, modes of cognition. I don't want to sound too nerdy-

Marc Berman 59:16 Yes.

Andrew Huberman 59:16 ... just to sound nerdy here, but-

Marc Berman 59:17 Yeah. Yes.

Andrew Huberman 59:17 ... but that, you know-

Marc Berman 59:18 Yes.

Andrew Huberman 59:18 ... there are all sorts of things-

Marc Berman 59:18 Yeah.

Andrew Huberman 59:19 ... in your brain that have, that are n- that are, that are... that can't have words assigned to them, like-

Marc Berman 59:23 Yeah.

Andrew Huberman 59:23 ... for instance, your childhood. You could give the whole story-

Marc Berman 59:26 (laughs) .

Andrew Huberman 59:26 ... but it still wouldn't capture it, right?

Marc Berman 59:28 Right. Right.

Andrew Huberman 59:28 But there was your trauma, there was your wins, there were your, um, falling in love. You know, we have these words, but they don't capture the experience. They don't capture, like, the-

Marc Berman 59:38 Yeah.

Andrew Huberman 59:39 ... the visceral experience, the smells, the tastes.

Marc Berman 59:41 Yep.

Andrew Huberman 59:41 And so, um, I love the idea that in nature things are sparse enough yet rich enough-

Marc Berman 59:48 Yes.

Andrew Huberman 59:49 ... that maybe these networks get, get triggered.

Marc Berman 59:51 Right. Right. And I think, you know, this is kind of a- another, if we want to get into the neuroscience a little bit, we have some of these ideas that, um, for what a brain looks like when it's kind of at rest. And, um, when we talk about fractalness, you know, most of us think about, like, a spatial fractal, so if there's a snowflake, it's got a characteristic shape. If you put that snowflake under a microscope and zoom in, it still kind of has that same shape. If you zoom in some more, it's still got that same shape. Um, so it doesn't matter at what scale you look at the snowflake, it's got the same shape. So that's called as a snowflake is sort of scale free spatially, or another way to say it is that it's fractal. It's got this repeated patterning at these different spatial scales. And nature is filled with fractals.

Andrew Huberman 1:00:40 Could you tell us more about some of those? I, I recall hearing about fractals of Mandelbrot that came up-

Marc Berman 1:00:44 Yeah, Mandelbrot, right.

Andrew Huberman 1:00:44 ... or that came up-

Marc Berman 1:00:45 Yeah, yeah.

Andrew Huberman 1:00:45 ... with fractals.

Marc Berman 1:00:45 Yes.

Andrew Huberman 1:00:46 But despite the fact that I remember Mandelbrot's name, um, all that tells you is that, uh, my brain is filled with meaningless information-

Marc Berman 1:00:52 (laughs) .

Andrew Huberman 1:00:52 ... 'cause what I want to know is not who came up with it, right? This is the problem with, with the hippocampus, right? You can encode perfectly useless information. No discredit to Mandelbrot. But where in nature, aside from snowflakes, do fractals show up? Are they in tree bark?

Marc Berman 1:01:07 Everywhere. I mean, a tree...... is also quite fractal, right? So you have the trunk of the tree, and then it breaks off into branches, which breaks off into smaller branches, which breaks off into leaves, and the leaves have the veins that also branch off. So it's very, very fractal. It's got this same branching structure at all these different scales.

Andrew Huberman 1:01:27 Really?

Marc Berman 1:01:27 Yeah.

Andrew Huberman 1:01:29 So when I look at, like, sand in the desert-

Marc Berman 1:01:31 Yeah.

Andrew Huberman 1:01:31 ... you're telling me that, that this regularity exists at every scale?

Marc Berman 1:01:34 Yeah, pretty much. I think a desert would also be fractal in terms of, um, you know, how the wind... 'cause the wind is also kind of a fractal, uh, sort of process. So it, the sand will be somewhat fractal. A mountainscape will also be quite fractal. A coastline will be fractal.

Andrew Huberman 1:01:51 Well, well, tell me for a mountain. So where am I gonna look at a smaller scale? I can see-

Marc Berman 1:01:54 So like-

Andrew Huberman 1:01:54 ... I can imagine a mountain.

Marc Berman 1:01:55 Mountain.

Andrew Huberman 1:01:56 Yeah.

Marc Berman 1:01:56 Now, if you zoomed in on-

Andrew Huberman 1:01:57 Yeah.

Marc Berman 1:01:57 ... a different portion of that mountain, it would have some of the same structural properties as the zoomed out version.

Andrew Huberman 1:02:02 Really?

Marc Berman 1:02:03 Yeah.

Andrew Huberman 1:02:03 Wild.

Marc Berman 1:02:04 Yeah. So and again, this kinda... (laughs) You know, to return back to, like, compression, again, if you have this repeated pattern, patterning, that might be easier for our brain to process 'cause really, you just have to only kinda encode one structure, 'cause that structure's repeated at all these different scales.

Andrew Huberman 1:02:21 Whereas human beings and advertisements and all that-

Marc Berman 1:02:24 (laughs)

Andrew Huberman 1:02:24 ... we try, you know, th- there's this thing in science, as you know. People are either lumpers or splitters.

Marc Berman 1:02:29 Yes.

Andrew Huberman 1:02:30 Right? And, and many a career has been made by, uh, splitting-

Marc Berman 1:02:33 Yeah.

Andrew Huberman 1:02:34 ... when lumping would have been sufficient.

Marc Berman 1:02:36 Right.

Andrew Huberman 1:02:37 Human behavior, human advertising, music. I mean, I'm sure there's immense regularity-

Marc Berman 1:02:42 Yes.

Andrew Huberman 1:02:42 ... but when we're bombarded with that, now I'm sort of, uh, making the segue to something like social media-

Marc Berman 1:02:47 Yeah.

Andrew Huberman 1:02:48 ... where you're just bombarded with sensory information.

Marc Berman 1:02:51 Yes.

Andrew Huberman 1:02:51 Like, one movement of my thumb takes me from one cognitive landscape to a completely different cognitive landscape.

Marc Berman 1:02:58 Right.

Andrew Huberman 1:02:58 I mean, if it were my preference, my entire feed would be dogs.

Marc Berman 1:03:02 Yep.

Andrew Huberman 1:03:03 But I'm going from dogs to politics to fitness to... and then stuff that the algorithm is testing on me. And I mean, it's amazing that we can do this-

Marc Berman 1:03:13 Yep.

Andrew Huberman 1:03:14 ... and yet the more we talk about nature-

Marc Berman 1:03:16 Yeah.

Andrew Huberman 1:03:16 ... and how restorative it is- (laughs)

Marc Berman 1:03:18 Yeah.

Andrew Huberman 1:03:18 ... or reading a book and what a kind of a, following a common narrative-

Marc Berman 1:03:21 Yeah, yeah.

Andrew Huberman 1:03:21 ... like kind of drilling down into that-

Marc Berman 1:03:23 Yeah.

Andrew Huberman 1:03:23 ... or watching a movie-

Marc Berman 1:03:24 Yeah.

Andrew Huberman 1:03:24 ... which hopefully has some continuity to the, to the plot, the more I realize that social media is, for lack of a better word, is kind of chaos.

Marc Berman 1:03:33 (laughs)

Andrew Huberman 1:03:33 It's like cognitive chaos.

Marc Berman 1:03:35 Or it's definitely not fractal. Yeah. It, it's definitely not fractal.

Andrew Huberman 1:03:39 Well put, yeah. It's not fractal.

Marc Berman 1:03:40 Um, and if we kind of return to fractals too, so we think, um... So we talked about fractals in terms of space, like, uh, there's got the shape and you zoom in, same shape, zoom in some more, same shape. You can also talk about fractalness in time. So you can have like a signal oscillating in time, fluctuating in time, and you can also quantify how fractal that signal is in time.

Andrew Huberman 1:04:04 Mm-hmm.

Marc Berman 1:04:05 So it's like if you look at the signal at one millisecond, 10 milliseconds, 50 milliseconds, 10 seconds, 30 seconds, an hour, does that signal look the same or does it look different? If the signal looks the same at all those different temporal windows, we say the signal is fractal in time.

Andrew Huberman 1:04:28 Can you give me an example from a nature environment and one by comparison from a urban environment? I'm thinking a car alarm in an urban environment-

Marc Berman 1:04:37 (laughs)

Andrew Huberman 1:04:37 ... is, like, the most alerting. I mean, it grabs our involuntary attention.

Marc Berman 1:04:41 (laughs) And it's not fractal, it's periodic. It's just, wah, wah, wah, wah. You know, over and over again. Like a fractal signal will kind of have low frequency stuff, will be, have a lot of power, but it also has all of the different frequencies are represented, but they're, um, how their amplitude is, this is gonna get a little nerdy, is proportional to their frequency. So low frequency stuff will have higher amplitude or higher power, and high frequency stuff will have lower amplitude or lower power. And a lot of natural sounds and stuff are also more fractal. But what's interesting is that you can also look at brain signals, like I, I can take... I'll put a person in an MRI machine and look at like how are the brain areas fluctuating? Or I can have an EEG cap on them and look at how their electrical activity is, is fluctuating. It turns out when brains are more fractal in time, brains are exerting less effort, less cognitive effort. So, you know, (laughs) it's kind of depressing, but as we age, our brains kind of get less fractal. Um, if you're learning, uh, a new task for the first time when it's harder, uh, the brain is less fractal than when you're well practiced at the task.

Andrew Huberman 1:05:58 Mm-hmm.

Marc Berman 1:05:58 If you're doing an easy task, the brain is more fractal than when you're doing a harder task. And so we think that maybe nature is kind of pushing the brain into this, like, higher fractal state that might be like this sort of critical rested state. Um, that's, that's kind of a really, um... that's gonna p- that's gonna, that's gonna allow you to actually have a lot of directed attention.

Andrew Huberman 1:06:30 When you need it.

Marc Berman 1:06:31 When you need it-

Andrew Huberman 1:06:32 Right, so-

Marc Berman 1:06:32 ... versus like the social media stuff is just pulling, grabbing. It's, it's not letting you get into this fractal rested state. It's, it's, it's driving fractalness down.

Andrew Huberman 1:06:43 Right. Well, the social media platforms-

Marc Berman 1:06:44 Yeah.

Andrew Huberman 1:06:44 ... not to paint them as evil-

Marc Berman 1:06:45 Sure, right.

Andrew Huberman 1:06:46 ... because I, I teach on social media, learn on social media-

Marc Berman 1:06:48 Yeah.

Andrew Huberman 1:06:48 ... enjoy social media, but it's a business.

Marc Berman 1:06:50 Right.

Andrew Huberman 1:06:51 They're not doing it for free.

Marc Berman 1:06:52 No.

Andrew Huberman 1:06:52 They're not doing it out of the goodness-

Marc Berman 1:06:53 Right.

Andrew Huberman 1:06:53 ... of their hearts.

Marc Berman 1:06:54 Right.

Andrew Huberman 1:06:54 And, um, uh, I basically think of social media as the reality TV show that we've all either chosen to be a part of-

Marc Berman 1:07:04 Yeah.

Andrew Huberman 1:07:05 ... we've cast ourselves in it.

Marc Berman 1:07:07 Yeah.

Andrew Huberman 1:07:07 The idea here is that it is not designed to be relaxing.

Marc Berman 1:07:11 No.

Andrew Huberman 1:07:11 It's designed to capture your directed attention.

Marc Berman 1:07:13 That's right.

Andrew Huberman 1:07:14 If it just grabbed your involuntary attention, it wouldn't work. Now, that might seem a little bit counterintuitive because I and everybody else has the experience...... of, you know, picking up your phone-

Marc Berman 1:07:22 Right.

Andrew Huberman 1:07:22 ... you're like, "Okay, I'm only going to spend a minute. I'm going to just kind of check what's on Instagram."

Marc Berman 1:07:25 Right, right.

Andrew Huberman 1:07:26 And all of a sudden, you're, you're taken down this-

Marc Berman 1:07:27 Right.

Andrew Huberman 1:07:28 ... um, this rabbit hole of one thing-

Marc Berman 1:07:30 Right.

Andrew Huberman 1:07:30 ... and then, you know, it's 30 minutes later and you're like, "Goodness-"

Marc Berman 1:07:32 Right.

Andrew Huberman 1:07:32 "... you know, I, I gotta get ready for work-"

Marc Berman 1:07:33 Right.

Andrew Huberman 1:07:33 "... or something like this." But the involuntary attention that you were talking about before is the kind of thing that cues you to something, and then you go down that direction, right?

Marc Berman 1:07:42 Right, or I would say that the social media, it's not softly fascinating, it's harshly fascinating.

Andrew Huberman 1:07:47 Mm-hmm.

Marc Berman 1:07:47 It's, it's, it's grabbing you and not letting you mind wander or think about anything else. It's, it's grabbing all of your attentional resources.

Andrew Huberman 1:07:55 And I would say it does that not by taking us typically down rabbit holes, but it's not like you spend a lot of time on one post.

Marc Berman 1:08:02 Right.

Andrew Huberman 1:08:03 You might go into the comments section-

Marc Berman 1:08:04 Yes.

Andrew Huberman 1:08:04 ... if you're interested in that.

Marc Berman 1:08:05 Correct.

Andrew Huberman 1:08:05 But it's the fact that you have a... I'm imagining now-

Marc Berman 1:08:09 Yeah.

Andrew Huberman 1:08:09 ... that there's some resource in the brain that's a combination of catecholamines, dopamine-

Marc Berman 1:08:13 Yeah.

Andrew Huberman 1:08:13 ... norepi- norepinephrine- nephrine- necessarily.

Marc Berman 1:08:15 Yeah.

Andrew Huberman 1:08:15 Plus a bunch of neural network metabolism-

Marc Berman 1:08:18 Yeah.

Andrew Huberman 1:08:19 ... stuff.

Marc Berman 1:08:19 Yeah.

Andrew Huberman 1:08:19 It will never be one thing, right?

Marc Berman 1:08:21 Yeah.

Andrew Huberman 1:08:21 It's not going to be, like, a molecule.

Marc Berman 1:08:22 Right.

Andrew Huberman 1:08:22 And that depending on how w- well rested we are, we go into the day with a certain amount of directed attention units that we can spend.

Marc Berman 1:08:31 Yup.

Andrew Huberman 1:08:32 And everything you're telling us today is that going into a fractal, AKA a nature environment, allows us to come off the, the sort of spending-

Marc Berman 1:08:45 Yeah.

Andrew Huberman 1:08:46 ... of our directed attention.

Marc Berman 1:08:47 That's right.

Andrew Huberman 1:08:48 And it also seems to reset the directed attention account.

Marc Berman 1:08:51 Yes.

Andrew Huberman 1:08:52 Are there any data that speak to whether or not it just allows us to not spend, or whether or not it actually replenishes this directed attention capability?

Marc Berman 1:09:01 Yeah, it's a good question. Or, or does it even, like, extend capabilities? Like, does it take you above your baseline?

Andrew Huberman 1:09:08 Right, is it a- an investment?

Marc Berman 1:09:09 Right.

Andrew Huberman 1:09:10 Lately, I think not so much about dopamine per se-

Marc Berman 1:09:13 Yeah.

Andrew Huberman 1:09:13 ... I think about, are you spending your dopamine down-

Marc Berman 1:09:16 Yeah.

Andrew Huberman 1:09:16 ... or are you investing your dopamine?

Marc Berman 1:09:18 Right. And I would say, I, I mean, unfortunately, I don't have a good answer for it. I'm, I'm not sure. It might actually... It could... It's possible that it might expand your store. It might, it might... You might be getting interest. (laughs)

Andrew Huberman 1:09:31 Mm-hmm.

Marc Berman 1:09:31 So, so one of the things too that we kind of struggle with a little bit is, like, is nature boosting us a lot, or is urban fatiguing us? (laughs)

Andrew Huberman 1:09:40 Right.

Marc Berman 1:09:40 You know, depleting us? And I think both things are kind of at play there.

Andrew Huberman 1:09:43 I have

Andrew Huberman 1:09:44 all set of questions popping to mind about sleep states and deep sleep being more like fractal environments, and rapid eye movement sleep being more like reality and therefore more challenging. But, um, I'm gonna just shelve those-

Marc Berman 1:09:56 Okay.

Andrew Huberman 1:09:57 ... and maybe we'll get back to them, maybe we won't. I wanna make sure that I understand correctly what the protocol, for lack of a better word, would be. Get out into nature, ideally move-

Marc Berman 1:10:08 Yes.

Andrew Huberman 1:10:08 ... for about 20 minutes minimum.

Marc Berman 1:10:10 Yup.

Andrew Huberman 1:10:11 And ideally, you remove yourself from phone. W- what if you have to make a phone call while you're doing it, is that-

Marc Berman 1:10:18 I mean, that's why I would just, you don't want to do it. And I'd, I'd even say too, I know you were saying you like to put the earbuds in sometimes, I would say, you don't want the earbuds in. You want all of your attentional capacity, or involuntary attention to be captured by that environment.

Andrew Huberman 1:10:33 Okay. Great.

Marc Berman 1:10:34 Um, you know, it's kinda... (laughs) I kind of joke with my students about this a little bit, where I would say, you know, "Uh, how many of you study with, uh, listening to music?" And a lot of students raise their hand, "Yeah, I study while listening to music." I say, "Okay, how many of you want to take the exam listening to music?" Nobody. (laughs) Nobody raises their hand. I say, "Well then, that's a, that's not consistent," you know?

Andrew Huberman 1:10:55 Mm-hmm.

Marc Berman 1:10:56 And, and, and it's, it's not because, you know, the students are, uh, not smart. It's, it's that studying sucks. (laughs)

Andrew Huberman 1:11:05 Mm-hmm.

Marc Berman 1:11:05 And, you know, listening to music just makes it more pleasurable. But you're not, you know, you're, you're, you're taking away attentional resources that could be used for the studying by listening to, to music. And I think, you know, on the flip side, I want you to be fully engaged with nature. I want your involuntary attention to be just automatically captured by this nature stimulation. I don't want anything else interfering with that. I think that's how you're going to get the most bang for your buck. And in fact, you know, you know, we did these studies where I wasn't sure how it was gonna work, so we did some studies, um, where we took participants who were diagnosed with clinical depression. (laughs) And this is kind of mean, but I think important, we had them walk in nature too. But before these participants went for a walk in nature, we had them think about a negative thought or memory that's been bothering them to try to induce rumination, to get them ruminating. And we thought, you know, maybe if you go for a walk alone in nature and you're restoring your attention, maybe they're gonna ruminate even more, that it's gonna be, uh, you know, not good. It's gonna, maybe it's gonna hurt, hurt performance. And we found just the opposite, that actually these participants with clinical depression who we had induced to ruminate got even stronger benefits walking in nature than our non-clinical sample.

Andrew Huberman 1:12:32 On, on working memory?

Marc Berman 1:12:33 On working memory.

Andrew Huberman 1:12:34 Mm-hmm.

Marc Berman 1:12:35 And, uh, and y- and you can imagine participants that are struggling with depression and rumination, their working memory is not as good, 'cause you've got cognitive resources devoted to these, these negative thoughts they're just repeating over and over again. You don't have your full bank account of attention 'cause you, you've had... you're spending it on the rumination. And we found that for these participants, the effects were, were stronger in improving their attention and working memory. And I think part of that might be that it's, it's actually giving them some of the attentional resources necessary to deal with the rumination.

Andrew Huberman 1:13:12 Super interesting. I know rumination is something that many people, depressed or not, uh, struggle with. Um, and I've long thought, and I'm certainly coming to this conclusion with each successive year of my life, that w-... uh, distraction is the enemy.

Marc Berman 1:13:26 Yeah. Yeah.

Andrew Huberman 1:13:26 Like, the ability to drop into work, creative work, or pre- for me, prepping a podcast or reading papers or, um, taking a walk with somebody, having a conversation with somebody, because relationships are important too, of course, and just being able to be fully present to that-

Marc Berman 1:13:41 Right.

Andrew Huberman 1:13:42 ... is only the basis of a great life.

Marc Berman 1:13:45 Right.

Andrew Huberman 1:13:46 Even if you're dealing with challenge.

Marc Berman 1:13:47 Right, right.

Andrew Huberman 1:13:48 It's a- it, uh, that when we spread ourselves out across all these different, uh, modalities that, um, no good comes of it.

Marc Berman 1:13:56 That's right.

Andrew Huberman 1:13:56 And, um, like any destructive force, uh, that's really bad, it's the fact that we don't notice that we were absent for large swaths of it-

Marc Berman 1:14:07 Right.

Andrew Huberman 1:14:07 ... and that it becomes so, so pervasive in society that it's not also frowned on.

Marc Berman 1:14:11 Yep.

Andrew Huberman 1:14:12 I actually put social media on an old phone. So, I have social media accounts, uh, on an old phone.

Marc Berman 1:14:18 Yeah.

Andrew Huberman 1:14:18 And that's the only way I can access social media.

Marc Berman 1:14:20 Yep.

Andrew Huberman 1:14:20 Somebody sends me something by way of social media, I don't do it because, I mean, it's the... I don't know what the best analogy is. It's like someone who's trying to eat clean and, and y- you're constantly handing them junk food or-

Marc Berman 1:14:31 Right, right.

Andrew Huberman 1:14:32 ... you know? And I enjoy social media, but I like to make it a designated time.

Marc Berman 1:14:35 Right.

Andrew Huberman 1:14:37 So, getting out for, for a walk in 20 minutes-

Marc Berman 1:14:39 And put the, I would say put the phone in a box.

Andrew Huberman 1:14:41 Put the phone away. The whole basis here seems to be allowing your brain to go into kind of, if I take it to its logical conclusion, to kind of its necessary state to reset.

Marc Berman 1:14:55 Yeah.

Andrew Huberman 1:14:55 Maybe.

Andrew Huberman 1:14:57 This state of getting into nature and f- let's call it high fractal environments-

Marc Berman 1:15:02 Yep.

Andrew Huberman 1:15:03 ... is similar or should be similar to the way that we've started to talk about sleep.

Marc Berman 1:15:07 Hmm.

Andrew Huberman 1:15:08 You know, prior to 2015, maybe it was 2018, um, the notion was sleep when you're dead.

Marc Berman 1:15:18 (laughs)

Andrew Huberman 1:15:19 Um, you know, Matt Walker of UC Berkeley-

Marc Berman 1:15:22 Yep.

Andrew Huberman 1:15:22 ... with the book Why We Sleep transformed what we now understand. And I've, and others have been, you know, arguing that people need sleep.

Marc Berman 1:15:30 Yeah.

Andrew Huberman 1:15:30 Now, I think everyone understands if you don't sleep, your mental health, your physical health-

Marc Berman 1:15:35 Yep.

Andrew Huberman 1:15:35 ... your performance-

Marc Berman 1:15:36 Yep.

Andrew Huberman 1:15:37 ... drops dramatically.

Marc Berman 1:15:38 Yep.

Andrew Huberman 1:15:38 You need sleep. And Matt has educated us that you need slow wave sleep, you need rapid eye movement sleep. Maybe we also need these, um, high fractal environments. And the fact that they come in their best form through walks in nature when we're not doing anything else, just like you wouldn't want to... I don't know, you don't wanna bring the phone into the bedroom kind of thing-

Marc Berman 1:15:59 No.

Andrew Huberman 1:16:00 ... um, late at night because you're not gonna get your deep sleep because you're gonna go to sleep too late and then you miss out on the opportunity for deep sleep.

Marc Berman 1:16:05 Right.

Andrew Huberman 1:16:06 Um, I love the idea that these waking states become, uh, better understood as, and perhaps even requirements. I feel like we understand so much about sleep, slow wave sleep-

Marc Berman 1:16:19 Yeah.

Andrew Huberman 1:16:19 ... growth hormone, REM sleep-

Marc Berman 1:16:21 Yeah.

Andrew Huberman 1:16:21 ... emotional repair, and everyone now is like, "Cool, we need sleep."

Marc Berman 1:16:24 Right.

Andrew Huberman 1:16:24 "And here are the different stages of sleep."

Marc Berman 1:16:25 Right.

Andrew Huberman 1:16:25 We actually know very little, it seems, about waking states-

Marc Berman 1:16:28 Right (laughs) .

Andrew Huberman 1:16:29 ... and the requirement for different waking states.

Marc Berman 1:16:31 Right.

Andrew Huberman 1:16:31 Because if you stay up all night-

Marc Berman 1:16:32 Yeah.

Andrew Huberman 1:16:34 ... you entirely expect to not be at your best the next day.

Marc Berman 1:16:38 That's right.

Andrew Huberman 1:16:38 But I have a feeling that based on your work, that we're doing all sorts of things that are making us far less than our natural best.

Marc Berman 1:16:46 That's right.

Andrew Huberman 1:16:47 And that some of us who are clinically diagnosed with things-

Marc Berman 1:16:50 Yeah.

Andrew Huberman 1:16:50 ... I haven't been clinically diagnosed with ADHD. If anything, I probably veer more towards the OCD side of things-

Marc Berman 1:16:57 Yeah.

Andrew Huberman 1:16:57 ... when it comes to work.

Marc Berman 1:16:57 Yeah.

Andrew Huberman 1:16:59 But my guess is that if we understand and engage in the proper waking states, that our lives are gonna improve markedly, irrespective of whether or not we need medication. I mean, that can only be determined, it seems, in when we're doing the right behavioral things.

Marc Berman 1:17:13 Right.

Andrew Huberman 1:17:14 So, what are your thoughts... This is a big question.

Marc Berman 1:17:16 Yeah.

Andrew Huberman 1:17:17 But what are your thoughts on really starting to understand what the different waking states are-

Marc Berman 1:17:23 Yeah.

Andrew Huberman 1:17:24 ... and our requirements for waking states? 'Cause I feel like that's pretty much what your work's about.

Marc Berman 1:17:29 Yeah. Yeah, that's right. That's right. And I think, um, (laughs) you know, the social media and things on the phone are kind of like the junk food. They're just ruining our waking states to a large extent. And I think what we're, what we're talking a lot about with, um, this attention restoration theory and walking in nature is that we need breaks. You need breaks during your waking time. Or if, like you were talking about before, that if we want to get into a state where we are gonna be able to concentrate well, maybe you have to take the nature walk first to kind of, to kind of recharge the battery even, you know, right at the beginning of the day. So, I think there's two elements there. One is that there's a lot of stuff that we're doing during our waking hours that's depleting directed attention, and we want to mitigate a lot of that stuff. The other thing is that you can't work 10 hours straight. I mean, I don't... I mean, maybe some people say they can, but I just don't think people really can direct their attention for 10 hours straight. I think-

Andrew Huberman 1:18:35 Not continuously.

Marc Berman 1:18:35 Not continuously.

Andrew Huberman 1:18:36 In talking to a lot of writers, um, because I've been working on this book-

Marc Berman 1:18:40 Yeah.

Andrew Huberman 1:18:42 ... most writers who are, like, career writers will say