How Nature & Other Physical Environments Impact Your Focus, Cognition & Health | Dr. Marc Berman

A 50-minute nature walk measurably restores cognitive performance

Huberman's guest describes attention restoration theory research showing that a 50-minute walk in nature significantly improved performance on cognitive tasks (backwards digit span) compared to urban walks, because natural environments softly capture attention without draining directed focus.

"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 was any performance change or not. Measure that. Then we have people repeat the whole procedure again. They come back to the lab a week later. So if they walked in nature the first week, they walked in the urban environment the second week, or vice versa. So it's all within subject, very 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 in the urban environment. And people might be thinking, well, maybe it's just because the nature walk was just more pleasant. They just liked the nature walk more, and people did tend to like the nature walk more, and we did measure improvements 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 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. Super interesting findings. And it leads me back to this finite resource of directed attention, whatever the underlying networks and chemicals happen to be. Could we speculate what might be occurring in the nature walks that is enhancing or allowing restoration of directed attention? And I guess the neurobiologist in me wants to say, okay, I'm walking in nature. That probably It means some greenery, some dirt, maybe some water."

Why your brain processes fractals in nature more efficiently

Nature's fractal patterns - self-similar structures repeating at different scales in trees, clouds, and coastlines - may explain why natural environments are restorative. The brain processes these patterns with less effort, requiring less memory encoding and reducing cognitive load.

"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"

Two hours per week in nature as a health minimum

Research suggests a minimum dose of about two hours per week in nature for cognitive and mental health benefits. Even 10 minutes of viewing nature pictures can help, and listening to nature sounds provides partial benefits when outdoor access is limited.

"There have been other studies that have suggested like overall, you might want to get about two hours a week in nature."

Curved edges in parks increase spiritual and reflective thinking

A striking finding that parks with more curved edges (measured by computer vision) caused people to write more about spirituality and life journeys, and that classrooms with more curved architectural features could potentially improve student performance.

"And it turns out if the park had more curved edges in it, people wrote more about topics related to spirituality and their life journey. Wild. Pretty wild. It gets wilder. So that was very correlational. And we kind of found, you know, like, I don't know, maybe there's some kind of confounding variables there. So we did another study where we actually manipulated, we had images that had more curved edges or less curved edges and also images that were more natural and less natural. And we did an online study where we would show people one image and then had them select, like, when you look at this image, do you think it's related more to nature or time or spirituality? And it turns out if the picture had more curved edges in it, people were more likely to say, yeah, this picture kind of has me thinking about spirituality in my life journey. So that's causal. It gets even crazier because we were kind of wondering, you know, when we looked at some of the images, we were saying, you know, some of the images that don't have as much curved edge structure, they have more water in them. So maybe there's like something about having water that maybe makes you think less about spirituality. You know, I don't know if I believe that, but maybe there's something in there. So we did something even crazier. We took these images and we scrambled them. So we would like, we have this image and it looks like, you know, a park with trees and some water. And then we scramble all the pixels and now you can't really tell what it is anymore. It just looks kind of like a Jackson Pollock painting. it turns out if those scrambled images have more curved edges people also say they think more about spirituality and their life journey. So there's something, you know, we don't know the mechanism, but there's something interesting there about just perceiving these curved edges that has people thinking more about spirituality. So it can't be object related because they're scrambled. That's right. This is almost reminiscent of this connect the dot experiment where if the dots are more distantly placed, it seems to trigger some different form of cognition related to creativity. Right. If nothing else, it's becoming increasingly clear that Visual scenes have a profound impact on our cognition. And I don't even know what brain network to think of when we think about spirituality, probably somewhere down the temporal lobe. Because if you don't know where something is in the brain, you almost always say it's down the infrotemporal lobe where all the other sort of mysterious stuff is. Super interesting. This also tells me that I need to introduce more curved edges to my home environment. And people seem to really like curved edges, and even they find that in other species, that other species tend to prefer curvature and curved edges. If you had a magic wand and you could wave that magic wand and have people change one, maybe two behaviors on a daily and weekly basis on the basis of everything that you've learned from your work and related work, what would you wish with that wand? Yeah. Um, I think I would, so I think in a couple things so one i would just the easy one is just people need to get out into nature more and they need to do it especially when they kind of feel mentally fatigued I think that's easier than saying you know get off of the devices it's not going to happen right then entirely. So I think, you know, forget about that for a moment. Go out in nature and do it without your phone and be engaged with it. And if you don't have access to nature, try these simulations. Bring nature into your home. You can even have fake plants in your home. There's been some evidence that even fake plants can work. You know, get some nature sounds going. Maybe think about where you're going to take your next vacation. Maybe think about going to a national park or something like that. So that's one thing. The other thing, and, you know, it's kind of building up kind of, you know, in the book, I kind of want to start this nature revolution where we're really take this work seriously. And I think part of it is that I think everybody has this intuition that nature is good for us, but it's sort of like, eh, it's an amenity, not a necessity. You know, it'd be nice to have, but we don't really need it. And I think if I wanted to wave my magic wand, I would want to change that to actually know nature, these experiences are a necessity, not an amenity. And it's not just a necessity because of climate change and things like that. It's a necessity for us as humans to reach our full potential. We can't reach our full potential without nature. So I think that's, that's another critical element. And then I think when people start feeling it and feeling the effects, then I think we need to start changing a lot of things like, you know, schools, like they want to take away recess and they want to take away playtime outside. Right. And that's almost exactly counter to what I would recommend. I would recommend that we actually want to have more recess and more recess out in nature that, you know, think about this, Andrew, what if, this would be incredible, but what if, you know, school is like an eight-hour day. What if instead of eight hours of instruction, it was six hours of instruction and two hours of a nature break? I'd go back to school."