360 | Marc Berman on the Science of Touching Grass

Advertiser

Summer's supposed to be the easy season, so why are so many people quietly googling a therapist between summer Fridays? Because more daylight doesn't fix the hard stuff. Sometimes it just turns the volume up. Grow Does Therapy Differently Therapy is not only for when you're in crisis. Grow therapy is here for all the moments when you decide you want more. More support, more clarity, more tools. Mental health isn't a destination you reach, it's something you build. And Grow makes that easier. Grow connects you with thousands of high quality licensed therapists across the US offering both virtual and in person sessions, nights and weekends. You can search by what matters like insurance, specialty, identity or availability and get started in as little as two days. There are no subscriptions, no long term commitments. You just pay per session. Grow helps you find therapy on your time. The therapist you want takes your insurance on. Grow Grow accepts over 125 insurance plans. Sessions average $21 with insurance and some pay as little as $0 depending on their plan. Visit growtherapy.com booknowtoday to get started. That's growththerapy.com booknow growththerapy.com booknow availability and coverage vary by state and insurance plan.

Monday.com Representative

This Monday.com ad was created by a team of people and AI agents. The agents wrote the copy and managed the timelines, while our human Creative director made sure it all made sense. Easy. Create your own AI agent today on Monday.com hello everyone.

Sean Carroll

Welcome to the Mindscape Podcast. I'm your host, Sean Carroll. Have you been told by one of the kids today to go touch grass? Or are you a kid today who has told people to go touch grass? I get the impression I do not pretend to be up on the lingo used by the youths of the world today, but in certain circles, you know, if you're having a conversation or interacting, usually online, and someone is trying to point out that maybe you become a little unmoored or unhinged or unrelated to the real world. Maybe it's time for you to get off the computer, go watch, wander outside in nature, look at a tree, touch the grass, get reconnected to the natural world around you to maybe find your bearings a little bit. And the good news is there is science to back up the idea that this would actually be a clever strategy to reconnect yourself to the world, or maybe even a better way of saying it is you would become a better thinker, not just someone who is in a better mood, but you can actually use your mental capacities more effectively. If you are experiencing nature in some way, at least that's the thesis being put forward in a book that came out last year by today's guest, Mark Berman. The book is called Nature and the the Science of How Nature Improves Cognitive, Physical and Social well being. And as we'll see, Mark has been a pioneer in an idea called environmental neuroscience, trying to judge how the brain functions differently in different contexts. One of those contexts might be literally, you're out in nature just taking a walk or whatever. Another might be you're in your room, in an office, or at home, or in an urban environment walking around the street. Maybe it's not surprising in retrospect, but our brains seem to function better, some evidence indicates, when we're in that natural environment. After all, we did evolve in a more natural environment. We didn't have cities 100,000 years ago. And the development of technology and urbanization has been a relatively recent occurrence in human history. So there's something about, and this is the fun part of the conversation, is that we're not exactly sure what it is, but there's something about just looking at natural things, whether it's coastlines or trees or whatever, that engages our brain in a way that is restorative rather than draining. And again, it's not just about, you know, you feel good, it puts you in a good mood. You can do better on cognitive tests when you are outside or even have recently been on a walk through the woods. So, as Mark wants to stress, we chatted about this after we actually recorded the podcast. It's not against cities. You know, we both live in cities. We love cities. There's something good and important and creative about living in a city in various methods, various measures that you could quantify. But there's also something important if you want to be at your best to get some nature in your life. And that might be literally taking a walk in nature or even something as simple as having a window that looks out at a tree rather than out at a brick wall or out at a street. So I think it's very interesting as a hypothesis and the evidence for it is very interesting. And as you'll see, we got derailed a couple of times during the conversation. Just there's interesting physics and information theory and complexity theory that comes in when you try to figure out why is it that this kind of thing helps the brain. And as an extra treat, I'm beginning to add these extra treats more and more. We did one with Daniel Harlow a few weeks ago where we talked like physicists at the very end here, the extra treat is at the very end, Mark and I switch roles and I give Mark a little chance to do an ama. So he's a fan of the podcast. He's listened to many other episodes, so he asks me questions, a few minutes at the end there. You know, why not? We've already done our work in explaining the science of his research to you. Why not have an informal chitchat? It is a podcast, after all. There are no rules. And with that philosophy in mind, let's go. Mark Berman, welcome to the Mindscape podcast.

Mark Berman

Thanks so much for having me on the podcast, Sean. I'm a huge fan and an avid listener.

Sean Carroll

Oh, great. This should be a wonderful conversation to start before we actually get into the specifics of what you're talking about. It reminds me of this fact that is sometimes trotted out. We all live in environments that are just changing very, very rapidly, especially compared to the timescales on which we're evolving as a species. You know, in a very real sense, we are inheriting a genetic legacy that was put together thousands or tens of thousands or millions of years ago. And here we are. I live in a house, right? Like, my genes are not adapted to living in a house. I've tried to build a house around it, etc. I mean, how do you think about this? Not even so much a question as an observation. I'd like for you to reflect on, like, you know, how important is it or how dramatic is it that we should be thinking about the differences between what we grew up to be in the environments we're in right now?

Mark Berman

I, I think it's a great question. I think it's something we have to pay a lot of attention to. And it's kind of ironic in a sense, Sean, that even though we are living in such arbitrary kinds of environments compared to the environments that we evolved in, in some sense, because humans have so much control over the environment, I believe we think we're almost immune to it. And that's something that we've been thinking a lot in my laboratory, is that, you know, we aren't immune to the environment and we're a part of the environment. I think people sometimes, you know, get this sort of feeling that humans are kind of distinct from the environment. But no, of course we're, we're very much part of the natural world. And it's interesting that because we have so much control over the environment, it's sort of this bi directional kind of relationship. So our brains have been shaped by the. In physical environment. Now our brains are designing the physical environment. And that new environment is now also shaping. Shaping our brains. And like you said, too, it is happening very, very rapidly. I mean, we've only lived in these cubicle boxes, you know, for, you know, hundreds. Few hundreds of years. You know, it's. It's kind of arbitrary. And that's something that we think a lot about, that our brains sort of adapted to a very different environment.

Sean Carroll

Right?

Mark Berman

And so now we're kind of in this. In this other kind of environment. And, you know, that can have positives and negatives. And, you know, I think in my lab, what we think a lot about is, you know, I don't want to poo poo a lot of architecture or design, but I would say that a lot of modern architecture and design or how we. How we build things that we live in, they haven't been designed to say, okay, let's make people more cooperative or let's, you know, let's build this environment so people have better working memory capacity or better attention. It's kind of just built, you know, to house people efficiently, move goods efficiently. So, yeah, I think in my lab, we're started thinking more about this. Okay. And just taking a pause and say, okay, you know, we think that this kind of, I say, quote, unquote, artificial environments that we kind of live in now is kind of changing our behavior, maybe changing our brains. And we need to think seriously about what that means and maybe what we can do about it or how we might want to change the environment.

Sean Carroll

I mean, there's some irony there, right, because we do have much more control over our own environments than we used to, but we don't always use that control for good. Or at least we're not always, you know, thinking at the right level about what it would mean to construct the right kind of environment.

Mark Berman

Right, exactly. And I think part of that too might be that I would say for a lot of years, maybe this would sort of be thought of as being sort of fringy kind of science, that this isn't, you know, the most hardcore rigorous science in part because it's. It's really hard to do carefully controlled experiments. You know, in an ideal world, I would love to be able to move people to different environments, you know, manipulate different elements in some people's environments. But you can't do that easily. So it's. It takes a lot of hard thinking, and you have to sort of triangulate research from a lot of different areas to be able to draw strong conclusions.

Sean Carroll

So why don't you just tell us sort of the High level message here. And you have a book out that came out last year. So remind us the title of the book and what it's all about.

Mark Berman

Yeah, so the title of the book is called Nature and the Mind, the science of how nature improves cognitive, Physical and Social well being. And the book talks a lot about this field called environmental neuroscience that I kind of helped to develop, which is very interested in the bi directional relationships between the physical environment and our brain. So again, as I kind of mentioned before, our brains have adapted to the physical environment. We as humans have a lot of control over the physical environment. So we're manipulating the physical environment. And then this environment that we've created is also impacting our brains in this kind of cyclical relationship. So in the book I focus a lot in my lab on natural environment. So contrasting people interacting with more natural environments. Like you could think about your local park or the trees on your tree lined street, maybe you go on vacation to a lake. So interacting with those kinds of environments that are sort of been less manipulated by humans compared to interacting with more human made environments. You know, cities, you know, towns, office spaces, schools. And you know, we find in my work that when we interact with these more natural spaces that can actually cause changes in our attention and our working memory, that people actually show improvements in their attention and working memory after spending short amounts of times in these more natural environments versus the more urban or built environments.

Sean Carroll

And I think it's important to distinguish here because lots of people will say so, yeah, I like spending time in nature. It relaxes me so it puts me in a good mood. But you're less talking about mood and more about really like cognitive abilities. Which is a different kind of claim.

Mark Berman

Yeah, absolutely. So, and you know, there had been research done. I wasn't the first person to look to see if interacting with nature had psychological benefits. There had been other studies where they had people interact with more natural environments versus more urban environments. And people reported feeling better. You know, maybe their mood improved or they maybe they felt like their attention was, was better, but they didn't use any objective measures of performance. So we did one of the first studies where we actually measured objectively people's changes in performance after interacting with these different environments. And one of the ways that we measured people's objective performance was with a task called the backwards digit span task. So that's a task where you would hear digits out loud at about 1 digit per second and you would need to repeat the digits back in backwards order. So you might hear the digits 8 3, 7. And then you need to repeat it back in backwards order, so 7, 3, 8. And we keep increasing the number of digits up to about nine digits at around five digits. The task is very challenging.

Sean Carroll

Yeah.

Mark Berman

So what we did is we gave people this difficult backwards digit span task. Then we had them go for a walk in a more natural environment or go, go for a walk in a more urban environment. They came back to the laboratory after the walk, and the walk was about 55, 0 minutes. They come back to the lab, they do this backwards digit span task again, and then they come back to the lab a week later and they repeat the whole procedure again. If they walked in the natural environment the first week, they walk in the urban environment the second week, second week, or vice versa. So everybody was their own control. It was a within subject design. And what we found is that when people walked in the natural environment, they showed about a 20% improvement on this backwards digit span task. So they improved by like a digit and a half compared to the urban walk, where they really didn't show any significant improvement. And again, a lot of listeners might be saying, well, you know, Mark, because people probably enjoyed the nature walk more, maybe they were more motivated. And it was certainly the case that people liked the nature walk more than the urban walk. We did have mood measurements too, and we saw that, yes, mood tended to improve after walking in nature, but we didn't see a strong correlation between the improvements in mood and the improvements in this backwards digitsband task. So that's, that's okay. So it wasn't like the people that were just getting happier were the ones that were showing the most improvement in the backwards digitsband task. But what I thought was a little bit more interesting is that we had participants walk at different times of the year. Some participants walked in June when It was like 80 degrees Fahrenheit. People loved the walk. They said, mark, I can't believe you're paying me to go for a walk in nature. Healthy mood benefits, healthy backwards digits band benefits. But we also had people walk in January when It was like 25 degrees Fahrenheit. People said, mark, I was freezing out there. That was not enjoyable. But the people that walked in January showed the same cognitive benefit, the same improvement on the back resistance band task as the people that walked in June. So sort of the takeaway message was, you don't even have to enjoy the nature walk to get these cognitive benefits. You do obviously have to enjoy the nature walk to get the mood benefits, but you don't have to enjoy the nature walk to get the cognitive benefits. And I think that's interesting because that's somewhat counterintuitive that this isn't some kind of hedonic kind of response like, oh, I like eating chocolate and you know, I eat some chocolate. I feel good that there's something deeper going on there in terms of why or how nature might be improving people's cognitive.

Monday.com Representative

This Monday.com ad was created by a team of people and AI agents. Reese, our content agent, wrote the copy based on our best practices, like mentioning Monday.com three times. That was the second. Johnny, our coordination agent, built the timeline and kept everyone aligned. Olivia, our human creative director, stayed in the loop because agents are great, but they don't always know when a joke lands. She had one note tell listeners it only takes minutes to build an agent. So minutes. Create your own AI agent. Today on Monday.com.

Mark Berman

close your eyes, exhale, feel your body relax and let go of whatever you're carrying today.

Advertiser

Well, I'm letting go of the worry

Mark Berman

that I wouldn't get my new contacts

Advertiser

in time for this class.

Monday.com Representative

I got them delivered free from 1-800-contacts. Oh my gosh, they're so fast.

Mark Berman

And breathe.

Advertiser

Oh, sorry. I almost couldn't breathe when I saw the discount they gave me on my first order.

Monday.com Representative

Oh, sorry. Namaste.

Commercial Narrator

Visit 1-800-contacts.com today to save on your

Mark Berman

first order 1-800-contacts performance.

Sean Carroll

I do have to say that a lot of these psychological tests seem pretty anxiety inducing. Like I would feel very bad not being able to say the digits backward.

Mark Berman

Absolutely. And you know, you know, we try to tell people before, again, this isn't an IQ test, but it's, yeah, it is anxiety provoking. And then, you know, that that could also be part of the phenomenon too, that if, if nature is sort of relaxing us a little bit more, maybe you can do perform better. And, and somewhat related to that, Sean, we, we repeated this same experiment, but this time with participants who are diagnosed with clinical depression. And clinical depression often is characterized by what's called, you know, negative rumination, that people kind of repetitively think about negative thoughts and feelings over and over again. And we kind of wondered, we actually had an NIH grant at that time to study people with depression and, and look for kind of working memory deficits for people with depression. And we thought, oh, we had this interesting result with nature. What's this going to look like for people who are suffering from depression? It might be that if you go for a walk alone, maybe that's going to increase rumination it's going to give you more opportunity to ruminate. So actually there we took these participants who had been diagnosed with clinical depression. We did the whole same walk in the park procedure that I outlined before, but this time we had people think about a negative thought or memory that was bothering them before they went on the walk. So we were sort of inducing them to ruminate beforehand and we found even stronger results here. So again, the procedure was all within subject. You know, participants walked in both nature and urban, but this time we had them ruminate about a negative thought or memory before the walk. And they showed even stronger improvements in backwards digiscan performance after the nature walk relative to the, to the urban walk. And you know, I know this isn't really a self help kind of podcast, but now there's actually, you know, in the UK and in Canada, physicians are prescribing walks in nature as sort of a supplemental therapy for people suffering from depression and anxiety. So, you know, again, we can, we're going to dig in, I think a little more about what mechanisms are going on here, but I think many of your listeners will have this idea that, you know, being in nature is sort of calming. Even if it's not improving your mood, it might be sort of calming to your nervous system.

Sean Carroll

I have to get, you know, right away the question on the board, which is this is a, an interesting finding in psychology, and we've all been trained that interesting findings in psychology should be looked at with skepticism because there's small sample sizes, they're hard to replicate, et cetera. But this was a while ago, you've been doing this. So what's the sort of state of the art?

Mark Berman

Yeah, so I'm pretty confident in these findings. And no one has IDed this effect as being something that's not replicable. So many other labs have replicated these effects. You're right. The sample size was small, you know, relatively small. So we had about 40 participants in that study. It was within subjects. So you, that's like equal to like a, a sample of like 80 participants between subjects. But yeah, not, not millions of people, not thousands of people. There have been other studies too, outside of the laboratory where they look at quantifying green space around people's homes and their schools and look at kids working memory performance and how they're doing in school. And they find that children that live in neighborhoods that have more green space have better attention and working memory, even when you control for things like age, education and income of their parents. There are some other really interesting studies that were done in public housing projects in Chicago. These are, you know, not desirable places to live.

Sean Carroll

Not the greenest spaces. I've been there.

Mark Berman

Yeah, not the greenest spaces. In fact, they've demolished many of these facilities. And what's interesting about these facilities is that the families were randomly assigned to different apartments. So. So it's almost like a controlled experiment. And what these researchers looked at this was Ming Kuo and Bill Sullivan from the University of Illinois. They looked at views out of the window in these public housing projects and also quantifying, sort of with, you know, satellite imagery, how much green space was around these, these public housing projects. And it turns out that the apartments that had the views of nature, people had better attention in those apartments. There was lower reported crime, lower reports of aggression, again suggesting that this nature, even if it's modest, could have some salubrious qualities to people's psychological functioning.

Sean Carroll

Okay, that's good to know. Yeah. I mean, you mentioned the theoretical background, which I did want to get into. You know, I'm a physicist who always loves to say, like, experiments are not real until they're confirmed by theory. So there's something that you talk about called the attention restoration theory. Tell us what that is and how it's relevant to your studies.

Mark Berman

Yeah, so this was a theory that was codified by one of my mentors in grad school, Steve Kaplan and his wife Rachel Kaplan, who are environmental psychologists. And one of the main tenets of this theory was sort of that humans have two kinds of attention. So one kind of attention he called directed attention. Sometimes people call this top down or endogenous attention. This is the kind of attention where you, as an individual person, are deciding what to pay attention to. So presumably, Sean, you're deciding to pay attention to me, your listeners are deciding to pay attention to what I'm talking about. But it's thought that that kind of attention is fatiguable or depletable, that you can only sort of control your attentional focus from for a limited amount of time before you become mentally fatigued, and then you can't focus anymore. And we've all had that sensation that, you know, after a long work day, you know, 3 o', clock, 4 o' clock in the afternoon, you might be staring at the computer screen and it's just hard to focus. Or I see this when I'm lecturing, I think I'm a decent lecturer, you know, but the first five minutes of lecture, I see a lot of eyes on me, people nodding along with me. 45 minutes into lecture. I see a lot of students kind of tilting their head back. They're kind of dozing off. It's just hard to control your attention. Yeah. So this directed attention ability is really important because it's, you know, it, it shows that humans are not just stimulus driven. We can decide what we're going to pay attention to, but we can really only do that for a limited amount of time before we've become mentally fatigued and we can't really do it. So when, when you can't really control your attention, we call that a directed attention fatigue state. That's when we think it's a good time to take a break in nature. That's different from another kind of attention that Steve called involuntary attention. Sometimes this is called bottom up or exogenous attention. And this is the kind of attention that's automatically captured by interesting stimulation in the environment. So bright lights, loud noises, those things automatically capture attention and we don't really have control over it. And it's thought that 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'm too tired, I have to look away. Or oh, I can't watch this really interesting movie anymore. It's so interesting, I'm just getting really exhausted. I have to shut it off. So the idea with attention restoration theory is that if you can find environments that don't place a lot of demands on directed attention while simultaneously having interesting stimulation to activate the involuntary attention, you could restore or replenish this precious directed attention resource. And it's thought that natural environments is one kind of environment that can do this. It doesn't mean it's the only kind of environment that can do this, but it's one kind of environment that can do this. There's one other thing that I think is important to mention too, which is we think it's important the kind of stimulation that activates this involuntary attention. So when I look at a beautiful waterfall, it captures my attention, but I can still kind of mind wander and think about other things. Looking at that beautiful waterfall, it doesn't capture all of my attentional resources. When I'm in Times Square in Manhattan.

Monday.com Representative

Wow.

Mark Berman

Also super interesting. Lots of stimulation to capture my attention, but it sort of does so in an all consuming and sort of harsh way. I can't really monitor mind wander or think about other things in Times Square. So we think the kind of stimulation that captures your involuntary Attention should be softly fascinating and not harshly fascinating. And we think that's the kind of environment that's going to be able to restore our directed attention abilities.

Sean Carroll

So the idea that really stands out to me here is you might have thought that attention is a finite resource. Like we have a bucket full of attention and we use it up. But you're saying that some ways of paying attention do use it up, but some restore it. Even as we're paying attention, we're still gaining more ability to do so.

Mark Berman

That's right. So I do kind of think of directed attention as a bucket or a bank account that you can kind of cash out or empty, but that this is not a passive process. So it's like engaging another kind of attention that's like, you know, it's like a Goldilocks rule. It's sort of interesting enough that it captures my attention, but not so interesting that it's all consuming. It kind of sits at this nexus that. That. Yes. That we think that can actually restore your directed attention. I mean, presumably sleep would do something similar. But I think often when we're mentally fatigued, we're actually not physically fatigued. Yeah, it's almost like our bodies are telling us, go do pay attention to something else, or you have to switch tasks. So that's the kind of fatigue that we're sort of talking about. As you're saying too, this is sort of like an active process that can kind of restore. Restore our attention. And people sometimes ask with me, well, Mark, what about sitting in a dark room? And my answer to that is, you know, no, in part for a number of reasons. So one, most people don't like sitting in dark rooms. That they find it boring or. And boredom is fatiguing. And again, it's back to this idea that this isn't just a completely passive process. This isn't just like sleep. This is sort of an active process of engaging maybe a different kind of attention, like involuntary attention or a different kind of attentional process that can actually refill that directed attention bucket.

Sean Carroll

This might go against everything that you believe in, but for me, I think I do that by taking a break from work and playing little cheap video games on my iPad. If you find that sweet spot where the game is engrossing enough that you want to play it for a little while, but not really requiring too much effort and thought and everything that can actually re. Energize me a little bit. Is that compatible with this, or am I just weird?

Mark Berman

I think that is compatible because again, there's Nothing in attention restoration theory that says it has to be nature.

Sean Carroll

Right.

Mark Berman

It only has to meet these criteria of not placing a lot of demands on directed attention and having softly fascinating, involuntary, softly fasting stimulation to activate involuntary attention. So if these little video games do that for you, that's good. However, I would say, you know, the video games that our kids are playing out there are much different and much more engrossing, and I think that's a different kind. And. And that. That actually is more harshly fascinating. And, you know, we maybe will get there in this podcast. But, you know, a lot of these new technologies, I would say, are very harshly fascinating. They're designed to keep your attention and not let go, and they're addictive and. And most addictions are not, you know, really good for cognitive.

Sean Carroll

Right. Is there a relationship here between this sort of directed and undirected attention versus System one and system two cognition that. Yeah, I'd say we would talk about.

Mark Berman

Yes, yes, I would.

Sean Carroll

For those who don't know, remind us what that is and how they might be related.

Mark Berman

Yeah, and I. Sometimes I get this wrong, but I think system one is sort of the sort of more heuristic kind of thinking. The easier kind of thinking in System two is more of the arduous kind of thinking. And so if we wanted to map this on here, we would say that involuntary attention is more like System one, and directed attention is. Is more like system two.

Sean Carroll

And an example came to mind when I was reading your stuff. Years ago, when cell phones first became popular, there was this, I don't know, controversy or whatever about driving while you were talking on your cell phone. And there was this thought that as long as you had a place to put the phone so you didn't have to actually literally pick it up, it shouldn't matter because you're still driving with your eyes and your hands and so forth. But I think, in fact, that's not true because talking on the phone is depleting your attention. Was that impression that I had correct?

Mark Berman

You have it? Correct. And now maybe I'll spend a moment on this because I think it's really, really important. So there's actually this. This idea that, you know, there was this peripheral hypothesis, the problem that talking on a cell phone and driving have to do with actually physically holding the phone and maybe only having one arm to do the driving, or is it attentional that it really doesn't have to do with holding the phone. It has to do with where your. Where your attention is, is directed. And it turns out it has nothing to do with holding the phone, and it has everything to do with attention. And one of the examples that I like to give, especially when I'm, when I'm teaching is, you know, we've kind of all had that sensation, you know, maybe, and it's not good. But driving on the highway and you might not remember what, you know, scenery was around you for the last couple minutes. Driving on the highway. Yep. Because your attention is somewhere else. You might be mind wandering. Even though the light from the road and from the environment is all hitting your retina. Right. So all those signals are, are getting to the retina. The brain is not attending to it. So that's the difference between what people call those overt attention and covert attention. So where your eyes are moving is, is the overt attention, but covert attention is actually really what, what you're paying attention to internally. And so what's the problem with the cell phone is that your covert attention is directed to the phone call, which means you're paying less attention to the road. And that's really dangerous. And that's like two, you know, if you're driving in an unfamiliar place, typically you turn down the radio.

Sean Carroll

Right.

Mark Berman

Because you want all of your attention to be driving. And the problem with the cell phone, the person on the other end doesn't know. They don't know the, what conditions you're in. If you've got a friend in the passenger seat, you tell them to shut up.

Sean Carroll

Yeah.

Mark Berman

When you're in hard road conditions, but that doesn't happen. The cell phone. So you can see all these examples

Sean Carroll

of

Mark Berman

lots of car accidents happening, people talking on the cell phone, even if it's hands free.

Sean Carroll

And not to be too grandiose about it, but maybe there's a lesson here for the philosophy of mind and maybe even for AI and its relationship to intelligence and consciousness, namely that we are much more than the surface level, input, output, machine. Right. Of, you know, reading and writing or listening and talking. There's just so many layers of things going on simultaneously, all of which do indeed interact with each other and feed into that final output that we have.

Mark Berman

Absolutely that. And that's why behaviorism failed in psychology. So, you know, Skinner and Watson, they were frustrated with, you know, late 19th century psychology and maybe, you know, early 20th century psychology that was all about introspectionism, just that we just look within ourselves and, and report our subjective experience. That would be enough. And they thought, you can't build a science around that. It's not verifiable. So they Went all the way to the other extreme and said, basically, we can explain all behavior and even all human behavior, just mapping stimuli to responses. But that turned out to be way, way too simple. There's a lot that's happening in the mind or the brain, a lot of processing happening there, and you can't ignore it. So I think now we've kind of settled more in the middle ground to say, you know, there's so much the brain is doing, interpreting these different signals from the environment and then producing outputs, even though it's very difficult to directly measure everything that's going on in the brain.

Monday.com Representative

This Monday.com ad was created by a team of people and AI agents. The agents wrote the copy and managed the timelines, while our human creative director mate made sure it all made sense. Easy. Create your own AI agent. Today on Monday.com.

Commercial Narrator

every bold journey starts with a decision to go. And if you're ready, the Defender is too. This is a vehicle built for more. Whether you're heading off the grid or just getting out of town for the weekend, Defender is a true icon reimagined for a new generation. Its rugged exterior is built from durable materials and tested in the toughest conditions. Inside, it's modern, functional, and refined, with smart storage and premium touches that keep you comfortable wherever the road leads. It's packed with tech like 3D surround cameras, ClearSight, ground and rear views, driver assist features, and an intuitive infotainment system. With three models, the Defender 90, 110, and 130, there's a Defender for every kind of adventure. From city streets to remote trails, this is a vehicle that, like you, is capable of great things. Explore the full Defender lineup@land roverusa.com.

Sean Carroll

yeah, that was my next question, actually, because you talk about environmental neuroscience, how much can we say, oh, like, there's different levels of attention or kinds of attention. Associate them with different processes or even different parts of our brain.

Mark Berman

Yeah, I mean, I think we can, we can do it. And I do a lot of neuroscience in, in my lab. What I'm trying to do is merge the environment with the neuroscience together, but it's, it's challenging for a number of reasons. So I don't know how many of your listeners have been in an MRI machine, but that's, you know, we do a lot of brain imaging and MRI machines. We, we call it functional MRI because we basically make a flip book of, of your brain to see the dynamics. It's such an uncomfortable and arbitrary environment. It's hard to give people a nice nature experience. Being in the MRI scanner, there is now new technology that we're starting to use now called functional near infrared spectroscopy, which is a little cap that people can wear. It looks kind of like an EEG cap. It shines infrared light into the brain and then it can measure basically blood oxygenation levels.

Sean Carroll

Okay.

Mark Berman

In a similar way to, to mri. And this is mobile. People can wear this with like a little backpack, and we can have them walk in natural environments versus urban environments. And I'm, I'm interested in that. We've started to do that. I think, you know, we know a lot. You know, the fact that we know that people's backwards digit span performance is changing after the walk in nature versus the urban walk. We know something's happening in the brain there. The question there is, okay, so what more do we need to know? Like, like, does it matter? And I think it does, but we have to think a little bit deeply. Like, it's not going to be satisfying. If I put people in an MRI scanner and show them nature pictures versus urban pictures, I'll find differences. But what's causing the differences? There's many, many features that differ between the images. The nature images have different fractalness, different entropy, different amounts of curved edges, different color palettes. So it's hard to zero in on what's causing the differences. And then, you know, if we find those features, is that the thing that's actually causing the changes in performance? It's not, it's not clear. So I'm still, you know, I'm, I'm very eager to bring more neuroscience in, but we, but we have to think hard about it. We can't just do some of these little experiments that people might think about. Well, just put people in MRI scanner, show them nature pictures versus urban pictures, look at the differences, and, you know, bada bing, bada boom. That's going to tell us why nature's restorative. It's going to be more complicated than that.

Sean Carroll

Well, good. That was exactly, again, where I wanted to lead to next. I mean, what is it about nature versus the urban environment that is more restorative? Because you can think of lots of different things. The colors are different, the shapes are different, the sounds are different, but also, you know, the purpose is different. We have this feeling like when we're in nature, we're there to chill out a little bit. When we're in the city, we're on an errand.

Mark Berman

Right, Right.

Sean Carroll

So what are our thoughts about what are the salient features there?

Mark Berman

Yeah, so this, it's A great question. Something we're really thinking a lot about. I'll back up just a little bit. Just to say too, that we've also done studies where you can show people just pictures of nature, or listen to nature sounds versus urban sounds, or watch nature videos versus urban videos and still get some of these similar changes in backwards digest band performance. Which suggests to us that it's something about the perceptual features of nature that might be producing these benefits. So then that kind of gets away from it just being leisure time, per se. You know, if you're sitting in a laboratory just looking at nature images and urban images, I guess if you're looking at the nature image, maybe you're thinking about your vacation more often, but we think that's less likely and more that there's something about the stimulation there. I will go back to something you said originally about being careful about replication. These effects with the pictures and the sounds and the videos are not as strong, these effects are not as strong as going into real nature. And, you know, sometimes you get the effects and sometimes you don't. It's not quite as robust, but the fact that you can get it suggests that there is something about the perceptual qualities of nature that are producing these effects. Okay, so what are those perceptual features? We started to become really, really interested in ideas of information and compression. So I did have a student, Omid Cardan, and we used to. He was actually an electrical engineer. And we would talk a little bit about nature images and urban images. And we wondered, you know, maybe nature images get compressed down into fewer bits than urban images, because there is a lot of repeated structure in a natural image compared to an urban image. So then a few years later, my current PhD student, Nakwon Rim, we actually tested this. We actually took hundreds of images where we had humans rate the images for how natural they thought the images were on a scale of 1 to 7, with 1 being not very natural and a 7 being very natural. Then we ran a JPEG compression style algorithm on these images. So, you know, I'm sure a lot of your listeners know, but just. Just to kind of reiterate, you know, what JPEG compression does is you might have an image that's 100 megabytes, but to save room on your computer, on your phone, maybe you can remove a lot of information from that image. So you. You throw away a lot of information. Your eye might not be able to tell that anything has changed, but maybe you've taken this image that's 100 megabytes, and now it's down to 10 megabytes. So you've saved so much room on your, your phone or your computer. So we ran these JPEG style algorithms on hundreds of nature and urban images, and we did find that more natural images tend to tended to get compressed down into fewer bits than the urban images, suggesting that, you know, there is more compression, there's more throwing away of information and nature things in urban scene then remember too, this is based, you know, these JPEG compression algorithms are based on human visual perception, right? They work well because they've been tuned to how the human eye sees things.

Sean Carroll

Actually, I didn't even know that. It's not purely mechanical.

Mark Berman

It's not purely mechanical. Yeah, it's tuned for humans. Yeah, it's tuned for humans. Although we could ask, you know, you had LV Smith here, he probably knows quite a bit more about this than I do. So that's fine. That's interesting. Then we asked this other question which was, okay, if nature images are sort of easier to process, maybe that might also mean that they're less memorable. And your listeners might be thinking, okay, but being less memorable sounds bad, but we think it might be good. If something is not memorable, it might mean that your brain has not exerted a lot of energy to process it. So what we wonder too is, are nature images less memorable than urban images? So we did an experiment where we show people hundreds of images that vary in how natural urban they are. And you see these images and you basically have to respond if you see an image that's repeated, which is a measure of memory. And it turns out that people do not remember the nature images as well. They remember the urban stuff better, which is also kind of consistent. And to bring these things together a bit, we find statistically that part of the reason why nature images are more forgettable is because they're more compressible.

Sean Carroll

So I'm going to wander off the reservation a little bit here and make a suggestion or a conjecture, right? Because what you're talking about, it sounds like it's right next to what I would have suggested, which is to think about entropy, but to think about it from the information theory perspective, not the physics thermodynamics perspective. Claude Shannon taught us that information comes about because you get a little bit of surprise when you get a message. If you just get the same message over and over again, you're not actually getting any information, even though you're getting a lot of symbols. Whereas if you want to convey a lot of information you invent a code where all of the different symbols, or equally unlikely, so that you're learning something from every symbol. And so you can calculate the entropy of a set of messages. And the bigger it is, the broader it is, the more information it contains. And it sounds like what you're saying is right up next to saying the information input from nature is low entropy. You're sort of not surprised when you see the tree or whatever. You're expecting what to see and you don't need to do a lot of processing. Whereas in the urban environment, maybe you know that there's going to be a street and a sign and whatever, but what sign is it? You actually have to pay attention. And it's that it would be a higher entropy visual input and therefore require more processing.

Mark Berman

Yes, and I think I would agree with you. It is interesting though, and I can't remember all the details. I know we've run grayscale entropy measurements on these images and that, if I remember correctly, doesn't show as big of a difference as we would think. Now, I don't know why that is. Maybe we have to do something actually with the color, you know, entropy or maybe the different color channels. But yes, Sean, it is. I, I agree with your conjecture there. Actually, when I was reading your book, the Big Picture, you have a figure in there sort of about this, which I actually took in another way. And I'll explain your figure. Then you correct me if I'm wrong. But the figure that you have, you have in one of your chapters, it's the Universe in a Cup of Coffee, I think is the title of that chapter. And one thing that's always bothered me a little bit is that the highest entropy image would be basically white noise, would be a high entropy image. But as a psychologist, neuroscience, we wouldn't think of that as being a very complex image per se. Like it's complex at one level, but it's got that, you know, it's just, it's just randomness.

Sean Carroll

I know exactly what you mean.

Mark Berman

Okay, so you have a, you have a figure in the book where in the beginning, you know, entropy and complexity are very highly correlated, but then at some point they deviate. Complexity kind of maximizes and then it starts to decay with increasing entropy and entropy continues to rise. So this is a long kind of circuitous route. But I think somehow it's, I think for an image to be restorative, I think actually it's got to have this kind of right amount of complexity and maybe not too much entropy. And then I don't know, too. There's some relationship here, too, that I think has to do with ease of processing, which I think later in your chapter, you talk about fractalness. Now, when I think about fractalness. So fractalness is sort of like repeated structure at different kinds of scale. So natural images tend to have high, high fractalness because it's built from the same kind of recursive process. So you can think of a tree and the tree structure. If we think of like a maple tree, it's somewhat sort of seen in a maple tree's leaf, the veins of that leaf that also have that same structure. So we kind of say that, you know, looking at the maple tree zoomed in or zoomed out, it's kind of got the same characteristic shape. Yeah, those kind of natural fractal patterns are ubiquitous in nature. They're not very ubiquitous in the urban environment. So he's like, you look at a city zoomed in and zoomed out. It looks very, very different than, like, looking at a forest zoomed in or zoomed out. So there. I think there's some. And we're trying to quantify this. I think there's some ease that the brain has when there is this fractal structure where you can get the gist very quickly of a scene just maybe looking, you know, in or out, you know, what's going on. But in an urban scene, you can't get it as much. So I think that's kind of more where we've been thinking about how to try to quantify these things. So may, you know, which I think is somewhat related to compression, but it also might have to do with this fractal structure. And it's not. You know, again, I'm not a fractal structure expert or I'm not a fractal geometry expert. It's actually not trivial to actually find the right way to measure this. But that's something else that we've been very, very interested in is saying, okay, well, maybe it's something about this fractal structure of nature that also makes it easier to process. But then maybe you might not remember it as well. Another thing that. Oh, sorry. Another thing that might be interesting to think about too, is also our language. You know, we don't really have a language of nature like we do for the urban environment. If I go to and see a forest, I might say trees, shrubs, gr. It's not very semantically complex. If I go into a city, you know, I might say volkswagen Toyota, BMW. Gothic architecture, you know, stop sign. There's just so many more objects and so much more semantic complexity that also might make it harder to process, but maybe also easier to remember.

Sean Carroll

Yeah, I think this is. I'm gonna. I'm gonna start biting my tongue just because we should. We should talk offline a little bit because there's too much to say. But. But this whole idea that it is relatively straightforward to invent quantitative measures that are small for perfect order and large for perfect disorder, but that's not what you want, right? Like, you want something that actually peaks in between. That's a whole full employment for complexity theorists to invent different ways to do that. Logical depth is one idea that I think is. Is very relevant here.

Mark Berman

Thank you for saying that because, yeah,

Sean Carroll

it's a classic problem, but, yeah, so it's great that you're suggesting. So if I can rephrase it to see if I got it. I mean, you're suggesting that somehow, just as with the people who are trying to capture the complexity of these strings or these images, if you just do the simplest thing of algorithmic complexity, if you have a very long string of random numbers, that's not, you know, that's high complexity in the sense that the best way to print it out is just to print it out. Right. There's no secret algorithm that saves you room or anything like that. But that's also not very helpful just to print out the whole thing. And so what you're doing is you're suggesting that when there is some kind of structure, there's something going on that is interesting, that is more than just perfect order, but there's also structure that the brain can sort of latch onto and therefore not fret too much about every detail separately. Maybe that's our happy place. Maybe that is what we evolved to do back in the environment we were in before.

Mark Berman

It's possible. And also, you know, Sean, too, it's a little more complicated, too, because I think if we showed people perfect statistical fractals, like a Sierpinski triangle, I don't think we'd see restoration, because that would be too boring in some sense, it's too perfect. And so, you know, you've had Carl Friston on the show and Tom Griffith, you know, talking about Bayesian models of the brain. And I think, again, there's this nexus where it's like, the brain likes predictability, but maybe not perfect.

Sean Carroll

Pretty.

Mark Berman

There's something interesting when there. When it's something deviates a little bit, not too much. You Know, because it's satisfying when the prediction is right, but having a little bit of jitter around that prediction can be good. And, and it seems like maybe, you know, I'm, I'm speculating here, but it seems like a lot of natural stimulation might kind of have that where it's, you know, you know, you imagine, you know, walking in nature and there's like a curve in the path. You don't know exactly what's behind that curve. And there's something interesting about that that captures intention, attention. We think in this kind of softly fascinating way.

Sean Carroll

It makes me think that psychology is not finished yet. You don't have the theory of everything right around the corner. There's still a lot of work to be done.

Mark Berman

Absolutely. I get you. You, You've had other, you know, Tom just wrote that book, you know, the Laws of Thought. You had another guest on who wrote the book, A Theory for Everyone. Yeah, no, we don't have it yet. And, and that's why, you know, I joke with, you know, Luis Betancourt, who's an SFI person, and Andrew, who's an sfi, my postdoc, one of my former students that I kind of want. I, I have this desire can we make psychology more like physics? But it's very challenging. It's very difficult. But it's like a dream of mine to get these kind of law, like formulas or even formula. You know, we don't have concepts. Like, even defining mental energy is not trivial, very complicated. So, so, you know, we, we're lacking those kinds of principles that, that a field like physics has. And then, you know, you can do so much more with. And you can just dream that if in psychology we have that we could do so much more in psychology and neuroscience, but we're certainly not. Not there yet.

Advertiser

We all prefer things a certain way, like groceries.

Mark Berman

If you want groceries just how you

Advertiser

like them, you gotta try Instacart. They have a new preference picker that lets you pick how ripe or unripe you want your bananas. Shoppers can see your preferences up front, helping guide their choices. Because when it comes to groceries, the details matter.

Mark Berman

Instacart get groceries just how you like.

Monday.com Representative

Summer is here, which means we all want to look and feel our best. A GLP1 may be right for you. Visit orderlymeds.com to learn more about which GLP1 you could be eligible for. Getting started is fast, easy, and happens virtually through telemedicine from licensed professionals. Professionals. Check it out for yourself. Go to orderlymeds.com podcast that's orderlymeds.com podcast. Taking care of yourself feels great. Compounded medications are not FDA approved. Eligibility required and determined by a licensed provider. Individual results may vary. See website for details.

Sean Carroll

Nevertheless, I'm going to ask you to do one more sort of crazy speculative thing because you talk about in the, in the book. I'm sorry, I like, look at some papers and your book. So I don't know which is in the book and which is in the papers and whatever, but there are debates in neuroscience communities about criticality in the brain and power law, scale free behavior and things like that. And it all gets very heated in a way that seems a little weird to me as an outsider, because they're fitting curves and arguing about is it a perfect fit everywhere or is it just a pretty good fit in many places. But do you think that there is some, any hay to be made out of whether or not structures and behaviors in the brain having similar architectures to what we see when we're out in nature can play a role in the, this restorative aspect?

Mark Berman

Absolutely. So this is something I'm really, really excited about. So I'll, I'll take us on a little detour. So I also, you know, I'm a neuroscientist too, and I, I became really, really interested in this idea of like, how do we quantify mental effort or cognitive effort? And with some colleagues of mine, this is when I was a postdoc at the University of Toronto. I, I was working with this grad student there, Nathan Churchill, and he was doing some interesting things with nonlinear dynamics. And we thought it'd be kind of interesting to apply some of these measures to some of these different data sets that we had in, in the laboratory. And I had mentioned to you this idea of fractalness in space, but you can also think about fractalness in time. So you can have like a time series. You know, maybe you're measuring one voxel in the brain and you're measuring its activity level over time. And you can also sort of try to measure how fractal or scale free that signal is in time. So basically that's sort of asking the question, okay, if you look at the signal at 1 second, 10 seconds, 60 seconds, 2 hours, does that signal have sort of the same characteristics? And one of the way when we talk about same characteristics here is sort of converting that signal into the frequency domain and looking at its power spectra. And it's thought that signals that show power that's proportional to one over frequency and it's one over F kind of shape that. That sort of maybe suggests sort of a signal that has this sort of repeated structure. And so what we did is. And sort of the perfect thing to get a little bit more in the weeds here. It's, you know, power is proportional to 1 over F to the H, where H is this thing called the Hurst exponent. And when H equals 1, people say, okay, that signal is perfectly fractal in time. So what we did is we basically measured how fractal people's brains were when they were doing different cognitive tasks. So when people were doing a really easy task, or even no task at all, like just sitting at rest or doing a very easy task versus a very hard task, we found that the signal when people were doing a very hard task was much less fractal than when they were doing the easy task. So it seemed like the brain deviated, okay, from this one over F or F to the one power to have a Hurst exponent of one. It deviated from that when you were doing something difficult.

Sean Carroll

Sorry. I mean, you were doing something difficult or difficult.

Mark Berman

Difficult.

Sean Carroll

It deviated from that when you were doing something different.

Mark Berman

Right. So the. So it. It's less fractal. Like, the Hearst exponent instead of one would be like 0.7 or something like that.

Sean Carroll

Can. Can. I mean, is it. Is it too cheeky to sort of conceptualize that as we're sort of focusing all of our energies on one?

Mark Berman

Yeah, exactly. Exactly. Yeah. And maybe some frequency dominates, maybe some frequency that's characteristic of whatever task people were doing. And then we saw this for other things too. Like, this is a little bit depressing, but you could have older and younger adults, and you've titrated the task that they're both having equal performance. So they're both 80 accuracy on the TAF. The older adults, their brains are less fractal than. I'm not surprised than the younger adults. People who are under distress, they've just been told that they are going to have. They have breast cancer. The brain is less fractal than people who are same age but don't have that. That kind of diagnosis. And what's really, really interesting, this is getting a little bit nerdy. FMRI. This is all measured with FMRI. And FMRI is a slow signal, maybe 1 Hz, 1 cycle per second. There's also EEG, which is another kind of neuroimaging technology that we have. It's got much, much higher temporal resolution. So it can measure things up to, like, you know, 50 hertz or 75 hertz even. It's got really bad spatial resolution. So you, you know something's happening. You don't know exactly where in the brain it's happening. I've got colleagues at UChicago, Edo and Ed Vogel. They use a lot of EEG, and they're very interested in using EEG signals to quantify how many things people have in working memory and how they. What they do that. One of the ways they do that is actually find the alpha power, which is like 7 to 12 hertz. That actually tells you how many things people have in working memory. So when alpha power is lower, there's not much in working memory. As alpha power starts to increase, there's more things in working memory. And actually the direction there might be a little bit off because, eg, they sometimes flip the plurality. So negative, sometimes it's positive. But just, just take it to me. The changes in alpha power track how many items people have in working memory. Okay. One thing that they have that's really interesting is they do these tasks where you're shown squares on the screen, like four squares, and the squares are colored, and they flash it very quick at like 200 milliseconds, and then they flash the screen again, and maybe one of the squares, the color has changed, and you need to report whether a change has occurred or not. The task is much easier to do when you're only looking at one square versus looking at three squares, four squares, six squares. But they've identified that humans really have a working memory capacity of about three items. You can't really. You can't really. You know, if you show people more than three or four squares, they can't grab anymore, their performance falls off. So here's what's interesting. So in their task, let's say they show you six items versus three items. In both cases, you can only really remember three items. So it doesn't matter doing three items out of three or three items out of six, your performance is going to be the same. You can only grab three items. But with our Hurst measure, we can distinguish those two. We can tell if somebody is trying to remember three things out of three or three things out of six. Because the Hurst exponent, the fractalness of the signal, is actually less fractal, trying to remember three things out of six versus three things out of three. So this, this befuddles them a little bit because it seems like fruitless effort. You can't grab that fourth item, you know, but. But it seems like people are Trying harder. So that's, that's kind of interesting.

Sean Carroll

So, so when you, when you say you can tell, you mean by looking at the eeg?

Mark Berman

Yes, by looking at the EEG and looking at how fractal the signals we can distinguish trials when people are trying to remember three things out of three versus as many as they can out of six, but they can only really remember three out of six.

Sean Carroll

There's some deep lesson there I don't even want to draw out right now. But, but I mean, maybe this is the right place to go to the. Maybe not deep lessons, but important lessons. So, okay, it's fun to conjecture and theorize about what's going on in the brain, how to explain it, but there's this still empirical finding that our attention is restored rather than depleted when we're interacting with nature in some way rather than within an urban environment. What can we do with that? What are the implications of this psychology matters for human life? So does this, this have therapeutic value? Does this have impacts for how we should design our urban environments?

Mark Berman

Absolutely. It's got wide ranging implications. There was, there was another classic study done by Roger ulrich in the 1980s where he looked at recovery from gallbladder surgery. And then in the 80s, gallbladder surgery was not an inpatient surgery. You had to stay or not sorry, it wasn't an outpatient surgery. You had to stay at the hospital to recover. And on this single hospital recorder in this hospital in Philadelphia, patients are in different rooms. And some of the rooms have a window to nature, modest nature, like some trees and some grass. Other rooms have a view of a brick wall, like the hospital kind of folding back around. And what Roger was interested in was looking at recovery time from gallbladder surgery. And what he found is that patients recovered about a day faster if they had the view of nature out of their hospital window and they use less pain medication compared to the patients that had the view of the brick wall. And again, this was sort of a quasi experiment because patients didn't get to pick what room they were in. They were just kind of randomly assigned to whatever room was available. But it had this really, you know, a significant impact on, on physical recovery, which is kind of wild. And I don't think this had to do with air quality. You know, I don't think the patients that had the room with the nature were exercising more or something about. There was something about the aesthetic of nature that maybe had these healing qualities. And maybe this was also somewhat mood related, maybe having the nature elevated mood which had Healing. Healing properties. You know, Sean, this is almost. You could do another podcast about this. So I think there's tons of implications here, tons of things that we can do. But I would say psychology as a science has not had as large of an impact on society as you would want. Economics has. Economics, you know, as a social science has had a really, really profound impact on society, but psychology really hasn't gotten there yet. And I think there's a number of reasons why for that. One is that I think to really make hay in society, you have to talk in terms that people can really grab onto, which I think are economics. It's difficult for me to say now, you know, what does a 20 improvement in backwards digit span mean economically? I don't know. I mean, I think people will be more productive at work, but I don't know how much more productive at work they'll be. They know that kids are going to be more productive at school and have less behavioral issues if there's more green space around the school. But is it worth it? You know, because these things are not. They're not inexpensive. I mean, they're not so expensive, but they're not inexpensive. So I think we need, as a field, we need to really quantify these things more in. In ways that I think a policymaker could really take them and do something with it. Roger's study in the hospital did have impact. People do design hospitals, I think, trying to incorporate more nature into. Into hospitals or around hospitals. But I would say in. In a large part this is something we're fighting against, that people view nature as an amenity and not a necessity. So they say, oh, that's nice if we had enough money, or, you know, oh, that's for rich people. You know, we don't all need to have this. And I think, think we're trying to make the argument that actually, no, this is kind of a necessity, that maybe to achieve human flourishing, to be our best selves, we need to incorporate more of these natural elements into. Into our lives. But how much? What kind? You know, I think these are still issues that we. We need to really, really work through and quantify.

Sean Carroll

And also, I wonder, going back to like, the fractals or whatever, these are, I know sort of conjectural at the moment, but is it literal nature that is the helpful thing, or are there just aspects of nature that we could incorporate into office design or apartment design, et cetera, that would get us some of the same benefits?

Mark Berman

I think it's sort of a staircase. So I would say, like Nothing beats the real nature. And as I said before, when we do the studies with the simulations of nature, the pictures and the sound, you can get effects, but they're not as strong as the real thing. Windows or views to nature can be good, but it's not quite as good as being out in real nature. Pictures of nature can work. Even having fake plants, people have found that can be beneficial, maybe designing with the textures of nature. So as I said, you know, mimicking patterns of nature without there actually being nature could have. Could have benefits too. So it's like if you can't get out into real nature, can you look at real nature? And if you can't look at real nature, can you bring some real nature inside? If you can't bring real nature inside, can you look at simulations of nature? So I kind of look at it as a staircase like that. And, you know, I would hope that we're trying to kind of make this be a more serious and important issue, that we really have to think about this. And it kind of goes back to the very first thing that we were talking about, which is that humans underestimate how much the physical environment impacts their behavior, impacts their cognition, in part because we have so much control over it. And I think we need to, you know, imagine we took that control and we really designed buildings and cities and towns with schools with this in mind, I think you, you know, you. It could have profound consequences.

Sean Carroll

We're not that far from thinking that we're just brains in vats and, you know, or we can upload ourselves. But it seems to me, just from talking to random people on the podcast, not completely random. There's all sorts of ways. The whole embodied cognition, the extended cognition, theses, it's changing very rapidly now with AI, but we're really. There are tendrils of the environment that reach into us and vice versa in crucial ways.

Mark Berman

Yeah, absolutely. So I think it's. It's folly to, to ignore it and. But it's. Again, it's. It's not trivial to, to, to make the case and, you know, to, to really take it seriously. And, you know, I don't want to be if somebody really asked me today. Okay. So, Mark, you know, design this school that will optimize, you know, kids attention and working memory. I think I would have some ideas, but I would feel a little uncomfortable, you know, because I, I'm not sure I would know exactly how, how to do it correctly. You know, I do believe, you know, having more green space around, letting the kids go out and Actually use the green space. Bringing some green space in, having, you know, natural patterns in the. On the walls or on the floors. I. I do think all those things would produce benefits, but it'd be hard for me if you said, okay, Mark, you know, here's $20 million. Is it worth it to do that versus doing something else? That's where I think I would feel a little bit uncomfortable. I want to know more to be able to make that decision, you know, where I'd have more confidence. I have confidence it'll work. Is it worth that much? That's the part that I don't know yet.

Sean Carroll

Yeah, well, like we said, psychology is not done yet. I think that's. That's the. That's the exciting part of it.

Mark Berman

Yes.

Sean Carroll

Okay. I wanted to. You know, we chatted before, at the beginning of the podcast, before we started recording that. You had questions for me based on previous podcasts and things like that. I wanted to, you know, give you a chance to ask these questions. I think this is the least I could do.

Mark Berman

Great. Yeah. So I've got a number of them, I guess, you know. Okay, this one might be too similar. Maybe I should have googled this one beforehand. But when you were talking about many worlds, you did say that it would. It's silly to think about the amount of energy that many worlds would take up. That. That's not a good argument. Could you just explain why. Why that is, or why that's a bad argument to think about? Oh, that would just take so much energy.

Sean Carroll

I have really struggled to explain this one. This is a classic question. I get it. It's a very, very good question. But it's. It's one of the very rare questions that if. If you know what the equations are saying, there is not a question. The equations are just perfectly transparent. And the only question is how to translate it into natural English speak. Right. I think the best I can do is to say that when you say that you're making another universe by, you know, doing a quantum measurement or something, in a sense. And then this is where all the difficulty is hidden, Right? Like, what sense is it? But in a very real sense, you're not doubling the size of the universe. You're taking a universe you had before and you're dividing it in two. Right? You're slicing it into copies that are almost exactly the same, but not quite the same. And so what happens when you have yourself, but also the Earth and the sun, and maybe you have some dumbbells in the gym that you're going to lift up and you say, well, this dumbbell seems just as heavy as it was before I made this quantum measurement. The point is that both you and the dumbbell and the earth and its gravitational field, they've all been sliced by exactly the same amount. Right. They've all been diminished in some sense in the whole wave function of the universe by the same amount. And there is less overall energy in the universe now, but there are more universes, but relative to each other, there's the same amount as there always was. Right. The Earth and the dumbbell and you all have the same relative amounts of energy. So even though the whole universe has half the energy it did, as far as your visible world is concerned, it's completely unnoticeable to you because you're embedded inside.

Mark Berman

Got it.

Sean Carroll

That's the best I can do.

Mark Berman

Okay, great. Okay, here's another one. Child. I'm going to start spitballing a little bit. So I've become a little bit. It's become a little of a pet project and huge interest of mine, this concept of free will and. And consciousness a bit. And it's kind of interesting to me that it seems like physicists are very easy to dismiss free will, but that consciousness is more mysterious or something, or it has, you know, almost more interesting. And it's funny to me, as a psychologist, I think just the opposite. It's like consciousness is not that interesting to me. It's like, yes, we have. I mean, maybe that's because we're studying people all day long, but it's, you know, it's like, yes, we have this conscious experience, you know, that's not interesting that the free will bit is a bit more interesting to me because it's. It, you know, brings up these existential ideas. Well, you know, if we. If we're really not in control and, you know, things are just following Schrodings or the equation, and we're just. Just going out there. It does, you know, it seems like. It almost seems like, what's the point? Why would we have a universe like that that, you know, that's just, you know, following all of. All of Schrodinger's laws like that? And I'm, you know, I'm an environmental neuroscientist. I'm very open to the idea that so much of our behavior is determined by other. Other factors, you know, that so many things are impacting our decisions. But it's. It's strange. We all have. We all feel this, such a strong sensation that we're choosing what we're doing. And it's also interesting, too. We don't have this Dr. Strangelove sensation where it's like, I want to do this, but I'm, you know, the, the universe is not letting me do it. It's like astounding if we had no free will, and yet somehow we're always picking or doing the things that sort of consistent with our desires and our wants. So that's kind of interesting. And then the other thing I'll say is, you know, I do kind of. I think of free will as sort of being this emergent property. So it's not like, like everything at the quantum level has to fully. You know, I might be saying this wrong. It doesn't have to, like, fully explain. Maybe that's not the right word. Maybe I think quantum does fully explain, but you might have this. I don't know what the right word is, but it's like, okay, maybe I'll just say that everything in the climb doesn't have to fully explain this aggregate complex idea. But you had David Krakauer on the podcast who basically said, don't that emergency. You can't use that as like a get out of jail free card and just apply it to, like, everything that you want to be true. Well, it's a complex system. So that sort of bothered me. Although it seems to me like a concept like free will or choice or decision making is a pretty emergent process. And then another thing that I've been thinking about with this too, is that what is it when we're trying to make a hard decision? Like, again, if everything was so determined and we were just this input output device, it would seem like, like, you wouldn't have to do deliberation like the, the Schrodinger equation. It would just solve it and you wouldn't have this deliberation. But when I'm like deciding do I want to have, you know, salmon for dinner or spaghetti, and, you know, why is there this time delay? You know, if, if everything was just sort of determined? So that's. That's another thing I've been kind of ruminating about a bit.

Sean Carroll

Yeah, I, I think that for me, and I don't think that physicists as a group have a take on this, to be perfectly honest, because they've trained themselves for many years not to think about questions like free will and consciousness. And there's only a few who've wandered off and we've lost them. But most of them just, they don't want to think about the foundations of Quantum mechanics, and they don't think about consciousness. They don't want to think about free will. But for me, there's a very close connection between why I think that I don't understand at the detailed level how to account for free will or consciousness, but I have a strong conviction that whatever that account will be will be 100% physical.

Mark Berman

I'm in a hundred. I'm 100% agreement with you. I'm 100% in agreement with you.

Sean Carroll

And I do think that, you know, reluctance to invoke magic aside, they will be emergent because they're not fundamental. Like, they're nowhere in the standard model or their consciousness and free will. Right. So that's enough to convince. Convince me that that's the framework to work in, even though many, many details still have to be worked out. That's why it surprised me when I was talking to Christian List, who did, I thought, a wonderful job of doing a much more detailed examination than I had ever done about what it means to say that free will is emergent. Right. Like, what are the ingredients you need? Here's the list. Here's how you sort of connect this wish list to what is going on in the brain or the person or whatever. And then I said, yeah, so it's kind of like consciousness in that way. And he goes, actually, no, I'm not a physicalist about consciousness. I was like, wait, what? It's the same road that you're walking down. I mean, it's logically possible. Like, you know, he clearly is. Like, any good philosopher is going to sometimes convince themselves of counterintuitive things because they try to think through things and make them all compatible. They just don't. They don't start with the answer and work backwards. So I thought that was very. That was very interesting. But it didn't change my own view. Right. Whatsoever that ultimately it will be explained as an emergent phenomenon. And that's just all the work is to connect all the different layers together.

Mark Berman

Yeah. One thing I do wonder too, with this free will element is, is there this conflation between determinism and causality that I think, you know, there are causes to my choices and stuff like that? I guess that's the part that would bother me the most, that it's, like, completely predetermined? That would be the thing that. I don't know. That's the part that maybe I'm just.

Sean Carroll

There is an old joke I think is. I think it was John Searle who told the joke, you know, about people who don't believe in free will because. And he basically said what, what you said, like when I go to a restaurant, should I just say, when they say ask me what I want, should I just say just give me whatever the universe has determined I'm going to have. Have. Right. Like I don't, I don't have any choice on it. And to me, like, there's not even a very closed door to push against here. I think that it's just confusing two different levels of description. Like at the microscopic level everything might be determined. Of course it's not because there's quantum mechanics and that's throw in there, but it's still mechanistic. Right. Like even though quantum measurement outcomes are not determined, they're also not created by our willpower or something like that, just obeying the laws of physics, even though they're not deterministic.

Mark Berman

Right.

Sean Carroll

But the language that we use to describe people and choices and desires and goals and so forth, that's almost unescapable, inescapable. I don't know anyone, I've said this many times. I don't know any hard determinist, anti free will person who doesn't, as soon as they stop talking about free will, instantly use the ordinary everyday language of making choices and thinking through and having reasons for making your choices and assigning responsibility for doing bad things. Right. Right. So I mean it's not that you should deny any of those. You just have to figure out how they're all compatible. And I think that that's doable. I mean maybe we're determined, but I don't know what the determination is. So who cares? It doesn't matter to me.

Mark Berman

Yeah. I just. Something tells me that's too simple of a universe or that's too simple. I don't know. Again, I don't have a good argument. I mean, I've been reading Hofstadter's book too. I am a strange loop of interesting too is like yes, the, the atoms are all deter, but then I'm doing stuff which is moving the atoms around so it's, it's complicated. Again, maybe that doesn't get you to, you know, I think that to the free will that maybe somebody like Penrose wants, you know, but it does, it

Sean Carroll

does get you somewhere. By the way, my colleague Janan Ismail is, is the world's expert at, at this. She's really explained at a very careful level how not only can we not predict the future because there's too much information in the world, we can't be Laplace's demon because the world is just too big.

Mark Berman

Right.

Sean Carroll

But also because we're in the universe. And, you know, it's. It's just simple. It's just very easy to come up with ways that you can literally interfere with what's happening. Like if you modeled the universe and you predicted that one thing would happen, you could then do things to prevent it from happening, and that prevents you. You from ever completely predicting what's going to happen in the future. I think it. Right. To me, it's like. It strikes me as a little bit of a technicality where free will is concerned, because I don't even have all the information. But still, it's. It's yet another reminder that. That we're not Laplace's demon, nor will we ever be.

Mark Berman

Right. That was Jen Ishmael.

Sean Carroll

Yes.

Mark Berman

Yeah. Okay. I think Andrew's talked to her, too. Yeah. Yeah.

Sean Carroll

Right.

Mark Berman

But then a guy like Penrose wants to say, no, the brain's a quantum computer, so it's. It's changing.

Sean Carroll

Yeah.

Mark Berman

So I don't know if I quite understand exactly, but it's. It's. It's. It's changing the fundamental level. So then he's saying Schrodinger equation cannot just tell me how my brain activity is going to unfold because it's manipulating.

Sean Carroll

That's right. I mean, Penrose. It's interesting to me because what Penrose actually says, it's sort of interesting and completely unconvincing to me. But also, people, including, I think Penrose, relate it to consciousness, but it kind of doesn't even relate to consciousness. It's really just about how the brain works. And it still doesn't help you if you're concerned with the hard problem of consciousness. Like, what is it like to have these internal experiences.

Mark Berman

Right.

Sean Carroll

And whether a certain quantum effect is happening in your brain. I don't see how that helps with that at all. Penrose is concerned with cognition. He thinks that human beings have the ability to reach conclusions that computers don't.

Mark Berman

Right.

Sean Carroll

And that's where he gets quantum mechanics into the game.

Mark Berman

I see.

Sean Carroll

And none of that has to do with consciousness, as far as I can tell.

Mark Berman

I see.

Sean Carroll

So I'm both unconvinced by it and pretty convinced that it doesn't relate to the problem that people relate to.

Mark Berman

Got it, got it, got it. So Penrose would say, you couldn't have an AI that would become conscious or something like that. There's something.

Sean Carroll

I think, that's right.

Mark Berman

Okay.

Sean Carroll

I'm actually. I mean, Certainly he would say, it's harder than you think. Yeah, I actually have never asked him exactly that question, but.

Mark Berman

Okay.

Monday.com Representative

Yeah.

Mark Berman

Whereas I think that's totally on the table.

Sean Carroll

Yeah, well, I think it's on the table, but like, one of the. So one of the disagreements that someone like me has with Penrose is he. He really puts a lot of emphasis on Godel's incompleteness.

Mark Berman

Yes, that's right.

Sean Carroll

So Girdle comes along and says, if I have a sufficiently powerful formal system, roughly speaking, if the system is itself internally consistent, which, by the way, I can never prove that it's internally consistent. But if it is.

Mark Berman

Yeah.

Sean Carroll

Then there will always be statements that are unprovable but true in that system. I mean, basically statements that are analogous to I cannot be proven in this system. Right, right. So it's true, but it's unprovable. And so Penrose says, therefore there are truths that cannot be reached by calculation or computation. And the response to that is, well, wait a minute. That assumed that you knew that the system was internally consistent. And. Well, Penrose says, yes, but I do know that. And the rest of us are like, how do you know that you know? And how do you know that you're working with it anyway in a certain set of assumptions about Turing Machines and things like that? So I think that he's just taking a little bit too literally the rules of mathematics and logic and applying them to the brain and therefore reaching very far, sweeping conclusions about how the brain must be working.

Mark Berman

Right, got it. So then. Yeah. Can you, Sean, tell me a little bit more about. So if consciousness and free will is a merge in property, does that mean that the quantum level can fully explain it? Or what, What?

Monday.com Representative

What?

Mark Berman

Or can't fully explain it?

Sean Carroll

Well, sadly, the word explain is a lot of heavy lifting I think Is consistent with. Is the best you can say. So philosophers invented the word supervenience to handle this question because.

Mark Berman

Oh, yeah, you were using that a lot with Christian.

Sean Carroll

I think supervenience comes up. It's actually fallen out of favor a little bit. They've moved on to grounding and other. Other things. That's okay. There's science in philosophy just like every other field of endeavor. But the idea is, look, I. I want to believe. Let's say I want to believe that there's a sort of lower level microscopic description and there's a higher level emergent description. And people will argue till they're blue in the face about, can you derive the higher level description from the lower level one? And some people will Say, well, there's certain cases where I certainly can, and therefore the ones where I can't, I just have haven't worked hard enough. I haven't been clever enough yet. Other people will say, there are cases where, even in principle, I couldn't derive it, no matter how hard I tried, but it is nevertheless there. And it's hard to prove that you can't derive something. That's a hard claim to make, but. So the idea of supervenience was like, even if I can't derive the relationship between the higher level and the lower level, I can still specify what it means for them to be compatible, which is that I can't imagine two different situations at the higher level which are the same situation at the lower level. Supervenience is. I can't change the higher without also having a difference at the lower level. Like, even if I don't know exactly what the relationship is, there's that strong of a relationship. And so I. I think that something like that is true for quantum mechanics and the world of our everyday experience. That I don't know how to. I don't know how to explain lots of things. I don't know how to explain how the table in front of me is solid, Right? Like, you know, you want to ask me to calculate the boiling point of water. Like, I have friends who can do that, but I can't do it. But it's doable. I'm 100% convinced it's doable. And I think the same thing is true for all of human behavior, too. I have no idea how to do it. No one else has any idea how to do it.

Advertiser

It.

Sean Carroll

I still am convinced it's doable.

Monday.com Representative

Yep.

Mark Berman

Yep. Yeah.

Monday.com Representative

Did you.

Mark Berman

Did you read Sapolsky's book Determined?

Sean Carroll

I did. I had him on the podcast.

Mark Berman

Okay.

Sean Carroll

No. And after I had him on the podcast, it was. I had him on the podcast before the book came out.

Mark Berman

Okay.

Sean Carroll

And he actually, you know, emailed me a couple of chapters to read and comment on, and I. I just thought that they were bad. I mean, the psychology parts of the book are fine, but the philosophy parts are not that good because he can't wrap his brain around the idea of compatibilism. Compatibilism is the idea that determinism at the lower level is compatible with our conception of free will. And he tries to argue against that by saying that the lower level is really deterministic and everyone else is like, but that we're compatible with that. Like, that's the whole idea. You can't argue against compatibilism by arguing for determinism. That's just a misunderstanding.

Mark Berman

Got it. Yeah. Interesting. Yeah. I. There was even some things when he was talking about the lebec. The Lebe experiments, you know, like. Yeah, the. You could predict what they were going to choose before they choose it. That didn't f. That to me.

Advertiser

Even.

Mark Berman

That doesn't. That doesn't. That you can't negate free will even from that either. Like just consciousness might be delayed, but you had some other process that really did the choosing.

Sean Carroll

Well, also, you know, again, a compatible list.

Mark Berman

Right.

Sean Carroll

Does think that what we call free will and making choices and stuff like that is all a higher level collective behavior that comes out of real physical things happening in the brain. So an experiment that illuminates what those real physical things are is in no sense a rejection. The compatibleist point of view.

Mark Berman

Right, right. But when you had Christoph Koch on he. Is he a dualist?

Sean Carroll

He's certainly dualist. Curious. I think. Yes. I think he's moved in that direction over the years. Panpsychism. He's very, very comfortable referring to himself as. As a panpsychist. But I don't. There. There are all these like, you know, splitter kind of distinctions that I can't always keep track of. So you can be a panpsychist without being a dualist. You can be sort of a monist who thinks that the, the monism stuff is mind, not physical reality. Yeah. So like, mind comes first and the physical world is just a projection of that to. In. In some way that I fail to quite wrap my own brain around. But. So, yeah, I cannot.

Mark Berman

Yeah. How would they explain what was the universe before there were humans?

Sean Carroll

There was mind, but it wasn't human minds. You know that there's a little bit of mind in every particle.

Mark Berman

Okay, right then. Okay. That's the panpsychism. Yeah.

Sean Carroll

Yes.

Mark Berman

Yeah. I love how you talk about Copenhagen too, because that always really bothered me about that you need this observer. It just seemed.

Sean Carroll

Yeah. And it's always. It's still the most popular way of thinking about quantum mechanics among physicists.

Mark Berman

But I, I think you're saying about this. I mean, the hard part for me is if many worlds is also hard to digest. Like, I understand it, but it's like, it's difficult. And like, how come we can't, you know, again, because that my knowledge is too naive. But you think we'd be able to detect some of those other worlds somehow or something? You know, there's.

Sean Carroll

There's there's good explanations for why we can't, but I think, you know, it's. I'm absolutely sympathetic to people who find many worlds hard to swallow. Yeah, but it's hard to swallow because it's really asking a lot of us, sort of metaphysically. Copenhagen is hard to swallow because it's not well defined. I think that, to me, that's a much more fatal blow than just asking a lot of the listeners or.

Mark Berman

Yeah, right, right. Could free will have any. Or choices have anything that plays into many worlds or that be kind of crazy?

Sean Carroll

My opinion on this has changed by a tiny, tiny amount in recent months. The short answer is no, because you're not saying in many worlds that you're creating a whole nother world by making a decision. You're saying that a quantum system that was in a superposition becoming entangled with its environment, is making another world. I know that. That. That sounds much less sexy, but that is actually what is what is going on. Right. But the other way around could be true. In other words, it's not that decisions branch the universe, but when the universe branches, that could be interpreted to us as making a decision. Right. In other words, things happen in our brain, and it's possible. It's conceivable, and I honestly don't know the answer. It's conceivable that. That if you're making a difficult decision, if you truly don't know which way you're going to go, that there ends up being a substantial quantum mechanical probability to go one way or the other.

Mark Berman

Right.

Sean Carroll

Because there's small quantum fluctuations in your brain rather than just all averaging out, which is what you might expect. There's part of the brain behavior that is chaotic. Right. And which amplifies tiny little fluctuations. And so maybe that's a possibility. And so that would still not say that your decisions are making the universe branch, but it would say that when you make a difficult decision, there is another branch of the wave function of the universe where you made the other one, which I think is an interesting thing to think about.

Mark Berman

Right. Yeah. Super, super interesting.

Sean Carroll

I hope that was. Yeah, I'm glad. Whenever we can all agree that all of these things are interesting and mixed up together and we should all talk about them, even though academia doesn't always encourage us to do that.

Mark Berman

No, no, for sure. But I. And, Sean, I hope it's okay if I bug you again sometime, because I've been thinking a lot about this and I don't have it all wrapped around. I did have a good talk with James Evans. He's like, oh, we should write an article about this. I'm like, we would need somebody like Sean to help us.

Sean Carroll

That sounds good to me. You know where to find me. All right, Mark. I hope everyone buys your boy book. And I hope I'm going to go outside and touch some grass just to follow your advice there. So thanks very much for being on the Mindscape podcast.

Mark Berman

Thanks so much, Sean. It was a pleasure, Sam.