Speaker 1: We need the tonic of wilderness. To wade sometimes in marshes,
Speaker 1: where the bittern and the meadow hen lurk, and hear
Speaker 1: the booming of the snipe, to smell the whispering sedge,
Speaker 1: where only some wilder and more solitary foul builds her nest,
Speaker 1: and the mink crawls with its belly close to the ground.
Speaker 1: At the same time that we are earnest to explore
Speaker 1: and learn all things, we require that all things be
Speaker 1: mysterious and unexplorable, that land and sea be infinitely wild, unsurveyed,
Speaker 1: and unfathomed by us. Because unfathomable, we can never have
Speaker 1: enough of nature. We must be refreshed by the sight
Speaker 1: of inexhaustible vigor, the vast and titanic features, the sea
Speaker 1: coast with its wrecks, the wilderness with its living and
Speaker 1: its decaying trees, the thunder cloud, and the rain which
Speaker 1: lasts three weeks and produces freshets. We need to witness
Speaker 1: our own limits transgressed, and some life pasturing freely where
Speaker 1: we never wander. Welcome to stot to blow your mind
Speaker 1: production of My Heart Radio. Hey, you welcome to stuff
Speaker 1: to blow your mind. My name is Robbert Land and
Speaker 1: I'm Joe McCormick, and that opening reading was from Walden
Speaker 1: by Henry David Thureaux, a classic piece of of literature
Speaker 1: appreciating nature. So today is a Monday, which is usually
Speaker 1: the day of the week we would feature a bit
Speaker 1: of listener mail, but instead, today we've got a special
Speaker 1: bonus episode for you. Unlike in our regular episodes, this
Speaker 1: is what we call in the industry a branded episode,
Speaker 1: which means it was created in partnership with our sponsor today, Mazda. Basically,
Speaker 1: Mazda came to us with a set of themes, mostly
Speaker 1: relating to the well documented positive effects of spending time
Speaker 1: in nature, and we thought, yeah, well we could absolutely
Speaker 1: do an episode on that, because the effective nature on
Speaker 1: the human body and is a huge, fascinating and complex subject,
Speaker 1: worthy probably of an entire series in itself. But in
Speaker 1: today's episode, we're going to focus on a few interesting
Speaker 1: questions and studies in the subject area that really struck us.
Speaker 1: So today's bonus episode will be our branded feature with
Speaker 1: Mazda called Why Nature, which we hope you really enjoy.
Speaker 1: And then we're going to be back to our regular
Speaker 1: schedule with a new Core episode tomorrow, and when I
Speaker 1: first started pondering the subject, I was thinking about how,
Speaker 1: you know, there are really multiple ways that we can
Speaker 1: frame our personal relationship with nature, because, of course, there
Speaker 1: is the very blunt fact that life depends on life,
Speaker 1: and that nature is the word we use for that
Speaker 1: complex web of relationships between the sun, the earth, the water,
Speaker 1: and all the different life forms that inhabit this environment,
Speaker 1: which in a literal sense, we could not live without,
Speaker 1: even with all of our technology. There's a line from
Speaker 1: the poet Denise Levertov where she writes that we call
Speaker 1: it nature only reluctantly admitting ourselves to be nature too.
Speaker 1: We could not live without it because we are it. Yeah,
Speaker 1: even when we put up walls against nature, often to
Speaker 1: distance ourselves from the aspects of nature that we're not
Speaker 1: crazy about, it's still there with us inside, hopefully in
Speaker 1: the plants and animals and works of art that we
Speaker 1: surround ourselves within our our unnatural habitats. But also nature
Speaker 1: is there in the biological reality of our existence and
Speaker 1: in the environmental conditions our senses are heightened to appreciate. Yeah, exactly.
Speaker 1: So that's like the first level. It's just like we
Speaker 1: bluntly needed. We can't live without it. The second thing,
Speaker 1: of course, is that there's a sort of metaphysical or
Speaker 1: metaphorical facet of nature, which I think is the main
Speaker 1: subject of that passage I read from thorough in the beginning.
Speaker 1: We're creatures that search the environment not only for aid
Speaker 1: and physical survival. You're not only looking for food and
Speaker 1: shelter and water in the in the landscape around you.
Speaker 1: But you know, because of our complex brains, we also
Speaker 1: search for meaning. And I think it's a surprisingly widespread
Speaker 1: suspicion that there is somehow meaning to be found in nature,
Speaker 1: that somehow the rocks, the trees, the birds, the vines,
Speaker 1: the algae, and the insects in some profound and ineffable
Speaker 1: way have implications for our lives. So you take a
Speaker 1: walk in the woods, and somehow it tends to suggest
Speaker 1: conclusions about the meaning of life and your place in
Speaker 1: the universe. So these conclusions can often be very difficult
Speaker 1: to put into words. Sometimes people like throw give it
Speaker 1: a try. Yeah. I think of it in two ways. First,
Speaker 1: there's the metaphorical side of the situation. Linguistically and cognitively,
Speaker 1: we need things to make sense of life, and everything
Speaker 1: in it, from skyward branches of the tree to tow
Speaker 1: its deep diving roots, from soaring hawks the snunbering dogs.
Speaker 1: We find metaphorical mirrors for our world and our thoughts
Speaker 1: in all of nature's details. But on the other hand,
Speaker 1: and this is something driven home by spiritual teacher at Cartole,
Speaker 1: if we engage with, say a flower in the wild,
Speaker 1: and experience it all of itself in the moment, and
Speaker 1: then we have in that case we have an excellent
Speaker 1: tool by which to momentarily step outside of our egos,
Speaker 1: uh quiet the voices of the default mode network and
Speaker 1: our head worrying about the past and the future, and
Speaker 1: simply experienced the now like that that flower. And the
Speaker 1: flower is especially good because of its enhanced if if
Speaker 1: a marility, it becomes a window into the now, a
Speaker 1: window into the timeless, and we're able to sort of
Speaker 1: let everything else, all the human complexities, fade away, and
Speaker 1: we become quite literally one with nature in the moment.
Speaker 1: I think we've all had some of these moments of
Speaker 1: a kind of profound connection with the natural environment. I
Speaker 1: think often in solitude, but sometimes with other people around
Speaker 1: as well. I mean, I think particularly of a time
Speaker 1: I felt a really strange kind of relationship to all
Speaker 1: of the dry desert brush when I took a very
Speaker 1: brief solo hike and Big Ben National Park. Um, you know,
Speaker 1: this was like half an hour. But but but something
Speaker 1: happened to me on that walk and I still remember it. Yeah.
Speaker 1: Nature is is pretty weird though, when you stop and
Speaker 1: think about it, because we do have countless reasons to
Speaker 1: wish to avoid it. Uh, let's let's not deny it.
Speaker 1: There are risks in nature, and for most of human history,
Speaker 1: nature itself pose the greatest risk to life and well being.
Speaker 1: Even today, our relationship with nature is often strained. Is
Speaker 1: it a thing we seek to distance ourselves from? Is
Speaker 1: it a thing we wish to dominate and control? I
Speaker 1: find that I find that even myself, when I venture
Speaker 1: into nature, I can still feel myself very much on
Speaker 1: the path. You know, I'm experiencing nature on my own
Speaker 1: particular terms. But then sometimes when you let that go,
Speaker 1: you can experience nature on its own terms and allow
Speaker 1: yourself to sort of dilute just a little bit back
Speaker 1: into the thing that we've always been a part of.
Speaker 1: So for my own part, I'd say some some of
Speaker 1: the more pronounced. Experiences like this that I've had include
Speaker 1: glimpsing a wild sloth in the cloud forests of Costa Rica,
Speaker 1: um tracking the movement and shifting form of an octopus
Speaker 1: beneath the waters in Maui. And and I have to say,
Speaker 1: you know, the encounters, of course, don't have to be
Speaker 1: anywhere near this exotic. I finally remember spotting some wild
Speaker 1: turkeys with my family while strolling through a local cemetery.
Speaker 1: Year around town, and on certain days in different parts
Speaker 1: of my life, you know that the sky has been
Speaker 1: just blue enough, something about a particular shade of blue sky,
Speaker 1: the clouds wispy enough, uh, that it kind of kind
Speaker 1: of forges as a renewing moment that is kind of
Speaker 1: unshackled from time itself. And when I get to experience
Speaker 1: the sky in just such a way, a combination of
Speaker 1: circumstance and awareness of the moment, it's the same sky
Speaker 1: you know that I saw these other times, and I'm
Speaker 1: the same person, and it's, uh, you feel this kind
Speaker 1: of connection to yourself into nature, and you get this
Speaker 1: a great sense of calm, and and that's something I
Speaker 1: could potentially experience anywhere as long as the sky looked
Speaker 1: just right, and I took the time out of my
Speaker 1: day to appreciate it. Right. So lots of us have
Speaker 1: these moments, we remember, these profound moments of connection with
Speaker 1: with nature and the natural environment. But of course those
Speaker 1: can be um, you know, difficult to put into words,
Speaker 1: much less to study in an organized way. Though when
Speaker 1: you want to get down to to quantifiable effects, you
Speaker 1: can actually look at like empirically documented effects of nature
Speaker 1: on our health, both mental and physical, and on our
Speaker 1: thoughts and behavior, Like what can scientific experiments and surveys
Speaker 1: tell us about the measurable impact of proximity to or
Speaker 1: immersion in natural environments? And to go a step deeper,
Speaker 1: do we have any idea why these effects would hold true?
Speaker 1: And it's this last set of questions that we're going
Speaker 1: to be primarily focusing on for the rest of this episode.
Speaker 1: So to start off by mentioning a few of the
Speaker 1: huge human health and life outcomes that have been correlated
Speaker 1: with exposure to nature or what sometimes called green space,
Speaker 1: a pretty self explanatory concept. Uh, this is by no
Speaker 1: means going to be a comprehensive overview, but it's we're
Speaker 1: worth mentioning a few things that seem to have good
Speaker 1: evidence behind them and caught our attention. Now, Fortunately, at
Speaker 1: this point there has been enough research on exposure to
Speaker 1: nature that we don't have to pick through all of
Speaker 1: the individual uh papers over the decades this has been
Speaker 1: looked into. We can actually look at meta analyzes that
Speaker 1: compile these existing studies to see what kind of trends emerge. Now,
Speaker 1: there is some difficulty in this domain because uh, not
Speaker 1: all studies that look into the benefits of nature study
Speaker 1: the exact same thing. Like one might look at people
Speaker 1: making trips out into the woods, and another might look at, uh,
Speaker 1: the outcomes in neighborhoods with nearer access to parks and
Speaker 1: urban forests, and other ones might just look at what
Speaker 1: are the effects of people looking at pictures of trees
Speaker 1: and stuff. But despite that heterogeneity, there is enough research
Speaker 1: now that you can kind of do this meta analysis
Speaker 1: and some signals come through pretty strong. So in terms
Speaker 1: of physiological health benefits benefits to the body, I was
Speaker 1: looking at an article by two big Bennett and Jones
Speaker 1: published in Environmental Research in called The Health Benefits of
Speaker 1: the Great Outdoors. A systematic review and meta analysis of
Speaker 1: green space exposure and health outcomes. So this review looked
Speaker 1: at a hundred and forty three studies on the health
Speaker 1: effects of exposure to green space, and when analyzed together,
Speaker 1: these studies show statistically significant reductions in diastolic blood pressure,
Speaker 1: in heart rate, and in salivary cortisol. Now you might wonder,
Speaker 1: what is that last one, salivary cortisol. This would be
Speaker 1: a measure of the concentration of the hormone cortisol in
Speaker 1: your spit. Cortisol is usually interpreted as a physical biomarker
Speaker 1: of stress. Cortisol is secreted by the adrenal glands and
Speaker 1: is largely responsible for can trolling the body's fight or
Speaker 1: flight response. The meta analysis also found reductions in the
Speaker 1: incidents of diabetes and cardiovascular mortality. And again these are
Speaker 1: not the only correlations that have been found, just the
Speaker 1: most significant and consistent ones. So these are some physiological
Speaker 1: outcomes measured in the health of the body. But what
Speaker 1: about like mental well being and cognitive performance. Well, first
Speaker 1: of all, I would say there is the simple, well
Speaker 1: documented fact that people seem to just really like nature
Speaker 1: in a subjective sense. Lots of people have a baseline
Speaker 1: preference for looking at nature, for hearing nature, for touching it,
Speaker 1: for being in it, and this has been measured dozens
Speaker 1: of different ways. Uh, this actually would probably be a
Speaker 1: good place to talk about the idea of the biophilia hypothesis. Yes,
Speaker 1: the biophelia hypothesis that was brought to us by American
Speaker 1: biologist E. O. Wilson. Now I do have to to
Speaker 1: mention briefly that that on December one, EO. Wilson passed
Speaker 1: away at the age of ninety two. Uh. So you know,
Speaker 1: rest in peace, U E. O. Wilson. But he leaves
Speaker 1: behind a career full of admiration for and study of
Speaker 1: the natural world, with a special focus on the world
Speaker 1: of ants. He's widely known and respected for his work
Speaker 1: and mermacology, but he will always be remembered as well
Speaker 1: for what he called the biophilia hypothesis. So Wilson proposed
Speaker 1: the term love of life in a short publication back
Speaker 1: in Biophilia the human bond with other species, and he
Speaker 1: defined it as humanities innate tendency to focus on living
Speaker 1: things as opposed to the inadamant. In effect, he argued
Speaker 1: for an innate love of nature. He wrote, quote, the
Speaker 1: object of my reflection can be summarized by a single word, biophilia,
Speaker 1: which I will be so bold as to define as
Speaker 1: the innate tendency to focus on life and lifelike processes
Speaker 1: quote from Infancy. We concentrate happily on ourselves and other organisms.
Speaker 1: We learn to distinguish life from the inanimate and move
Speaker 1: toward it like moths to a porch. Light. Novelty and
Speaker 1: diversity are particularly esteemed. The mere mention of the world
Speaker 1: extraterrestrial evokes reveries about still unexplored life, displacing the old
Speaker 1: and once potent exotic that drew earlier generations to remote
Speaker 1: islands and jungle interiors. That much is immediately clear, but
Speaker 1: a great deal more needs to be added. I will
Speaker 1: make the case that to explore and affiliate with life
Speaker 1: is a deep and complicated process in mental development, to
Speaker 1: an extent, still undervalued in philosophy and religion. Our existence
Speaker 1: depends on this propensity. Our spirit is woven from it.
Speaker 1: Hope rises on its currents, and he goes on to
Speaker 1: state that the modern scientific understanding of biology allows us
Speaker 1: to place a greater value upon them and ourselves quote,
Speaker 1: the living environment is what really sustains us. The living
Speaker 1: environment creates, the soil creates most of the atmosphere. It's
Speaker 1: not just something out there. The biosphere is a membrane,
Speaker 1: a very thin membrane of a living organism. And we
Speaker 1: have to stress that this hypothesis goes beyond the mere
Speaker 1: generalities of hey, people love nature. It gets into the
Speaker 1: idea that there's at least impart a genetic link involved,
Speaker 1: that there are genes for biophilia. In the same way
Speaker 1: that humans are wired, hardwired, as we say, to respond
Speaker 1: to an infant's laughs and cries, we are also wired
Speaker 1: to respond to various things in nature. Uh, and it's
Speaker 1: been a part of our evolution, or so argues the hypothesis,
Speaker 1: and in the end Wilson ultimately argues that yes, nature
Speaker 1: is out there, it's in here, and nature is the
Speaker 1: thing that sustains us. Wilson also embodied biophilia in a
Speaker 1: very inspiring way. I think you you'll recall that documentary
Speaker 1: we watched where he goes up to a mound of
Speaker 1: fire ants and he plunges his hand into it and
Speaker 1: he's just beaming with delight, saying, look at how they're
Speaker 1: biting me, and he just loves these ants. Yeah, I
Speaker 1: mean my son likes to um to carefully stir up
Speaker 1: a fire ant nest and watch them swarm and uh,
Speaker 1: and just observe them, you know, not not harm them
Speaker 1: in any way. It make can make walks very slow.
Speaker 1: But in a sense like this drives home the difference
Speaker 1: between what sometimes a busy adults walk can be and
Speaker 1: what like the pure biophilic walk of a child is like,
Speaker 1: I just want to get from point A to point
Speaker 1: B and back. I need to get a certain amount
Speaker 1: of steps in and I needed to be back to
Speaker 1: work on something. But to to the child, uh, it
Speaker 1: is that you're just on the way and here is
Speaker 1: some nature. Let us observe it, let's watch it, even
Speaker 1: though Dad thinks that a walk at least this afternoon
Speaker 1: is supposed to be there and back again in under
Speaker 1: a certain amount of time. Yeah. So there are tons
Speaker 1: of demonstrations that people have this this baseline attraction to
Speaker 1: and subjective aesthetic preference for nature, and this this is
Speaker 1: translated even to very abstracted form. So it's not just
Speaker 1: like people like being out nature. You can even show
Speaker 1: like there are a lot of experiments that show people
Speaker 1: prefer looking at pictures of nature as opposed to pictures
Speaker 1: of other things, you know, built human environments or objects,
Speaker 1: inanimate objects, or other types of imagery. There was one
Speaker 1: study I was looking at from nineteen seventy two that found,
Speaker 1: interestingly that there was a preference not just for imagery
Speaker 1: that had nature in it, but especially imagery that had
Speaker 1: nature in it with a certain amount of visual complexity.
Speaker 1: People kind of like an intermediately complex natural scene, something
Speaker 1: that might involve many different kinds of plants, landscape patterns
Speaker 1: and shapes, and so forth. Yeah, there's been some interesting
Speaker 1: work on this talking about these these vistas and paintings
Speaker 1: that you could essentially walk into and then once you're
Speaker 1: in there, you could develop a foraging strategy. You can
Speaker 1: decide where you might seek shelter, where you might get
Speaker 1: the best view of the surroundings, and so forth. But
Speaker 1: there have also been empirical studies into the effect acts
Speaker 1: of exposure to nature on mental health and cognitive performance,
Speaker 1: so not just physiological health like we already mentioned. Uh,
Speaker 1: some of the things that have been found are that,
Speaker 1: like access to green space has associations with lower levels
Speaker 1: of stress and anxiety. This would sort of go along
Speaker 1: with the lower concentrations of salvary cortisol that we mentioned
Speaker 1: in the Physiological Review, fewer symptoms of depression, improved mood.
Speaker 1: And some studies have found that immersion in or interaction
Speaker 1: with nature gives a sort of time dependent power up
Speaker 1: to some forms of cognition. Just to cite one study,
Speaker 1: there have been many like this, but one was by
Speaker 1: Andrea Faber Taylor and Francis E. Co published in Journal
Speaker 1: of Attention Disorders in two thousand nine called children with
Speaker 1: Attention deficits concentrate better after a walk in the park.
Speaker 1: And so this points out that other pre existing studies
Speaker 1: had already found that working memory and the ability to
Speaker 1: pay attention are enhanced after spin time in certain physical environments,
Speaker 1: particularly in natural settings, and this study tried to apply
Speaker 1: the principle to children diagnosed with a d h D
Speaker 1: between seven and twelve years of age. So the study
Speaker 1: compared the children's performance on a test of attention and
Speaker 1: working memory known as the digit span backwards test. Basically,
Speaker 1: you read out a sequence of numbers and then you
Speaker 1: test how well the subject can repeat those numbers back
Speaker 1: to you in reverse order. And so they tried this
Speaker 1: test with children after three different walks of twenty minutes
Speaker 1: in length, that walk through a neighborhood, will walk through
Speaker 1: a downtown area, and to walk through a foliated park
Speaker 1: most resembling the natural setting, and the children apparently performed
Speaker 1: substantially better after the walk in the park than after
Speaker 1: the other two walks, adding to this pile of evidence
Speaker 1: that for some reason, people including children with a d
Speaker 1: h D, can pay attention and use their working memory
Speaker 1: better after a short period of immersion in nature, and
Speaker 1: the author has used this finding to suggest it's possible
Speaker 1: that regular quote doses of nature, just nature walks or
Speaker 1: other ways of immersing yourself in those kind of surroundings
Speaker 1: might be helpful to kids with a d h D
Speaker 1: on on attention taxing tasks. But it doesn't stop there.
Speaker 1: There have been plenty of other findings about cognitive improvements
Speaker 1: after periods of exposure to nature. One example I came
Speaker 1: across was a study by heartig at All published in
Speaker 1: Environment and Behavior in nineteen one called Restorative Effects of
Speaker 1: Natural environment Experiences. This apparently found that compared to relaxing
Speaker 1: indoors or taking a walk in the city, people who
Speaker 1: took a walk in nature scored better on a proof
Speaker 1: reading task that's something else that is sort of taxing
Speaker 1: on your your find a control of attention. And another
Speaker 1: common finding seems to be that spending time in nature
Speaker 1: may improve our ability to block out distracting stimuli or
Speaker 1: unnecessary information when we're trying to focus, which I would
Speaker 1: say that absolutely checks out with my experience when my
Speaker 1: brain is taxed and like I can't read the words
Speaker 1: on the computer screen anymore, going for a walk in
Speaker 1: in the forest does noticeably make a difference there for me. Yeah,
Speaker 1: And and it's interesting how it can work in both ways,
Speaker 1: like just on a not only on an audible level,
Speaker 1: but also visual level. Walk in nature can give you
Speaker 1: less stimuli when you're over stimulated, and it can also
Speaker 1: give you the stimulation you need when you feel understimulated.
Speaker 1: So regardless if you're you know, especially in today's work environment,
Speaker 1: you might be at home and working most of the
Speaker 1: day and then you're just like, I gotta get out.
Speaker 1: I've got to see something different than what I've seen,
Speaker 1: and here's something different than what I've been listening to.
Speaker 1: And then likewise, you could be in the office across
Speaker 1: town and you've had back to back meetings and constant
Speaker 1: stimuli and you're like, I need to bring it down
Speaker 1: a notch. You can also you can both go to
Speaker 1: the same forest and you can find your relief. Yes,
Speaker 1: And I think we'll come back to that a little
Speaker 1: bit later in the episode because that connects to ideas
Speaker 1: about different types of stimuli that capture our attention in
Speaker 1: different ways. Um, but this whole thing we've been talking about,
Speaker 1: like the the ability of nature to say, improve cognitive
Speaker 1: performance in certain ways. This is what is often referred
Speaker 1: to in the scientific literature as the quote restorative potential
Speaker 1: of nature immersion. The finding is that natural environments tend
Speaker 1: to speed our recovery from conditions like stress or mental fatigue.
Speaker 1: So we have pretty strong evidence from many different studies
Speaker 1: over decades now that exposing oneself to nature and green
Speaker 1: space is correlated with a range of positive effects on
Speaker 1: body health, on psychological well being, and on temporary mental performance,
Speaker 1: which brings us to the big question why nature. If
Speaker 1: exposure to nature does in fact bring these measurable benefits
Speaker 1: to mind and body, Why why nature in particular, and
Speaker 1: what is the biological mechanism leading to these positive effects. Now,
Speaker 1: I think it's worth noting that it's possible that different
Speaker 1: effects have different explanations, or that a single effect could
Speaker 1: arise from a combination of inputs. For example, one question
Speaker 1: that immediately occurred to me when I was reading about
Speaker 1: some of the physiological benefits benefits to body health. Could
Speaker 1: things like lower blood pressure and lower risk of cardiovascular
Speaker 1: disease from spending time and nature be due to the
Speaker 1: fact that green space encourages people to get more exercise.
Speaker 1: That seems possible, so I found one study directly addressing
Speaker 1: this question when I looked. This was by Richardson at
Speaker 1: All published in Public Health in called Role of Physical
Speaker 1: Activity in the Relationship between Urban green space and Health. Basically,
Speaker 1: it found that exposure to green space was in fact
Speaker 1: correlated with better mental and physical health outcomes, and this
Speaker 1: was true when you controlled for other confounding factors, and
Speaker 1: people who lived in places with more access to green
Speaker 1: space did actually get more exercise, but that difference wasn't
Speaker 1: enough to explain the full green space effect on health.
Speaker 1: So just as a hypothetical, it's possible that part, but
Speaker 1: not all, of the improved health outcomes UH could have
Speaker 1: something to do with increases in outdoor exercise, while other
Speaker 1: outcomes such as performance on attention and working memory tasks
Speaker 1: could have a totally different cause. But for the rest
Speaker 1: of the episode, I think we're going to focus on
Speaker 1: several hypothesized frameworks for explaining these effects of nature on
Speaker 1: our brains and bodies. Why are we drawn to nature
Speaker 1: and why does it appear to be so good for us?
Speaker 1: But first we're going to take a break to hear
Speaker 1: from our sponsor, and then immediately on returning, I think
Speaker 1: we'll we'll ease in with a short meditation of some
Speaker 1: natural sound. All right, we're back. We hope everybody's refreshed
Speaker 1: from that that meditation moment. Now, before the break, we
Speaker 1: were talking about some of the documented positive effects of
Speaker 1: h immersion in an access to nature, and now we're
Speaker 1: going to take a look at some possible explanations for
Speaker 1: some of these effects. So I figured we should start
Speaker 1: with the semantic stuff, the body health, and then and
Speaker 1: then come to the more mental realm. So I already
Speaker 1: mentioned that meta analysis by to Hick, Bennett and Jones
Speaker 1: about the the health effects of nature, and it actually
Speaker 1: has a good background section reviewing some of the main
Speaker 1: ideas that have been put forward about why exposure to
Speaker 1: nature might be for health. Uh. These are by no
Speaker 1: means exhaustive of the possible explanations. None of them are
Speaker 1: proven to be the main one. But these are some
Speaker 1: of the main ideas that scientists have offered as as
Speaker 1: good possibilities. One is the one I already mentioned that
Speaker 1: maybe natural environments promote opportunities for and motivation toward physical exercise,
Speaker 1: and the positive health effects of exercise are pretty obvious.
Speaker 1: Another is that some public green spaces may actually promote
Speaker 1: social interaction, which is also highly correlated with health and
Speaker 1: well being, though this seems to vary a lot depending
Speaker 1: on what kind of natural environment you're talking about, though
Speaker 1: I can certainly say from experience that's say, I don't know,
Speaker 1: I feel like I probably am more likely to to
Speaker 1: chat it up with with strangers when walking around in
Speaker 1: a park that as opposed to walking around on a sidewalk.
Speaker 1: I don't I don't know what the difference is there,
Speaker 1: but that that does ring true to me. Well, I
Speaker 1: guess part of it is you generally have a pretty
Speaker 1: good idea why the other person is there, Like you
Speaker 1: both have a shared reason to be here. Uh, you're
Speaker 1: not on your way to somewhere else. This is the destination.
Speaker 1: That makes sense. Yeah, on the sidewalk, you just assume
Speaker 1: people are trying to go about their business. You're you're
Speaker 1: less likely to strike up social conversation, right, But then again,
Speaker 1: there is something different about nature versus say a video store.
Speaker 1: You go to a video store, everyone's there to potentially
Speaker 1: rent a video, but it's more it's often more of
Speaker 1: a solitary situation with occasional conversations uh popping up. But yeah,
Speaker 1: you go and you go into nature. There is this
Speaker 1: kind of sort of shared understandings like, hey, we're all
Speaker 1: here because we dig this, and and there's something about
Speaker 1: this that opens opens us up for conversation. Sure, yeah,
Speaker 1: that makes sense. Another idea they offer exposure to sunlight.
Speaker 1: This may be increased when you have access to pleasant
Speaker 1: natural environments, leading to increases in vitamin D synthesis and
Speaker 1: possibly counteracting seasonal mood disorders. Another idea this is pretty interesting,
Speaker 1: is the old friends hypothis versions of this I think
Speaker 1: we're formerly known more as the hygiene hypothesis. Old friends,
Speaker 1: I think is an attempt to recast it to focus
Speaker 1: on ancestral relationships with certain microbe strains. So the idea
Speaker 1: here is that spending time in green space may increase
Speaker 1: our exposure to beneficial strains of micro organisms, which could
Speaker 1: help the development of a healthy immune system. So I
Speaker 1: think this is still partially in the phase where the
Speaker 1: details are being worked out, but it has been hypothesized
Speaker 1: that too little exposure to certain environmental microbes contributes to
Speaker 1: immune system disregulation and inflammatory disorders, which in turn are
Speaker 1: major contributors to a host negative health outcomes. And so
Speaker 1: spending time exclusively in built synthetic environments might well give
Speaker 1: us too much exposure to the wrong kinds of germs
Speaker 1: and too little exposure to the right kind. Yeah. I've
Speaker 1: seen it argue that just having a dog that goes
Speaker 1: outside and there's an indoor outdoor pet exposes one to
Speaker 1: secondhand microorganisms that can have a beneficial effect on your
Speaker 1: health and well being. So to be clear of sending
Speaker 1: your dog out on one of those hike in the
Speaker 1: wood dog walking trips, you know where the van comes
Speaker 1: and collects all the neighborhood dogs. That's not going to
Speaker 1: make up for your time away from the forest, your
Speaker 1: time away from nature. But the argument is out there
Speaker 1: that it might help you a little bit. Okay, here's
Speaker 1: one where I abandoned all skeptical scrutiny. I just choose
Speaker 1: to believe, whatever the evidence, that when my dog goes out,
Speaker 1: gets filthy, and then comes inside and loves on me,
Speaker 1: that's good. That's good. Now, Again, as I said earlier,
Speaker 1: that these explanations are by no means exhaustive, and it's
Speaker 1: not just one or the other. It could be a
Speaker 1: combination of these things. But there's another thing that occurs
Speaker 1: to me that has been touched on in a number
Speaker 1: of the studies I looked at, which is the effect
Speaker 1: of stress. There's already plenty of empirical evidence that exposure
Speaker 1: to natural environments can cut down on subjective or ports
Speaker 1: of stress and can help measurably reduce levels of cortisol,
Speaker 1: which again is a biomarker of psychological stress. Chronic stress
Speaker 1: and the cascades that it creates in the body are
Speaker 1: are known to have a number of bad consequences for health.
Speaker 1: So I would also wonder if just simple stress reduction
Speaker 1: were not a pretty large contributor toward improved health outcomes
Speaker 1: from time and nature. Now, of course, this raises a
Speaker 1: secondary question, why is it that nature reduces stress? Uh?
Speaker 1: This is probably a harder question to answer, but there
Speaker 1: have been attempts, and and here I think we have
Speaker 1: to stray more into the realm of the totally hypothetical.
Speaker 1: But you know, at least there's some interesting ideas out there,
Speaker 1: even though they may remain unproven. Yes, and of course
Speaker 1: we want to drive home again that certainly just because
Speaker 1: you're in nature doesn't mean you're having a stress free
Speaker 1: right experience. There are plenty of ways that being in
Speaker 1: nature can be stressful. But we're talking about, like, you know,
Speaker 1: all things being equal. Uh, if I am here in
Speaker 1: a building where I'm here in nature struggling about uh,
Speaker 1: there does seem to be some sort of of benefit
Speaker 1: and why would that be exactly? Yes, So one hypothetical
Speaker 1: answer that addresses a lot of these questions like maybe
Speaker 1: why is it we're less stressed after spending positive time
Speaker 1: in nature, or why do we get some of these benefits.
Speaker 1: One explanation has to do with the shape of our
Speaker 1: ancestral environments, and this would actually connect to the biophelia hypothesis.
Speaker 1: You already mentioned that this would be I say that
Speaker 1: the class of explanations that you could put under the
Speaker 1: umbrella of evolutionary psychology, and this would explain our preferences
Speaker 1: for natural environments and their mental effects on us, because
Speaker 1: our species arose in certain types of environments, and there
Speaker 1: are features of those environments that represented clear risks and rewards.
Speaker 1: So under this framework, you know, you would say that
Speaker 1: to some extent, our brains are still affected by mechanisms
Speaker 1: that evolve to help us select the right behavior and
Speaker 1: maximize survival in those ancestral environments. Now, how would this
Speaker 1: apply to natural environments. Well, for just a very simple example,
Speaker 1: think about water sources. Humans without access to water will
Speaker 1: die within a few days. Maintaining constant access to water
Speaker 1: is about as close to a survival absolute as you
Speaker 1: can imagine. Therefore, most evolutionary psychology frameworks would predict that
Speaker 1: we will probably still to some degree have instinctual preferences
Speaker 1: for proximity to water, even if those instincts are no
Speaker 1: longer strictly relevant to survival anymore. Because now you can
Speaker 1: get water out of a tap, or you can bring
Speaker 1: along a water bottle wherever you go, there may be
Speaker 1: some evolved module in the brain that creates a kind
Speaker 1: of mild stress response when there is not a water
Speaker 1: source in the nearby environment, and that motivates you to
Speaker 1: get closer one and maybe maybe it alleviates some stress
Speaker 1: when water is audible nearby or is in view. Now, again,
Speaker 1: this is not something that I have direct evidence for.
Speaker 1: This is just a possible example of how something like
Speaker 1: this could work. But this could be applied to the
Speaker 1: larger environment as a whole. The world around you is
Speaker 1: full of sensory cues that could trigger instinctual reactions that
Speaker 1: are attuned for survival in our ancestral environments. So why
Speaker 1: do we enjoy the high ground with a wide view. Well,
Speaker 1: it could be because this is a position of safety.
Speaker 1: You can see other things approaching from a long way.
Speaker 1: Why do we prefer certain types of tree shapes? You know,
Speaker 1: people seem to This has been tested in experiments. People
Speaker 1: seem to really like certain types of trees, trees with
Speaker 1: like enmeshed canopy and like low lying limbs and stuff.
Speaker 1: And it seems like a reasonable thing to say, Well,
Speaker 1: those are also the trees that are like that provide
Speaker 1: really good canopy habitats and are easy to climb and
Speaker 1: you could get up away from predators in them. Now,
Speaker 1: there's a very important caveat to evolutionary psychology explanations, which
Speaker 1: is that they on one hand, on the pro side,
Speaker 1: they can make a lot of sense of human preferences
Speaker 1: and behaviors, but on the other hand, they can also
Speaker 1: be notoriously difficult, though not impossible, to test in a
Speaker 1: rigorous way. So you know, you've probably heard before people
Speaker 1: just saying like, oh, you know, we do this or
Speaker 1: we like that because of and then they give some
Speaker 1: evolutionary story and it's like, but yeah, how do you
Speaker 1: know that? So you know, it's always good to remember that,
Speaker 1: just because you've managed to come up with a plausible
Speaker 1: story in your head about why survival pressures in the
Speaker 1: ancestral environment might have led to preferences and reactions we
Speaker 1: still have today, you haven't necessarily discovered the explanation. You
Speaker 1: would still need to like work out some predictions that
Speaker 1: explanation would make and then test to see if those
Speaker 1: predictions are true. But for the moment, dwelling in this
Speaker 1: hypothetical space, you can easily imagine a pretty plausible chain
Speaker 1: of mechanisms that would go something like this. So you
Speaker 1: have an ancestral landscape that affects our survival, and this
Speaker 1: gives rise to instinct ual preferences for and against certain
Speaker 1: landscape features. Maybe we like proximity to water, we like
Speaker 1: certain kinds of tree cover, and so forth, and that
Speaker 1: perhaps those preferences still affect us today, exerting an influence
Speaker 1: on our levels of anxiety and stress when the landscape
Speaker 1: is less than favorable, and then anxiety and stress or
Speaker 1: of course upstream of a raft of other mental health
Speaker 1: outcomes in general cognitive performance. So I would consider that
Speaker 1: like a very uh plausible explanation space, but unfortunately a
Speaker 1: lot of the stories that it comes up with can
Speaker 1: be difficult to test. Uh. There's another interesting explanatory framework,
Speaker 1: especially for the restoration aspect of our nature experience, that
Speaker 1: has come up in a lot of the papers I've
Speaker 1: looked at, and this is a framework known as attention
Speaker 1: restoration theory. This was developed by a couple of psychologists
Speaker 1: affiliated with the University of Michigan named Rachel and Stephen Kaplan.
Speaker 1: I think, especially in their book from Cambridge University Press
Speaker 1: in eighty nine called The Experience of Nature a Psychological Perspective.
Speaker 1: Now essentially, attention restoration theory argues that uh, nature and
Speaker 1: synthetic environments are different and their effects on us are
Speaker 1: different because of the different ways that they capture our attention. Now,
Speaker 1: I found this one very interesting. I'll try to do
Speaker 1: a brief summary of this idea. I found it summarized
Speaker 1: in a paper by Berman, Jenniades, and Kaplan and published
Speaker 1: in Psychological Science in two thousand eight called the Cognitive
Speaker 1: Benefits of Interacting with Nature. Uh A art is based
Speaker 1: on a body of research showing that there are two
Speaker 1: functionally different types of attention. So there's involuntary attention, and
Speaker 1: this is where your attention drifts effortlessly to things that
Speaker 1: are inherently interesting or important. And then on the other hand,
Speaker 1: there is voluntary or directed attention, and this is where
Speaker 1: you give attention to things through effortful cognitive control. I
Speaker 1: think actually there's a pretty good linguistic shorthand for this.
Speaker 1: Voluntary or directed attention roughly corresponds to anything you would
Speaker 1: describe as quote, paying attention to rather than just being
Speaker 1: aware of it automatically. But so the basic idea goes
Speaker 1: like this, So we engage with the world through the
Speaker 1: executive attention network, which is mediated by the brain's prefrontal cortex,
Speaker 1: and like many other parts of the body, It can
Speaker 1: become exhausted when it is used to consistently for too long.
Speaker 1: You've you've been putting a lot of demands on it,
Speaker 1: it gets overworked. Tons of tasks in our environment involves
Speaker 1: sustained use of executive attentional resources. Obviously, most kinds of
Speaker 1: work do this. You have to pay attention when you're
Speaker 1: working on something, but even some recreational tasks or things
Speaker 1: you have to effortfully pay attention to, like misery scrolling
Speaker 1: on your phone is despite the fact that it's like addictive,
Speaker 1: you're still like paying attention to things with effort full control.
Speaker 1: Attention restoration theory argues that engaging with nature is good
Speaker 1: at giving your attentional resources a replenishing rest period. By
Speaker 1: immersing yourself in an environment full of things that attract
Speaker 1: involuntary attention through what they call soft fascination, you make
Speaker 1: yourself better at performing subsequent tasks that require directed, effort
Speaker 1: full attention. The executive attentional system is basically just allowed
Speaker 1: to rest during this type of fascination because there's nothing
Speaker 1: that you have to fixate on, right It's that experience.
Speaker 1: They're just walking through the woods and you're you're hearing
Speaker 1: birds what birds? Who knows? They're just they're making bird noises,
Speaker 1: You're passing trees, You're not necessarily identifying you know, not
Speaker 1: to say that identification of various organisms isn't also a
Speaker 1: rewarding aspect of spending time in nature. But there's this yet,
Speaker 1: this feeling of just moving through it, your attention drifting
Speaker 1: among the various stimuli that you're presented with. Uh and
Speaker 1: and and also allowing your mind to sort of wander. Yeah,
Speaker 1: and I think it's in a special middle category because
Speaker 1: it's also not just like a blank room with nothing
Speaker 1: in it, nothing that you can pay attention to. It
Speaker 1: is an environment that is not boring, like boredom in
Speaker 1: itself can be a type of stress inducing thing because
Speaker 1: then maybe you start paying really close attention to, say
Speaker 1: your internal monologue or something. Well, I mean, a boring
Speaker 1: room is a human construction, you know. This is these
Speaker 1: are not environments that we evolve to thrive, and we
Speaker 1: evolve to thrive in spaces where other organisms have access
Speaker 1: to those spaces, be they plants, their animals, where they're
Speaker 1: changes in weather pattern, where the sky is visible. I mean,
Speaker 1: certainly you can there are caves and whatnot where I
Speaker 1: guess you could make a case for saying, well, this
Speaker 1: is a a sensory deprivation environment that one might encounter
Speaker 1: in the natural world. But for the most part, this
Speaker 1: this is just not how it works. The boy Ring
Speaker 1: spaces are the ones we created for ourselves. Yeah, so
Speaker 1: nature is this kind of perfect middle. It's not boring,
Speaker 1: but it's also not something you have to pay attention to. Now,
Speaker 1: A lot of studies about the restorative potential of nature
Speaker 1: do appeal to UH to a art, but it's not
Speaker 1: the only possible explanation. It's not the proven theory. We're
Speaker 1: not going to get deep into it here. But there's
Speaker 1: another similar framework I was reading about multiple times, called
Speaker 1: s RT instead of a RT, standing for I think
Speaker 1: stress reduction theory, explaining some of the cognitive benefits of
Speaker 1: nature via its stress reducing properties rather than through its
Speaker 1: attention replenishing properties. I don't know how to sort out
Speaker 1: between those right now, but it's possible that they may
Speaker 1: both have some kind of purchase on the truth. Now,
Speaker 1: I think maybe we should take another break to hear
Speaker 1: from our sponsor, followed by another brief natural meditation. But
Speaker 1: when we come back, I want to talk a bit
Speaker 1: about creativity. Yeah, yeah, alright, we're back. I hope everyone
Speaker 1: is refreshed and ready for more. Right, So we've talked
Speaker 1: about physiological health, mental health, and cognitive restoration, but there
Speaker 1: have been a number of other positive, higher level mental
Speaker 1: benefits to nature exposure that have been proposed. Just to
Speaker 1: mention one, I wanted to talk about creativity for a minute.
Speaker 1: So this question is can spending time in nature actually
Speaker 1: make you better at creative thinking? I think the answer
Speaker 1: is possibly yes. Some experiments do point in that direction,
Speaker 1: and one, just one study in this area I wanted
Speaker 1: to look at was called Creativity in the Wild Improving
Speaker 1: Creative Reasoning through Immersion in Natural Settings, published in Plus
Speaker 1: one by actually at all. Uh So, first big question here,
Speaker 1: like how do you test for something like creativity? Obviously
Speaker 1: that is much harder to quantify than say tests of
Speaker 1: working memory that ask you to repeat a sequence of numbers,
Speaker 1: the number sequence repetition. That that's a pretty straightforward test.
Speaker 1: But like for creativity, what do you do? Do you
Speaker 1: have somebody write a poem and then see how good
Speaker 1: it is? I mean, no, obviously that would not be
Speaker 1: very objective, but there actually are some simpler tests for
Speaker 1: creativity that that don't capture everything we think of when
Speaker 1: we think of creativity, but they but they do get
Speaker 1: it some core aspects of it, and I think they're
Speaker 1: pretty clever. So the one used in this paper is
Speaker 1: known as the Remote Associates test or rat, and the
Speaker 1: test goes like this, I'm gonna give you three words,
Speaker 1: and then I ask you to come up with a
Speaker 1: fourth word that and next the three I gave you.
Speaker 1: So here's an example, same tennis head. Do we want
Speaker 1: to do some some license for EE Jeopardy type music
Speaker 1: for this same tennis head. I don't know if I
Speaker 1: would have got this because the answer is right there
Speaker 1: in the paper when I read it, so I didn't
Speaker 1: have a chance to like test myself. But the answer
Speaker 1: is match matching. When things are the same, they match.
Speaker 1: There's a tennis match, there's a match match head. And
Speaker 1: this is an interesting test because the path to the
Speaker 1: answer in each puzzles, you know, they give you a
Speaker 1: long list of these things. It's not obvious. It requires
Speaker 1: you to make associative leaps and novel connections and to
Speaker 1: sort of reinterpret linguistic clues in a way that does
Speaker 1: model part of what we mean when we say creative thinking.
Speaker 1: Creative thinking, I would argue, is making connections that are
Speaker 1: useful or fruitful, but that are not obvious. Right. I
Speaker 1: think I would have been thrown off by this test
Speaker 1: because I would have tried to think of something like
Speaker 1: maybe clever and humorous that ties them all together, without
Speaker 1: thinking of something that's something like match like maybe I
Speaker 1: would think of say Pete Sampre's doppelgangers. Oh, you're too
Speaker 1: creative for the test. That's the problem. Yeah, that's that's
Speaker 1: my problem. Well, so this particular study used that type
Speaker 1: of test, and the different conditions were whether people had
Speaker 1: um a multi day immersion in nature through a hiking
Speaker 1: trip versus control conditions where they did not go out
Speaker 1: on a natural hiking trip. And they found a pretty
Speaker 1: sizeable difference. They found it nearly fifty percent increase in
Speaker 1: the in the performance on these puzzle tests by the
Speaker 1: group of naive hikers. Now, that sounds like a large
Speaker 1: effect to me, So I would want to see that
Speaker 1: replicated in other studies. Um, But it again does not
Speaker 1: seem implausible to me that there is some effect that
Speaker 1: spending time in nature has not only the sort of attention,
Speaker 1: restoring potential, but maybe clears the mind in other types
Speaker 1: of ways that haven't even been fully articulated, uh, in
Speaker 1: ways that allow you to make these sort of uh
Speaker 1: non obvious connections and creative turns in logic more than
Speaker 1: you would have been able to do otherwise. I mean
Speaker 1: I I I feel that I feel that process uh
Speaker 1: in in my own creative work sometimes. And there have
Speaker 1: also been some other studies connecting time and nature to
Speaker 1: higher level creativity. One I was looking at was not
Speaker 1: actually an experiment. It was just a survey of creative
Speaker 1: professionals about their processes and the role of nature in
Speaker 1: their process and and this one indicated that time and
Speaker 1: nature was especially helpful in the early stages of a
Speaker 1: creative project, more so than in the later stages. That
Speaker 1: that totally rings true to me, because I think of
Speaker 1: the early stages of a creative process are the ones
Speaker 1: that require those sort of strange mental connections, and then
Speaker 1: the later stages are often more mechanical or about draft. Yeah. Yeah,
Speaker 1: I find this to be true as well. Like from
Speaker 1: from for me, if I need to then want to
Speaker 1: think creatively about something, uh, there's nothing beats just walking
Speaker 1: on a beach. If I can get access to a
Speaker 1: beach with just enough of it to where I can
Speaker 1: have a decent stroll up and down the beach for
Speaker 1: a while, like that is where I do some of
Speaker 1: my best creative thinking. And then once you develop some ideas,
Speaker 1: then yeah, you're gonna then you're gonna have to work
Speaker 1: with them. Then you're gonna have to do the harder part.
Speaker 1: And the beach might not be the best place for that.
Speaker 1: But you didn't come out to the beach to to
Speaker 1: do the harder part. You didn't. You come out to
Speaker 1: the beach to feel the sense of renewal and to
Speaker 1: then to get into this creative mindset. Yeah, anecdotally, I
Speaker 1: can totally get behind that process. If you're if you
Speaker 1: want to start a new creative project, go for a
Speaker 1: walk in the woods, go out to a state park,
Speaker 1: you know, do whatever that's like. It's great to do
Speaker 1: right at the beginning, and and then to do again
Speaker 1: once you get sick of the harder part or you're
Speaker 1: fed up with the various meetings that you've had to
Speaker 1: have to try and bring this idea to fruition, then
Speaker 1: go back of the woods because you'll need it. Then
Speaker 1: too well. I feel like this has been really interesting
Speaker 1: and um again, as as we so often end up
Speaker 1: lamenting after after a fun episode, like we we really
Speaker 1: only scratched the surface there. There was so much stuff
Speaker 1: in the domain of the effects of nature on on
Speaker 1: our minds and our bodies that we didn't even have
Speaker 1: time for today. It's something we could totally return to
Speaker 1: in the future. Yeah. Yeah, And of course, as always,
Speaker 1: we'd love to hear from listeners about this. Share your
Speaker 1: experiences with walking in nature both you know so certainly
Speaker 1: in the past, but also we challenge you to take
Speaker 1: some of this new inside with you when you go
Speaker 1: back into nature again. So whatever your next you know,
Speaker 1: minor neighborhood walk happens to be, or epic adventure that
Speaker 1: you've been planning for months and months. Uh. Once you've
Speaker 1: gone on those adventures, right back to us and tell
Speaker 1: us what you think and tell us how how all
Speaker 1: of that connects with what we discussed here today. I
Speaker 1: want to hear about people's favorite trees. Tell me your
Speaker 1: favorite tree shape. This will not be a scientific sample,
Speaker 1: but I am interested. Do you like the trees with
Speaker 1: the low, drooping branches, Do you like the tall trunk
Speaker 1: with a big canopy up above. I want to know
Speaker 1: all right, well right in, we'd love to hear from you.
Speaker 1: In the meantime, we'll remind you to check out other
Speaker 1: episodes of Stuff to Blow Your Mind with core episodes
Speaker 1: of our show on Tuesdays and Thursdays UM. On Monday's
Speaker 1: usually we do a listener mail episode, on Wednesday's we
Speaker 1: do a short form artifact or monster fact episode, and
Speaker 1: on Friday's we do Weird How Cinema. That's our time
Speaker 1: to set aside most serious concerns and just chat about
Speaker 1: a weird film. Huge thanks as always to our excellent
Speaker 1: audio producer Seth Nicholas Johnson. If you would like to
Speaker 1: get in touch with us with feedback on this episode
Speaker 1: or any other, to suggest a topic for the future,
Speaker 1: or just to say hello, you can email us at contact.
Speaker 1: That's Stuff to Blow your Mind dot com. Stuff to
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