Speaker 1: Welcome to Stuff to Blow Your Mind production of My
Speaker 1: Heart Radio. Hey you welcome to Stuff to Blow your Mind.
Speaker 1: My name is Robert Lamb and I'm Joe McCormick. And
Speaker 1: today we're gonna be taking a look at interior spaces. Yeah,
Speaker 1: the year certainly brings to mind the old curse, May
Speaker 1: you live in interesting times? And one of the factors
Speaker 1: here has of course been the coronavirus COVID nineteen pandemic,
Speaker 1: and in an effort to fight the spread of the illness,
Speaker 1: save lives, and prevent overwhelming our hospitals, we've made a
Speaker 1: lot of changes to our lives and these range from
Speaker 1: the simple such as just wearing a mask when you're
Speaker 1: out in public and you can't social distance from people,
Speaker 1: to the harder choices about employment and uh in life choices,
Speaker 1: we've all been social distancing and stay at home orders,
Speaker 1: teleworking and quarantine have meant that we've all been spending
Speaker 1: a lot more time at home now. Depending on your home,
Speaker 1: this could mean a lot of things, but we wanted
Speaker 1: to explore what this means from a biological standpoint for
Speaker 1: the most part here now now, make no mistakes, spending
Speaker 1: more time at home has absolutely been the right move.
Speaker 1: But just as it's forced you to focus more on,
Speaker 1: say that weird staying on your ceiling, we wanted to
Speaker 1: focus on the other, often unseen aspects of life in
Speaker 1: the home right much the same way that being say
Speaker 1: on a Spanish galleon out in the middle of the
Speaker 1: ocean might have made you pay much more attention to
Speaker 1: the biology and behavior of of ship rats than you
Speaker 1: ever would have otherwise. I think being at home more
Speaker 1: and more is forcing all of us to turn our
Speaker 1: eyes and maybe our microscopes and magnifying glasses to the
Speaker 1: corners and the cornices, and the shower heads and the
Speaker 1: drain traps and all of the wonderful places in our
Speaker 1: house where life dwells. Yeah, we're gonna really get into
Speaker 1: the difference really between the natural world outside of our
Speaker 1: homes and the unnatural world inside, and get into some
Speaker 1: ideas about how how we could perhaps enable our interior
Speaker 1: world to be a little more on the natural side
Speaker 1: of things. But before we get into all that, I
Speaker 1: wanted to take a moment here just to discuss the
Speaker 1: history of houses in general, you know, just to get
Speaker 1: into the concept of what a house is. Our our
Speaker 1: first and still most important interior artificial environment. So you
Speaker 1: can certainly look at a home as an artificial cave
Speaker 1: to a certain extent. And indeed, we have lots of
Speaker 1: early evidence that early hominids sought out shelter in caves
Speaker 1: in the same way that many other animals do. UH.
Speaker 1: These can shelter one against the elements and against predators,
Speaker 1: And as recently as a hundred and thirty thousand years ago,
Speaker 1: cave dwellers were already augmenting these natural interior environments with
Speaker 1: things like rough stone walls. They were using timbers so um.
Speaker 1: So you know, even a hundred thirty thousand years ago,
Speaker 1: we were taking naturally occurring interior space paces and making
Speaker 1: them a little less natural. Um. And of course, on
Speaker 1: top of just the shelter that caves can provide, it
Speaker 1: also seems that caves had a strong sacred meaning to
Speaker 1: many of these UH prehistoric peoples. Those might be important,
Speaker 1: but ultimately proximity to water is far more important. Thus,
Speaker 1: as Kate Spence and Brian M. Fagan point out in
Speaker 1: UH in the section of the seventy Grade Inventions of
Speaker 1: the Ancient World about homes, most early hominids lived out
Speaker 1: in the open near streams and lakes, they built temporary structures,
Speaker 1: and most of this has been lost to time, but
Speaker 1: some of the earliest evidence of potential structures for homes
Speaker 1: goes back one point seven two point seven million years
Speaker 1: ago with Homo erectus sites in southern Africa, and these
Speaker 1: were potentially contemporary with the domestication of fire um and
Speaker 1: these would have been temporary tents, but but they still
Speaker 1: would have been artificial interior environments. Now more secure evidence
Speaker 1: come from the Ukraine roughly forty four thousand years ago,
Speaker 1: the mammoth bone structures from Maladova, which we recently discussed
Speaker 1: on the show. Actually, yeah, we did uh talking about
Speaker 1: these uh. That would have been structures in one of
Speaker 1: the northernmost habitable regions of the Earth at the time,
Speaker 1: because this was during a time of glacial advance where
Speaker 1: the polar ice caps from the north were coming deep
Speaker 1: down into Europe and Asia and uh and so this
Speaker 1: would have been far far north, way up among the
Speaker 1: ice and for some reason humans were building these structures
Speaker 1: out of the bones of mammoth and we don't know that.
Speaker 1: There's still things we don't know about those structures, like
Speaker 1: how how consistently they were inhabited and for how long
Speaker 1: and so forth. Right Now, beyond this, the history of
Speaker 1: human homes is is largely dictated by local resources and
Speaker 1: a local climate. A long process of trial and air
Speaker 1: ends up leading to the development of regional and cultural
Speaker 1: building forms construction methods. But before nine tho see we
Speaker 1: see evidence of clay houses in Palestine and what is
Speaker 1: today Palestine, and before seven thousand b C. We see
Speaker 1: rectangular dwellings in Anatolia. But but at home is far
Speaker 1: more than just a shelter. As the authors here point out,
Speaker 1: houses became key to social structure as well. They point
Speaker 1: out that the ethnographic studies in West Africa reveal complex
Speaker 1: and layered symbolic associations and rituals in the context of dwelling,
Speaker 1: and that this is it shows that a clear role
Speaker 1: of physically structuring and expressing the relationship between different members
Speaker 1: of the household. And we see this of course in
Speaker 1: um and cultures. You know, throughout history and throughout the world.
Speaker 1: There's this physical shape of the place, uh, and then
Speaker 1: that ends up defining or influencing like that, there's this
Speaker 1: this feedback between the two. It goes both ways. Right,
Speaker 1: it's kind of like pouring a liquid into a container. Oh,
Speaker 1: of course. And this actually got me thinking about how
Speaker 1: having permanent, constructed dwellings must have changed the way that
Speaker 1: power and hierarchy are expressed in social groups. And of
Speaker 1: course this is true with normal social status. You know,
Speaker 1: it's it's staked out through displays of wealth. There certain
Speaker 1: kinds of taste or aesthetics in your house, your apartment,
Speaker 1: your you know, your living space. But this also made
Speaker 1: me think about the way that for many leadership positions,
Speaker 1: there is a special house, there's a special dwelling place
Speaker 1: that comes with the job, rather than belonging to an individual.
Speaker 1: So here in Georgia we have the governor's mansion. There
Speaker 1: is the White House there, you know, the palace that
Speaker 1: the king stays at in many cultures, and there's a
Speaker 1: there's a strange metonomy that derives from this. Often the
Speaker 1: house identified with the position of power is used as
Speaker 1: a metaphorical stand in for the person, you know, like
Speaker 1: today the white House said such that, like, the permanent
Speaker 1: dwelling place is actually almost the source of the power,
Speaker 1: and there just happens to be a particular person living
Speaker 1: there right now. Yeah, it's weird. We get so used
Speaker 1: to it because it's just part of our daily um,
Speaker 1: you know, our daily you know linguistic world. You know,
Speaker 1: you can read the news, you read about these various locations,
Speaker 1: these houses, and it's almost as if they have some
Speaker 1: sort of intrinsic power to them, right, I mean, if
Speaker 1: you weren't familiar with their cultures, you would read this
Speaker 1: then and people might think, oh, well, they they clearly
Speaker 1: thought that this big, white um house had some sort
Speaker 1: of magical powers and whoever was allowed to go inside
Speaker 1: it became the ruler of a country and got to
Speaker 1: do whatever they want. Yeah, And it's funny that it's
Speaker 1: so normalized for us, like we've forgotten to notice that
Speaker 1: that's weird that like the power is somehow linked to
Speaker 1: the house itself. Um. But it also makes me wonder,
Speaker 1: you know, did we think about power differently before living
Speaker 1: in artificially built environments? Yeah? To what extent did we? Um?
Speaker 1: Did we end up yet changing the way we live
Speaker 1: our lives by altering this physical environment which we live?
Speaker 1: I mean it makes sense, right, because so much of
Speaker 1: what we do, you know, it's dictated by the environments
Speaker 1: that we evolve to thrive in right. So anyway, I
Speaker 1: don't think we need to remind everyone about the value
Speaker 1: of a home. Housing tends to be one of, if
Speaker 1: not the most expensive parts of your life, but it's
Speaker 1: it's interesting to think about them not simply as this
Speaker 1: valuable thing in your life, for a valuable location where
Speaker 1: your life takes place. The basic idea of the house
Speaker 1: may be as old as our mastery of fire, and
Speaker 1: it forms out of and forms ideas of who and
Speaker 1: what we are, and of course it may do so
Speaker 1: in more and more powerful ways every year, as humanity
Speaker 1: slowly transitions to become a more indoors e on average species.
Speaker 1: All the time, I was reading some interesting figures about
Speaker 1: this trend in a book by the science writer Emily
Speaker 1: and This uh in the book is called The Great
Speaker 1: Indoors The Surprising Science of How Buildings shape our behavior, health,
Speaker 1: and happiness. This is a really interesting book and I'm
Speaker 1: going to refer to it throughout this episode because she
Speaker 1: has an early chapter that's very good about the microbial
Speaker 1: ecology of indoor spaces. But she also gets into some
Speaker 1: interesting territory about the trends in how much built environment
Speaker 1: and floor space we're actually creating. Obviously, this currently varies
Speaker 1: a lot by culture and climate, but in some parts
Speaker 1: of the world human kind is transitioned to an almost
Speaker 1: entirely indoor existence. And this really shows in the way
Speaker 1: we've transformed our environments to convert to this largely indoor existence.
Speaker 1: Uh Anthes writes, quote, the island of Manhattan is only
Speaker 1: twenty three square miles in size, but has three times
Speaker 1: that much indoor floor space. And furthermore, she refers to
Speaker 1: a report put together by a United Nations commission in
Speaker 1: which concluded that over the next forty years, humankind is
Speaker 1: going to roughly double the amount of indoor floor space
Speaker 1: that exists currently. And the way this works out is
Speaker 1: quote those additions are equivalent to building the current floor
Speaker 1: area of Japan every single year from now until Wow.
Speaker 1: That much floor is going to take a lot of
Speaker 1: pine sawl Yeah. I mean it is crazy to think
Speaker 1: about how certainly during pre pandemic times, you know, you
Speaker 1: would you had this home, this interior space that you
Speaker 1: live in, you sleep in, you bathe in, you spend
Speaker 1: time in, and then uh and it is you know,
Speaker 1: very much like the center of your life. And then
Speaker 1: you're getting into another interior space, which happens to be
Speaker 1: motorized and on wheels, and use that to travel then
Speaker 1: a certain distance to another interior space that you'll go
Speaker 1: into to work, either set at a desk or you know,
Speaker 1: work with some sort of machinery or what have you. Uh,
Speaker 1: and then at the end of the day back into
Speaker 1: this uh, motorized interior space and then return to the
Speaker 1: one in which you live. It's worth remembering yet again,
Speaker 1: biologically speaking, this is not normal. This is not like
Speaker 1: what our bodies are naturally adapted to. Spending this much
Speaker 1: time indoors is still fairly historically novel, and it is
Speaker 1: very weird. Yes. But the other big thing, and this
Speaker 1: is going to be a recurring theme throughout the rest
Speaker 1: of the episode, is that these artificial spaces that we made,
Speaker 1: they are they're not completely alien, you know, they're they're
Speaker 1: constructed all of the natural world. They're not the natural environment,
Speaker 1: but they are made out of it. And uh and
Speaker 1: and much of the natural world is still present, just
Speaker 1: in um rebalanced and unbalanced ways. Uh. So that that
Speaker 1: is going to be what we're going to really get into, Like,
Speaker 1: what in creating these interior spaces, what sort of environments
Speaker 1: have we created? Right, Indoor spaces are not unnatural in
Speaker 1: that they're completely separate from the rest of the world,
Speaker 1: but they're also not just like outdoor spaces. They're kind
Speaker 1: of like a special niche environment, like a like a
Speaker 1: cliff face or an island. You know, it's a place
Speaker 1: where you have to investigate. Okay, what kinds of life
Speaker 1: from around and other places are going to colonize this space? Yeah?
Speaker 1: And and who are your roommates? Who are your inhuman
Speaker 1: roommates in this space where you've been trapped? Uh these
Speaker 1: past several months. Well, maybe we should take a break
Speaker 1: and then when we come back, we can start talking
Speaker 1: about those in human roommates. All right, we're back, so uh.
Speaker 1: Rob Donne, a professor of applied ecology at North Carolina
Speaker 1: State University and Raleigh, wrote an excellent book titled Never
Speaker 1: Home Alone. From Microbes to Millipedes, camel, crickets and honey bees,
Speaker 1: then Natural History of Where We Live. That's a nice
Speaker 1: long title. I know you'd be like those those long
Speaker 1: coland titles, want like a whole paragraph after the colon,
Speaker 1: but it's it's it's hard as they go. It's pretty
Speaker 1: good title. Anyway, it came out last October and it's
Speaker 1: currently available in all format. So however, you read your books.
Speaker 1: But I remember hearing an interview with the author around
Speaker 1: the time that came out, and I picked it up
Speaker 1: for this episode because it's, yeah, it's it's it's just
Speaker 1: a very well written book and it really gets into
Speaker 1: some just crazy, uh mind bending facts about these artificial environments,
Speaker 1: most of which we won't even really be able to
Speaker 1: get into in this episode, but we wanted to touch
Speaker 1: on it. So if you look around its science papers,
Speaker 1: you'll find Dunn's name um all over the place when
Speaker 1: it comes to this area of microbial life. For instance,
Speaker 1: he's the co author on a two thousand eighteen paper
Speaker 1: that found that chimpanzee tree top beds, which are like
Speaker 1: a daily affair, contained fewer microbes and Arthur pods than
Speaker 1: human beds, which is not shocking given again the the
Speaker 1: idea that ore beds that are kind of like set
Speaker 1: in place, Um, you know, we will change the sheets,
Speaker 1: but it's not every night probably, whereas the chimps are
Speaker 1: going to be refreshing things a bit more. Also, thirty
Speaker 1: of the bacteria in human beds stem from our own
Speaker 1: bodies and includes fecal, oral, and skin bacteria. Yeah. The
Speaker 1: way I heard it put, because this is covered in
Speaker 1: Anthesis book too, is that with the with the human bed,
Speaker 1: basically you're just gonna find tons of human type stuff
Speaker 1: in it. But for a chimpanzees bed, you will find
Speaker 1: you know, bugs, arthur pods, and microbes in in this bed,
Speaker 1: but they're almost all from the surrounding environment. Uh. The
Speaker 1: way it was put was that you might not be
Speaker 1: able to tell that a chimpanzee had ever been there. Right,
Speaker 1: very strange. But from Anthesis book there's uh So there's
Speaker 1: a chapter that discusses a lot of the work of
Speaker 1: the same researcher, robbed On, the the ecologist at North
Speaker 1: Carolina State, but also a researcher that he's collaborated with
Speaker 1: a lot named Noah Fierre, who's a microbiologist at u C. Boulder,
Speaker 1: And there's a part where it talks about a survey
Speaker 1: that they tried to conduct called the Wildlife of Our
Speaker 1: Homes Project. There was a pilot study they started in
Speaker 1: North Carolina, and so they would do was they would
Speaker 1: get a bunch of families to take cotton swab samples
Speaker 1: of seven different surfaces from inside their homes, and this
Speaker 1: would include a countertop, a cutting board, a refrigerator shelf,
Speaker 1: a pillow case, a toilet seat, a TV screen, and
Speaker 1: then the trim around an interior doorway. And the results
Speaker 1: were interesting. They found more than two thousand types of
Speaker 1: microbes in these samples, and there were distinct microbial habitats
Speaker 1: within the house. So perhaps on surprisingly, kitchens would have
Speaker 1: a lot of bacteria that are naturally associated with food
Speaker 1: that might be you know, found on food or aid
Speaker 1: in the decomposition of food. Meanwhile, doorways would have a
Speaker 1: lot of environmental species stuff you might find outside the house,
Speaker 1: you know, things you would find on plant leaves and
Speaker 1: in the soil. But then this was the quote that
Speaker 1: really stuck with me, And this writes quote from a
Speaker 1: microbiological perspective, toilet seats and pillow cases looked strikingly similar.
Speaker 1: But we're dominated by bacteria that typically live on our
Speaker 1: skin and in our mouths. All right, So that's that's
Speaker 1: kind of a shocking sounding statement that might make you
Speaker 1: want to instantly go and wash your pillowcase and maybe
Speaker 1: your toilet seat too. But but but hold on, wait
Speaker 1: till we get through the whole episode, because I think
Speaker 1: one of the big tacomes here is like, if you
Speaker 1: think that your pillow is going to be a microbial
Speaker 1: sterile um experience, you know you should think again, likewise
Speaker 1: with the toilet seat, likewise with anything in the house.
Speaker 1: So in Dunn's book, one of one of the things
Speaker 1: he drives home is that again our our house environments
Speaker 1: are again not natural environments, but they are made out
Speaker 1: of the natural environment, and they are not cut off
Speaker 1: from the natural environment. So what we end up with
Speaker 1: is an artificial environment that kind of mashes up all
Speaker 1: of these various environmental parameters, sometimes in surprising ways, especially
Speaker 1: when it comes to microbes, because if we as we've
Speaker 1: discussed on the show plenty of times before, there is
Speaker 1: no microbe free living our bodies, independent of anything else,
Speaker 1: our home to multitudes of microbes. To come back to
Speaker 1: a quote that we've pulled up on the show in
Speaker 1: discussion in the past. In a Life in a World
Speaker 1: without Microbes by Gilbert and Newfeld published in PRST Biology,
Speaker 1: the authors contend that quote it would be false to
Speaker 1: claim that macroscopic life cannot exist without microbes. However, although
Speaker 1: life would persist in the absence of microbes, both the
Speaker 1: quantity and quality of life would be reduced drastically. So
Speaker 1: Done points out that even the outer layer of our
Speaker 1: skin is just this rich microbial environment. Our armpit bacteria
Speaker 1: are essentially fed by glands nurturing what has likely been
Speaker 1: an historically important microbe passenger. And we can we can
Speaker 1: look at this as an example of the sort of
Speaker 1: microbe that then thrives in our creative environments. We tend
Speaker 1: to find the same bacteria uh that that that thrives
Speaker 1: in our under arms living in our homes, especially homes
Speaker 1: where males live. If there's like a predominantly male population
Speaker 1: of a house sold, you will find this particular bacterium.
Speaker 1: I believe it's uh corn a bacterium just thriving Coarina bacterium,
Speaker 1: Coarina bacterium. Yes. Yeah, So this thing about the sex
Speaker 1: composition of the household versus the household microbiome was also
Speaker 1: mentioned in anthesis book, and it's very interesting. So just
Speaker 1: as you say, homes with more male residents tend to
Speaker 1: have higher counts of bacteria such as Rosa burria and
Speaker 1: this is commonly a gut bacteria, as well as Karina
Speaker 1: bacterium and Derma bacter and uh at this points out
Speaker 1: that these are most common on the skin. Now, Coarina
Speaker 1: bacterium is often found in the armpit. As you say,
Speaker 1: it is a contributor to body odor. But also it's
Speaker 1: been found that just on average, men tend to have
Speaker 1: more Coarina bacteria on their skin than women do, and
Speaker 1: men tend to shed more skin microbes into the environment
Speaker 1: than women do. And then on the other hand, households
Speaker 1: that have more women living in them tend to have
Speaker 1: higher counts of Lactobacillus, which is our old friend from
Speaker 1: the fermentation episode. I don't know if this translates to
Speaker 1: a workable difference, maybe not, but it makes me wonder
Speaker 1: if it's possible that houses occupied by higher numbers of
Speaker 1: women might be a better place to make sauerkraut. Interesting,
Speaker 1: just some to think about, but sort of. What this
Speaker 1: suggests is that humans are walking fountains of microbes. We
Speaker 1: we shed our microbial passengers everywhere we go, and it
Speaker 1: turns out this can be kind of quantified to creepy levels.
Speaker 1: So consider this. No two people's microbiomes are exactly the same.
Speaker 1: Each person is a unique ecosystem. So if everybody has
Speaker 1: their own unique profile of microbiota, and everybody is shedding
Speaker 1: microbial life all the time, are we essentially leaving identifiable
Speaker 1: microbial evidence of our presence everywhere we go, you know,
Speaker 1: kind of the slug trail of our microbiome all over
Speaker 1: the place. And the answer appears to be kind of yeah.
Speaker 1: At this reports one study led by Jack Gilbert at
Speaker 1: the University of Chicago. I think that might be the
Speaker 1: Gilbert of the Gilbert and Neufeld study that you mentioned
Speaker 1: a minute ago. But it followed three families that were
Speaker 1: in the process of moving into new homes. And what
Speaker 1: Gilbert and colleagues found was that each family began to
Speaker 1: colonize the new house with their microbes within just hours
Speaker 1: of arriving there. Uh. And that the researchers quote could
Speaker 1: even detect the individual microbial contributions of each family member. Uh.
Speaker 1: And then Gilbert says, people who spent more time in
Speaker 1: the kitchen, their microbiome dominated that space. People who spent
Speaker 1: more time in the bedroom, their microbiome dominated there. You
Speaker 1: could start to forensically identify their movement. Oh wow, So
Speaker 1: this this makes one try to imagine like law and
Speaker 1: order microbiology, yes, surveillance biotech. Yeah. But to come back
Speaker 1: to to Rob Dunn's example about Corina bacteria in homes,
Speaker 1: especially where males live. You you had an interesting thing
Speaker 1: about that, Yeah, because he brings up a very curious
Speaker 1: case of of an interior environment in interier home that
Speaker 1: had a predominantly certainly at the time of the study,
Speaker 1: had a predominantly male um population, and that is the
Speaker 1: International Space Station. So this was basically there was a
Speaker 1: study of the micro buyouta one finds inside the I
Speaker 1: S S. This was conducted in two thousand thirteen by
Speaker 1: Jonathan Ien, a microbiologist at u C. Davis. So, the
Speaker 1: the I S S done rights, is very much like
Speaker 1: a house on Earth. Quote, in nearly every way, the
Speaker 1: bacteria of the I S S are the sorts of
Speaker 1: bacteria we would expect in a house on Earth if
Speaker 1: all the environmental influences were removed. I S S is
Speaker 1: what you get when you scrub and scrub and close
Speaker 1: the windows, doors and hatches. So the I S S
Speaker 1: might be kind of like a very well scrub department
Speaker 1: in a high rise in a big city. Yeah, I mean,
Speaker 1: there's there's no outside to get inside, right, Um, I
Speaker 1: mean immediately so obviously, um, stuff can be brought up,
Speaker 1: but anyway, done also points out that in this study
Speaker 1: of iss microbes, quote, everything was everywhere. The interior was
Speaker 1: just codd in human bacteria, and nothing from outside was
Speaker 1: getting in. Obviously. He points out that in a small
Speaker 1: traditional home made out of mud and leaves, which would
Speaker 1: have been you know, the normal for the vast uh,
Speaker 1: you know, the vast majority of human existence, everything would
Speaker 1: be everywhere as well, but environmental microbes would be everywhere.
Speaker 1: What's outside would be inside. But for the I s
Speaker 1: s there there is no outside. Really, it is a
Speaker 1: you know, this sterile environment that is then inhabited by
Speaker 1: human beings certainly, but then inhabited populated by human microbes.
Speaker 1: So so environmentally sterile, but heavily colonized by what the
Speaker 1: humans bring with them, right, He writes, quote, if you
Speaker 1: scrub and scrub your home, this is what you may
Speaker 1: achieve too. It is not unlike what we see in
Speaker 1: some apartments in Manhattan, And as we and others have
Speaker 1: begun to study such apartments, we have found a problem.
Speaker 1: The problem is not what is present, but instead what
Speaker 1: is absent. The problem has to do with what happens
Speaker 1: when we create homes devoid of nearly all biodiversity except
Speaker 1: that which falls from us, and then for twenty three
Speaker 1: hours of the day we don't go outside. So they're
Speaker 1: kind of getting high on our own supply here. Yeah,
Speaker 1: I mean, that's that's exactly. I mean, it's we're in
Speaker 1: these interior worlds. We're not we're actually going to great
Speaker 1: pains and many times or just by the virtue of
Speaker 1: the shape of our cities, in the shape of our lives,
Speaker 1: we're not bringing anything in or we're ringing in as
Speaker 1: little as as possible, and except for everything that just
Speaker 1: sheds off of us. This kind of like constant um um,
Speaker 1: you know, fog of detritus that we're leaving in our way. Now,
Speaker 1: this isn't to say there aren't some really interesting things
Speaker 1: living in the average human home. In his book, Done discusses,
Speaker 1: for instance, the thermophilic bacteria Thermus aquaticus, which normally thrives
Speaker 1: in hot springs and geyser's uh, you know, kind of
Speaker 1: a you know, a specialist in that regard, but you
Speaker 1: can pretty much rely on the fact that you can
Speaker 1: find it in your hot water. Here a part of
Speaker 1: your artificial environment that recreates environmental conditions that it finds favorable. Yeah.
Speaker 1: Anthes discusses the research on shower heads. Apparently there tends
Speaker 1: to be a lot of bacteria living in biofilms. And
Speaker 1: biofilms are you know, these mats that microbes make when
Speaker 1: they gather in big concentrations. For example, the dental plaque
Speaker 1: on your teeth is a biofilm. These tend to form
Speaker 1: on shower heads in our showers. We don't know exactly why,
Speaker 1: but maybe because you know, hey, it's the shower, doesn't
Speaker 1: it just get mean by itself, Like do I really
Speaker 1: need to clean it? Uh? It is clean, it's water
Speaker 1: coming out of it, exactly. It's kind of the logic
Speaker 1: that's like, why would I ever need to wash my
Speaker 1: bath towels? You know, they only touch me when I'm
Speaker 1: at my cleanest um. But Anthus quotes Noah Noah Fear,
Speaker 1: explaining that when hot water suddenly starts shooting out of
Speaker 1: the shower head where these films are perched, it creates
Speaker 1: this kind of mist and spray that carries bacteria with it,
Speaker 1: and then of course, standing there under the spray in
Speaker 1: the shower. We ingest that spray, we breathe it right in,
Speaker 1: and Fierra says, quote, I think it's a really important
Speaker 1: mechanism by which we're exposed to bacteria. Which, okay, so
Speaker 1: you might be thinking again like, oh my god, my
Speaker 1: shower head, you're filled with horror, But it's not necessarily
Speaker 1: a bad thing. Again, like a lot of our exposure
Speaker 1: to microbes is either neutral or beneficial, though of course
Speaker 1: not all of it. Yeah, yeah, the bio films in
Speaker 1: your shower head contained mostly harmless bacteria, but it but it.
Speaker 1: Interestingly enough, it includes non tuberculosis uh micro bacteria, which
Speaker 1: are relatives of leprosy and tuberculosis. Um. The interesting thing
Speaker 1: here is that their chlorine tolerant. So while the chlorine
Speaker 1: in a like a major metropolitan water system kills a
Speaker 1: lot of the micro organisms that it might otherwise be
Speaker 1: found there, it doesn't hurt these guys and actually creates
Speaker 1: room for them to grow and to thrive. So they
Speaker 1: are otherwise quite rare, and say, well water, uh, these
Speaker 1: are I think I read that these biofilms are typically
Speaker 1: found in general, are found in swamps totally adapted to
Speaker 1: altering between wet and dry conditions much like your shower head. Um.
Speaker 1: But yeah, in the natural world, they're just gonna have
Speaker 1: their their niche to occupy. But we've created an artificial
Speaker 1: environment where they have room to just really grow and
Speaker 1: thrive and then of course rain down upon us, and
Speaker 1: there could be health and cations about those microbacterial films.
Speaker 1: We don't know for sure, but there's a there's a
Speaker 1: possibility Anthes talks about. She writes, quote in fact, Fire
Speaker 1: and Donne discovered that showerheads harboring potentially dangerous strains of
Speaker 1: microbacteria clustered in the same regions mentioning Hawaii, southern California,
Speaker 1: Florida in the mid Atlantic that are known to be
Speaker 1: hot spots for microbacterial related respiratory infections. So the question
Speaker 1: is are people getting these infections from their shower heads
Speaker 1: of Fiarre suspects that might be the case, but that
Speaker 1: doesn't necessarily mean your shower head is making you six.
Speaker 1: Some microbacteria, when inhaled, are are not harmful. They might
Speaker 1: even strengthen your immune system. Now Done points out that
Speaker 1: that we've been studying microbiota in our homes actually since
Speaker 1: the earliest days of microbiology. Uh, you have. This individual
Speaker 1: by the name of Anthony van Lewenhoek who lived sixteen
Speaker 1: thirty two through seventeen twenty three, and he's often called
Speaker 1: is the father of microbiology and and weirdly enough, he's
Speaker 1: possibly the model for two different Vermeer paintings. I don't
Speaker 1: know if you've read about this. Yeah, um, well, I
Speaker 1: encouraged listeners to look it up. It's pretty fascinating. Like,
Speaker 1: basically he knew Vermier and may have posed for these paintings.
Speaker 1: But he's the first individual known to have engaged in
Speaker 1: this sort of study. He charted the microbial populations of
Speaker 1: his own house, of his own body, and also some
Speaker 1: neighbors homes and bodies. Um with permission I believe. But
Speaker 1: but after his death, no one really bothered with the
Speaker 1: sort of study again until we realized later that some
Speaker 1: of the microbes we encountered could make us sick. And
Speaker 1: so it's really it's it's really getting into modern times
Speaker 1: here where we're finally, uh, taking a close look at
Speaker 1: our household microbial environment with researchers like done playing a
Speaker 1: key role. Um. Here's another great quote where he's just
Speaker 1: talking about, you know, undertaking this this project and what
Speaker 1: they expected to find. He says, quote, we expected to
Speaker 1: find hundreds of species. Instead we discovered depending on just
Speaker 1: how you do the math, upward of two hundred thousand species.
Speaker 1: Many of these species are microscopic, but others are larger
Speaker 1: and yet nonetheless overlooked. Breathe in inhale deeply. With each breath,
Speaker 1: you bring in oxygen deep into the alveoli of your lungs,
Speaker 1: along with hundreds or thousands of species. Sit down. Each
Speaker 1: place you sit, you are surrounded by a floating, a leaping,
Speaker 1: crawling circus of thousands of species. We are never home alone.
Speaker 1: And this is on top of tins and perhaps hundreds
Speaker 1: of different types of vertebrates, as well as various plants.
Speaker 1: And then there are the arthropods and the fun guys.
Speaker 1: Something like forty thousand species of fungi that can be
Speaker 1: found in the home um. But the bacteria are just
Speaker 1: really the crazy Party points out that more species of
Speaker 1: bacteria have been found in human homes than there are
Speaker 1: species of birds and mammals on Earth. Yeah. This type
Speaker 1: of research is also explored in in ant this book,
Speaker 1: where there's a section where she talks about how done
Speaker 1: and fear followed up on their initial research from you know,
Speaker 1: asking people to take the swabs from the different parts
Speaker 1: of their home to find out what was there. They
Speaker 1: decided to do like a bigger, deeper study of the
Speaker 1: microbes found specifically along the trim of interior doorways. And
Speaker 1: they picked this area because nobody ever cleans it, so dust,
Speaker 1: you know, collects for years maybe without being sterilized, and
Speaker 1: this would give you potentially a fuller inventory. And they
Speaker 1: just found enormous numbers of bacteria. In anthesis book, the
Speaker 1: number is over a hundred and sixteen thousand species of bacteria,
Speaker 1: more than sixty three thousand species of fungi. And the
Speaker 1: count of fungi species was especially interesting to them because
Speaker 1: they found more numbers of species of fungi in these
Speaker 1: samples around doorway trims than there are named species of
Speaker 1: fungi in all of North America. So it means that
Speaker 1: inside our houses, it's it's very likely that there are
Speaker 1: species of fungus that have not yet been discovered or
Speaker 1: cataloged by science. And they also found that that for
Speaker 1: some of these samples, there was more uh fungi diversity
Speaker 1: inside the house than outside the house, which interest which
Speaker 1: reminds me of the scene in Primer where they don't
Speaker 1: realize they've created a time machine yet and they think
Speaker 1: that that the box that they put together as an
Speaker 1: incubator for mold. Oh I forgot about that detail that
Speaker 1: a while since have seen that one. And fungi in
Speaker 1: our homes are somewhat different than bacteria in our homes,
Speaker 1: so that they have a different, different vectors in different
Speaker 1: ways of living. Anthests discusses how the bacteria in our
Speaker 1: houses they mostly come from us and from the other
Speaker 1: creatures that live with us, like dogs, and we'll get
Speaker 1: into more on that in a bit, but the fun
Speaker 1: guy are not as populous on and in our own bodies.
Speaker 1: They tend to come more from the environment outside. And
Speaker 1: what kind of fungi are found within a home is
Speaker 1: largely determined by where the home is regionally, in the
Speaker 1: climate around the home, what kind of fungi are prevalent
Speaker 1: in the exterior environment. But there are other factors that
Speaker 1: have an effect as well. And there's one that I
Speaker 1: found very interesting. It was what the house is made of,
Speaker 1: And she quotes from done saying it's kind of a
Speaker 1: three pigs thing. A stone house feeds different fungi from
Speaker 1: a woodhouse from a mud house, because unlike the bacteria,
Speaker 1: they're eating the house. So it's like, what have you
Speaker 1: put out on the buffet for them? Yeah, I mean again,
Speaker 1: it comes down to the fact that our home is
Speaker 1: not this um, this alien thing, you know, it is
Speaker 1: made out of the natural world, and therefore there are
Speaker 1: things that want to eat it. They eat those materials
Speaker 1: that made up your home. Uh So, yeah, it's it's
Speaker 1: easy to overlook that. But yeah, it makes perfect sense.
Speaker 1: So obviously, I'm sure some people despite our our warnings
Speaker 1: early on or like, okay, I'm just getting the bleach.
Speaker 1: I'm gonna sterilize my entire living space. Maybe now we
Speaker 1: should explain why that that might not be a good idea. Yeah,
Speaker 1: that that might be your inclination. And and really it
Speaker 1: kind of falls in line with what advertising has has
Speaker 1: been has been telling us for years, you know, the
Speaker 1: sort of world that we grew up in, where it's
Speaker 1: like we got to disinfect the house, you gotta keep
Speaker 1: the house clean, as if there is this absolute cleanliness,
Speaker 1: this nobiotic um aspect of our homes. But but this
Speaker 1: way of thinking is essentially treats our homes again like
Speaker 1: some sort of lifeless, nobiotic box, hermetically sealed from the outside,
Speaker 1: an impervious to occupation by anything but the presumably nobiotic
Speaker 1: creatures living inside it. But all of this, you know,
Speaker 1: nothing could be further from the truth, because nature of
Speaker 1: horrors of vacuum and your home will come to harbor
Speaker 1: a robust ecosystem. But our actions and our choices have
Speaker 1: an effect on that ecosystem, as we saw with the
Speaker 1: showerhead in the and the water heater or example above.
Speaker 1: You may keep certain things out, but that just means
Speaker 1: there's more room for other things to make themselves at home.
Speaker 1: All right, Well, we need to take a second break,
Speaker 1: but we will be right back with more than thank
Speaker 1: thank Alright, we're back. So raining anti microbial death down
Speaker 1: on your apartment or house is is also crazy, given that,
Speaker 1: as Done and Sebastian Tilt discussed in a two thousand
Speaker 1: nineteen study published in Nature Ecology and Evolution, only a
Speaker 1: relatively small proportion of the micro organisms in our environment
Speaker 1: actually cause disease. It's also worth noting that insects and
Speaker 1: other arthur pods, especially spiders that live in in the home,
Speaker 1: are important actors in the ecosystem, as they can exterminate mosquitoes, bedbugs, cockroaches,
Speaker 1: and house flies, all of which actually can transmit diseases.
Speaker 1: And it's not a universal thing around the world that
Speaker 1: people see a spider in their house and say, oh,
Speaker 1: we've got to kill that. Like some cultures are much
Speaker 1: more taller rent of spiders with the knowledge that they're
Speaker 1: performing this important cleaning service. Yeah, I personally like seeing
Speaker 1: the spider in the bathroom every day. You know it's
Speaker 1: it's a friend. You know that it's it's he or
Speaker 1: she is working to to to help make this bathroom
Speaker 1: a better environment. In that paper by Done and Tilt Uh,
Speaker 1: the authors agree that there there's simply no need to
Speaker 1: weigh devastating war against all of these organisms, but more
Speaker 1: to the point, a lot more work is needed to
Speaker 1: determine just what sorts of environments are more susceptible to
Speaker 1: the bad stuff. Another interesting wrinkle in all of this
Speaker 1: is that and and this is one Done discusses in
Speaker 1: his book, is exactly what household dogs reveal about the
Speaker 1: contrast between the exterior ecosystem and our interior worlds. Dogs
Speaker 1: are amazing at bringing you filth that I think about
Speaker 1: this with my dog every day. It's like every single
Speaker 1: day he's like, let me nourish your microbiome. Well, I
Speaker 1: think ultimately the way to look at it is the
Speaker 1: dog is not just bringing filth in. The dog is
Speaker 1: nurturing your filth. Like there's going to be filth if
Speaker 1: you wish to categorize the microbial world as filth. Uh,
Speaker 1: there's no escaping it. Um. So the dog is ultimately
Speaker 1: just bringing something to the equation. So for a lot
Speaker 1: of us, we tend to leave our our artificial interial world,
Speaker 1: you know again, hop into another one that happens to
Speaker 1: have wheels, travel, does to work, come back, etcetera. A
Speaker 1: lot of us do get out into the natural world,
Speaker 1: but there are plenty of us that don't do it
Speaker 1: on a regular basis. If you have pets, indoor only
Speaker 1: varieties contribute to the microbial stew that is your home.
Speaker 1: But there's no beating a dog for a bridge between
Speaker 1: inner and outer ecosystems. There's also no beating a dog
Speaker 1: just in general. I don't want to encourage anybody, but
Speaker 1: for starters, your dog is likely drawing you out into
Speaker 1: the outside environment. Uh, you know, you're gonna probably hopefully
Speaker 1: you're gonna take your dog on walks, You're gonna, you know,
Speaker 1: go out into the world with it. But at the
Speaker 1: very lead, that dog is going out to get all
Speaker 1: up in the natural world and then bring some of
Speaker 1: it back home. This, this has been your experience with
Speaker 1: his a dog owner. Correct. Now, Now, there's certainly harmful
Speaker 1: possibilities here, such as if your dog were to bring
Speaker 1: back fleas or ticks, and this has always been an
Speaker 1: issue with ancient Egyptian dog remains showing signs of brown
Speaker 1: dog ticks, which certainly do carry pathogens. But there's also
Speaker 1: a plethora of harmless effects and a seemingly beneficial um
Speaker 1: impact as well. Done points out that by looking at
Speaker 1: household microbes alone, first of all, one can tell if
Speaker 1: there's a dog in the house at all of the time.
Speaker 1: The dog just leaves a microbial footprint that's hard to
Speaker 1: mess But beyond this, it's hard to tell at this
Speaker 1: point what specific effects dogs and cats have on the
Speaker 1: inner and microbial environment, because there's a lot of complexity there.
Speaker 1: But Done says that we certainly see, especially in urban
Speaker 1: environments with dogs, that the children in those households are
Speaker 1: less prone to allergy and asthma. So the dogs might
Speaker 1: actually be a vehicle connecting the children to nature, and
Speaker 1: just the dirt on their paws, for instance, might be
Speaker 1: enough uh to essentially provide some sort of uh replacement
Speaker 1: for spending time in nature and in the natural microbial environment. Yeah.
Speaker 1: This is the connection to what used to be known
Speaker 1: as the hygiene hypothesis, though Anthesy notes that some researchers
Speaker 1: have pointed out that this name can be kind of
Speaker 1: misleading because the point of the hygiene hypothesis is not
Speaker 1: that you like, shouldn't wash your hands. Uh. It's more
Speaker 1: about having an exposure to a diverse array of microbiota
Speaker 1: early in life can, if this hypothesis is correct, help
Speaker 1: help strengthen your immune system in various ways and make
Speaker 1: you less prone to say, allergies and asthma and things
Speaker 1: like that. More recently, people have tried to to recoin
Speaker 1: this thing not as the hygiene hypothesis but as the
Speaker 1: old friends hypothesis, Like the the natural microbial world is
Speaker 1: an old friend that we should reacquaint ourselves with, and
Speaker 1: that it's good to get acquainted with early in life. Uh,
Speaker 1: not necessarily that you like shouldn't wash your hands or
Speaker 1: shouldn't wipe down the counter after you've been slicing chicken
Speaker 1: or something. Yeah, now this is primarily with dogs. With
Speaker 1: with cats, there seems to be far less of a connection. Uh.
Speaker 1: And also it's noted that in rural environments, uh, we
Speaker 1: see less evidence of this and the ideas that individuals
Speaker 1: in a rural environment are probably getting more exposure to
Speaker 1: to the outside of the natural world in general, so
Speaker 1: the dog isn't going to make that much of a difference.
Speaker 1: The dog is less of a tap of hot and
Speaker 1: cold running exterior microbes. And I think all of that
Speaker 1: helps to underline, you know, our desire and our inn indeed,
Speaker 1: our need to get out of the house and interact
Speaker 1: with nature on a regular basis. Uh. Dunn says that
Speaker 1: that one day we might be able to manage our
Speaker 1: interior microbiota in a way that will help ensure that
Speaker 1: we're healthy and uh and that you know, everything's in balance.
Speaker 1: But for now that's just not the case. We just
Speaker 1: we don't understand and enough of we haven't explored, uh,
Speaker 1: the the interior world enough to know exactly what we're
Speaker 1: dealing with. And again, like what kind of environments are
Speaker 1: are more prone to be occupied by the bad stuff
Speaker 1: versus the the the beneficial stuff, or the stuff that
Speaker 1: is just uh there and part of the world we
Speaker 1: live in. Though, I think it is clear that built
Speaker 1: environments do make a difference. Uh that we we don't
Speaker 1: fully understand exactly what all the causal relationships are yet,
Speaker 1: but there have definitely been measured differences that show, for example,
Speaker 1: where rooms are placed and what their relationships to other
Speaker 1: rooms where different things happen, uh, that that does affect
Speaker 1: what kinds of microbiota we find in those rooms. Just
Speaker 1: the example of having open windows that open to the
Speaker 1: outside world as opposed to having a room that's all
Speaker 1: closed off to the outside world and just ventilated by
Speaker 1: you know, HVAC systems. That makes a difference to what
Speaker 1: the microbiome of the room look like. Yeah, I mean,
Speaker 1: I mean even if the windows don't open. You know,
Speaker 1: we've looked at studies before, they've looked on the psychological
Speaker 1: impact of just being able to see the outside world,
Speaker 1: especially in hospital environment. Uh. And we do know a
Speaker 1: few other things too, Like one of the things that
Speaker 1: ant this mentions it seems to be a pretty straightforward
Speaker 1: finding is that one good way to encourage healthy ecosystems
Speaker 1: of microbes within the house is basically to keep the
Speaker 1: house dry. Moisture seems to activate a lot of unwanted
Speaker 1: fungal activity, but you can still have a lot of
Speaker 1: healthy microbes with the house that's that's relatively dry. Uh.
Speaker 1: You know that. She says that a lot of these
Speaker 1: experts who are looking at this do not recommend using
Speaker 1: anti microbial agents in the house, as you've been talking about.
Speaker 1: So there are a few things we know, but yeah,
Speaker 1: there's still a whole lot more to learn about the
Speaker 1: interactions between our our living space architecture and our home
Speaker 1: cleaning regimes and all that stuff with the microscopic invisible world. Yeah,
Speaker 1: and it's interesting. I mean, obviously it's gonna be more
Speaker 1: of a challenge and damper environments, say like, um, you know,
Speaker 1: a rainforest environment. But I guess there, I guess one
Speaker 1: is tempted to to ask the question, well, what are
Speaker 1: the traditional modes of housing? You know, what were the
Speaker 1: were the were the trial and error developments in housing
Speaker 1: there versus the um that the modern solutions that have
Speaker 1: been brought in from other environments without perhaps without really
Speaker 1: taking full account of the local conditions. Yeah, that's an
Speaker 1: interesting question. I haven't considered that. Yeah, I mean, I
Speaker 1: don't know. You walk around any given neighborhood, right and
Speaker 1: you you you see these trends and homes and occasionally
Speaker 1: you'll see a home that is that it's clearly out
Speaker 1: of place. But it makes you wonder, like, just how
Speaker 1: out of place is it? Is? The design like not
Speaker 1: suited for the you know, the energy consumption rates or
Speaker 1: the or or just the like the the level of
Speaker 1: the amount of sun you get in a given part
Speaker 1: of the world, that sort of thing. Uh, you know,
Speaker 1: I think one of the things we can take from
Speaker 1: this episode is that homes are are far more complicated.
Speaker 1: They're not just the the space we in which we live,
Speaker 1: you know, a container for our lives. Like they they're
Speaker 1: gonna shape who we are on a microbial level, on
Speaker 1: a symbolic level, Um, it's uh, you know, it's it's
Speaker 1: it's mind blowing stuff, definitely. And then sometimes you find yourself,
Speaker 1: you know, during a pandemic, spending a lot of time
Speaker 1: in your closet recording podcasts in your laundry room. Yeah,
Speaker 1: rooms that were never designed or intended for this kind
Speaker 1: of lengthy habitation. Luckily, my my closet here does have
Speaker 1: an air event in it um, which has been a lifesaver.
Speaker 1: I don't think my laundry room does around for it.
Speaker 1: I have I've had a few sweaty times in here. Well,
Speaker 1: it's this good news for when the winter sets in,
Speaker 1: right for both of us, because I think this is
Speaker 1: gonna be pretty cozy in here. And if you get
Speaker 1: cold in the laundry room, you can always just turn
Speaker 1: on the dryer. I'm really trying to get it's set
Speaker 1: up so that I can record from a different room.
Speaker 1: I'm trying to to make a different room in the
Speaker 1: house less echoy, so I can get good sound and
Speaker 1: not have to hunch over next to the washing machine.
Speaker 1: I am digging an earthen pit in my backyard, which
Speaker 1: I am told will have a really good uh sound installation.
Speaker 1: So we'll see how that goes. Mammoth Bones Studio. Yes,
Speaker 1: all right, Well, there you have it. Hopefully this provides
Speaker 1: some some food for thought. Again, we're not trying to
Speaker 1: encourage anybody to go on a any kind of a
Speaker 1: killing spree in their house concerning microbes or Arthur pods
Speaker 1: or anything like that. Uh, just we thought that as
Speaker 1: we're spending more time looking at our homes and thinking
Speaker 1: about getting out of nature, we should really look at
Speaker 1: what the in the relationship between those two environments actually is.
Speaker 1: In the meantime, if you like to check out other
Speaker 1: episodes of Stuff to Blow Your Mind, well you can
Speaker 1: find us wherever you get your podcast and wherever that
Speaker 1: happens to be. Just make sure you rate your you
Speaker 1: and subscribe and if you get in touch with us,
Speaker 1: I mean clearly we'd love to hear your thoughts on
Speaker 1: this episode. How do you relate to the content here?
Speaker 1: How does it change or back up your own thoughts
Speaker 1: and observations concerning your interior environment or the external world?
Speaker 1: Hughes thanks as always to our excellent audio producer Seth
Speaker 1: Nicholas Johnson. If you would like to get in touch
Speaker 1: with us with feedback on this episode or any other,
Speaker 1: to suggest a topic for the future, just to say hi,
Speaker 1: you can email us at contact at stuff to Blow
Speaker 1: your Mind dot com. Stuff to Blow Your Mind is
Speaker 1: production of I Heart Radio. For more podcasts for My
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