Speaker 1: Welcome to Stuff to Blow Your Mind production of My
Speaker 1: Heart Radio. Hey, 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 talking about an interesting and perhaps
Speaker 1: hidden property of plants. And to start us off, I
Speaker 1: wanted to read a selection from one of the lesser
Speaker 1: known works by the English romantic poet Percy Biss Shelley. Uh,
Speaker 1: this is a poem called the Sensitive Plant. Rob Am,
Speaker 1: I write that you've never heard of this one before. No,
Speaker 1: you know, obviously I've I've read a little bit of
Speaker 1: Shelley here and there, but this this must I'm assuming
Speaker 1: this is a deeper cut. It is. I think it
Speaker 1: was one of the final things he wrote before his death,
Speaker 1: So this would have been I think sometimes in the
Speaker 1: early eighteen twenties. Um, and it was published I believe
Speaker 1: as a standalone work at least at some point it was.
Speaker 1: I was reading through like a book version of it
Speaker 1: on that have been scanned into Google books, and every
Speaker 1: other page on it was like washed out on the scan.
Speaker 1: So so that was beautiful. But um, yeah, this one's
Speaker 1: kind of weird. It's it's not one of his best poems,
Speaker 1: but it has some really great lines in it, so
Speaker 1: I just wanted to read, uh, just a selection from it.
Speaker 1: It's too long to read in full, but this is
Speaker 1: an exerpt from the end of part one of The
Speaker 1: Sensitive Plant by Percy Miss Shelley. For the Sensitive Plant
Speaker 1: has no bright flower, radiance and odor or not its dour.
Speaker 1: It loves even like love. Its deep heart is full.
Speaker 1: It desires what it has not the beautiful, the light winds,
Speaker 1: which from unsustaining wings shed the music of many murmurings,
Speaker 1: the beams which dart from many a star of the flowers,
Speaker 1: whose hues they bear afar, the plumid insects, swift and free,
Speaker 1: like golden boats on a sunny sea, laden with light
Speaker 1: and odor, which pass over the gleam of the living grass,
Speaker 1: The unseen clouds of the dew, which lie like fire,
Speaker 1: and the flowers till the sun rides high, then wander
Speaker 1: like spirits among the spheres, each cloud faint with the
Speaker 1: fragrance it bears. The quivering vapors of dim noontide, which
Speaker 1: like a sea over the warm earth, glide in which
Speaker 1: every sound and odor and beam move as reads in
Speaker 1: a single stream. Each and all like ministering angels, were
Speaker 1: for the sensitive plant, sweet joy to bear, whilst the
Speaker 1: lagging hours of the day went by like windless clouds
Speaker 1: over a tender sky, And when evening descended from heaven above,
Speaker 1: and the earth was all rest, and the air was
Speaker 1: all love and delight, though less bright was far more deep,
Speaker 1: and the day's veil fell from the world of sleep,
Speaker 1: and the beasts and the birds and the insects were
Speaker 1: drowned in an ocean of dreams without a sound, whose
Speaker 1: waves never mark, though they ever impressed the light sand
Speaker 1: which paves it consciousness only overhead. The sweet Nightingale, ever,
Speaker 1: sang more sweet as the day might fail, and snatches
Speaker 1: of its elazy enchant were mixed with the dreams of
Speaker 1: the sensitive plant. Very nice. Yeah, so I don't think
Speaker 1: it's one of Percy's best poems. Like I was saying,
Speaker 1: the rhythm is a little too regular and sing songy.
Speaker 1: Sometimes some of the rhymes are a little obvious, you know,
Speaker 1: the rhyming love with above and all that. You could
Speaker 1: you could imagine like a an eighties rat bait thrown
Speaker 1: in the background some of those, or this could be
Speaker 1: a song like every rose has its thorn, you know,
Speaker 1: monster ballad. But but there are also lines that really
Speaker 1: love the dew which lies like fire, and the flowers
Speaker 1: and the nighttime as a as an ocean paved under
Speaker 1: with the sands of consciousness. But it's aesthetic qualities aside.
Speaker 1: I think it's really interesting that Percy is suggesting in
Speaker 1: his unorthodox and emotionally charged for you of the world,
Speaker 1: that this particular plant, the sensitive plant, which is a
Speaker 1: species of plant, may somehow have a kind of humanity
Speaker 1: of its own, like a soul or a mind, or
Speaker 1: as I believe he implies later in the poem, and afterlife.
Speaker 1: So you might wonder why would he say that about
Speaker 1: this species of plant, which he acknowledges is not a
Speaker 1: particularly beautiful flower. It's it's a mimosa, so it's got
Speaker 1: a little pink puffball kind of thing. Well, I think
Speaker 1: the answer is actually tied to some of the biological
Speaker 1: qualities of the sensitive plant as a species. So the
Speaker 1: sensitive plant is one of the many names of Mimosa pudica,
Speaker 1: pudica being Latin for chaste or modest, shamefaced or bashful.
Speaker 1: And this is a flowering plant in the family Fabasi,
Speaker 1: which is the pa or legume family, which means, yes,
Speaker 1: this plant is a cousin of the common being. So
Speaker 1: we are we are dealing in being can today, we're
Speaker 1: getting into into supernatural territory then, oh boy. Mimosa pudica
Speaker 1: is native to South and Central America and the Caribbean,
Speaker 1: though since transatlantic contact it has spread to all other
Speaker 1: parts of the world. I think it's pervasive throughout the tropics.
Speaker 1: And it's also known by by tons of different names.
Speaker 1: It's called the humble plant, the shame plant, that touch
Speaker 1: me not, and all of these names connect to the
Speaker 1: most striking feature of this species, which is that it
Speaker 1: is a plant that recoils when touched. And this is
Speaker 1: one of a handful of examples of rapid movement in
Speaker 1: the plant kingdom, movement on the time scale that we
Speaker 1: would normally associate only with animals. So, if you want
Speaker 1: to picture it, the sensitive plant is a spiny little
Speaker 1: shrub that grows up to about a foot off the ground.
Speaker 1: It has these pink flower puffs and small forking branches
Speaker 1: with compound leaves. So to picture the leaves of this plant,
Speaker 1: they are the ones that kind of like a feather,
Speaker 1: you know, with a stalk running up the middle, and
Speaker 1: then lots of tiny, little opinionle leaflets shooting out from
Speaker 1: that middle stalk, parallel to each other and perpendicular to
Speaker 1: the stalk like the teeth of a comb, or like
Speaker 1: the barbs of a feather. And to see the sensitive
Speaker 1: plant in action, all you need to do is touch
Speaker 1: a finger on one of these branches and suddenly what
Speaker 1: happens is the leaflets all fold inward like a closing suitcase.
Speaker 1: And then sometimes even the branch or the stalk that
Speaker 1: they're on will droop away from the stimulus, will droop down.
Speaker 1: From what I can tell, there is not yet a
Speaker 1: full consensus on the main function of the shrinking behavior
Speaker 1: in the wild, like why does it do that? But
Speaker 1: botanists have long suspected that it's some kind of defensive
Speaker 1: action by the plant to protect its leaves from grazing
Speaker 1: herbivores or insects. And this can actually work in multiple ways.
Speaker 1: So one of them is that maybe it works by
Speaker 1: physically moving the leaves away from a grazer. You know,
Speaker 1: something comes bides it's munching the leaves, and this causes
Speaker 1: the leaves to kind of pull away from the mouth
Speaker 1: or it could work by hiding the leaves so you know,
Speaker 1: it is disturbed something is around, it might be trying
Speaker 1: to eat the plant, and by closing up it makes
Speaker 1: it less obvious where the leaves are. Yeah, and I
Speaker 1: guess one can imagine this working within the context of,
Speaker 1: you know, of an enormous grazing animal that is eating
Speaker 1: a lot of plants and it's maybe not gonna stop
Speaker 1: to really get particular about this one, if this one
Speaker 1: has made itself uh smaller, you know, retreated into you know,
Speaker 1: amidst other plants, etcetera. Like, it's just gonna keep eating
Speaker 1: whatever is readily available to eat, Right, But I think
Speaker 1: there's also a focus on insects. Maybe insects are also
Speaker 1: the reason it does this, And it could also work
Speaker 1: maybe by startling a predator like an insect or grazing
Speaker 1: her before. Because of course plants don't usually move rapidly
Speaker 1: like animals do, so you know, if you're an insect
Speaker 1: or whatever that's grazing and then suddenly there is movement
Speaker 1: on the time scale of animal movement in your in
Speaker 1: your vicinity that might startle you and send you on
Speaker 1: the run. Yeah, on the time scale of animal movement.
Speaker 1: That's that's key because of course, the other main plant
Speaker 1: we think of in terms of this is the venus
Speaker 1: fly plant, which you know, well we'll come back to
Speaker 1: uh that you know, that is a plant that is
Speaker 1: acting aggressively on the timescale of of of animals um
Speaker 1: in an attempt to capture a set animal. But but
Speaker 1: here we see the reverse. Here we see something that
Speaker 1: is uh that is acting you know, defensively, that is
Speaker 1: moving away from us, that is not saying I want
Speaker 1: to touch you and envelop you, but I would rather
Speaker 1: not touch you at all. Yes, I would rather not.
Speaker 1: I would prefer not to. Yeah. Uh. So usually after
Speaker 1: a sensitive plant closes up its leaflets and droops away,
Speaker 1: it will reopen within some short time period, maybe only
Speaker 1: a few seconds, uh sometimes a few minutes, but it
Speaker 1: doesn't take long. It'll it'll open back up, get those
Speaker 1: leaves out there again, and and and start all over.
Speaker 1: And the sensitive plant also has a circadian rhythm to
Speaker 1: its closure, because it will close its leaves in the
Speaker 1: darkness and then reopen them in the daylight. Now, I
Speaker 1: found a wonderful post on j Store Daily by Rebecca
Speaker 1: Friedel about the history of mimosa putica, and also a
Speaker 1: similar Old World plant called Biophytem sensitivum, which is actually
Speaker 1: not a close relative of the sensitive plant, but does
Speaker 1: almost exactly the same thing with its leaves. So it
Speaker 1: looks like this would be a case of convergent evolution.
Speaker 1: But this article points to the work of a sixteenth
Speaker 1: century Portuguese naturalist living in India named Cristo baal Acosta,
Speaker 1: who authored a book in fifteen seventy eight called Tractado
Speaker 1: de las Drogas e Metaicinas de las Indias Orientales or
Speaker 1: treat Us on the Drugs and Medicines of the East
Speaker 1: and East Indies. I really wanted to find an English
Speaker 1: translation of this so I could quote it directly, because
Speaker 1: it sounds like it's a hoot, But I could not,
Speaker 1: so I'm gonna have to rely on a couple of
Speaker 1: secondhand summaries, including a Friedel's article here. But anyway, in
Speaker 1: this book by Christo ball Acosta in the sixteenth century,
Speaker 1: he describes a plant among the medicinal herbs of India
Speaker 1: called the Yerba della more or the herb the herb
Speaker 1: of love. Do you do you ever say herb with
Speaker 1: the H pronounced sometimes I'm afraid I'm gonna keep doing that. Yeah,
Speaker 1: sometimes it slips out. I don't know why. I try
Speaker 1: to fix this in my brain by like saying the
Speaker 1: name herb without the H pronounced so like I I go,
Speaker 1: I I said herb Herbert Hoover, Herbert Hoover. That that'll
Speaker 1: fix it. Well, yeah, I mean it's easy to fall
Speaker 1: into because herbivore, herbivoret. Anyway, why the herb of love?
Speaker 1: Why would it be called the herb of love? Well,
Speaker 1: Acosta says that, according to an Indian physician he talked to,
Speaker 1: the herb of Love was a potent seduction drug with
Speaker 1: a one percent success rate never fails. And after this passage,
Speaker 1: Acosta has an aside to assure readers of this medicinal
Speaker 1: catalog that he definitely never personally tried to use the
Speaker 1: sex herb, never, not once. Probably a good thing, considering
Speaker 1: that other more well known sex aerbs, if you will,
Speaker 1: are you know, essentially poisons right, But aside from the
Speaker 1: dubious allegations about cupids ero type powers, this plant, the
Speaker 1: herb of Love is remarkable for its ability to close
Speaker 1: its leaves rapidly, moving at the speed of an animal
Speaker 1: recoiling from a needle prick, and uh, I was looking
Speaker 1: at another source which mentions Acosta. This is by JF.
Speaker 1: Veld Camp called Notes on biophytem of the Old World,
Speaker 1: polished in tax On in ninety nine. I cite this
Speaker 1: just because veld Camp tells the story that Acosta claimed
Speaker 1: he knew of a philosopher in Malabar, so region along
Speaker 1: the southwest coast of India. A philosopher who lived in
Speaker 1: Malabar who was so tortured by the mystery of the
Speaker 1: of Love's rapid movement that he literally lost his mind
Speaker 1: trying to study it. He was like, how does it move?
Speaker 1: And and that was that was it for him. No
Speaker 1: word on whether that guy ever used it for cupid
Speaker 1: zero type purposes. Yeah. Because again, and this will be
Speaker 1: something that we'll just we'll discuss later as well. I mean,
Speaker 1: it's it's acting in a way that other plants do
Speaker 1: not act. It seems unnatural, right. I mean if I
Speaker 1: had never seen a rapidly moving plant before and I
Speaker 1: just like stumbled across one of these in the wild,
Speaker 1: saw it folding up like that, I would be freaked out.
Speaker 1: I don't know what to think of this. I mean,
Speaker 1: it's hard to imagine because I grew up with venus
Speaker 1: fly traps, you know, Like I remember when I was
Speaker 1: a kid, and uh, I would have like one of
Speaker 1: those really boring weekend days where my mom wanted to
Speaker 1: go to the plant nursery and get some plants around
Speaker 1: the house. And I think my consolation there was that
Speaker 1: a couple of times I got a little pott of
Speaker 1: venus fly trap. Yeah, they're they're pretty fun little plants.
Speaker 1: They always have a huge container off them out at
Speaker 1: the UH at the Botanical Garden in Atlanta for the
Speaker 1: kids to interact with an inevitably stick a little sticks
Speaker 1: into their into their their their mouths, if you will. Right, So,
Speaker 1: we we know about that one. But if you're previously
Speaker 1: unfamiliar with the plant like that, or or one of
Speaker 1: these leaf closing plants like Mimosa putica or biophytum uh,
Speaker 1: I imagine it would be shocking. Yeah. I mean we're
Speaker 1: hardwired really to to expect that sudden movement in the
Speaker 1: grass might be something dangerous. It might be a snake,
Speaker 1: for example, Like that's the first place my mind goes
Speaker 1: if I'm on a walk and there's some sort of
Speaker 1: rustling in the bushes. It might it might be a snake,
Speaker 1: or or it's something like you know, chipmunk or squirrel.
Speaker 1: Probably not a squirrel because they're a bit bolder. But
Speaker 1: but certainly the snake is never far from one's mind.
Speaker 1: Very true. So anyway, for several centuries there was confusion
Speaker 1: about how to taxonomize this plant that Christo Baul Acosta
Speaker 1: was talking about, the herb of love and free Dell
Speaker 1: points to an i've volume of the Botanical Register which says, hey,
Speaker 1: we know about this plant from South America called the
Speaker 1: Mimosa putica. It does that leaf shutting things. So maybe
Speaker 1: this herb of love that Acosta is talking about in
Speaker 1: India and the sixteenth century is actually the same plant.
Speaker 1: After all, it does seem that pretty quickly after transatlantic
Speaker 1: contact the mimosa spread all around the globe. But now
Speaker 1: that doesn't seem to be the case. Botanists are pretty
Speaker 1: clear that the herb of love was actually this other
Speaker 1: species I mentioned a minute ago, Biophytum sins ativum and
Speaker 1: freedl rights. This was funny quote. Perhaps the erotic claims
Speaker 1: Acosta made so enthralled some that they failed to turn
Speaker 1: the page to the next entry on Erba mimosa, a
Speaker 1: likely description of the actual mimosa putica. Do your homework, guys,
Speaker 1: come on. But anyway, I was thinking about this mechanism.
Speaker 1: So immediately when I see a plant with rapid movement
Speaker 1: like this, the leaf closing behavior, I wonder, how on
Speaker 1: earth does it do that? Because, of course we can
Speaker 1: move rapidly, but we can only do that because we
Speaker 1: have a nervous system and a muscular skeletal system muscles.
Speaker 1: Plants don't have either one. There are no muscles and
Speaker 1: a plant. So what mechanism could a plant used to
Speaker 1: contract on the order of seconds. Well, scientists have actually
Speaker 1: figured out the answer to this one. The types of
Speaker 1: movement on display in the sensitive plant and other rapid
Speaker 1: moving plants like the venus fly trap are known as
Speaker 1: seismo nastic movements, and these are an example of a
Speaker 1: bigger category of nastic movements, which can be defined by
Speaker 1: their difference from another type of plant movement called tropisms. Now,
Speaker 1: tropisms I think we've all seen in action. You know
Speaker 1: what this is if you've ever had house plants. A
Speaker 1: tropism is growth in a specific direction based on an
Speaker 1: external stimulus. So plants will grow toward a light source.
Speaker 1: In fact, right in front of me, right out. I
Speaker 1: have a potted plant here on my desk, and over time,
Speaker 1: it's leaves all start reaching out for the lamp next
Speaker 1: to it, until I turned the pot around, and then
Speaker 1: gradually they all start to hook back in the opposite direction.
Speaker 1: And uh, it just now struck me for the first time.
Speaker 1: That might sound kind of cruel, like I'm toying with it,
Speaker 1: but I really don't think the plant's feelings are hurt.
Speaker 1: Another example this would be trees seeing to grow around
Speaker 1: power lines. Sure. Yeah, So plants can grow in different directions,
Speaker 1: responding to objects or or stimuli in their environments. Nastic movements,
Speaker 1: in contrast to tropisms, are not oriented in the direction
Speaker 1: of a stimulus, but rather are fixed reflexes that are
Speaker 1: determined by the plant's anatomy. So, for example, a venus
Speaker 1: fly trap shows a nastic response. It doesn't go off
Speaker 1: in a particular direction to catch a fly, but rather
Speaker 1: when it since his movement in its trap area, the
Speaker 1: hinge clothses, so it has a predetermined, a directionally predetermined
Speaker 1: movement that is in keeping with the plant's anatomy, not
Speaker 1: in an adaptable direction, and the sensitive plant is another
Speaker 1: example of a nastic response. And I think it's interesting
Speaker 1: to note that the stimulus direction dependent movements of plants
Speaker 1: tend to be very slow, very very slow, and based
Speaker 1: on growth, while the few plants that are able to
Speaker 1: move rapidly in all cases that I'm aware of, certainly
Speaker 1: in most cases their movement is constrained to these directionally
Speaker 1: fixed reflexes. Now, of course, we animals have the best
Speaker 1: of both worlds, right. We can move rapidly and we
Speaker 1: have the flexibility to respond in whatever direction makes sense
Speaker 1: given the stimulus. But you know that's because we're different
Speaker 1: types of creatures, different anatomy, different energy requirements and so forth.
Speaker 1: But okay, that's now stick movements now seised monastic movements
Speaker 1: are nastic movements that are triggered by touch or by vibration.
Speaker 1: Now again, um, without muscles, how it all this work?
Speaker 1: How does the nastic movement actually happen? Well, here we
Speaker 1: come to a really excellent new word I learned. The
Speaker 1: word is turger spelled t u r g o r uh.
Speaker 1: It's a good like a leather diaper, Barbarian name. But
Speaker 1: it also it is a name for something that happens
Speaker 1: within plants. It's related to the word turgid or turgidity. Uh.
Speaker 1: And so within plants there is a principle called turger pressure.
Speaker 1: And one simple way to think about turger pressure is
Speaker 1: that it is like water pressure inside a plant. So
Speaker 1: you think about the difference between a wilted flower baking
Speaker 1: dry in the sun. You know it's parched, and you
Speaker 1: see it drooping over, and then you think about what
Speaker 1: that flower does after you water it. If things go well.
Speaker 1: Usually you give a wilted plant water and its leaves
Speaker 1: and stems stops sagging and they become rigid again. It
Speaker 1: stands straight up the you know, the it's it's almost
Speaker 1: like it's inflated like a balloon. Yeah, And in some
Speaker 1: plants it's it's it's amazing the difference just a quick
Speaker 1: watering can can have. Uh. We have a linen bomb, uh.
Speaker 1: And I always find that that one among our plants
Speaker 1: is the first to just immediately seem to give up
Speaker 1: the ghost and start wilting away. But then you know,
Speaker 1: you give it enough water and it's just back just
Speaker 1: you know, bushy and full of life as ever totally.
Speaker 1: In fact, you might have even observed this not with
Speaker 1: a live plants, but uh, giving some veggies in the
Speaker 1: kitchen a soak or even just a wash. This is
Speaker 1: a good trick for resurrecting what appeared to be wilted
Speaker 1: salad greens that are past their prime. You might think
Speaker 1: they're no good, you know, you gotta toss them. You
Speaker 1: would be surprised how salvageable some greens are after a
Speaker 1: soak in cold water. Really like like spinach, this verst
Speaker 1: of spinach. I don't know if I ever tried it
Speaker 1: on spinach, but I've tried it on other types of
Speaker 1: greens like you know, arugula and things like that that
Speaker 1: are uh, you know, they're starting not like if they're
Speaker 1: gonna slimy, you know, but if they're just like they're
Speaker 1: clearly they're getting desiccated and wilted. It looks like, oh,
Speaker 1: these are going to be no good, So come in
Speaker 1: some cold water. They might come back to life and
Speaker 1: be crisp again. I didn't know about this trick, but
Speaker 1: now I I will have to try this sometime. But anyway, so,
Speaker 1: turger pressure is when a plant's cells are swollen with
Speaker 1: water so that in the inside of the cells within
Speaker 1: the plasma membrane. Uh, the water pressure is actually pushing
Speaker 1: out against the cell wall, and so when turger pressure
Speaker 1: is high, the plant is said to be turgid. And
Speaker 1: so to come back to the sensitive plant, when the
Speaker 1: leaves are touched or disturbed and electrochemical chain reaction is
Speaker 1: set off, you know, that's sensed by cells in the leaves,
Speaker 1: and then it sets off this electrochemical chain reaction that
Speaker 1: eventually ends in water gushing out from so called motor
Speaker 1: cells at the base of the leaflets that were previously turgid.
Speaker 1: So the sudden loss of turger pressure the cells purging
Speaker 1: their water contents causes the leaflet to move, basically to collapse.
Speaker 1: That it's hinge, and this is known as turger movement.
Speaker 1: So in in in a strange way, you can think
Speaker 1: about it like the plant moving by causing itself to
Speaker 1: very selectively and rapidly wilt like a parched plant. Then
Speaker 1: over the course of the following minutes, turger pressure can
Speaker 1: be restored and the leaves go ridgid again and they
Speaker 1: go back to their extended state. But to come to
Speaker 1: the next thing, UH, even more astonishing than the plant's
Speaker 1: ability to behave physically in ways that seem more at
Speaker 1: home in animals with muscles. Is potential evidence that the
Speaker 1: Mimosa putica may also, in a qualified sense, behave mentally
Speaker 1: in ways that seem more at home in animals with brains. Specifically,
Speaker 1: there has been research arguing that this plant, an organism
Speaker 1: entirely without a brain or without a nervous system, actually
Speaker 1: has its own rudimentary form of memory. And uh, we'll
Speaker 1: talk about one of the studies allegedly showing this in
Speaker 1: a minute, But first I thought it might be good
Speaker 1: to spend a few minutes disentangling concepts about the alleged
Speaker 1: mental or cognitive properties of plants, because I think once
Speaker 1: you get into this area, you run a whole gamut
Speaker 1: of different types of claims of extremely variable evidential backing. Yeah,
Speaker 1: and you also get into into areas of confusion over
Speaker 1: like what constitutes uh, you know, animal intelligence and human
Speaker 1: intelligence and so so I thought it might be helpful
Speaker 1: to sort through some sort of general ideas regarding the
Speaker 1: nature of plants in Western thought fourth century b c. E.
Speaker 1: Thinker Aristotle, of course, casts along shadow, and he wrote
Speaker 1: that plants have a vegetative soul or to threapticon, which
Speaker 1: I believe just means the vegetable soul, not to be
Speaker 1: confused with two megathereon, which means the great beast in
Speaker 1: Greek and is of course a uh a Celtic frost
Speaker 1: album um. But I couldn't help but think of that
Speaker 1: when I was reading about twopon. Yeah, a lot of these. Well,
Speaker 1: so there were people in like the nineteenth century and
Speaker 1: stuff who were very interested in the sensitive plant, and
Speaker 1: I think a lot of them made references back to
Speaker 1: Aristotle and like, is this is what Aristotle was talking about?
Speaker 1: Plants have a soul, they can feel right. But but
Speaker 1: of course yes and no right, because they are two
Speaker 1: important things to keep in mind about all of it.
Speaker 1: First of all, he attributes nourishment and reproduction to the
Speaker 1: plant soul. And we have to remember that the Greek
Speaker 1: notion of a soul or suka is rather different than
Speaker 1: modern or even early Christian notions of a soul. We're
Speaker 1: not talking about like an inner ghost person that moves
Speaker 1: on and has an afterlife, that sort of thing. This
Speaker 1: would be more like the concept of a mind or
Speaker 1: like or would it be like the idea of an
Speaker 1: animating breath? There are a lot of different ideas of
Speaker 1: things that get translated into English as soul from the
Speaker 1: ancient world. Yeah. I was reading about this in an
Speaker 1: excellent paper that I will probably continue to refer to
Speaker 1: in this series by Michael Martyr from in Plant Signal
Speaker 1: Behavior titled Plant Intentionality and the Phenomenological Framework of Plant Intelligence,
Speaker 1: And in this he writes that the soul in this context,
Speaker 1: in Aristotle's context, is quote a set of active capacities
Speaker 1: of an organism, not an invisible entity connected to the divine. Okay,
Speaker 1: that makes sense. So the soul is sort of like
Speaker 1: the essence of the organism. It's like what the form
Speaker 1: of the organism apart from its physical body. Right. And
Speaker 1: while the vegetative soul here is defined by nourishment and reproduction,
Speaker 1: animals and humans additionally have capacities of sensation and rational
Speaker 1: thought added atop these baser soul characteristics. Now, I think
Speaker 1: an interesting division there is that, uh so it's attributing
Speaker 1: animals and humans with sensation and rational thought. I think
Speaker 1: a lot of people have made some what seemed to
Speaker 1: me to be pretty um spurious claims about evidence for
Speaker 1: rational thought in plants. But I would say it's completely
Speaker 1: uncontroversial that plants experience a form of sensation, they can
Speaker 1: gather information about their environment, and they do constantly. Yeah,
Speaker 1: but in Aristotle's hierarchy, you have basically have animals and
Speaker 1: then you have plants in the minerals. Uh. And there's
Speaker 1: also this added caveat that aspects of the vegetative soul
Speaker 1: continue on into forms that follow um, which which might
Speaker 1: not be all that helpful in what we're thinking about here,
Speaker 1: but perhaps bears mentioning. Now, aristotle shadow again is long,
Speaker 1: and we see his ideas carried on into medieval Europe.
Speaker 1: Thirteenth century CE thinker Thomas Aquinas wrote in Puma Theology
Speaker 1: that quote, the very fact that the acts of the
Speaker 1: vegetative soul do not obey reason shows that they rank lowest, lowest,
Speaker 1: lower than minerals. Or was he not lower than minerals?
Speaker 1: That I think it would say in reference to animals
Speaker 1: and of course humans. Now, one thing that that martyr
Speaker 1: points out is that while the aristotle view here, uh,
Speaker 1: you know, it kind of used plants as baser and
Speaker 1: that they're only carrying out nourishment and reproduction. But he
Speaker 1: writes that that's that's actually it's actually quite impressive within
Speaker 1: the modern context of certainly planned intelligence research, because these
Speaker 1: impulses nourishment and reproduction quote entail complex decisions related to
Speaker 1: the availability of resources. Now that's interesting because that could be,
Speaker 1: on one on one hand, very true, but also could
Speaker 1: easily be misinterpreted to to lead people to unjustified conclusions.
Speaker 1: And I want to get into a little more disentangling
Speaker 1: on concepts in a minute here, but yeah, flag that. Yes,
Speaker 1: Martyr also adds quote Additionally, plants express almost all known neurotransmitters,
Speaker 1: confirming the extension of two threpticon well beyond the activities
Speaker 1: Aristotle and his followers allotted to them. Hence, the lines
Speaker 1: of demarcation between the higher and the lower capacities, between
Speaker 1: consciousness and non consciousness, and by implication, between biological regna
Speaker 1: are not as rigid as classical thinkers believed, and there
Speaker 1: are a few other strains of more modern thought that
Speaker 1: Martyr shares. He points out that, according to late eighteenth
Speaker 1: and early nineteenth century German philosopher Hegel, plants are passive,
Speaker 1: they have negative selfhood, and they lack quote an organismic whole. Okay,
Speaker 1: I don't know what that means. But that's hegel yeah,
Speaker 1: not a not a plant fan. Nineteenth century English naturalist
Speaker 1: Charles Darwin, on the other hand, this I believe was
Speaker 1: like a later um thing that he wrote about. But
Speaker 1: he had the root brain hypothesis that held that the
Speaker 1: root apex of a plant served as a brain like
Speaker 1: oregon that was both sensitive and capable of navigating soil
Speaker 1: in search of resources. Now, I think it might be
Speaker 1: going a little overboard to call it brain like, but
Speaker 1: Charles Darwin was clearly enthralled by plants like the venus
Speaker 1: fly trapp Like he got really excited about what this means.
Speaker 1: And uh, maybe we can come back to Darwin in
Speaker 1: in in part two of this, because I think some
Speaker 1: of his ideas might connect more to to some of
Speaker 1: the research we're going to talk about later on. Yeah,
Speaker 1: it's my understanding. And uh, and I believe the author
Speaker 1: mentions this that some of these ideas that Charles Charles
Speaker 1: Darwin had regarding this root brain hypothesis, like they've people
Speaker 1: have come back to them, uh in modern plant intelligence
Speaker 1: research and and said, well, yeah, and then there's more
Speaker 1: to this than than people of of Darwin's day thought.
Speaker 1: Then there's also a nineteenth century German philosopher, Frederick Niici,
Speaker 1: who is very much I believe inspired by Darwin. In
Speaker 1: this wrote that a plant's nourishment and growth are expressions
Speaker 1: of its will to power, or the wills who mocked,
Speaker 1: which he identifies as the core driving force behind human beings.
Speaker 1: Oh my god, So this this plot, this potted plant
Speaker 1: in front of me, when it reaches for the lamp,
Speaker 1: and then I turn it around, I am thwarting its
Speaker 1: will to power. But I I am like the naysaying
Speaker 1: crowd that it must rebel against and and show its might. Yeah.
Speaker 1: And every day you don't kill it, you make it stronger,
Speaker 1: right now. Um. In Eastern thought, there of course strong
Speaker 1: traditions of all of this, as discussed in, among other
Speaker 1: many sources, uh In Richard Nesbits The Geography of Thought.
Speaker 1: China's Taoism and japan Japan's Shinto is Um both emphasize
Speaker 1: the spirits of animals, plants, natural objects, and artifacts. Uh
Speaker 1: And And for my part, I've been reading a little
Speaker 1: bit about this um earlier when I was looking for
Speaker 1: things to cover for Artifact and Monster Fact episodes. But um,
Speaker 1: you know, I don't want to steal any thunder from
Speaker 1: some possible potential episodes long or short form about these.
Speaker 1: But you know, we have strong folkloric, legendary and mythological
Speaker 1: um concepts of plant animal hybrids, which, of course, with
Speaker 1: all hybrids, they certainly perform various functions and symbolic um
Speaker 1: uh you know, metaphoric and per natural thought. But they
Speaker 1: also raised the question inevitably of animal nous and plants
Speaker 1: and plant nous in animals. You know, like you you
Speaker 1: can't think of something like say a screaming man dreak,
Speaker 1: or say the vegetable lamb of Targari. You know this
Speaker 1: this sheeplike thing that is growing out of the ground
Speaker 1: that is a plant but also seems like an animal,
Speaker 1: Like you can't. I don't think you can really have
Speaker 1: a concept like that without its sort of by blurring
Speaker 1: the lines, by invoking the hybrid, making you think about
Speaker 1: the characteristics of the opposite side that are present in
Speaker 1: this side. Yeah, yeah uh. In fact, I think several
Speaker 1: years back we did a an October episode called something
Speaker 1: like the Killer Tree that was legends of of trees
Speaker 1: that would eat people. It's a surprisingly common recurring motif,
Speaker 1: though apparently has no basis in in real biology. No,
Speaker 1: but I mean certainly not at the not not on
Speaker 1: the the animal time scale of things, but I guess
Speaker 1: on the plant time scale of things. Yeah, you can
Speaker 1: get into more nuanced discussions of plants eating people, plants
Speaker 1: eating human corpses and that sort of thing, right, but
Speaker 1: not not the active predation like in that Oh that
Speaker 1: is like a William Friedkin movie about the killer tree
Speaker 1: that gobbles people up. Oh my gosh, I don't remember
Speaker 1: this one. Okay, yeah, well we'll have to revisit. But there, Yeah,
Speaker 1: there are clearly a lot of killer trees. And I
Speaker 1: mean you have things like the ants, right, uh, trees
Speaker 1: walking around like humans. And yeah, all these concepts they
Speaker 1: they they're they're performing a number of different functions. But
Speaker 1: I think one of them is that it inevitably makes
Speaker 1: you think about about plants and animals, what do they
Speaker 1: have in common when and what ways do they differ in? Indeed, yeah,
Speaker 1: in what ways might they be more alike than we
Speaker 1: often realize. Another thing is that as we're going forward
Speaker 1: talking about research potentially indicating something like a plant basis
Speaker 1: for memory or learning, I think we also have to
Speaker 1: be very careful because the whole the realm of plant
Speaker 1: uh so called plant cognition research, I think, has a
Speaker 1: history that is filled with stuff that is not so great.
Speaker 1: Like there are a number of different concepts regarding the
Speaker 1: hidden complexity of plants that people seem to get confused
Speaker 1: with each other. And this is unfortunate because these topics
Speaker 1: range from what appears to me to be maybe controversial
Speaker 1: but at least potentially evidence backed biology, and that would
Speaker 1: be things like, you know, some of the memory research
Speaker 1: we're gonna talk about, all the way over to pure
Speaker 1: pseudoscience and paranormal stuff. And uh, just to give some
Speaker 1: quick flavor of the latter end of that spectrum, I'm
Speaker 1: reminded of something we talked about briefly in an episode
Speaker 1: that we did a long time ago. Rob, You remember
Speaker 1: when we did the Science of Stranger Things that New
Speaker 1: York Comic con. Yes, I do remember this. So it
Speaker 1: was in the context of that episode we were talking
Speaker 1: about government research into psychic and paranormal phenomena during the
Speaker 1: Cold War, which absolutely did happen, and the extent of
Speaker 1: it is hilarious. But I read a couple of whole
Speaker 1: books about this. One, uh, of course, one if you
Speaker 1: want a quick read that's very funny is The Men
Speaker 1: Who Stare It Goes by John Ronson. But also there
Speaker 1: was a book by Annie Jacobson that was a big, complete,
Speaker 1: sort of history of the Stanford Research Institute and all
Speaker 1: of these paranormal government research projects that were fueled by
Speaker 1: Cold War paranoia, but looked into that. They looked into
Speaker 1: things like remote viewing and UH and and UH telekinesis
Speaker 1: and stuff like that. And unfortunately, I think a lot
Speaker 1: of that was just was just tricks and poorly designed experiments.
Speaker 1: But but but one brief episode from this, one of
Speaker 1: the people we talked about in that episode was a
Speaker 1: CIA interrogation expert named Cleave Baxter, who specialized apparently in
Speaker 1: narcotic and hypnotism based interrogation techniques and then later in
Speaker 1: the polygraph And according to a New York Times article
Speaker 1: I was reading about Baxter by Josh Eels, Baxter developed
Speaker 1: a method for conducting polygraph sessions called the Baxter zone
Speaker 1: comparison technique, which, according to this article, is still used
Speaker 1: in polygraph test today. So cool. Anyway, later in his career,
Speaker 1: Baxter quite famously became obsessed with the idea that plants
Speaker 1: could read our minds, and he claimed to show it
Speaker 1: with experiments. So the discovery of this the story goes
Speaker 1: like this. One night in nineteen sixty six, Baxter stayed
Speaker 1: up all night. He was drinking coffee, and he got
Speaker 1: an amazing idea. He would hook a potted plant up
Speaker 1: to a polygraph machine. I guess I don't know if
Speaker 1: he was going to see if it was telling lies
Speaker 1: or maybe you just I don't know. Uh. So, allegedly
Speaker 1: this plant was a quote corn plant or dressina fragrance, which,
Speaker 1: in a confusing twist, is completely different for the plant
Speaker 1: z maze, which is the grain plant that produces maize
Speaker 1: or corn, the food. So this is called a corn plant,
Speaker 1: but it's not the corn that would be planted in
Speaker 1: a as a crop. The corn plant had been a
Speaker 1: gift from his secretary, intended to brighten up his office,
Speaker 1: which I have not seen pictures of. I don't know
Speaker 1: what was in there, but I'm imagining a kind of
Speaker 1: dungeon full of chairs with leather straps on them and
Speaker 1: needles full of quack truth serums. So, yeah, you can
Speaker 1: imagine some plants would be nice. Yeah, you want to
Speaker 1: get some corn down there? Uh, so from here, I
Speaker 1: just want to quote from the article by Eels summarizing this, uh,
Speaker 1: this this experiment quote. In human subjects, a polygraph measures
Speaker 1: three things pulse, respiration rate, and galvanic skin response otherwise
Speaker 1: known as perspiration. If you're worried about being caught in
Speaker 1: a lie, your levels will spike or dip. Baxter wanted
Speaker 1: to induce a similar anxiety in the plant, so he
Speaker 1: decided to set one of its leaves on fire. But
Speaker 1: before he could even get a match, the polygraph registered
Speaker 1: and intense reaction on the part of the Dressina. To Baxter,
Speaker 1: the implication was as indisputable as it was unbelievable. Not
Speaker 1: only had the plant demonstrated fear, it had also read
Speaker 1: his mind. Uh. So Baxter became convinced that plants had
Speaker 1: psychic powers, consisting of a sensibility that he called primary perception,
Speaker 1: which they could use to read our minds and emotions
Speaker 1: from afar. And upon this discovery, he did what any
Speaker 1: responsible seeker of the truth would do. He went straight
Speaker 1: to the popular media. Uh. And there was a book
Speaker 1: based on his claims, and apparently uh he did a
Speaker 1: TV spot, multiple TV spots. But I like Johnny Carson
Speaker 1: and stuff. But one of them I wanted to note was,
Speaker 1: apparently with Leonard Nimoy, was this in search of. I
Speaker 1: don't know if the time frames right for that. I
Speaker 1: don't know if the time frames right either, but anseling
Speaker 1: makes me think of in search of And unfortunately skeptical
Speaker 1: scientists were unable to reproduce his results. They tried to
Speaker 1: do the same thing and got nothing. But if you
Speaker 1: poke round about this on the internet, you will find
Speaker 1: many believers even today still overflowing with faith in Baxter's claims.
Speaker 1: It's one of those ideas that lots of people just
Speaker 1: seem to like. It feels really true and wholesome and
Speaker 1: good to believe. Yes, plants can think, they can feel,
Speaker 1: they can know what we're thinking if we tell them,
Speaker 1: or maybe even if we don't tell them, if we
Speaker 1: just think it really hard, they can detect it somehow.
Speaker 1: But obviously there are there are major problems if you're
Speaker 1: trying to put together a coherent, scientifically informed worldview. First
Speaker 1: of all, I would say the theoretical basis is weak.
Speaker 1: Like you know, we could always discover something new, but
Speaker 1: it is not clear that there's any kind of physical
Speaker 1: mechanism that could allow something like that. And then the
Speaker 1: second part is just the empirical basis, like the controlled
Speaker 1: experiments by skeptics don't find the same thing. So yeah,
Speaker 1: this appears to be nonsense. I can't help but wonder
Speaker 1: if okay, this experiment was sixty six. Uh, Frank Herbert's
Speaker 1: Dune was first published in sixty five, and of course
Speaker 1: has the you know, very early on in the novel
Speaker 1: has the scene where we have the Benegesta test of
Speaker 1: the box and the com jabbar the box, which of
Speaker 1: course makes you feel like your hand is burning and
Speaker 1: on fire. And here in this test behalf that part
Speaker 1: of the plant is actually caught on fire. Wow, that's interesting.
Speaker 1: Yeah uh yeah. And the box is supposedly a kind
Speaker 1: of polygraph of its own. Yeah yeah, yeah yeah. And
Speaker 1: of course you have the Benegestate yeah, you know, truthsayers
Speaker 1: and so forth. Though, I think in our episode on
Speaker 1: that did we both come to the conclusion that we
Speaker 1: think that the real power is the box actually does
Speaker 1: nothing and it's just all in. It's all the reverend
Speaker 1: mother like she's the real test. Yeah. I think it's
Speaker 1: ultimately unknown, but we did. I think we we both
Speaker 1: liked that idea the most. Yeah, it felt the most
Speaker 1: herbert E of the ideas. It's just a prop But anyway,
Speaker 1: So to come back to all this, so we're gonna
Speaker 1: be talking about plant memory research. But I think I
Speaker 1: want to be clear that if you say that a
Speaker 1: plant could have such a thing as a memory or
Speaker 1: an ability to learn, that is truly surprising and fascinating.
Speaker 1: But it is not the same thing as saying or
Speaker 1: showing that plants can quote think, that plants are conscious,
Speaker 1: that plants have emotions, or that they get upset when
Speaker 1: you say or do negative things around them, all of
Speaker 1: which are claims that people have tried to make over
Speaker 1: the years, but which seemed to me to be lacking
Speaker 1: an evidential basis, with with the possible exception of quote
Speaker 1: thinking under some very broad or inclusive definitions of what
Speaker 1: counts as thought. Yeah. Like another area related to this
Speaker 1: is the relationship doing plants and sound. So can plants
Speaker 1: respond to sound, Yes they can, But can do plants
Speaker 1: then benefit from listening to music? There's no evidence for that.
Speaker 1: But I mean, this was an idea that was very
Speaker 1: much in tho zeitgeist, especially in the UH That's where
Speaker 1: we there was actually a wonderful album that came out,
Speaker 1: an early electronic music album by Mort Garson, who is
Speaker 1: a you know, early synth wizard who did a lot
Speaker 1: of a number of different projects under different names, but
Speaker 1: he put out this uh. This album titled UH Mother
Speaker 1: Earth's plant Asia, and it is supposed to be music
Speaker 1: that you play for your house plants, and your house
Speaker 1: plants then benefit from it. Um. I don't think, you know,
Speaker 1: house plants actually get nothing out of listening to this album.
Speaker 1: But it's a wonderful ambient, experimental electronic album for for humans.
Speaker 1: I love this. I would say I'm all for playing
Speaker 1: music for your plants. I don't think it does anything
Speaker 1: for the plants, but playing music for your plants might
Speaker 1: do something nice for you. Yeah, yeah, just like the plant.
Speaker 1: The presence of the plants certainly can have a very
Speaker 1: pleasant effect on the human psyche, so can UH ambient music.
Speaker 1: So double up, have them both and benefit. But anyway,
Speaker 1: before we end part one of this series, I did
Speaker 1: want to look at at least one of the studies
Speaker 1: that claims to find evidence for what you might call
Speaker 1: memory learning or habituation in plants. And in the next episode,
Speaker 1: we'll come back and talk about some reaction, criticism, and
Speaker 1: follow up of these types of ideas. So this is
Speaker 1: not without its accompanying controversy, but I thought it would
Speaker 1: be at least worthwhile to look at, like, what what
Speaker 1: the evidential claims of the recent research are. So earlier
Speaker 1: we mentioned that scientists are actually not sure why Mimosa
Speaker 1: putica closes its leaves, though it is generally believed to
Speaker 1: be some kind of defensive reaction to prevent the leaves
Speaker 1: from being eaten by grazing herbivores or insects. So if
Speaker 1: that's the case, you might wonder, well, why don't the
Speaker 1: plants just keep their leaves folded up all the time?
Speaker 1: Would then they'd be protected always? Why do they have
Speaker 1: to do it rapidly suddenly? Uh? Well, because if they
Speaker 1: were to keep their leaves closed all the time, the
Speaker 1: plant would be drastically reducing its ability to collect unlight
Speaker 1: and feed through photosynthesis. And this is the classic risk
Speaker 1: reward paradigm that we know well with all kinds of animals.
Speaker 1: You have a small prey animal that might be much
Speaker 1: safer if it stays and it's cozy little burrow all day.
Speaker 1: But if it never leaves, it foregoes opportunities to get food.
Speaker 1: It needs to go out to do the things that
Speaker 1: it must do to sustain its life cycle and reproduce.
Speaker 1: So it's got to find food, it's got to find mates.
Speaker 1: And you know you're not going to get that just
Speaker 1: sitting in your hole. And you could say the same
Speaker 1: is true for this plant. So the evolutionary logic that
Speaker 1: drives the folding behavior of the leaves and the sensitive
Speaker 1: plant will reward the folding in scenarios where it actually
Speaker 1: protects the leaf from predation, but it will punish unnecessary folding,
Speaker 1: which wastes precious opportunities to harvest the sunlight. And we've
Speaker 1: already seen a couple of demonstrations of this balance. One
Speaker 1: is that the leaves tend to fold at night time
Speaker 1: when there's no point in being exposed because there's no
Speaker 1: sunlight to absorb. And another is that once the leaves
Speaker 1: close in response to a seismic stimulus, they reopen again,
Speaker 1: usually within a few minutes. They're ready to get back
Speaker 1: to the buffet. But to continue the logic of this
Speaker 1: risk reward balance, it would also obviously benefit the plant
Speaker 1: if it had a mechanism for discriminating between a potentially
Speaker 1: dangerous seismic stimulus and a harmless one. And you can
Speaker 1: imagine scenarios in the wild where plants are repeatedly shaken
Speaker 1: in some way or subjected to physical contact with objects
Speaker 1: in the environment, maybe by wind or something uh in
Speaker 1: a way that is not actually a threat to the plant.
Speaker 1: Were closing the leaflets every time that happened would be
Speaker 1: pointless and harmful to survival. So do these plants have
Speaker 1: a mechanism that allows them to discriminate like that? And
Speaker 1: according to this following study, it looks like maybe they do. So.
Speaker 1: This was a study published in Ecologia in by Monica Gagliano,
Speaker 1: Michael Renton, Martial dip Chinsky, and stuff Fauno Mancuso called
Speaker 1: experience teaches plants to learn faster and forget slower in
Speaker 1: environments where it matters. So the authors write in their
Speaker 1: abstract quote, the nervous system of animals serves the acquisition, memorization,
Speaker 1: and recollection of information. Like animals, plants also acquire a
Speaker 1: huge amount of information from their environment, Yet their capacity
Speaker 1: to memorize and organized learned behavioral responses has not been
Speaker 1: demonstrated in Mimosa putica, the sensitive plant. The defensive leaf
Speaker 1: folding behavior in response to repeated physical disturbance exhibits clear habituation,
Speaker 1: suggesting some elementary form of learning. So how do they
Speaker 1: actually demonstrate this, Well, they did a series of experiments,
Speaker 1: but one of their models is they took potted specimens
Speaker 1: of Mimosa putica and they mounted them on this contraption
Speaker 1: that would repeatedly drop the potted plant a distance of
Speaker 1: fifteen centimeters onto a padded surface, and the drops were
Speaker 1: organized into repeated sessions of multiple exposures. And sure enough,
Speaker 1: the plants, after they were repeatedly exposed to the same
Speaker 1: fifteen centimeter drop, started reopening their leaves more quickly and
Speaker 1: eventually started ignoring the stimulus more or less entirely, just
Speaker 1: keeping their leaves open during a drop. And that's really interesting.
Speaker 1: It might seem to indicate that the plant is becoming
Speaker 1: habituated to this particular thing. It's like, Okay, being dropped
Speaker 1: fifteen centimeters is just something that happens. Now, This is
Speaker 1: just how things are. I know what it feels like.
Speaker 1: It doesn't hurt me. I'm over it. By the way
Speaker 1: that I guess I am anthropomorphizing there, so I don't
Speaker 1: mean to imply that it is actually reasoning out in
Speaker 1: in uh semantic logic like that. But that's to give
Speaker 1: you the idea that it's somehow becoming habituated to something
Speaker 1: that's happening over and over again without hurting it, and
Speaker 1: it's just learning to ignore that thing. Now, there's an
Speaker 1: obvious other explanation if this was all they discovered. What
Speaker 1: if this was just the plant's leaf closing mechanism getting
Speaker 1: worn out over time, It's just becoming exhausted and running
Speaker 1: out of the juice that it needs to use to
Speaker 1: close its leaves. Well, the researchers they thought about this,
Speaker 1: and they controlled for this by introducing a new novel
Speaker 1: stimulus after the plant became habituated. This was the shake,
Speaker 1: so different from the drop, but it would also stimulate
Speaker 1: the seismonastic closure of the leaflets to shake the potted plant.
Speaker 1: And they found that even when a plant had become
Speaker 1: desensitized to the drop, apparently through habituation, it would still
Speaker 1: close its leaves just like normal when given a shake.
Speaker 1: So this would seem to help rule out the idea
Speaker 1: that it's just the plant's leaf closure mechanisms becoming exhausted
Speaker 1: by repeated use. Now, there are some more interesting details
Speaker 1: from this and this one that we might get into
Speaker 1: in the in the next part of this series. For example,
Speaker 1: they found that apparently this uh, this habituation to the
Speaker 1: fifteen centimeter drop was still present weeks later after the
Speaker 1: initial sessions, and that it was variable and adaptable depending
Speaker 1: on the hostility of the conditions, like the light conditions
Speaker 1: in which it was happening. But maybe if we get
Speaker 1: into those, we can do that in part two, because
Speaker 1: I think we need to wrap up part one for now,
Speaker 1: but I'm so excited all the things we get to
Speaker 1: talk about when we come come back next time. More
Speaker 1: research on plants and memory. Uh. If plants do in
Speaker 1: fact possess some rudimentary form of memory and learning, how
Speaker 1: what is the physical basis of that, given of course
Speaker 1: that they don't have brains, uh? And what would that
Speaker 1: mean for our understanding of what intelligence and its subdivided
Speaker 1: parts are. Yeah? Yeah, this should continue to be a
Speaker 1: fun exploration. And this is this is an exploration that
Speaker 1: we've we've been talking about doing for years and I
Speaker 1: know we've had some listeners, right in requesting that we
Speaker 1: cover this topic. So it's great to finally be able
Speaker 1: to dive in. All right, so we're gonna go and
Speaker 1: close it out, but we'll be back next time with
Speaker 1: more on on this topic. Uh. In the meantime, if
Speaker 1: you want to check out other episodes of Stuff to
Speaker 1: Blow Your Mind, our core episodes come out on Tuesdays
Speaker 1: and Thursdays, we have a rerun that comes out of
Speaker 1: fault episode. On the weekend, we do listener mail on Monday,
Speaker 1: we do a short form artifactor Monster Fact on Wednesday,
Speaker 1: and on Friday we set aside most serious matters and
Speaker 1: just discuss a weird film on Weird House Cinema. Huge
Speaker 1: thanks as always to UH well, actually to our regular
Speaker 1: producer Seth Nicholas Johnson, and thanks to our guest producer
Speaker 1: today Paul decand uh Paul really appreciate you seven in
Speaker 1: for us today. If you would like to get in
Speaker 1: touch with us with feedback on this episode or any other,
Speaker 1: to suggest a topic for the future, or just to
Speaker 1: say hello, you can email us at contact at stuff
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