Plant Memories, Part 1

I write that you've never heard of this one before. No, you know, obviously I've I've read a little bit of Shelley here and there, but this this must I'm assuming this is a deeper cut. It is. I think it was one of the final things he wrote before his death, So this would have been I think sometimes in the early eighteen twenties. Um, and it was published I believe as a standalone work at least at some point it was.

I was reading through like a book version of it on that have been scanned into Google books, and every other page on it was like washed out on the scan. So so that was beautiful. But um, yeah, this one's kind of weird. It's it's not one of his best poems, but it has some really great lines in it, so I just wanted to read, uh, just a selection from it. It's too long to read in full, but this is an exerpt from the end of part one of The

Sensitive Plant by Percy Miss Shelley. For the Sensitive Plant has no bright flower, radiance and odor or not its dour. It loves even like love. Its deep heart is full.

It desires what it has not the beautiful, the light winds, which from unsustaining wings shed the music of many murmurings, the beams which dart from many a star of the flowers, whose hues they bear afar, the plumid insects, swift and free, like golden boats on a sunny sea, laden with light and odor, which pass over the gleam of the living grass, The unseen clouds of the dew, which lie like fire, and the flowers till the sun rides high, then wander

like spirits among the spheres, each cloud faint with the fragrance it bears. The quivering vapors of dim noontide, which like a sea over the warm earth, glide in which every sound and odor and beam move as reads in

a single stream. Each and all like ministering angels, were for the sensitive plant, sweet joy to bear, whilst the lagging hours of the day went by like windless clouds over a tender sky, And when evening descended from heaven above, and the earth was all rest, and the air was all love and delight, though less bright was far more deep, and the day's veil fell from the world of sleep, and the beasts and the birds and the insects were drowned in an ocean of dreams without a sound, whose

waves never mark, though they ever impressed the light sand which paves it consciousness only overhead. The sweet Nightingale, ever, sang more sweet as the day might fail, and snatches of its elazy enchant were mixed with the dreams of the sensitive plant. Very nice. Yeah, so I don't think it's one of Percy's best poems. Like I was saying, the rhythm is a little too regular and sing songy. Sometimes some of the rhymes are a little obvious, you know,

the rhyming love with above and all that. You could you could imagine like a an eighties rat bait thrown in the background some of those, or this could be a song like every rose has its thorn, you know, monster ballad. But but there are also lines that really love the dew which lies like fire, and the flowers and the nighttime as a as an ocean paved under with the sands of consciousness. But it's aesthetic qualities aside.

I think it's really interesting that Percy is suggesting in his unorthodox and emotionally charged for you of the world, that this particular plant, the sensitive plant, which is a species of plant, may somehow have a kind of humanity of its own, like a soul or a mind, or as I believe he implies later in the poem, and afterlife. So you might wonder why would he say that about this species of plant, which he acknowledges is not a particularly beautiful flower. It's it's a mimosa, so it's got

a little pink puffball kind of thing. Well, I think the answer is actually tied to some of the biological qualities of the sensitive plant as a species. So the sensitive plant is one of the many names of Mimosa pudica, pudica being Latin for chaste or modest, shamefaced or bashful. And this is a flowering plant in the family Fabasi, which is the pa or legume family, which means, yes, this plant is a cousin of the common being. So we are we are dealing in being can today, we're

getting into into supernatural territory then, oh boy. Mimosa pudica is native to South and Central America and the Caribbean, though since transatlantic contact it has spread to all other parts of the world. I think it's pervasive throughout the tropics. And it's also known by by tons of different names. It's called the humble plant, the shame plant, that touch me not, and all of these names connect to the most striking feature of this species, which is that it

is a plant that recoils when touched. And this is one of a handful of examples of rapid movement in the plant kingdom, movement on the time scale that we would normally associate only with animals. So, if you want to picture it, the sensitive plant is a spiny little shrub that grows up to about a foot off the ground. It has these pink flower puffs and small forking branches

with compound leaves. So to picture the leaves of this plant, they are the ones that kind of like a feather, you know, with a stalk running up the middle, and then lots of tiny, little opinionle leaflets shooting out from that middle stalk, parallel to each other and perpendicular to the stalk like the teeth of a comb, or like

the barbs of a feather. And to see the sensitive plant in action, all you need to do is touch a finger on one of these branches and suddenly what happens is the leaflets all fold inward like a closing suitcase. And then sometimes even the branch or the stalk that they're on will droop away from the stimulus, will droop down. From what I can tell, there is not yet a full consensus on the main function of the shrinking behavior

in the wild, like why does it do that? But botanists have long suspected that it's some kind of defensive action by the plant to protect its leaves from grazing herbivores or insects. And this can actually work in multiple ways. So one of them is that maybe it works by

physically moving the leaves away from a grazer. You know, something comes bides it's munching the leaves, and this causes the leaves to kind of pull away from the mouth or it could work by hiding the leaves so you know, it is disturbed something is around, it might be trying to eat the plant, and by closing up it makes

it less obvious where the leaves are. Yeah, and I guess one can imagine this working within the context of, you know, of an enormous grazing animal that is eating a lot of plants and it's maybe not gonna stop to really get particular about this one, if this one has made itself uh smaller, you know, retreated into you know, amidst other plants, etcetera. Like, it's just gonna keep eating whatever is readily available to eat, Right, But I think

there's also a focus on insects. Maybe insects are also the reason it does this, And it could also work maybe by startling a predator like an insect or grazing her before. Because of course plants don't usually move rapidly like animals do, so you know, if you're an insect or whatever that's grazing and then suddenly there is movement on the time scale of animal movement in your in your vicinity that might startle you and send you on the run. Yeah, on the time scale of animal movement.

That's that's key because of course, the other main plant we think of in terms of this is the venus fly plant, which you know, well we'll come back to uh that you know, that is a plant that is acting aggressively on the timescale of of of animals um in an attempt to capture a set animal. But but here we see the reverse. Here we see something that is uh that is acting you know, defensively, that is moving away from us, that is not saying I want to touch you and envelop you, but I would rather

not touch you at all. Yes, I would rather not. I would prefer not to. Yeah. Uh. So usually after a sensitive plant closes up its leaflets and droops away, it will reopen within some short time period, maybe only a few seconds, uh sometimes a few minutes, but it doesn't take long. It'll it'll open back up, get those leaves out there again, and and and start all over. And the sensitive plant also has a circadian rhythm to its closure, because it will close its leaves in the

darkness and then reopen them in the daylight. Now, I found a wonderful post on j Store Daily by Rebecca Friedel about the history of mimosa putica, and also a similar Old World plant called Biophytem sensitivum, which is actually not a close relative of the sensitive plant, but does almost exactly the same thing with its leaves. So it looks like this would be a case of convergent evolution.

But this article points to the work of a sixteenth century Portuguese naturalist living in India named Cristo baal Acosta, who authored a book in fifteen seventy eight called Tractado de las Drogas e Metaicinas de las Indias Orientales or treat Us on the Drugs and Medicines of the East and East Indies. I really wanted to find an English translation of this so I could quote it directly, because it sounds like it's a hoot, But I could not, so I'm gonna have to rely on a couple of

secondhand summaries, including a Friedel's article here. But anyway, in this book by Christo ball Acosta in the sixteenth century, he describes a plant among the medicinal herbs of India called the Yerba della more or the herb the herb of love. Do you do you ever say herb with the H pronounced sometimes I'm afraid I'm gonna keep doing that. Yeah, sometimes it slips out. I don't know why. I try to fix this in my brain by like saying the name herb without the H pronounced so like I I go,

I I said herb Herbert Hoover, Herbert Hoover. That that'll fix it. Well, yeah, I mean it's easy to fall into because herbivore, herbivoret. Anyway, why the herb of love? Why would it be called the herb of love? Well, Acosta says that, according to an Indian physician he talked to, the herb of Love was a potent seduction drug with

a one percent success rate never fails. And after this passage, Acosta has an aside to assure readers of this medicinal catalog that he definitely never personally tried to use the

sex herb, never, not once. Probably a good thing, considering that other more well known sex aerbs, if you will, are you know, essentially poisons right, But aside from the dubious allegations about cupids ero type powers, this plant, the herb of Love is remarkable for its ability to close its leaves rapidly, moving at the speed of an animal recoiling from a needle prick, and uh, I was looking at another source which mentions Acosta. This is by JF.

Veld Camp called Notes on biophytem of the Old World, polished in tax On in ninety nine. I cite this just because veld Camp tells the story that Acosta claimed he knew of a philosopher in Malabar, so region along the southwest coast of India. A philosopher who lived in Malabar who was so tortured by the mystery of the of Love's rapid movement that he literally lost his mind trying to study it. He was like, how does it move?

And and that was that was it for him. No word on whether that guy ever used it for cupid zero type purposes. Yeah. Because again, and this will be something that we'll just we'll discuss later as well. I mean, it's it's acting in a way that other plants do not act. It seems unnatural, right. I mean if I had never seen a rapidly moving plant before and I just like stumbled across one of these in the wild, saw it folding up like that, I would be freaked out.

I don't know what to think of this. I mean, it's hard to imagine because I grew up with venus fly traps, you know, Like I remember when I was a kid, and uh, I would have like one of those really boring weekend days where my mom wanted to go to the plant nursery and get some plants around the house. And I think my consolation there was that a couple of times I got a little pott of venus fly trap. Yeah, they're they're pretty fun little plants.

They always have a huge container off them out at the UH at the Botanical Garden in Atlanta for the kids to interact with an inevitably stick a little sticks into their into their their their mouths, if you will. Right, So, we we know about that one. But if you're previously unfamiliar with the plant like that, or or one of these leaf closing plants like Mimosa putica or biophytum uh, I imagine it would be shocking. Yeah. I mean we're hardwired really to to expect that sudden movement in the

grass might be something dangerous. It might be a snake, for example, Like that's the first place my mind goes if I'm on a walk and there's some sort of rustling in the bushes. It might it might be a snake, or or it's something like you know, chipmunk or squirrel. Probably not a squirrel because they're a bit bolder. But but certainly the snake is never far from one's mind.

Very true. So anyway, for several centuries there was confusion about how to taxonomize this plant that Christo Baul Acosta was talking about, the herb of love and free Dell points to an i've volume of the Botanical Register which says, hey, we know about this plant from South America called the Mimosa putica. It does that leaf shutting things. So maybe this herb of love that Acosta is talking about in India and the sixteenth century is actually the same plant.

After all, it does seem that pretty quickly after transatlantic contact the mimosa spread all around the globe. But now that doesn't seem to be the case. Botanists are pretty clear that the herb of love was actually this other species I mentioned a minute ago, Biophytum sins ativum and freedl rights. This was funny quote. Perhaps the erotic claims Acosta made so enthralled some that they failed to turn the page to the next entry on Erba mimosa, a

likely description of the actual mimosa putica. Do your homework, guys, come on. But anyway, I was thinking about this mechanism. So immediately when I see a plant with rapid movement like this, the leaf closing behavior, I wonder, how on earth does it do that? Because, of course we can move rapidly, but we can only do that because we have a nervous system and a muscular skeletal system muscles. Plants don't have either one. There are no muscles and

a plant. So what mechanism could a plant used to contract on the order of seconds. Well, scientists have actually figured out the answer to this one. The types of movement on display in the sensitive plant and other rapid moving plants like the venus fly trap are known as seismo nastic movements, and these are an example of a bigger category of nastic movements, which can be defined by their difference from another type of plant movement called tropisms. Now,

tropisms I think we've all seen in action. You know what this is if you've ever had house plants. A tropism is growth in a specific direction based on an external stimulus. So plants will grow toward a light source. In fact, right in front of me, right out. I have a potted plant here on my desk, and over time, it's leaves all start reaching out for the lamp next to it, until I turned the pot around, and then gradually they all start to hook back in the opposite direction.

And uh, it just now struck me for the first time. That might sound kind of cruel, like I'm toying with it, but I really don't think the plant's feelings are hurt. Another example this would be trees seeing to grow around power lines. Sure. Yeah, So plants can grow in different directions, responding to objects or or stimuli in their environments. Nastic movements, in contrast to tropisms, are not oriented in the direction of a stimulus, but rather are fixed reflexes that are

determined by the plant's anatomy. So, for example, a venus fly trap shows a nastic response. It doesn't go off in a particular direction to catch a fly, but rather when it since his movement in its trap area, the hinge clothses, so it has a predetermined, a directionally predetermined movement that is in keeping with the plant's anatomy, not in an adaptable direction, and the sensitive plant is another

example of a nastic response. And I think it's interesting to note that the stimulus direction dependent movements of plants tend to be very slow, very very slow, and based on growth, while the few plants that are able to move rapidly in all cases that I'm aware of, certainly in most cases their movement is constrained to these directionally fixed reflexes. Now, of course, we animals have the best

of both worlds, right. We can move rapidly and we have the flexibility to respond in whatever direction makes sense given the stimulus. But you know that's because we're different types of creatures, different anatomy, different energy requirements and so forth. But okay, that's now stick movements now seised monastic movements are nastic movements that are triggered by touch or by vibration. Now again, um, without muscles, how it all this work?

How does the nastic movement actually happen? Well, here we come to a really excellent new word I learned. The word is turger spelled t u r g o r uh. It's a good like a leather diaper, Barbarian name. But it also it is a name for something that happens within plants. It's related to the word turgid or turgidity. Uh. And so within plants there is a principle called turger pressure. And one simple way to think about turger pressure is

that it is like water pressure inside a plant. So you think about the difference between a wilted flower baking dry in the sun. You know it's parched, and you see it drooping over, and then you think about what that flower does after you water it. If things go well. Usually you give a wilted plant water and its leaves and stems stops sagging and they become rigid again. It stands straight up the you know, the it's it's almost

like it's inflated like a balloon. Yeah, And in some plants it's it's it's amazing the difference just a quick watering can can have. Uh. We have a linen bomb, uh. And I always find that that one among our plants is the first to just immediately seem to give up the ghost and start wilting away. But then you know, you give it enough water and it's just back just you know, bushy and full of life as ever totally.

In fact, you might have even observed this not with a live plants, but uh, giving some veggies in the kitchen a soak or even just a wash. This is a good trick for resurrecting what appeared to be wilted salad greens that are past their prime. You might think they're no good, you know, you gotta toss them. You would be surprised how salvageable some greens are after a soak in cold water. Really like like spinach, this verst

of spinach. I don't know if I ever tried it on spinach, but I've tried it on other types of greens like you know, arugula and things like that that are uh, you know, they're starting not like if they're gonna slimy, you know, but if they're just like they're clearly they're getting desiccated and wilted. It looks like, oh, these are going to be no good, So come in some cold water. They might come back to life and be crisp again. I didn't know about this trick, but

now I I will have to try this sometime. But anyway, so, turger pressure is when a plant's cells are swollen with water so that in the inside of the cells within the plasma membrane. Uh, the water pressure is actually pushing out against the cell wall, and so when turger pressure

is high, the plant is said to be turgid. And so to come back to the sensitive plant, when the leaves are touched or disturbed and electrochemical chain reaction is set off, you know, that's sensed by cells in the leaves, and then it sets off this electrochemical chain reaction that eventually ends in water gushing out from so called motor cells at the base of the leaflets that were previously turgid.

So the sudden loss of turger pressure the cells purging their water contents causes the leaflet to move, basically to collapse. That it's hinge, and this is known as turger movement. So in in in a strange way, you can think about it like the plant moving by causing itself to very selectively and rapidly wilt like a parched plant. Then over the course of the following minutes, turger pressure can be restored and the leaves go ridgid again and they

go back to their extended state. But to come to the next thing, UH, even more astonishing than the plant's ability to behave physically in ways that seem more at home in animals with muscles. Is potential evidence that the Mimosa putica may also, in a qualified sense, behave mentally in ways that seem more at home in animals with brains. Specifically, there has been research arguing that this plant, an organism entirely without a brain or without a nervous system, actually

has its own rudimentary form of memory. And uh, we'll talk about one of the studies allegedly showing this in a minute, But first I thought it might be good to spend a few minutes disentangling concepts about the alleged mental or cognitive properties of plants, because I think once you get into this area, you run a whole gamut

of different types of claims of extremely variable evidential backing. Yeah, and you also get into into areas of confusion over like what constitutes uh, you know, animal intelligence and human intelligence and so so I thought it might be helpful to sort through some sort of general ideas regarding the nature of plants in Western thought fourth century b c. E. Thinker Aristotle, of course, casts along shadow, and he wrote that plants have a vegetative soul or to threapticon, which

I believe just means the vegetable soul, not to be confused with two megathereon, which means the great beast in Greek and is of course a uh a Celtic frost album um. But I couldn't help but think of that when I was reading about twopon. Yeah, a lot of these. Well, so there were people in like the nineteenth century and stuff who were very interested in the sensitive plant, and I think a lot of them made references back to Aristotle and like, is this is what Aristotle was talking about?

Plants have a soul, they can feel right. But but of course yes and no right, because they are two important things to keep in mind about all of it. First of all, he attributes nourishment and reproduction to the plant soul. And we have to remember that the Greek notion of a soul or suka is rather different than modern or even early Christian notions of a soul. We're not talking about like an inner ghost person that moves

on and has an afterlife, that sort of thing. This would be more like the concept of a mind or like or would it be like the idea of an animating breath? There are a lot of different ideas of things that get translated into English as soul from the

ancient world. Yeah. I was reading about this in an excellent paper that I will probably continue to refer to in this series by Michael Martyr from in Plant Signal Behavior titled Plant Intentionality and the Phenomenological Framework of Plant Intelligence, And in this he writes that the soul in this context, in Aristotle's context, is quote a set of active capacities of an organism, not an invisible entity connected to the divine. Okay, that makes sense. So the soul is sort of like

the essence of the organism. It's like what the form of the organism apart from its physical body. Right. And while the vegetative soul here is defined by nourishment and reproduction, animals and humans additionally have capacities of sensation and rational thought added atop these baser soul characteristics. Now, I think an interesting division there is that, uh so it's attributing

animals and humans with sensation and rational thought. I think a lot of people have made some what seemed to me to be pretty um spurious claims about evidence for rational thought in plants. But I would say it's completely uncontroversial that plants experience a form of sensation, they can gather information about their environment, and they do constantly. Yeah, but in Aristotle's hierarchy, you have basically have animals and

then you have plants in the minerals. Uh. And there's also this added caveat that aspects of the vegetative soul continue on into forms that follow um, which which might not be all that helpful in what we're thinking about here, but perhaps bears mentioning. Now, aristotle shadow again is long, and we see his ideas carried on into medieval Europe.

Thirteenth century CE thinker Thomas Aquinas wrote in Puma Theology that quote, the very fact that the acts of the vegetative soul do not obey reason shows that they rank lowest, lowest, lower than minerals. Or was he not lower than minerals? That I think it would say in reference to animals and of course humans. Now, one thing that that martyr points out is that while the aristotle view here, uh, you know, it kind of used plants as baser and

that they're only carrying out nourishment and reproduction. But he writes that that's that's actually it's actually quite impressive within the modern context of certainly planned intelligence research, because these impulses nourishment and reproduction quote entail complex decisions related to the availability of resources. Now that's interesting because that could be, on one on one hand, very true, but also could easily be misinterpreted to to lead people to unjustified conclusions.

And I want to get into a little more disentangling on concepts in a minute here, but yeah, flag that. Yes, Martyr also adds quote Additionally, plants express almost all known neurotransmitters, confirming the extension of two threpticon well beyond the activities

Aristotle and his followers allotted to them. Hence, the lines of demarcation between the higher and the lower capacities, between consciousness and non consciousness, and by implication, between biological regna are not as rigid as classical thinkers believed, and there are a few other strains of more modern thought that Martyr shares. He points out that, according to late eighteenth and early nineteenth century German philosopher Hegel, plants are passive,

they have negative selfhood, and they lack quote an organismic whole. Okay, I don't know what that means. But that's hegel yeah, not a not a plant fan. Nineteenth century English naturalist Charles Darwin, on the other hand, this I believe was like a later um thing that he wrote about. But he had the root brain hypothesis that held that the root apex of a plant served as a brain like oregon that was both sensitive and capable of navigating soil

in search of resources. Now, I think it might be going a little overboard to call it brain like, but Charles Darwin was clearly enthralled by plants like the venus fly trapp Like he got really excited about what this means. And uh, maybe we can come back to Darwin in in in part two of this, because I think some of his ideas might connect more to to some of the research we're going to talk about later on. Yeah,

it's my understanding. And uh, and I believe the author mentions this that some of these ideas that Charles Charles Darwin had regarding this root brain hypothesis, like they've people have come back to them, uh in modern plant intelligence research and and said, well, yeah, and then there's more to this than than people of of Darwin's day thought. Then there's also a nineteenth century German philosopher, Frederick Niici,

who is very much I believe inspired by Darwin. In this wrote that a plant's nourishment and growth are expressions of its will to power, or the wills who mocked, which he identifies as the core driving force behind human beings. Oh my god, So this this plot, this potted plant in front of me, when it reaches for the lamp, and then I turn it around, I am thwarting its will to power. But I I am like the naysaying crowd that it must rebel against and and show its might. Yeah.

And every day you don't kill it, you make it stronger, right now. Um. In Eastern thought, there of course strong traditions of all of this, as discussed in, among other many sources, uh In Richard Nesbits The Geography of Thought. China's Taoism and japan Japan's Shinto is Um both emphasize the spirits of animals, plants, natural objects, and artifacts. Uh And And for my part, I've been reading a little bit about this um earlier when I was looking for

things to cover for Artifact and Monster Fact episodes. But um, you know, I don't want to steal any thunder from some possible potential episodes long or short form about these. But you know, we have strong folkloric, legendary and mythological um concepts of plant animal hybrids, which, of course, with all hybrids, they certainly perform various functions and symbolic um uh you know, metaphoric and per natural thought. But they also raised the question inevitably of animal nous and plants

and plant nous in animals. You know, like you you can't think of something like say a screaming man dreak, or say the vegetable lamb of Targari. You know this this sheeplike thing that is growing out of the ground that is a plant but also seems like an animal, Like you can't. I don't think you can really have a concept like that without its sort of by blurring the lines, by invoking the hybrid, making you think about the characteristics of the opposite side that are present in

this side. Yeah, yeah uh. In fact, I think several years back we did a an October episode called something like the Killer Tree that was legends of of trees that would eat people. It's a surprisingly common recurring motif, though apparently has no basis in in real biology. No, but I mean certainly not at the not not on the the animal time scale of things, but I guess

on the plant time scale of things. Yeah, you can get into more nuanced discussions of plants eating people, plants eating human corpses and that sort of thing, right, but not not the active predation like in that Oh that is like a William Friedkin movie about the killer tree that gobbles people up. Oh my gosh, I don't remember this one. Okay, yeah, well we'll have to revisit. But there, Yeah, there are clearly a lot of killer trees. And I mean you have things like the ants, right, uh, trees

walking around like humans. And yeah, all these concepts they they they're they're performing a number of different functions. But I think one of them is that it inevitably makes you think about about plants and animals, what do they have in common when and what ways do they differ in? Indeed, yeah, in what ways might they be more alike than we

often realize. Another thing is that as we're going forward talking about research potentially indicating something like a plant basis for memory or learning, I think we also have to be very careful because the whole the realm of plant uh so called plant cognition research, I think, has a history that is filled with stuff that is not so great. Like there are a number of different concepts regarding the hidden complexity of plants that people seem to get confused

with each other. And this is unfortunate because these topics range from what appears to me to be maybe controversial but at least potentially evidence backed biology, and that would be things like, you know, some of the memory research we're gonna talk about, all the way over to pure pseudoscience and paranormal stuff. And uh, just to give some quick flavor of the latter end of that spectrum, I'm reminded of something we talked about briefly in an episode

that we did a long time ago. Rob, You remember when we did the Science of Stranger Things that New York Comic con. Yes, I do remember this. So it was in the context of that episode we were talking about government research into psychic and paranormal phenomena during the Cold War, which absolutely did happen, and the extent of it is hilarious. But I read a couple of whole books about this. One, uh, of course, one if you want a quick read that's very funny is The Men

Who Stare It Goes by John Ronson. But also there was a book by Annie Jacobson that was a big, complete, sort of history of the Stanford Research Institute and all of these paranormal government research projects that were fueled by Cold War paranoia, but looked into that. They looked into things like remote viewing and UH and and UH telekinesis and stuff like that. And unfortunately, I think a lot of that was just was just tricks and poorly designed experiments.

But but but one brief episode from this, one of the people we talked about in that episode was a CIA interrogation expert named Cleave Baxter, who specialized apparently in narcotic and hypnotism based interrogation techniques and then later in the polygraph And according to a New York Times article I was reading about Baxter by Josh Eels, Baxter developed a method for conducting polygraph sessions called the Baxter zone comparison technique, which, according to this article, is still used

in polygraph test today. So cool. Anyway, later in his career, Baxter quite famously became obsessed with the idea that plants could read our minds, and he claimed to show it with experiments. So the discovery of this the story goes like this. One night in nineteen sixty six, Baxter stayed up all night. He was drinking coffee, and he got an amazing idea. He would hook a potted plant up to a polygraph machine. I guess I don't know if he was going to see if it was telling lies

or maybe you just I don't know. Uh. So, allegedly this plant was a quote corn plant or dressina fragrance, which, in a confusing twist, is completely different for the plant z maze, which is the grain plant that produces maize or corn, the food. So this is called a corn plant, but it's not the corn that would be planted in a as a crop. The corn plant had been a gift from his secretary, intended to brighten up his office,

which I have not seen pictures of. I don't know what was in there, but I'm imagining a kind of dungeon full of chairs with leather straps on them and needles full of quack truth serums. So, yeah, you can imagine some plants would be nice. Yeah, you want to get some corn down there? Uh, so from here, I just want to quote from the article by Eels summarizing this, uh,

this this experiment quote. In human subjects, a polygraph measures three things pulse, respiration rate, and galvanic skin response otherwise known as perspiration. If you're worried about being caught in a lie, your levels will spike or dip. Baxter wanted to induce a similar anxiety in the plant, so he decided to set one of its leaves on fire. But before he could even get a match, the polygraph registered and intense reaction on the part of the Dressina. To Baxter,

the implication was as indisputable as it was unbelievable. Not only had the plant demonstrated fear, it had also read his mind. Uh. So Baxter became convinced that plants had psychic powers, consisting of a sensibility that he called primary perception, which they could use to read our minds and emotions from afar. And upon this discovery, he did what any responsible seeker of the truth would do. He went straight

to the popular media. Uh. And there was a book based on his claims, and apparently uh he did a TV spot, multiple TV spots. But I like Johnny Carson and stuff. But one of them I wanted to note was, apparently with Leonard Nimoy, was this in search of. I don't know if the time frames right for that. I don't know if the time frames right either, but anseling makes me think of in search of And unfortunately skeptical scientists were unable to reproduce his results. They tried to

do the same thing and got nothing. But if you poke round about this on the internet, you will find many believers even today still overflowing with faith in Baxter's claims. It's one of those ideas that lots of people just seem to like. It feels really true and wholesome and good to believe. Yes, plants can think, they can feel, they can know what we're thinking if we tell them, or maybe even if we don't tell them, if we just think it really hard, they can detect it somehow.

But obviously there are there are major problems if you're trying to put together a coherent, scientifically informed worldview. First of all, I would say the theoretical basis is weak. Like you know, we could always discover something new, but it is not clear that there's any kind of physical mechanism that could allow something like that. And then the second part is just the empirical basis, like the controlled experiments by skeptics don't find the same thing. So yeah,

this appears to be nonsense. I can't help but wonder if okay, this experiment was sixty six. Uh, Frank Herbert's Dune was first published in sixty five, and of course has the you know, very early on in the novel has the scene where we have the Benegesta test of the box and the com jabbar the box, which of course makes you feel like your hand is burning and on fire. And here in this test behalf that part of the plant is actually caught on fire. Wow, that's interesting.

Yeah uh yeah. And the box is supposedly a kind of polygraph of its own. Yeah yeah, yeah yeah. And of course you have the Benegestate yeah, you know, truthsayers and so forth. Though, I think in our episode on that did we both come to the conclusion that we think that the real power is the box actually does nothing and it's just all in. It's all the reverend mother like she's the real test. Yeah. I think it's ultimately unknown, but we did. I think we we both

liked that idea the most. Yeah, it felt the most herbert E of the ideas. It's just a prop But anyway, So to come back to all this, so we're gonna be talking about plant memory research. But I think I want to be clear that if you say that a plant could have such a thing as a memory or an ability to learn, that is truly surprising and fascinating.

But it is not the same thing as saying or showing that plants can quote think, that plants are conscious, that plants have emotions, or that they get upset when you say or do negative things around them, all of which are claims that people have tried to make over the years, but which seemed to me to be lacking an evidential basis, with with the possible exception of quote thinking under some very broad or inclusive definitions of what counts as thought. Yeah. Like another area related to this

is the relationship doing plants and sound. So can plants respond to sound, Yes they can, But can do plants then benefit from listening to music? There's no evidence for that. But I mean, this was an idea that was very much in tho zeitgeist, especially in the UH That's where we there was actually a wonderful album that came out, an early electronic music album by Mort Garson, who is a you know, early synth wizard who did a lot of a number of different projects under different names, but

he put out this uh. This album titled UH Mother Earth's plant Asia, and it is supposed to be music that you play for your house plants, and your house plants then benefit from it. Um. I don't think, you know, house plants actually get nothing out of listening to this album. But it's a wonderful ambient, experimental electronic album for for humans. I love this. I would say I'm all for playing

music for your plants. I don't think it does anything for the plants, but playing music for your plants might do something nice for you. Yeah, yeah, just like the plant. The presence of the plants certainly can have a very pleasant effect on the human psyche, so can UH ambient music. So double up, have them both and benefit. But anyway, before we end part one of this series, I did want to look at at least one of the studies that claims to find evidence for what you might call

memory learning or habituation in plants. And in the next episode, we'll come back and talk about some reaction, criticism, and follow up of these types of ideas. So this is not without its accompanying controversy, but I thought it would be at least worthwhile to look at, like, what what

the evidential claims of the recent research are. So earlier we mentioned that scientists are actually not sure why Mimosa putica closes its leaves, though it is generally believed to be some kind of defensive reaction to prevent the leaves from being eaten by grazing herbivores or insects. So if that's the case, you might wonder, well, why don't the plants just keep their leaves folded up all the time? Would then they'd be protected always? Why do they have

to do it rapidly suddenly? Uh? Well, because if they were to keep their leaves closed all the time, the plant would be drastically reducing its ability to collect unlight and feed through photosynthesis. And this is the classic risk reward paradigm that we know well with all kinds of animals. You have a small prey animal that might be much safer if it stays and it's cozy little burrow all day. But if it never leaves, it foregoes opportunities to get food.

It needs to go out to do the things that it must do to sustain its life cycle and reproduce. So it's got to find food, it's got to find mates. And you know you're not going to get that just sitting in your hole. And you could say the same is true for this plant. So the evolutionary logic that drives the folding behavior of the leaves and the sensitive plant will reward the folding in scenarios where it actually protects the leaf from predation, but it will punish unnecessary folding,

which wastes precious opportunities to harvest the sunlight. And we've already seen a couple of demonstrations of this balance. One is that the leaves tend to fold at night time when there's no point in being exposed because there's no sunlight to absorb. And another is that once the leaves close in response to a seismic stimulus, they reopen again, usually within a few minutes. They're ready to get back

to the buffet. But to continue the logic of this risk reward balance, it would also obviously benefit the plant if it had a mechanism for discriminating between a potentially dangerous seismic stimulus and a harmless one. And you can imagine scenarios in the wild where plants are repeatedly shaken in some way or subjected to physical contact with objects in the environment, maybe by wind or something uh in a way that is not actually a threat to the plant.

Were closing the leaflets every time that happened would be pointless and harmful to survival. So do these plants have a mechanism that allows them to discriminate like that? And according to this following study, it looks like maybe they do. So. This was a study published in Ecologia in by Monica Gagliano, Michael Renton, Martial dip Chinsky, and stuff Fauno Mancuso called experience teaches plants to learn faster and forget slower in

environments where it matters. So the authors write in their abstract quote, the nervous system of animals serves the acquisition, memorization, and recollection of information. Like animals, plants also acquire a huge amount of information from their environment, Yet their capacity to memorize and organized learned behavioral responses has not been

demonstrated in Mimosa putica, the sensitive plant. The defensive leaf folding behavior in response to repeated physical disturbance exhibits clear habituation,

suggesting some elementary form of learning. So how do they actually demonstrate this, Well, they did a series of experiments, but one of their models is they took potted specimens of Mimosa putica and they mounted them on this contraption that would repeatedly drop the potted plant a distance of fifteen centimeters onto a padded surface, and the drops were

organized into repeated sessions of multiple exposures. And sure enough, the plants, after they were repeatedly exposed to the same fifteen centimeter drop, started reopening their leaves more quickly and eventually started ignoring the stimulus more or less entirely, just keeping their leaves open during a drop. And that's really interesting. It might seem to indicate that the plant is becoming habituated to this particular thing. It's like, Okay, being dropped

fifteen centimeters is just something that happens. Now, This is just how things are. I know what it feels like. It doesn't hurt me. I'm over it. By the way that I guess I am anthropomorphizing there, so I don't mean to imply that it is actually reasoning out in in uh semantic logic like that. But that's to give you the idea that it's somehow becoming habituated to something that's happening over and over again without hurting it, and it's just learning to ignore that thing. Now, there's an

obvious other explanation if this was all they discovered. What if this was just the plant's leaf closing mechanism getting worn out over time, It's just becoming exhausted and running out of the juice that it needs to use to close its leaves. Well, the researchers they thought about this, and they controlled for this by introducing a new novel

stimulus after the plant became habituated. This was the shake, so different from the drop, but it would also stimulate the seismonastic closure of the leaflets to shake the potted plant. And they found that even when a plant had become desensitized to the drop, apparently through habituation, it would still close its leaves just like normal when given a shake. So this would seem to help rule out the idea that it's just the plant's leaf closure mechanisms becoming exhausted

by repeated use. Now, there are some more interesting details from this and this one that we might get into in the in the next part of this series. For example, they found that apparently this uh, this habituation to the fifteen centimeter drop was still present weeks later after the initial sessions, and that it was variable and adaptable depending on the hostility of the conditions, like the light conditions

in which it was happening. But maybe if we get into those, we can do that in part two, because I think we need to wrap up part one for now, but I'm so excited all the things we get to talk about when we come come back next time. More research on plants and memory. Uh. If plants do in fact possess some rudimentary form of memory and learning, how what is the physical basis of that, given of course

that they don't have brains, uh? And what would that mean for our understanding of what intelligence and its subdivided parts are. Yeah? Yeah, this should continue to be a fun exploration. And this is this is an exploration that we've we've been talking about doing for years and I know we've had some listeners, right in requesting that we cover this topic. So it's great to finally be able to dive in. All right, so we're gonna go and close it out, but we'll be back next time with

more on on this topic. Uh. In the meantime, if you want to check out other episodes of Stuff to Blow Your Mind, our core episodes come out on Tuesdays and Thursdays, we have a rerun that comes out of fault episode. On the weekend, we do listener mail on Monday, we do a short form artifactor Monster Fact on Wednesday, and on Friday we set aside most serious matters and

just discuss a weird film on Weird House Cinema. Huge thanks as always to UH well, actually to our regular producer Seth Nicholas Johnson, and thanks to our guest producer today Paul decand uh Paul really appreciate you seven in for us today. If you would like to get in touch with us with feedback on this episode or any other, to suggest a topic for the future, or just to say hello, you can email us at contact at stuff to Blow your Mind dot com. Stuff to Blow Your

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