Guided by Plant Voices
By Steve Paulson
Plants are intelligent beings with profound wisdom to impart—if only we know how to listen. And Monica Gagliano knows how to listen. The evolutionary ecologist has done groundbreaking experiments suggesting plants have the capacity to learn, remember, and make choices. That’s not all. Gagliano, a senior research fellow at the University of Sydney in Australia, talks to plants. And they talk back. Plants summon her with instructions on how to live and work. Some of Gagliano’s conversations happened in prophetic dreams, which led her to study with a shaman in Peru while tripping on psychoactive plants.
Along with forest scientists like Suzanne Simard and Peter Wohlleben, Gagliano raises profound scientific and philosophical questions about the nature of intelligence and the possibility of “vegetal consciousness.” But what’s unusual about Gagliano is her willingness to talk about her experiences with shamans and traditional healers, along with her use of psychedelics. For someone who’d already received fierce pushback from other scientists, it was hardly a safe career move to reveal her personal experiences in otherworldly realms.
Gagliano considers her explorations in non-Western ways of seeing the world to be part of her scientific work. “Those are important doors that you need to open and you either walk through or you don’t,” she told me. “I simply decided to walk through.” Sometimes, she said, certain plants have given her precise directions on how to conduct her experiments, even telling her which plant to study. But it hasn’t been easy. “Like Alice, [I] found myself tumbling down a rather strange rabbit hole,” she wrote in a 2018 memoir, Thus Spoke the Plant. “I did doubt my own sanity many times, especially when all these odd occurrences started—and yet I know I do not suffer from psychoses.”
Shortly before the COVID-19 lockdown, I talked with Gagliano at Dartmouth College, where she was a visiting scholar. We spoke about her experiments, the new field of plant intelligence, and her own experiences of talking with plants.
Pavlov’s Peas: Monica Gagliano sketches a pea plant in her lab at the University of Sydney (above). She conducted experiments with pea plants to determine if, like Pavlov’s famous dogs, the plants learned to anticipate food. They did. “Although they do not salivate,” Gagliano says.
Scene from the documentary, AWARE ©umbrellafilms.org
You are best known for an experiment with Mimosa pudica, commonly known as the “sensitive plant,” which instantly closes its leaves when it’s touched. Can you describe your experiment?
I built a little contraption that allowed me to drop the plants from a height of maybe 15 centimeters. So it’s not too high. When they fall, they land in a softly padded base. This plant closes its leaves when disturbed, especially if the disturbance is a potential predator. When the leaves are closed, big, spiny, pointy things stick out, so they might deter a predator. In fact, they not only close the leaf, but literally droop, like, “Look, I’m dead. No juice for you here.”
You did this over and over, dropping the plants repeatedly.
Exactly. It makes no sense for a plant or animal to repeat a behavior that is actually useless, so we learn pretty quick that whatever is useless, you don’t do anymore. You’re wasting a lot of energy trying to do something that doesn’t actually help. So, can the plant—in this case, Mimosa—learn not to close the leaves when the potential predator is not real and there are no bad consequences afterward?
After how many drops did they stop closing their leaves?
The test is for a specific type of learning that is called habituation. I decided they would be dropped continuously for 60 times. Then there was a big pause to let them rest and I did it again. But the plants were already re-opening their leaves after the first three to six drops. So within a few minutes, they knew exactly what was going on—like, “Oh my god, this is really annoying but it doesn’t mean anything, so I’m just not going to bother closing. Because when my leaves are open, I can eat light.” So there is a tradeoff between protecting yourself when the threat is real and continuing to feed and grow. I left the plants undisturbed for a month and then came back and repeated the same experiment on those individuals. And they showed they knew exactly what was going on. They were trained.
You say these plants “understand” and “learn” that there’s no longer a threat. And you’re suggesting they “remember.” You’re not using these words metaphorically. You mean this literally?
Yes, that’s what they’re doing. This is definitely memory. It’s the same kind of experiment we do with a bee or a mouse. So using the words “memory” and “learning” feels totally appropriate. I know that some of my colleagues accuse me of anthropomorphizing, but there is nothing anthropomorphic about this. These are terms that refer to certain processes. Memory and learning are not two separate processes. You can’t learn unless you remember. So if a plant is ticking all the boxes and doing what you would expect a rat or a mouse or a bee to do, then the test is being passed.
Do you think these plants are actually making decisions about whether or not to close their leaves?
This experiment with Mimosa wasn’t designed to test that specific question. But later, I did experiments with other plants, with peas in particular, and yes, there is no doubt the plants make choices in real decision-making. This was tested in the context of a maze, where the test is actually to make a choice between left and right. The choice is based on what you might gain if you choose one side or the other. I did one study with peas that showed the plants can choose the right arm in a maze based on where the sound of water is coming from. Of course, they want water. So they will use the signal to follow that arm of the maze as they try to find the source of water.
So plants can hear water?
Oh, yeah, of course. And I’m not talking about electrical signals. We have also discovered that plants emit their own sounds. The acoustic signal comes out of the plant.
What kind of sounds do they make?
We call them clicks, but this is where language might fail because we are trying to describe something we’re not familiar enough with to create the language that really describes the picture. We worked out that, yes, plants not only produce their own sound, which is amazing, but they are listening to sounds. We are surrounded by sound, so there are studies, like my own study, of plants moving toward certain frequencies and then responding to sounds of potential predators chewing on leaves, which other plants that are not yet threatened can hear. “Oh, that’s a predator chewing on my neighbor’s leaves. I better put my defenses up.” And more recently, there was some work done in Israel on the sound of bees and how flowers prepared themselves and become very nice and sweet, literally, to be more attractive to the bee. So the level of sugars gets increased as a bee passes by.
Secret Life of Plants: Monica Gagliano says her experiences with indigenous people, such as the Huichol in Mexico (above), informed her view that plants have a range of feelings. “I don’t know if they would use those words to describe joy or sadness, but they are feeling bodies,” she says.
Scene from the documentary, AWARE ©umbrellafilms.org
You are describing a surprising level of sophistication in these plants. Do you have a working definition of “intelligence?”
That’s one of those touchy subjects. I use the Latin etymology of the word and “intelligere” literally means something like “choosing between.” So intelligence really underscores decision-making, learning, memory, choice. As you can imagine, all those words are also loaded. They belong in the cognitive realm. That’s why I define all of this work as “cognitive ecology.”
Do you see parallels between this kind of intelligence in plants and the collective intelligence that we associate with social insects in ant colonies or beehives?
That kind of intelligence might be referred to as “distributed intelligence” or “collective intelligence.” We are testing those questions right now. Plants don’t have neurons. They don’t have a brain, which is often what we assume is the base for all of these behaviors. But like slime molds and other basal animals that don’t have neural systems, they seem to be doing the same things. So the short answer is yes.
What you’re saying is very controversial among scientists. The common criticism of your views is that an organism needs a brain or at least a nervous system to be able to learn or remember. Are you saying neurons are not required for intelligence?
Science is full of assumptions and presuppositions that we don’t question. But who said the brain and the neurons are essential for any form of intelligence or learning or cognition? Who decided that? And when I say neurons and brains are not required, it’s not to say they’re not important. For those organisms like ourselves and many animals who do have neurons and brains, it’s amazing. But if we look at the base of the animal kingdom, sponges don’t have neurons. They look like plants because when they’re adults, they settle on the bottom of the ocean and pretty much just sit there forever. Yet if you look at the sponge’s genome, they have the genetic code for the neural system. It’s almost like from an evolutionary perspective, they simply decided that developing a neural system was not useful. So they went a different way. Why would you invest that energy if you don’t need it? You can achieve the same task in different ways.
Your critics say these are just automatic adaptive responses. This is not really learning.
You know, they just say plants do not learn and do not remember. Then you do this study and stumble on something that actually shows you otherwise. It’s the job of science to be humble enough to realize that we actually make mistakes in our thinking, but we can correct that. Science grows by correcting and modifying and adjusting what we once thought was the fact. I went and asked, can plants do Pavlovian learning? This is a higher kind of learning, which Pavlov did with his dogs salivating, expecting dinner. Well, it turns out plants actually can do it, but in a plant way. So plants do not salivate and dinner is a different kind of dinner. Can you as a scientist create the space for these other organisms to express their own, in this case, “plantness,” instead of expecting them to become more like you?
There’s an emerging field of what’s called “vegetal consciousness.” Do you think plants have minds?
What is the mind? [Laughs] You see, language is very inadequate at the moment in describing this field. I could ask you the same question in referring to humans. Do you think humans have a mind? And I could answer again, what is the mind? Of course, I have written a paper with the title “The Mind of Plants” and there is a book coming called The Mind of Plants. In this context, language is used to capture aspects of how plants can change their mind, and also whether they have agency. Is there a “person” there? These questions are relevant beyond science because they have ethical repercussions. They demand a change in our social attitude toward the environment. But I already have a problem with the language we are using because the question formulated in that way demands a yes or no answer. And what if the answer cannot be yes or no?
Let me ask the question a different way. Do you think plants have emotional lives? Can they feel pain or joy?
It’s the same question. Where do feelings arise from, and what are feelings? These are yes or no questions, usually. But to me, they are yes and no. It depends on what you mean by “feeling” and “joy.” It also depends on where you are expecting the plant to feel those things, if they do, and how you recognize them in a human way. I mean, plants might have more joy than we do. It’s just that we don’t know because we’re not plants.
We have only talked about this from the scientific perspective, which is the Western view of the world. But I’ve also had a close relationship with plants from a very different perspective, the indigenous world view. Why is that less valuable? And when you actually do explore those perspectives, they require your experience. You can’t just understand them by thinking about them. My own personal experience tells me that plants definitely feel many things. I don’t know if they would use those words to describe joy or sadness, but they are feeling bodies. We are feeling bodies.
You’ve studied with shamans in indigenous cultures and you’ve taken ayahuasca and other psychoactive plants. Why did you seek out those experiences?
I didn’t. They sought me. So I just followed. They just arrived in my life. You know, those are important doors that you need to open and you either walk through or you don’t. I simply decided to walk through. I had this weird series of three dreams while I was in Australia doing my normal life. By the time the third dream came, it was very clear that the people that I was dreaming of were real people. They were waiting somewhere in this reality, in this world. And the next thing, I’m buying a ticket and going to Peru and my partner at the time is looking at me like, “What are you doing?” [laughs] I have no idea, but I need to go. As a scientist, I find this is the most scientific approach that I’ve ever had. It’s like there is something asking a question and is calling you to meet the answer. The answer is already there and is waiting for you, if you are prepared to open the door and cross through. And I did.
What did you do in Peru?
The first time I went, I found this place that was in my dream. It was just exactly the same as what I saw in my dream. It was the same man I saw in my dream, grinning in the same way as he was in my dream. So I just worked with him, trying to learn as much as I could about myself with his support.
This was a local shaman whom you identify as Don M. And there was a particular plant substance, a hallucinogen, that you took.
I did what they call a “dieta,” which is basically a quiet, intense time in isolation that you do on your own in a little hut. You are just relating with the plant that the elder is deciding on. So for me, the plant that I worked with wasn’t by itself a psychedelic in the normal way of thinking about it. But of course, all plants are psychedelic. Even your food is psychedelic because it changes your brain chemistry and your neurobiology all the time you eat. Sugars, almonds, all sorts of neurotransmitters are flying everywhere. So, again, even the idea of what a psychedelic experience is needs to be revised, because a lot of people might think that it’s only about certain plants that they have a very strong, powerful transformation. And I find that all plants are psychedelic. I can sit in my garden. I don’t have to ingest anything and I can feel very altered by that experience.
You’ve said the plant talked to you. Did you actually hear words?
When you’re trying to describe this to people haven’t had the experience, it probably doesn’t make much sense because this kind of knowledge requires your participation. I don’t hear someone talking to me as if from the outside, talking to me in words and sound. But even that is not correct because inside my head it does sound exactly like a conversation. Not only that, but I know it’s not me. There is no way that I would know about some of the information that’s been shared with me.
Are you saying these plants had specific information to tell you about your life and your work?
Yeah, I mean, some of the plants tell me exactly how wrong I was in thinking about my experiments and how I should be doing them to get them to work. And I’m like, “Really?” I’m scribbling down without really understanding. Then I go in the lab and try what they say. And even then, there is a part of me that doesn’t really believe it. For one experiment, the one on the Pavlovian pea, I was trying to address that question the year before with a different plant. I was using sunflowers. And while I was doing my dieta with a different tree back in Peru, the plant just turned up and said, “By the way, not sunflowers, peas.” And I’m like, “what?” People always think that when you have these experiences, you’re supposed to understand the secrets of the universe. No, my plants are usually quite practical. [laughs] And they were right.
Do you think you are really encountering the consciousness of that plant? Maybe your imagination has opened up to see the world in new ways, but it’s all just a projection of your own mind. How do you know you are actually encountering another intelligence?
If you had this experience of connecting with plants the way I have described—and there are plenty of people who have—the experience is so clear that you know that it’s not you; it’s someone else talking. If you haven’t had that experience, then I can totally see it’s like, “No way, it must be your mind that makes it up.” But all I can say is that I have had exchanges with plants who have shared things about topics and asked me to do things that I have really no idea about.
What have plants asked you to do?
I’m not a medical scientist, but I’ve been given information by plants about their medical properties. And these are very specific bits of information. I wrote them in my diary. I would later check and I did find them in the medical literature: “This plant is for this and we know this.” I just didn’t know. So maybe I’m tapping into the collective consciousness.
What do you do with these kinds of personal experiences? You are a scientist who’s been trained to observe and study and measure the physical world. But this is an entirely different kind of reality. Can you reconcile these two different realities?
I think there are some presuppositions that a scientist should just explore the consensus reality that most of us experience in more or less the same way. But I don’t really have a conflict because I find this is just part of experimenting and exploring. If anything, I found that it has enriched and expanded the science I do. This is a work in progress, obviously, but I think I’m getting better at it. And in the writing of my book, which for a scientist was a very scary process because it was laying bare some parts of me that I knew would likely compromise my career forever, it also became liberating because once it was written, now the world knows. And it’s my truth. This is how I operate. This is who I am. And nobody has the right or the authority to tell me that it’s not real.
Steve Paulson is the executive producer of Wisconsin Public Radio’s nationally syndicated show “To the Best of Our Knowledge.” He’s the author of Atoms and Eden: Conversations on Religion and Science. You can subscribe to TTBOOK’s podcast here.
This article was first published in Nautilus magazine
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