Monica Gagliano: Can Plants Think?

Vegans might just be buggered. According to Monica Gagliano, an evolutionary ecologist based in Sydney, plants can feel, think and remember more than we ever realised. Which is to say, that they can think at all - botanical science has long rejected claims to sentient vegetation, damning it as hogwash that hippy love children should scrub from their mouths. Yet thanks to Monica’s research, things may be about to change. She has proven (controversially) that pea seedlings can ‘hear’ running water and grow towards it. More impressively, 60-70% of the same peas learnt to associate the gentle blowing of a fan on their leaves with access to a light source. When the light was taken, the plants grew in the direction of the fan anyway - an unprecedented discovery. She details these experiments, and others, in her book Thus Spoke The Plant, which might just open your third eye after a strong cognac.

I took the chance to speak to her about facts, fighting her corner, and what plant consciousness can teach us about ourselves . . .

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It was amazing seeing the blend of spiritualism and science in your book. Do you see your experiments as proof that there’s something beyond our known reality?

From a personal perspective, I feel there is way more than what we know. But I think this is true for many people. Science is about discovery. We don’t even need to introduce spirituality as there’s already an extra ingredient, the sensation of life that is always escaping us. The fundamental questions remain open. Attempts to answer them from a philosophical or religious perspective has filled that gap for a long time. And it still does for some people. For me, I see [these interrogations] as pure science, as we’re looking for that which we don’t know. We should be open to whatever the mind brings up, instead of having a pre-conceived idea of what is acceptable. Experiential experiments are what science is really about.

Yes. Charles Darwin was a Christian, after all. Do you feel that balance has been lost in science today?

By closing that instinct, you’re reducing the possibility of learning anything because you’re only asking one question in the first place. By closing the question, you close the possibility to find the right answers. If any of my colleagues ever read my book, it will make no sense in some cases – the worse-case scenario is a metaphorical nail in the coffin. “I knew she was crazy!” they’ll say.

Like a manifesto of insanity over 120 pages?


Surely people must have tried to replicate your findings.

It’s been interesting. My paper on Pavlovian learning in pea plants was published in 2016. In the last two weeks, I’ve had two separate refutations on the result. And the way these people are talking is very strong. One of them goes, “Pavlovian plant? Whoa, hang on. Not so fast . . .” and another is like, “There is no evidence whatsoever.” I’m invited to respond to these papers which is annoying in the sense that it’s wasting my time. There was an attempt to re-do the experiment, but they didn’t redo it.

How did they mess it up?

They changed the treatment. I think it was a young person, in fact – you could tell from the style of writing, that they lacked research experience. They told me they had technical issues in another control circumstance, and therefore they changed it. Well, suddenly, we can’t compare the result anymore. Resolve the issues and then do it. It was a shame, but the interesting part was the attitude. There’s a saying that ‘an extraordinary claim requires extraordinary evidence.’ But the extraordinary claim here was admitting that they did something wrong, which doesn’t prove a thing. Anybody can see our data. In another analysis, the data was brought up and it was agreed that yes, the same results were achieved. Then different statistical approaches were used to say that none of it is right. You can twist it and turn it into whatever model you want, but the model we used was the simplest, most parsimonious kind. Why create a more complicated model? It happened with mimosa as well, so it’s not surprising.  

I mean, to me it all seems quite straightforward. What have they got to lose?

Well, it’s about how we define ourselves as The Human and situating that in the realm of intelligence.

Should we draw up a bill of rights for plant-life, with ethics and practices?

That was already attempted 10 years ago. The Swiss government called in a group of experts. They did a really thorough job, saying “If this is so, then you do that,” asking questions on morality, ethics, law . . . A decade ago, we still didn’t know a lot. In light of the new science though, can we say that plants have moral right for their own sake? It took the Swiss a year to conclude they didn’t have enough to support the case for plant sentience. Yet we don’t really understand what ‘sentience’ really means, y’know? So the conclusion was that there is no conclusion! Whereas now, in my own work and others’, we are learning that plants do have agency in their own lives.

It’s fascinating that there are so many simultaneous discussions around consciousness, when we don’t know what it is.

There is no better or worse form of consciousness if it manifests in various forms that aren’t our own. Sentience is never more advanced or evolved, like a proto-something – there is just what it is. Until now, we’ve had a top-down approach of taking humans as the golden standard. You create a pyramid with us at the top. Everything else is bound to fail in some form or another because it is lesser.

So how do we set any benchmark whatsoever to test consciousness in plants?

Evolution is not an innovator. It’s a tinkerer. And that what’s we’re doing: not reinventing a method, but using exactly what we have, just deploying it differently. Let’s go from the bottom-up instead. What we see as The Human – or more generically, the brain – isn’t necessarily the best neural system. I’m allowing for other ways to appear. How is it possible that no-one has wondered about Pavlovian learning in peas before? It was assumed you need neurons and brains to do what they did. Why not try regardless? The secret is allowing myself to ask.

Can you explain plant acoustics?

I should clarify that I’m not a plant scientist. I actually don’t know anything about plants in a scientific way, but I am an animal ecologist. Communication is something we study all the time in the animal field. Working with tropical fish taught me how they flash colours, shapes, all form of behaviour including acoustics. It’s for navigation, reproduction, all sorts of things. For an animal it’s like “Oh yeah, of course, whatever,” but sound is actually a very good way of transferring information. It’s fast, it can move in a predictable way. If you’re producing a colour, you have to use the body’s entire infrastructure to do so. And then you have to hope that the patterns are delivering the messages you really mean. Birds, obviously use sound too – so the question was very simple. Like before: instead of assuming plants can’t do this, can we ask how they might be able to?


Plants enter acoustics from both perspectives. Ideas to experiment came from the fish, just as I was getting into more anthropological literature and the folklore concerning sounds and plant-life. How human singing, for example, is amplified by vegetation; it’s a very recurrent story. It’s still alive in the world. From an evolutionary perspective, this story is still with us because it has value.

In the experiment, I removed the opportunity for plants to sense anything via humidity gradient, which they use to find water. And they can hear water. Detecting a humidity gradient tells them they’re pretty close except, in the absence of something better, they had to listen. I don’t think that’s much of a big deal. If we keep getting these findings, it’ll be normal soon enough.

Are they trying harder to communicate their message, with things being as they are and if their evolution is linked to ours?

There is no difference between us and them. We are the same one consciousness arising and emerging into various forms. Some are a tree, human, bacteria. No difference. Consciousness is not the emergent property; it’s the other way around. The background to everything. Buddhists have projected this view for many years, and you see it through history. Death is an amazing process really since it allows you to change form.

The mimosa experiment was a favourite of mine… So how long can a plant theoretically remember something?

In the case of mimosa, it was at least a month, but I feel it could be longer. I want to spend more time and see.

The book seems to disparage the idea of control. But there’s a counter argument - control has been a necessary scaffold for human society to have created and built wondrous things. How would you respond to that?

Well it comes in various forms, right? So what you need to do is make sure something works. We are having this conversation on the phone, over wi-fi. But we have to be careful of fearing no control, of feeling something is wrong if it isn’t exactly how you want it to be. Subsequently, you enter a loop in which control equates to a greater life. But some of our most amazing stories are about those who surrender control and find themselves again. It’s invigorating since you realise that you’re shrinking life into smaller forms, the destructiveness of that. And it becomes very depressive. You’re seeing this. When we cut such opportunity off from the brain, we don’t have wider inspirations. It’s better to say, “Come on people, it’s time to be happy now.” And then you let go.

What about your analogies to stories, though - The Odyssey, a five-act play, all of that? Aren’t they a frame of reference we can’t escape? Perhaps one that we need?

It gives me a useful point of reference because I can make sense of it. Anything; other systems, other animals, other organisms in general – that’s the language we head to. The experience is indescribable otherwise. It only ever remains an idea or construct. Nothing changes for you; it remains in your mind. It doesn’t really enter or imbue your body and your heart. Words are trying to bridge the two extremes. You can tell even between that and stepping outside, to a forest, where there is a presence of The Other. I guess that is my own limitation.   

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