The Intelligence of Plants By Cody Delistraty The Paris RevoiewSeptember 26 , 2019 The Big Picture What if plants are smarter than we think — a lot smarter ? Miguel Rio Branco , Untitled , Tokyo , 2008 © Miguel Rio Branco A few years ago , Monica Gagliano , an associate professor in evolutionary ecology at the University of Western Australia , began dropping potted Mimosa pudicas . She used a sliding steel rail that guided them to six inches above a cushioned surface , then let them fall . The plant , which is leafy and green with pink - purple flower heads , is commonly known as a “ shameplant ” or a “ touch - me - not ” because its leaves fold inward when it ’ s disturbed . In theory , it would defend itself against any attack , indiscriminately perceiving any touch or drop as an offense and closing itself up . The first time Gagliano dropped the plants — fifty - six of them — from the measured height , they responded as expected . But after several more drops , fewer of them closed . She dropped each of them sixty times , in five - second intervals . Eventually , all of them stopped closing . She continued like this for twenty - eight days , but none of them ever closed up again . It was only when she bothered them differently — such as by grabbing them — that they reverted to their usual defense mechanism . Gagliano concluded , in a study published in a 2014 edition of Oecologia , that the shameplants had “ remembered ” that their being dropped from such a low height wasn ’ t actually a danger and realized they didn ’ t need to defend themselves . She believed that her experiment helped prove that “ brains and neurons are a sophisticated solution but not a necessary requirement for learning . ” The plants , she reasoned , were learning . The plants , she believed , were remembering . Bees , for instance , forget what they ’ ve learned after just a few days . These shameplants had remembered for nearly a month . The idea of a “ plant intelligence ” — an intelligence that goes beyond adaptation and reaction and into the realm of active memory and decision - making — has been in the air since at least the early seventies . A shift from religion to “ spirituality ” in the sixties and seventies unlocked new avenues of belief , and the 1973 bestseller The Secret Life of Plants catalyzed the phenomenon . Written by Peter Tompkins and Christopher Bird , the book made some wildly unscientific claims , such as that plants can “ read human minds , ” “ feel stress , ” and “ pick out ” a plant murderer . Mostly , it proved to be a touchstone . Wrapped in pseudoscience , these claims , the authors said , were “ proven ” by “ experiments . ” Cleve Backster , a polygraph tester for the CIA , did one such experiment in 1966 when , “ on a whim , ” he attached a galvanometer ( a machine that registers electrical currents ) to a dracaena , a tropical palm houseplant . Silently , Backster imagined the plant was on fire . The galvanometer flickered . Backster concluded the plant was feeling stress from his thoughts . “ Could the plant have been reading his mind ? ” ask Tompkins and Bird in the book . In another experiment , Backster had a friend stomp on a plant . Then , that friend and five other human “ suspects ” walked out in front of the plant that had “ witnessed ” the stomping . The plant was hooked up to a galvanometer . When the killer entered the room , the plant sent out a wave of electricity , thereby “ identifying ” the murderer . Cássio Vasconcellos , A Picturesque Voyage Through Brazil , # 28 , Courtesy of the artist and Galeria Nara Roesler , São Paulo © Cássio Vasconcellos Richard Fortey , a former professor of paleobiology at Oxford and paleontologist at the Natural History Museum in London , scorns the idea of “ smart plants . ” “ It ’ s so anthropomorphized that it ’ s really not helpful , ” he told Smithsonian . “ Trees do not have will or intention . They solve problems , but it ’ s all under hormonal control , and it all evolved through natural selection . ” These “ magical ” notions of plant intelligence are worrisome , he says , because people “ immediately leap to faulty conclusions , namely that trees are sentient beings like us . ” But while it is easy to dismiss lonely men conducting electrical experiments on their houseplants and savvy authors taking advantage of a gullible public , there may , in fact , be some truth to the idea . Darwin floated the first modern ideation of plant intelligence in 1880 . Writing in The Power of Movement in Plants , he concluded that the root of a plant has “ the power of directing the movements of the adjoining parts ” and thus “ acts like the brain of one of the lower animals ; the brain being seated within the anterior end of the body , receiving impressions from the sense organs and directing the several movements . ” Darwin was talking about how plants react to shifts in vibrations , sounds , touch , humidity , and temperature — but these are just adaptive reactions . Facing toward the sun or closing at a touch does not require quasi - neurological abilities . There is no processing or choice involved — unlike the apparent memory shown by Gagliano ’ s experiment . ( Many of the Ancient Greeks — like Plato , Anaxagoras , Democritus , and Empedocles — shared the belief that plants have a kind of brain where sensitivities could be “ processed . ” ) Cássio Vasconcellos , A Picturesque Voyage Through Brazil , # 37 , Courtesy of the artist and Galeria Nara Roesler , São Paulo © Cássio Vasconcellos Recently , more findings have seemed to support — or at least point toward — a more restrained version of plant intelligence . Plants may not be capable of identifying murderers in a lineup , but trees share their nutrients and water via underground networks of fungus , through which they can send chemical signals to the other trees , alerting them of danger . Peter Wohlleben , a forest ranger for the German government , has written extensively on trees , about diseases or insects or droughts . When Wohlleben came across a tree stump that had been felled probably half a millennium ago , he realized — scraping at it and seeing that it was still bright green beneath — that the trees around it had been keeping it alive , sending it glucose and other nutrients . This plant communications system works similarly to the nervous system of animals . Trees can send out electrical pulse signals underground as well as signals through the air , via pheromones and gasses . When an animal , for instance , begins chewing on a tree ’ s leaves , the tree can release ethylene gas into the soil , alerting other trees , whereupon those nearby trees can send tannins into their leaves so that if they , too , get their leaves chewed , they might be able to poison the offending animal . José Cabral Cabo Delgado , Tete , 2002 . © José Cabral ( Photo © Cyrille Martin ) Trees can differentiate between threats , as well . They respond differently to a human breaking off one of its branches than they do to an animal eating at them — with the former , it will try to heal ; with the latter , it will try to poison . Plants even share space with one another . In a 2010 study , when four Cakile edentula , or “ sea - rocket plants , ” were put in the same pot , they shared their resources , moving their roots to accommodate the others . If the plants were just acting evolutionarily , it would follow that they would compete for resources ; instead , they seem to be “ thinking ” of the other plants and “ deciding ” to help them . Even the slightest possibility of a proven plant intelligence would have massive scientific and existential implications . If plants can “ learn ” and “ remember , ” as Gagliano believes , then humans may have been misunderstanding plants , and ourselves , for all of history . The common understanding of “ intelligence ” would have to be reimagined ; and we ’ d have missed an entire universe of thought happening all around us . * On a recent afternoon in Paris , I felt particularly disconnected from nature . Across the street from the hulking glass facade of the Fondation Cartier is the famous , and very green , Montparnasse Cemetery . But the historical humans beneath its grounds , like Charles Baudelaire and Simone de Beauvoir , define the space far more than any of its plant life . The exhibition “ Nous Les Arbres ” ( “ We the Trees ” ) at the Fondation Cartier attempts to show that humans are a just small part of a world that belongs to plants . ( Plants , after all , make up about 99 percent of earth ’ s biomass . ) There are installations of herbariums with bits of trash scattered throughout , videos of countryside pensioners discussing their favorite trees and how they care for them , and massive jungle canvases by the Brazilian painter Luiz Zerbini . Nearly every appeal to nature , however , evokes only a sense of alienation . The older people fawning over their favorite trees come off as fanatics with hyperniche interests , and the installations showing the human impact on the environment are so distressingly common that it ’ s difficult to engage with them as if for the first time . More than anything , the exhibition accidentally proves that humans are so accustomed to viewing ourselves as fundamentally separate — even insulated — from the environment that we must make a museum show within a major urban capital to try to reconnect with it . Sebastián Mejía , Série Quasi Oasis , 17 , Santiago du Chili , 2012 © Sebastián Mejía A notable exception : In the Chilean photographer Sebastian Mejia ’ s black - and - white images , trees burst through houses and gas station roofs in Santiago . A massive palm grows in the middle of a car dealership . A tilted pine threatens to crash onto a street . Similarly shocking is a film called EXIT by the architects Diller Scofidio + Renfro , which shows the destruction of major forests . These works succeed because they make no attempt to appeal . Instead , they accost the viewer with nature ’ s power and its fragility . Our houses , stores , and filling stations can be overrun and destroyed by a single palm ; a centuries - old forest can be decimated by a single fire . Our lack of respect for nature is at once astounding and ordinary . It allows us to remain in the comforts of late - stage capitalism . If we were to be honest with ourselves about our individual capacity for harm , we would no longer eat meat , live in big homes , drive cars , use plastic water bottles or bags . But rather than numbing ourselves , we might at least allow ourselves to feel some pain at our complicity . Over the long - term , this might push us toward change . If we respected nature more — the power it has to not only be destroyed by us but to destroy us in turn — would we see more clearly how imbricated we are ? Would we be more hesitant about growing plants in monocultures , genetically manipulating them for our pleasure , destroying forests ? Would we try harder to protect the environment , if we understood that by protecting plants and trees we are protecting ourselves ? If plants can learn , as Gagliano suggests , they may be able to slowly adapt to fight climate change on their own , adopting and passing down traits of hardiness , stockpiling nutrients , sharing and alerting . This kind of learning would , in a way , be the ultimate intelligence : the ability to actively reshape their existence in order to survive . Cesare Leonardi and Franca Stagi , Fraxinus excelsior L , 1963 - 1982 © Cesare Leonardi and Franca Stagi Intelligence is really the central question in all of this . What , precisely , is it ? Must the ability to remember , learn , and decide come from neurons and a “ brain , ” as we tend to think of it , or should we broaden the definition to include a “ mindless mastery , ” as Anthony Trewavas , an emeritus professor of biological sciences at the University of Edinburgh , calls it ? The crux of the question rests on whether we think we are the center of the universe and that our mechanisms for remembering and learning , are superior . Or , might we be willing to see that there are other , nonneurological modes of thought ? Might we be willing to de - center ourselves and view the environment through a nonhuman lens ? Plants , as Gagliano concluded , might have a far greater sentience than we ’ d ever thought possible . The implications of plants that “ remember ” being dropped and “ decide ” it ’ s safe to not protect themselves aren ’ t best expressed in anthropomorphic terms , but we don ’ t yet have other language . In truth , we know so little even about ourselves ; our science cannot fully explain how humans learn and remember . Why not consider that plants have been doing the same for far longer than we have been around , with an intelligence that is radically different from ours ? Cody Delistraty is a writer and critic in Paris and New York . A Letter to My SonsBy Imani PerrySeptember 25 , 2019 The Interior Decorators of BloomsburyBy Emma GarmanSeptember 25 , 2019 You , Too , Can Have a Viral Tweet Like Mine : Demystifying Poetic MeterBy Frankie ThomasSeptember 24 , 2019 What ’ s the Point ? By Michael ChabonSeptember 23 , 2019 From the ArchiveMrs . 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