Do Plants Think?
Evidence Hints at Plant Communication, Memory, and Decision-making Sentience
For centuries, science viewed plants as silent, passive background scenery. But a wave of groundbreaking research into how flora communicate, adapt, and make decisions is smashing that paradigm—revealing that plants possess complex forms of memory, kin recognition, and decentralized problem-solving.
As researchers debate whether these capabilities amount to a form of plant sentience, this scientific revolution is converging with a growing global movement to grant legal rights to nature. Together, these developments challenge our human-centered worldview, pushing us to rethink not only what it means to “think” but whether the green world deserves fundamental rights and ethical protections.
1960s Plant Experiments
The debate over floral “thinking” began in earnest in 1966 with controversial claims stemming from Cleve Backster’s experiments suggesting that plants could perceive human thoughts. Backster was a CIA lie detector specialist who hooked up his machine to plants and got sharp electrical readings when he even thought, for example, of touching a lit match to a plant.
Although Backster's work was never reliably replicated and is rejected by most scientists, modern research has nevertheless revealed a surprisingly dynamic inner life of plants that is stranger—and more fascinating—than many imagined.
“There is solid evidence of anticipatory behavior, decision-making, numerosity, kin recognition, and other complex behavioral capacities in plants.”
Today, findings on trees and a “wood wide web” are capturing the popular imagination.
Researchers are beginning to understand that trees can communicate, exchange nutrients, and support neighboring trees via the “mycelium” network, which is the collective fungi that live within soil.
A mycelium is the main body of a fungus. It lives and persists year after year below ground, sending up temporary fruiting bodies we see as mushrooms, shelf fungi, and the like. The mycelium is like the trunk and branches of a tree, while the mushrooms, etc. are akin to the fruits that grow on trees and then are harvested or fall to the ground and decay. Each mycelium is composed of millions of microscopic threads called “hyphae” that interpenetrate the soil.
Miguel Segundo Ortín is a research fellow at the Universidad de Murcia, Spain, and a member of the Minimal Intelligence Lab (MINT Lab). Together with colleagues, he has been exploring the science behind plant behavior and cognitive capacity.
Science has gone a long way toward overturning the idea that plants are solitary, inert natural forms, Ortín told The Earth & I in an email exchange.
“There is solid evidence of anticipatory behavior, decision-making, numerosity, kin recognition, and other complex behavioral capacities in plants,” he said.
But does this amount to thinking?
Plant Communication
Michael Marder, research professor of philosophy at the Universidad del País Vasco, in Spain, and author of Plant Thinking, argues that plants pay attention to their above- and below-ground environments, have several types of short- and long-term memory, and can communicate and make decisions.
Together with colleagues from the UK and Brazil, he has conducted theoretical–empirical studies of plant attention and has just written an as-yet-unpublished scientific paper on possible mechanisms of decision-making in plants.
“In their broadest scope,” he said in an email interview with The Earth & I, “our studies have proposed a model of extended (and extending) plant cognition, involving not only plant tissues and organs but also the intermediate zones between root tips, the surface of leaves, or the meristems [growing tips] spread out throughout a plant and the world.”
One topic of research is communication. Plants, scientists now understand, do “communicate” via mycelium networks and complicated root systems.
Plant root systems don’t just aid plant growth: They use chemical signals, vibrations, and electrical impulses to transmit information about environmental conditions and events in the plant’s surroundings, either to different parts of the same plant or to other plants nearby.
Root systems further interact with fungi, producing so-called mycorrhizal (meaning “fungus/root”) networks. These can connect plants for sharing water and nutrients and sending danger alerts.
Mycorrhizal systems exist around plant roots, and the mycelia’s thread-like hyphae create symbiotic networks that allow plants to get nutrients from the soil in exchange for what the nonphotosynthetic fungi need: sugars produced via green-plant photosynthesis. And these networks are the means by which plants can send signals to nearby flora.
Plants can also release volatile organic compounds (VOCs) over longer distances, which can attract species such as parasitic wasps that help protect the plant against predators. The VOCs signal other plants that they should prepare their own defense mechanisms against pests and threats.
Plants have epigenetic memory; in other words, they can “learn” from environmental conditions and pass these memories along to their offspring.
Plant Memory
Another target of research is something we largely view as unique to mammals—memory.
Recent research has shown that plants have epigenetic memory; in other words, they can “learn” from environmental conditions and pass these memories along to their offspring.
A research team at the University of York in the UK discovered that plants hold a “winter memory” via two proteins: VIN3 and VRN5. In cold conditions, these proteins gather and double in size. According to Prof. Mark Leake, “these long-lasting clusters act like miniature ‘memory hubs,’ helping the plant remember it has been through winter and it's now time to start new growth.”
Plants can also engage in “stress priming.” That is, they react to a mild environmental stressor, such as a pest attack, through epigenetic changes occurring within their cells. This then primes them to resist much stronger stressors more effectively.
Research led by Dr. Estrella Luna-Diez and colleagues at the University of Birmingham, UK, for example, showed that trees subject to environmental stressors can pass resilience on to their offspring, including drought tolerance and resistance to powdery mildew.
These two examples (and there are more) show patterns that parallel capabilities often regarded as mammalian. But does this amount to thinking or sentience?
As far as the science is concerned, says Ortín, we don’t have any definitive answers. He argues, however, that “many claims that plants aren’t (or can’t be) sentient rely on unproven a priori assumptions. … The proposal [of his research] is to take the hypothesis of plant sentience seriously as a falsifiable scientific hypothesis, rather than dismissing it a priori as an impossibility.”
Redefining ‘Consciousness’?
It would be very difficult to convince people that plants are sentient based on this research, but perhaps this reflects our human-centric view of sentience.
For example, Prof. Stefano Mancuso, a world-leading plant neurobiologist (a controversial, or cutting-edge, term depending on one’s point of view) based at the University of Florence, argues that we should perhaps move away from concepts like consciousness and sentience and use the term “awareness” to describe plant capabilities. He suggests thinking about intelligence differently, not as originating from a brain but “diffused.” In this paradigm, plants’ decision-making occurs throughout their root systems, stems, and leaves, rather than centered in one area.
Mancuso argues that we have a tendency to center humans as the pinnacle of life on Earth—its highest and most advanced species. And we see the consequences of that thinking, he says, written across our damaged landscapes, extermination of other species, and warming climate.
Ortín draws a parallel with animal ethics. “Most theories of animal ethics (though certainly not all) hold that sentience is morally relevant: Because nonhuman animals have a subjective point of view and are capable of feeling, they qualify as ‘moral patients,’” a philosophical term meaning entities that have a right to be free of undue harm or suffering.
That thinking could apply to plants were it established that they have a form of sentience. But, he argues, “it is far too early to draw any firm conclusions about what those ethical implications might be.”
A Broader Morality
But many people in the wider world today have already concluded, based on their own felt experience of consciousness in nature, that animals, plants, and even entire natural systems deserve treatment as “moral patients.”
In August 2026, for example, some citizens in Oregon aimed to pass a Rights of Nature initiative—Measure 20-373—to protect all watersheds in a county from existential threats.
The Rights of Nature agenda … invites us to rethink our relationship to nature, just as many world leaders become more aggressively extractivist.
While it failed, the Rights of Nature agenda, which posits that nature has a right to exist, flourish, regenerate, and evolve for its own sake, fundamentally challenges perspectives on the place of nature—animals, plants, soil, and water—in the world. It invites us to rethink our relationship to nature, just as many world leaders become more aggressively extractivist.
This new rights framework is a logical accompaniment to the evolving thinking about plant intelligence and capabilities.
Marder, however, told The Earth & I that we should perhaps think of the ethical implications of plant intelligence and a rights framework as very different from human/animal intelligence and human/animal rights.
Human rights, and to some degree those of animals, are predicated on individual subjects, he thinks. Plant intelligence, however, is located within an ecosystem, with a symbiotic relationship between plant life and place. Plants, he argues, “solve some of the ethical and political dilemmas generated by the individualistic figures of personhood. To put it in a slogan-like form … plant rights are the rights of the environment.”
What this could mean, therefore, is that humans could learn much from plant “sentience”—a more communal, Earth-connected, symbiotic, and respectful relationship with the environment.
And it underlines the importance of the Rights of Nature framework. Far from being a fringe preoccupation of extremist environmental activists, assigning rights to nature or to trees may be where the science and our understanding of the place of all living beings are heading.
*Deborah Talbot is a journalist with three decades of research experience in sustainability as a concept, focusing on cities, the environment, eco-tech, and education.
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