Plant Intelligence – A Philosophical Discourse on Cognitive Awareness in Plants



Dr jillian stansbury

A system is cognitive if and only if sensory inputs serve to trigger actions in a specific way….”

 From an article on Artificial Life, Polytechnic Institute, Massachussets


Meanderings on Phytophenomenology

Higher plants represent about 99% of the eukaryotic biomass of the planet. Plants are certainly successful as a life form, which itself is evidence that they have “skills”.  Some believe that the phytophemonological skills that plants display is evidence of “intelligence”.  The standing green nation, as some native peoples referred to our photosynthetic brethren, are increasingly being realized to map their environments in order to locate and utilize resources, suggesting that they are aware.  More anthropomorphic terms for describing this mapping – such as consciousness or intelligence – are argued against by the scientific community, but none the less, appeal to me personally, given my extensive study of Plant Spirit Medicine in the Amazon.  I would like to weave together my studies on Plantas Maestras, and my own metaphysical musings, with the following ideas and studies emerging from the scientific community.


What is “Intelligence”?

Intelligence is defined in various ways, but generally includes the ability of an organism to respond to environmental stimuli and challenges with appropriate responses, given the situation.  The biological functions that enable this in living systems include sensation and interpretation of sensation, learning and memory that allow for motor or other responses to information received, and all allowing for informed decision-making and creative problem solving.

The evolutionary perspective is that intelligence involves pattern recognition in its simplest form, and that more information, and more complex patterns are processed as life forms have evolved to be more and more complex themselves.  Further, different life forms have evolved as they have become specialists in solving problems in specific ways.


Plant Neurobiology

Plants are sensitive organisms.  It is odd how rarely it is discussed, but plants possess a nervous system of sorts, albeit different than that of animals.  In mammals, brains, nerves, and neural nets enable memory and learning.  Even though plants have no such discernable equivalent organs or tissues, they still appear to display behaviors in response to environmental clues, and can even be said to “remember”.  Rather than under the direction of a neural net, plant tissues appear to act in coordinated holographic ways – throughout the entire organism.  The integrated signals and responses include electrical signals, vesicle-mediated transport of auxin, and production of diverse chemicals, including compounds identical to mammalian neurotransmittors.  In fact, almost all of the known neurotransmitters are also found in plants.  As with animals, genes may be up or down regulated in response to stresses such as dehydration, over hydration, cold temperature, hot temperature, tactile stimuli, environmental ques, etc.

Luigi Galvani first demonstrated that electrical stimulation would cause frogs’ legs to twitch, leading to the earliest nerve research, and early concepts of action potentials, furthering the understanding of the mechanisms of nerve conduction. Some of the obviously “sensitive plants” were tested, such as Mimosa pudica, and it was realized that they too, reacted to electrical stimuli.  It has since been established that all plants are electrically active.  The field of neurobiology is still rather new to plant research, despite these early realizations.  Plants may be able to respond to a variety of stimuli via subtle and holographic electromagnetically active molecules.  Plant may hold water and molecules in a semi-crystalline array, rather than in discrete organs akin the central and peripheral nervous system of animals.  Through flickers and waves through this ordered molecular network, plants may be every bit as electrically, tactilely, and chemically sensitive as animals.

There are many similarities between plant cells and neurons, such as polarity where electric signals enter through one pole, travel through the cell and flow out of the opposite pole, and cells arrange themselves in along electromagnetic gridworks.  As with neuronal end-bulbs and synapses in animal neurons, plant cells secrete signaling molecules and generate action potentials.  Instead of the action potentials traveling down neural axons, the xylem and phloem channels in plants, with their regular linear arrangements, may serve similar functions and allow for water, electrolytes and other molecules to become ordered with the chambers and plant cells, with each cell to cell arrangement behaving like a synapse. Some researchers have termed this “neuroid conduction”, meaning neuron-like electrical conduction.  Plants are able to monitor for the various nutrients, chiefly minerals, in their surroundings with complex sensing and signaling mechanisms.  Once ingested, minerals influence phytohormone biosynthesis, and as with animals, complex K+ and Ca2+ signaling cascades have been identified to move minerals across a wide spectrum of concentration gradients, all helping to establish electrically active tissues.  Endocytotic vesicles also transmit sensory input through the cell, and plant cells can integrate multiple sensory inputs at once, recognize patterns, and act on the information.


The Root Brain

Roots are particularly electronically active and sensitive where the transition zone interpolates between the apical meristem and elongation region.  Darwin reported plants to have a “root brain”, noting that the growing tip has brain-like properties, sensing the soil and choosing where and how to grow.  Roots discern humidity, mineral gradients, and encroachment of competition from other plants.  Charles Darwin wrote several books on plants, including The Power of Movement of Plants, in which the final summary sentence concludes, “It is hardly an exaggeration to say that the tip of the radicle thus endowed [with sensitivity] and having the power of directing the movements of the adjoining parts, 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.”


Auxin as a Neurotransmitter-Like Substance

Auxin was first noticed early in the 20th century due to the role is plays in allowing plants to respond to the directionality of available light. Auxin has since been noted to play an important role in plant growth, and also acts like a plant neurotransmitter, playing numerous roles in responding to various environmental stimuli in addition to light.

Technically, auxin is considered to be a phytohormone that moves with the help of polarized influx and efflux carriers in plant cell plasma membranes, creating a direction flow and flow gradients plant tissue. Plants secrete auxin at presynaptic poles of transition zone cells of the root tips and elicit electrical responses and signaling cascades.  The xylem and phloem transport steams in plants then move nutrients from the tips of roots to new shoots. Auxin is asymmetrically distributed in plant tissues and auxin gradients are established, and may change dynamically in response to various stimuli, stressors, development processes.  Auxin helps to establish polarity and patterning in plant tissues.

Auxin is also involved in the diverse regulation of various plant developmental processes, including embryogenesis, organogenesis, vascular tissue formation and tropisms.  Auxin controls division, elongation, and differentiation as well as the polarity of the cell. Numerous other complex mechanisms help modulate auxin’s signaling and contribute to extensive roles the phytohormone plays plant growth, sensation, defense, and neurobiology.


Minimal Cognition

Awareness or Cognition is a self-organizing phenomenon usually attributed to animals.  The term minimal cognition has emerged to acknowledge that plants display consciousness of their surroundings, but so many scientists seem uncomfortable with saying so, the term minimal cognition is preferred.  Whatever term is used, the fact is that plants ARE sentient and attentive. Plants respond actively to the environment thus philosophers have said that plant attention is active.  It is difficult to say if they are contemplative. Plants integrate many different signals including light, humidity, gravity, tactile sensation, molecular sensation, and various signals that correspond to the presence of allies and predators, in real time. In animals, cognition is considered to be embedded in the body, and the fact that it is decentralized in plants, should not necessarily make it less sophisticated. Plants process information and may therefore be argued to be cognizant.


Individual versus Group Wills

Nietzsche contended that plants’ search for nutrients was a manifestation of its will.  My own studies, and overlap with concepts from Plant Spirit Medicine, help me to recognize that all plants exert their “will” to survive in creative ways.  Plants overcome the challenges of drought, salt marshes, insect predation, wind storms, and a myriad of other issues, in unique ways.  The ways and methods that plants have evolved, or expressed their will to find a way to survive, has given them skills, and dare I say, personalities.  There are strong plants and weak plants, shy plants and aggressive plants, stoic plants and dramatic plants, and so on.  However, unlike humans, each individual plant specimen does not have its own personality, but rather, each species of plants shares the same personality.


Plant Intelligence – More than Darwinian Survival of the Fittest?

Intelligence is generally defined to include the phenomena of retaining memories and learning from those memories.  And the concept of memory itself is the ability to store and access specific events, actions, and consequences of actions.  Do plants remember that a certain insect is a harmful predator?  Do plants remember the consequences of inundated riverbanks and take measures to limit water uptake?  Does an individual “store and access” that information?  Does the collective plant species have the capacity to share the experiences, memories, and information with members of its species?


Plant Intelligence – Something Different than Free Will

In some philosophy circles, judgement of the degree of intelligence in animals has been equated with freedom of choice, or free will – the ability to discern the outcomes of various choices and make a judgement as to which course of action will bring the most desirable life, make a choice, and act on it. For example, turkeys are known to drown in a heavy downpour as they stare at the sky with their mouths agape.  Their intelligence is not sufficient to act on the sensory input in order to survive.  They could choose to get out of the rain but apparently lack the intelligence to do so.  They have some basic survival instincts sufficient to eat and roost, but no higher or rational thought capacity to recognize patterns and discern suitable choices.

Are plants “mindless” and the seeming behaviors only a manifestation of rote survival mechanisms?  Can plants display intelligent behavior superior to that of a turkey?  Plants receive numerous complex signals, interpret, and act upon them and these responses are not automatic, but rather intelligent, and aware.  Various signals compete for the plants’ “attention” and those given the highest priority can contribute to the plant’s behavior.

An interesting question remains, that if there are choices being made by plants, where in the body of the plant is the discerning and judging taking place?  It there a local choice happening, a non-local quantum collective, something science has not yet identified?


The “Parsimony principle’ and Plant Intelligence

Parsimony is the concept that the simplest ideas, and the least number of assumptions needed to propose plausible explanations of scientific phenomena, are the ideas most likely to be true.  So what is the simplest explanation of how plants appear to be purposeful and willful?  The simply explanation may be that they have a will!   We can observe that plants display complex mechanisms of signaling, communication, patterning, and organization, making the underlying idea that they do this to survive and thrive, both simple and reasonable.  This explains how they appear to have a will.  Making the more spiritual leap to ask why plants “want” to survive, why they have the “will” to survive is more difficult. If a lifeform displays a will to survive, what is it that sparks or motivates that will?  The very notion that something has a will, begs a bit of selfhood, does it not?

Aristotle thought that plants had a vegetative soul, and that animals had the additional quality of sensation, and humans the further additional quality of rational thought.  But some botanists and environmental philosophers argue that plants, too, display some higher rational capacities – displaying decision-making, and thereby a type of rational intelligence in the acts of rejecting pollen sharing the same alleles, and of roots preferring a certain patch of soil over another.  Plants may actually be more aware of, and more sensitive to their immediate surroundings than animals.  Being rooted to a particular space may have driven plants to develop a greater degree of sensitivity to their environments than animals.  The bio-attention of plants, may be more present and more attentive than that of animals.  Being rooted to a particular location may also lead to a need to have creative ways of accessing information from the non-local environment.


Non-Passivity of Plants

Although Aristotle granted plants a vegetative soul, he has stated them to be “deficient animals”, a perspective perpetuated for millennia.  Plants were seen as inferior, lacking selfhood, and only having existence in relation to the sun and minerals, wholly subordinate to animals, and passively bound to the inorganic world.  This view of plants has been found to be erroneous.  Plants produce toxins in response to herbivory, for example.  Plants can communicate with other individuals of the same species, as well as different species, and perhaps even to highly different species, such as insects and animals, with volatile compounds that can travel in the air significant distances.  Plants may even anticipate coming threats, and begin producing more alkaloids, or bitter compounds, when they receive information and signals that a herd of elk is coming their way.   Plants may communicate via chemical messengers to attract or repel different pollinators and predators, and likely serve other purposes we have yet to discover.


A Darwinian Mechanism for Phenotypic Plasticity

The phenotype of a plant, that is to say its outward appearance or morphology, is plastic and malleable given environmental situations.  For example, one can take ordinary pumpkin seeds and grow ordinary pumpkins or extraordinarily large pumpkins given different soil, water, and environmental parameters, yet with the same underlying genetic make-up. Nasturtiums grown in rich soil will produce abundant vegetation and few flowers, while in dry poor soils, will produce few leaves and many flowers.  The plants express themselves differently, even though the genetic makeup is identical.  Plants may display “intention” when they express various phenotypes, making “choices” based on the information and resources they are given. Plants may have a small, but none the less significant, degree of control to how they move and grow, to best help them to survive. Part of the phytophenomena driving the divergence of plant species appears to be co-evolutionary phenomena, whereby plants are aware of their surroundings, and of the other life forms with which they coexist.  Due to this awareness, plants may have intended or willed to offer nectar to beneficial insects, domiciles to insect work crews, and beautifully patterned landing platforms for pollinators.    The plants’ response to sensory information contributes to its shape, form, and phenotypic expression, and thereby plants evolve in part, in response to their wills and creativity.

Living systems embody their memories and store their knowledge in their tissues.  The experiences and sensory input received in living systems affect the genome, i.e. gene expression, but can affect non-genomic, “plastic” phenotypic expressions as well.  The phenotype is shaped structurally by experience, and experience is mediated via neural process that receive the sensory input.  The accumulation and storage of sensory-mediated experiences in sensory cells changes the structure of the cell.  As with human brain plasticity, so too are plant sensory cells and neurobiological tissues “plastic.”  This in turn affects the evolution, development, behavior, “personality”, shape and form of the plant.  Due to their life “experiences”, like all sensory and neuronal tissues, the shape and structures of the tissue can morph accordingly.  In this way, the shape and form of a plant is a reflection of its experiences, choices, will, and creativity.


The Doctrine of Signatures

Part of the ancient ideas on the Doctrine of Signatures, whereby the shape, color, pattern, and form of a plant has significance, and can hint at its medicinal and nutritional qualities, may itself be a phytophenomena.  Plants may grow and hold their leaves in a manner that benefits certain plants, protectors, or symbionts, who then defer them a survival advantage.  This trait is shared with all species, and specific insects co-evolve over millennia to only survive with the aid of their companion plant (Figs and Fig moths, Milkweeds and Monarch, etc.)  Insects may “read” the signature of plants, animals can of course taste the sugar and see the beauty, and highly aware humans may receive information from the plant by its very appearance. Plants may evolve to willfully and creatively express color, number, habit, shape, form, and personality, even though they lack the sense organs to which those traits have evolved to appeal.  Plant display beauty that seems intended for animal eyes, aroma that seems intended for olfactory apparati, and all manner of creative seed dispersal and propagation methods that involve insects and animals to do their bidding.  Clever that.


Plants are Aware of Their Surroundings

Plants are known to map their surroundings, and move their bodies in intentional ways in 3-dimensional space.  Plants orient themselves and respond dynamically to the gravitational field, with respect to the arc and rays of the sun, with respect to available nutrients and water, and with respect to other plants, fungi, microorganisms, and in some cases other life forms.  Researchers are starting to say that plants “forage” for resources, just like animals do.  Plants can interpret numerous chemical signals from other plants, and likely other animals and insects as well.  Furthermore, plants not only sense these things, plants communicate and interact with these surroundings, releasing volatile oils into the air, and chemical signals underground.

This is an example of intention or will in plants – growing in desired directions due to an awareness of 3 dimensional space.  Plants are aware of other plants that may compete for resources, and may take measures to prevent further growth and encroachment. Plants’ willfulness can include control over directional growth vectors toward heat, light, open space, and kin, away from unsuitable environments, predators, and undesirable neighbors.


Don’t be so Hasty – Differences in Time Scale Between Plants and Animals

Human time frame is much faster than plants.  Although some bamboos species can grow a centimeter per hour, and some seaweed many feet in a single day, in general, human beings operate in second and minute-based time scales, while plants usually operate in weeks and months, or even year-based time scales.   Only through time lapse photography are humans able to appreciate the movements, responsiveness, and intentionality or willfullness of plants. It may be that we miss other plant phenomena as we lack research techniques that operate on their time-frames, and look hastily for physiology with which we are familiar.  Indeed, it takes time for herbalists to “see” the personalities of plants and develop familiarity with the unique behavior of various species.  But most gardeners learn, over years’ time, the plants that are rather annoying (Dulcamara, Rununculus), the plants that are rather charming (Johnny Jump Ups), and the plants that are touchy drama queens (Begonias).  Those who don’t “get” that last sentence, have probably never slowed down to observe plants and their behaviors on their own time-scales.


Plants have Group Souls

Now I am really treading in taboo waters for a scientist, but I am nearing retirement, and emboldened to share my honest observations and opinions.  If anything has a soul at all, something more than the sum total of its chemical parts, than I don’t see why humans would be anymore soulful than other animals, nor why animals would be any more soulful than plants.  All religious ideation aside, who can say why the universe goes to all the bother of existing?  And if the most basic laws of thermodynamics dictate that order decays away into disorder, and that all organized life breaks down into a steady state of homogeneity with its surroundings – that is to say reach entropy – then why has there been a slow and patient evolutionary timeline heading towards more and more order, and increasingly complex organisms?  If the “arrow of time” points toward chaos and disorder sooner or later, then why has life evolved to be increasingly ordered and complex?  One commonly overlooked “given” hidden in the laws of thermodynamics is, ….wait for it……that there can be order.    If the law is for all matter to reach a steady state of disorder, then why is there any order at all?

Rudolph Steiner used the term negentropy to refer to the force that opposes entropy.  I believe that negentropy is akin to, if not the same thing as, the “vital force”, that innate healing wisdom that causes minerals to accrete, plants to exert their will in creative ways, and animals to become more and more complex, to the point of contemplating their navels.  It is negentropy that drives minerals to accrete into the highly ordered living crystals of our bones, drives our wounds to repair themselves, and our organs to continually regenerate.  It is this healing, negentropic, vital force with which true healers work.

I was taught in Naturopathic medical school that a large part of helping people to heal, no matter how fancy and biochemical our evidence-based research evolved, was to simply remove the obstacles to cure and stimulate the vital force.  There is an innate wisdom and impetus in the body to continually repair and regenerate itself, oppose entropy, and keep the order, the body heat, and the “aliveness” going. Plants too, exert their will, and maintain their order and biochemical systems sufficient to sustain their aliveness.  Plants appear to do this collectively among their own kind – that is to say, among their own species.  While humans have individual wills, plants appear to have group wills.  There are some animals, the animals which are most linked to humans such as dogs and cats, that seem to have individual personalities, but many animals, and all plants, seem to have identical wills and personalities within the species.  For example, while there may be aggressive dogs and lazy dogs, or skittish cats and social cats, one sparrow is more less the same, personality-wise, as another sparrow, and one gold fish more or less identical to the next.  In the same way, one plantain is identical to another plantain growing on another continent.  Ditto that a lotus blossom, a yarrow, a tomato, or a coconut tree.  Plants do not have individual wills or souls, if you believe in souls, but rather, a group personality or spirit that is shared collectively among the species.  So rather than search for the seat of the soul, the brain behind the will, or the ghost in the machine in the tissues of any one individual plant, perhaps we should look a little wider.  Could there be collective consciousness shared among all species in a non-local way?  Could there be microrrhizal communication networks?  Could there be volatilized communication networks, or other yet to be discovered systems of intelligence in plants?


Examples of Plant Intelligence

Plants can sense reflective infrared and red light, and note its movement, and respond to coming shade ahead of time.  Taraxicum, Dandelions, can realize the they are being repeatedly mowed down in the lawn, and begin flowering at the level of the ground, rather than on a 6 inch or loner stem.  Plants may have a memory of winter in that seeds may not be fooled into breaking dormancy during an unusual February warm spell, because they “know” that the real spring may not be until April.


Many plant leaves, such as the laminas of Lavatera cretica, will track the trajectory of the sun, moving across the sky and maximize the photosynthetic surfaces.  Researchers have shown that you can place such plants in a darkened box, and the plants will still display the movement for a number of days. Thus, the plant anticipates the sun, rather than just responding to it.  It displays an action based on a memory, and the memory appears to be stored in the collective of plant cells, rather than a centralized organ.


Cuscuta species, Dodder, responds to touch stimuli and coiling around other host plants to parasitize their cholorphyll, have given up producing their own.  Cuscuta will touch various plants and discern plants that are rich nutrient sources.  Cuscata will invest more energy in coiling around a plant and usurping its nutrients then it anticipates gaining as a reward for the expenditure.


The “Sandbox Tree” Euphorbia hirta, releases chemical toxins from its roots that prevent other trees, vines, and herbaceous plants from sprouting in the vicinity of its trunk.  Thus this jungle tree always has a lot of space around it.


Many jungle trees possess ant domatia, living quarters for specific ant species that protect the tree and prune any vines or parasites that would otherwise grow on the trees.  For example, Palo Santo, a Triplaris species houses ants that will come pouring out by the millions anytime the tree is touched.  They will prune away vines and epiphytes, but will also inflict highly painful bites on animals who disturb the trees.


The Stilt Palms, Geonoma species have tall adventitial roots that can “walk”.  When conditions are difficult, or the other plants encroach upon its territory, the plant can grow new roots in the desired direction, and allow others to die off, effectively taking a step.


Syngonium is tropical climbing plant that has scale-like leaves on the ground, and then changes its form entirely as it grows into the canopy, and to spread to other trees, can by seeking darkness and growing an extension back down to the ground and start the process over again.


Glechoma and Hydrocotyle, choose patches of soil to colonize, and then grow just the right number and vigor of leaves to match the resources that the particular patch has to offer.


Pisum sativum, peas, are able to communicate environmental stress or hardship to other peas through chemical signaling from root to root.


Lycopersicon, tomato, can communicate mechanical trauma from a wounded leaf, to adjacent leaves via chemical signals.


The Venus flytrap, Dionaea muscipula, will not close its trap when rain drops or leaf matter strike its surface, but will only spend the energy for choice insects.  It does this by having a memory of the precise sensory hair stimulated, and if another nearby sensory hair is stimulated within a short time frame, will invest the energy to obtain a valuable return.  It can discern between rain and other disturbances and insects with sophisticated judgements based on both time frame and spatial arrangements of sensory input.


Potentilla reptans will decrease the length between internodes when in nutrient-rich soil. When cuttings are made of these ramets and allowed to grow new ramets, that information from the older cells was passed on.  Information from a different time and space was house, like a memory in the new clones.  These data suggest that the decision to grow a stolon or to root a ramet at a given distance from the older ramet results from the integration of the past and present information about the richness and the variability of the environment.


What are some of the plants which you have observed display a personality, an intelligence, an intentionality?

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