Quick Answer
The Secret Life of Plants is a 1973 bestseller by Peter Tompkins and Christopher Bird claiming plants perceive, feel and respond to human intention, built on Cleve Backster's polygraph experiments. The experiments failed independent replication and the scientific community rejected the hypothesis.
Key Takeaways
- The core evidence did not survive testing: controlled replications reported in 1974 and at the AAAS meeting found nothing, and a panel of biologists judged primary perception unsupportable.
- The intuition was better than the evidence: plants really are more responsive than a mechanical picture allows, through chemistry and electrical signalling with no nervous system.
- Scientific costume did the persuading: polygraph equipment and laboratory language gave the claims an authority the work had not earned.
- The damage outlasted the book: serious plant signalling research spent decades distancing itself from Backster, which made careful claims harder to make.
- Goethean science does not support it: that method is disciplined observation with your concepts held back, not a theory that plants read intentions.
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What the Book Claims
Peter Tompkins and Christopher Bird published The Secret Life of Plants in 1973, and it sold enormously. Its thesis is that plants are sentient in a strong sense: they perceive their surroundings, respond emotionally to the people near them, register the intentions of those people before any action is taken, and detect the death of other organisms at a distance.
The book assembles this from many sources, including the work of Jagadish Chandra Bose on plant electrical responses, various claims about music and growth, and a long tradition of anecdote about talking to plants. Its centre of gravity, and the material everyone remembers, is the work of Cleve Backster.
We are reviewing it here for a specific reason. This site covers material that mainstream science does not accept, and a readership drawn to that has a professional interest in knowing how such claims fail. This one failed in a well-documented way, and the anatomy of the failure is more useful than the book.
What is actually being claimed
It is worth separating two things the book runs together. The weak claim is that plants respond to their environment in complex ways not captured by treating them as passive chemistry. That claim is now well supported. The strong claim is that plants perceive, in the sense of having experience, and that they register human mental states specifically. That is what Backster proposed and what failed. Almost every popular defence of this book quietly retreats from the second to the first when challenged.
Backster and the Polygraph
Cleve Backster was a polygraph examiner, trained in the interrogation use of the instrument, not a plant physiologist. In February 1966, by his account, he attached polygraph electrodes to a dracaena in his office and watched the trace.
His reported findings, published in 1968 in a parapsychology journal, were dramatic. The trace changed when he formed the intention of burning a leaf, before he moved. Plants registered the death of brine shrimp dropped into boiling water in another room. A plant could apparently identify, from among several people, the one who had earlier destroyed another plant.
He called the proposed faculty primary perception and argued it operated at a level beneath the senses, common to all living cells.
The instrument matters to how this was received. A polygraph is a piece of laboratory equipment producing a continuous physical trace, and a trace looks like data. What a polygraph measures in humans is skin conductance, itself a contested proxy for arousal, and what it measures when attached to a plant is electrical resistance affected by moisture, temperature, contact quality and the movement of anyone nearby.
One detail about Backster's own position deserves recording, because it shows how the claim insulated itself. He held that primary perception operated at the level of the individual cell rather than the organism, which is why he extended the work to yoghurt cultures, eggs and human cheek cells in later years. That move is theoretically convenient: it explains why plants without sense organs could perceive, and it simultaneously removes any structural constraint on where the effect might appear. A hypothesis that predicts a response from any living tissue under any circumstance predicts nothing in particular, and cannot be shown wrong by any specific negative result. Backster spent decades reporting positive findings and the field never accumulated, which is the signature of a claim shaped so that failure cannot register against it.
What Happened When People Checked
The claims were tested, which is the part popular accounts omit.
At the American Society of Plant Physiologists meeting in June 1974, independent and well-controlled experiments were described that had attempted to reproduce Backster's results and had failed. At the 141st annual meeting of the American Association for the Advancement of Science, researchers from Cornell and elsewhere presented controlled replications which found no evidence supporting the claims, and a panel of biologists concluded that the primary perception hypothesis was unsupportable.
The pattern in the failed replications is instructive. When the experimenter was blind to the timing of events, the effects disappeared. When the plant was isolated from vibration, temperature change and the movement of people, the effects disappeared. When automated equipment triggered the stimulus with no person present, the effects disappeared.
Backster's response was that the phenomenon does not perform under sceptical conditions and requires the involvement of an experimenter in genuine relationship with the plant. That reply is unfalsifiable by construction, and once a claim requires a sympathetic observer to appear, it has left the domain where evidence can settle anything.
The honest state of the question
Fifty years on there is no protocol that produces reliable replication of the Backster effect. That is not a temporary gap awaiting better instruments. It is the ordinary way a proposed phenomenon is found not to exist. A reader who wants to keep the possibility open is entitled to, and should be clear that they are holding it as a hope rather than as a finding.
The Rest of the Book
Backster is the centre but not the whole of it, and the other material fails in ways worth distinguishing, because they are not all the same kind of failure.
Jagadish Chandra Bose. The book leans on the Indian polymath who, in the early twentieth century, built sensitive instruments to record plant electrical responses to stimuli. Bose was a serious scientist and his instrumentation was genuinely innovative. His finding that plants produce measurable electrical responses to injury and stimulus is correct and has been confirmed. What Tompkins and Bird add is the interpretation that these responses indicate feeling, which Bose's data cannot establish and which does not follow from it. Here real work is being extended past its reach.
The music experiments. Claims that plants grow better toward certain music and away from others rest on studies with tiny samples, no blinding, and no control for the vibration, heat and airflow that playing music in a small space produces. This is not fraud, it is amateur experimental design, and the results have not held.
Kirlian photography. Presented in the book as revealing an energy field around living tissue, including a phantom outline where part of a leaf has been cut away. The images are real and their cause is well understood: corona discharge, strongly affected by moisture, pressure and the exposure conditions. The phantom leaf effect has straightforward physical explanations involving residual moisture on the plate.
Dowsing and radionics. The later chapters move into territory with no evidential support at all, and their presence tells you something about the editorial standard applied throughout.
Three different failures, one book
Sorting them is worth the effort because it stops the argument becoming all-or-nothing. Bose is good work over-interpreted. The music studies are bad experiments. The radionics material is unsupported from the start. A reader who defends the book as a whole has to defend all three, and a reader who dismisses it entirely loses Bose, who was doing something real. The useful habit is to grade the claims separately rather than to accept or reject the volume.
Why It Persuaded So Many People
The book's success is more interesting than its content, and worth understanding by anyone who cares about how ideas spread.
It arrived in 1973 to a readership already estranged from institutional authority, watching official science defend positions that turned out to be industry-serving. In that atmosphere, a claim rejected by scientists carried a certain credibility on the face of it, and the rejection functioned as evidence.
The writing is good. Tompkins and Bird tell stories well, and a book of vivid episodes beats a careful literature review on every measure except accuracy.
And the equipment did enormous work. Electrodes, a chart recorder, a continuous trace on paper. The apparatus of measurement was present, which persuades readers that measurement occurred. What was absent was the rest of the method: controls, blinding, independent replication, and a mechanism that could be stated and tested.
The result was a book with the appearance of science and the epistemology of anecdote, arriving exactly when a large audience wanted to hear it.
What Turned Out to Be True Anyway
Here is the uncomfortable part for sceptics, and the reason this review is not simply dismissive.
The general intuition, that plants are far more responsive to their surroundings than the mid-century mechanical picture allowed, was correct. Plants release volatile compounds when damaged, and neighbouring plants exposed to those compounds alter their own chemical defences. They detect the quality and direction of light and adjust growth accordingly. They respond to touch, to gravity, and in some studies to vibration. They exchange carbon and nutrients through mycorrhizal fungal networks connecting their roots.
None of that requires perception, emotion, or awareness of a human being's private intentions. It is signalling and response in organisms with no nervous system, which is genuinely strange and does not need improving.
So Tompkins and Bird were pointing in a direction where something real was located, and the specific route they took led nowhere. Being roughly right about the territory while being wrong about everything checkable is a common and underrated failure mode.
The Cost of Getting It Wrong
This is the part that matters most for a reader of this site.
The failure of this book did not merely leave the question where it was. It made the defensible version harder to argue for a generation. Researchers working on plant signalling with proper controls found their work associated in the public mind with talking to houseplants and polygraph traces, and had to spend energy distancing themselves from a popular account they had never endorsed. Journals became warier. Careful claims about plant behaviour were received with the eye-rolling that Backster had earned.
Overstatement is not a neutral error that gets corrected later. It poisons the ground for the modest version of the same claim.
The lesson worth carrying
Anyone who believes the living world is more than mechanism has a direct interest in that case being made carefully, because a carelessly made case is worse for the position than silence. This book is the clearest available demonstration. It took a real intuition, dressed it in borrowed scientific authority, could not survive testing, and left the honest version of its own claim weaker than it found it. Our reading is that the discipline this requires, holding a conviction while refusing to overstate the evidence for it, is the single most valuable habit a spiritual reader can develop, and the one most often skipped.
The same fault line, less severely, runs through The Hidden Life of Trees, and the positive example of reverence carried by evidence is Rachel Carson's Silent Spring.
What Goethean Observation Actually Is
This book is sometimes invoked as support for a participatory approach to nature, and the tradition it is borrowed from would not recognise it.
Goethe's method of studying plants, later formalised by Rudolf Steiner, is a discipline of attention. You observe a plant through its transformations over time, holding back the concepts you already have, until the organising pattern of its development becomes apparent. Goethe worked this way for decades and produced a morphology, an account of how plant forms relate to one another as variations of a common process.
Nothing in that method claims plants have emotions, read intentions, or perceive at a distance. It makes a claim about the observer rather than about the plant: that trained sustained attention can perceive relationships which a single measurement cannot.
The distinction matters because the two get conflated constantly. Goethean observation is demanding and produces nothing dramatic. Backster's claims are dramatic and require nothing of the observer but a machine. They are opposite kinds of enterprise, and the second borrows credibility from the first.
Practice: the actual discipline
Take one plant you can visit regularly. Over six weeks, draw it four times, badly, without reference to photographs. Do not interpret, do not ask what it is feeling, do not conclude anything. Simply record the form as it changes. What emerges is not a message from the plant. It is the beginning of a capacity in you to see a developmental process rather than a series of static objects, which is what Goethe was training. It is slower and duller than anything in this book, and unlike anything in this book it works.
Who Should Read It
Read it if you are interested in how claims propagate. It is an excellent case study in scientific costume, countercultural timing, and the difference between having evidence and having apparatus.
Read it if you find yourself drawn to material that mainstream science rejects, and want a clear example of a case where the rejection was correct. Building that discrimination is more valuable than any individual claim.
Do not cite it. Do not use it in an argument. Do not give it to someone as an introduction to plant science, which is what still happens and is how the confusion perpetuates.
Our position: a fascinating and thoroughly unreliable book, worth reading as history and worthless as evidence. The intuition underneath it was sound and the execution damaged the very case it was trying to make. Take that lesson, which is genuinely valuable, and get your plant science elsewhere.
For the careful treatment of what plants actually do, see plant consciousness research, and for the disciplined observational tradition, Goethean science. Readers interested in the older tradition of treating nature as populated, held as tradition rather than presented as biology, should see nature spirits and elementals, and the ethical framework in A Sand County Almanac.
Read it as history, not as evidence.
Affiliate disclosure: Thalira earns a small commission on purchases made through the link above, at no additional cost to you. We recommend books we have read and think are worth your time, and we say plainly when we think parts of them are weak.
Frequently Asked Questions
What is The Secret Life of Plants about?
Peter Tompkins and Christopher Bird's 1973 bestseller arguing that plants perceive, respond emotionally to human intention, and register events at a distance. Its central evidence is the work of Cleve Backster, a polygraph examiner who attached electrodes to a houseplant and reported responses he attributed to what he called primary perception.
What is the Backster effect?
Cleve Backster's claim, published in 1968, that plants connected to polygraph equipment show electrical responses when a person merely intends to harm them, and register the death of nearby organisms. He named the proposed faculty primary perception. The claim entered popular culture through this book and was rejected by the scientific community.
Has the Backster effect been replicated?
No. Independent, well-controlled attempts to reproduce the results were presented at a plant physiology meeting in June 1974, and further controlled replications by researchers at Cornell and elsewhere were reported at the AAAS annual meeting. None found evidence supporting primary perception, and a panel of biologists judged the hypothesis unsupportable. No protocol producing reliable replication has been established since.
Is anything in the book true?
The underlying intuition, that plants are more responsive to their environment than a purely mechanical picture allows, has since been vindicated by real research. Plants do signal chemically, do respond to touch, light quality and vibration, and do exchange resources through fungal networks. None of that requires perception, emotion or awareness of human intention, which is what the book actually claims.
Why was the book so influential?
It arrived in 1973 into a readership already suspicious of institutional science and hungry for evidence that the living world was more than mechanism. It was well written, full of striking anecdotes, and presented laboratory equipment as the source of its claims. That combination of countercultural sympathy and scientific costume was extremely persuasive and its influence long outlasted its credibility.
Do plants respond to music or being talked to?
The evidence for music is weak and the studies are poorly controlled. Talking to a plant may benefit it for a mundane reason unrelated to communication, since a person speaking close to a plant increases local carbon dioxide slightly, and someone who talks to their plants is generally a person who is paying attention to them and watering them correctly.
Should I read The Secret Life of Plants?
Read it as a historical document rather than as an account of plants. It is genuinely interesting on how a claim spreads, how scientific apparatus can lend authority to work that has not earned it, and what a generation wanted to believe. Do not cite it, and do not use it as an argument for anything, because everything load-bearing in it failed replication.
What does the failure of this book teach?
That a correct intuition can be attached to a wrong mechanism, and that the wrong mechanism does the intuition long-term damage. Serious plant signalling research spent decades having to distance itself from Backster, and researchers making careful claims were tarred with the popular version. Overstating a case does not merely fail; it makes the defensible version harder to argue.
What does actual plant science say now?
That plants sense and respond to a remarkable range of stimuli through chemical and electrical mechanisms with no nervous system involved. They release volatile compounds when damaged which neighbours respond to, they detect light quality and direction, and they exchange material through mycorrhizal fungi. The word most researchers avoid is perception, because responding is not the same as experiencing.
How does this compare to The Hidden Life of Trees?
They fail in the same direction and by different amounts. Wohlleben builds on real published research and overstates what it establishes. Tompkins and Bird build on work that never replicated at all. Wohlleben's book is a case of interpretation running past evidence; this one is a case of the evidence not being there.
Does Goethean science support these claims?
No, and it is worth being clear about that. Goethe's method requires prolonged disciplined observation of a phenomenon with your own concepts held back, and it makes no claim that plants have emotions or read human intention. It is a discipline of attention, not a theory of plant consciousness, and invoking it to support Backster misrepresents it.
What should I read instead?
For the real science of plant signalling, current work on plant behaviour and mycorrhizal networks, read critically. For disciplined participatory observation of plants, Goethe's Metamorphosis of Plants, which is the genuine article this book gestures at. For nature writing that respects evidence, Rachel Carson and Aldo Leopold.
Hold the conviction, check the claim
You can believe the living world exceeds the mechanical account and still refuse to accept bad evidence for it. Those are not in tension. They are the same discipline, and this book is what happens when only the first half is present.
Sources & References
- Tompkins, P., and Bird, C. (1973). The Secret Life of Plants. Harper and Row.
- Backster, C. (1968). Evidence of a primary perception in plant life. International Journal of Parapsychology, 10(4).
- Kmetz, J. M. (1978). Plant primary perception: the other side of the leaf. The Skeptical Inquirer.
- Galston, A. W., and Slayman, C. L. (1979). The not-so-secret life of plants. American Scientist.
- Goethe, J. W. von. (1790). The Metamorphosis of Plants.
- Steiner, R. Goethean Science (GA 1). Rudolf Steiner Press.
- The Skeptic's Dictionary. Plant perception (the Backster effect). skepdic.com.
- Psi Encyclopedia, Society for Psychical Research. Cleve Backster. psi-encyclopedia.spr.ac.uk.