Do Plants Have Feelings?

By Larry Rettig (LarryR) on August 23, 2011

When I first came upon this issue a number of years ago, I chuckled to myself, deeming it silly to even pursue such a topic. But curiosity eventually got the better of me. I started doing some research.

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        Charted polygraph results

 
 
ne of the first items I ran across was a popular book, The Botany of Desire (Random House, 2001), by author Michael Pollan.  In it he views the world from a plant’s perspective.  He shows how plants manipulate their environment—and that environment includes humans—to their own benefit.  They draw us into their web in several ways:  through sweetness (fruit), beauty (blossoms), intoxication (marijuana), and desire for control of our food production (potato).  His examples are quite convincing, but he does eventually admit that the scenarios he paints are just metaphors, not actual fact.  So the book is a great read, but in the end, plants are not sentient beings after all.  Not quite what I was after.

Pioneers

Then I hit pay dirt.  It came by way of the October 1998 issue of Free Spirit Magazine.  Here is the introduction to an article on Cleve Backster in that issue:

Sometimes it happens that a person can name the exact moment when his or her life changed irrevocably. For Cleve Backster, it was early morning on February 2, 1966, at thirteen minutes, fifty-five seconds of chart time for a polygraph he was administering. One of the world's experts on polygraphs, and the creator of the Backster Zone Comparison Test, the standard used by lie detection examiners worldwide, Backster had threatened the subject's well-being in hopes of triggering a response. The subject had responded electrochemically to this threat. The subject was a plant.
 2011-08-21/LarryR/44dbcc
      Modern polygraph equipment

Backster, it turns out, perfected the modern polygraph (lie detector) used around the world.  His machine reveals human stress levels by measuring, among other things, the flow of electricity through the skin.  Subjects hooked to the machine via electrodes on their fingers or palms are asked a series of questions.  If the response to a question is a lie, the flow of electricity in the skin increases and is recorded on graph paper (or on a computer screen) as a spike by a needle that fluctuates with the electrical flow.

In his initial experiment with plants, Backster attached polygraph wires to the leaves of a potted dracena cane plant (later to a philodendron and a rubber plant as well).  Then he dipped one of the leaves in warm coffee.  No response.  He pondered about what to try next.  As soon as he thought to himself, “I'm going to light a match and burn a stem," the polygraph needle spiked wildly.  Next, in the presence of the wired plant, he dropped live shrimp into boiling water.  Without fail, whenever he dropped a shrimp into the water, the electrical current in the plant’s leaves spiked.

He was astounded.  Can plants really read human thoughts?  Can they really empathize with other creatures who are suffering?  He ultimately decided they could.

What convinced him were many additional experiments.  Here is his description of one, in his own words, during an interview with a reporter from The Sun (July 1997):

It is very very hard to eliminate the interconnection between the experimenter and the plants being tested. Even the briefest association with the plants--just a few hours--is enough to let them become attuned to you. Then, even though you automate the experiment and leave the laboratory, and even though you set a time delay switch for random intervals, guaranteeing you are entirely unaware of when the experiment starts, the plants will remain attuned to you, no matter where you go. At first, my partner and I used to go to a bar a block away, and after a time we began to grow suspicious that the plants were not responding to the death of the brine shrimp at all, but instead to the rising and falling levels of excitement in our conversations. Finally, we came up with a way around this. We had someone else buy the plants, and store them in another part of the building we didn't frequent. On the day of the experiment we went to the holding area, brought the plants in, hooked them up, and left. This meant the plants were in a strange environment, they had the pressure of the electrodes, they had a little trickle of electricity going through their leaves, and they'd been deserted. Because they were not attuned to us or to anyone else, they began "looking around" for anything that would acquaint them with their environment. Then, and only then, did something so subtle as the deaths of the brine shrimp get picked up by the plants.

Here is another from the same interview:

I was on an airplane once, and had with me a little battery-powered galvanic response meter that I could hook to electrodes. I had the aisle seat, and I can still remember the poor guy strapped in next to the window. Just as the attendants started serving lunch, I pulled out this meter and said to him, "You want to see something interesting?" I put a piece of lettuce between the electrodes, and when people started to eat their salads we got some reactivity, which stopped as the leaves went into shock. Then I said, "Wait until they pick up the trays, and see what happens." When attendants removed our meals, the lettuce got back its reactivity. The point is that the lettuce was going into a protective state so it would not suffer. When the danger left, the reactivity came back. This ceasing of electrical energy at the cellular level ties in, I believe, to the state of shock that people, too, enter in extreme trauma.

Backster’s research builds on that done by the Indian scientist, Sir Jagdish Chandra Bose, at the beginning of the 20th Century. Bose found that plants grew more quickly when subjected to pleasant music and more slowly when they experienced harsh sounds.  Without conducting the kinds of experiments that Backster did, Bose postulated that plants could feel pain and understand affection.  He claimed that the cell membranes of plants had the potential to give out different vibrations, depending on whether their reaction was positive or negative.

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               Dracaena Cane

Bose, in turn, owes his interest and exploration of plant sentience to Gustav Theodor Fechner, a professor at the University of Leipzig, who is recognized as one of the founders of modern experimental psychology.  In his book, Nanna (Verlag von Leopold Voß, 1848), he suggested that plants are capable of emotions and that lavishing attention and affection on them results in vigorous growth.  However, he didn’t pursue research on his theory.

The Naysayers

In 1975, scientists K.A. Horowitz, D.C. Lewis, and E.L. Gasteiger, repeated Backster’s experiment with shrimp.  This time the researchers introduced more control factors, grounding the plants to reduce electrical interference and rinsing them to remove dust particles.  Instead of the 13 shrimp that Backster used, they upped the number to 60.  The result was pretty unremarkable.  They got nowhere near the reactions from the plants that Backster reported.  He immediately criticized them for not understanding that the time spent rinsing the plants affected their relationship to the scientists and thus their results.

On September 6, 2006, the cast of the MythBusters TV series attempted to replicate Backster’s polygraph experiments by hooking a polygraph and later a more sensitive and thus more accurate EEG machine to plants.  The result was not statistically significant, and the show declared Backster’s claims a myth that they had “busted.”  If it's not repeatable, the show declared, it's not science.

The general scientific community sees the experiments done to date as pseudoscience as well. Most scientists feel that there is no concrete, universally verifiable evidence that the theories put forward are valid.  Their criticism reflects their belief that plant perception experiments are not conducted in properly controlled conditions and thus the results are not verifiable.  Skeptics also point out that, since plants lack nervous systems, they are incapable of having feelings or perceiving the intentions of humans.

Recent Mainstream Research

In his Web-published article, “Prodigious Plants,” Rakesh Mohan Hallen discusses the current state of mainstream science regarding plant traits similar to those of humans:

Plants do not feel pain the same way as we do, but they do sense injury to their body and can communicate it to other plants by releasing certain chemicals, which the other plants can interpret as a message. Thus plants do feel injuries and can talk with other plants but their medium of communication is not sound waves; it is through chemicals like our sense of smell.

Plants can indeed be vaccinated. But the immune system in plants is somewhat different from that in humans. In mammals, every time an infectious agent challenges the immune system, it continues to produce antibodies that are highly specific for the agent long after the invader has been defeated. This confers specific immunity to the disease. Individual plants by contrast have only a limited repertoire of resistance genes. And thus produce a hypersensitive response against a fixed set of infectious agents. Yet plants that do not possess resistance against a particular infectious organism can still acquire immunity through being exposed to some other organism. Unlike animals, plants infected with one disease can acquire immunity to a wide range of other diseases.

What does the future hold?

So where does that leave us as far as plants and their ability to perceive and react to their environments?  That plants can communicate with each other via chemistry is a recent discovery.  It raises a question about what else plants might be able to do that we haven’t yet discovered.

As far as Cleve Backster’s experiments are concerned, they will not gain credence in the scientific community unless they have been replicated many times by mainstream scientists under strictly controlled conditions with consistently positive results.  I don’t see that happening anytime soon.

________________________________________


This video shows Clive Backster performing some of his experiments.  It also shows other experiments with plant sentience by Japanese and Russian scientists that, quite frankly, strain my credulity.  The video is courtesy of YouTube.

The polygraph chart image is courtesy of Cornell University.

The other two images are courtesy of wikipedia.org and are used under the terms of the GNU Free Documentation License.


Related articles:
Cleve Backster, experiments with plants, plant interactions with humans, plants, polygraph, psychobotany

About Larry Rettig
"An enthusiastic gardener for over 50 years, my first plant was a potted Ponderosa Lemon tree ordered from a comic book ad at age 15. I still have it, and it’s still bearing lemons! My wife and I garden on 3/4 of an acre, both flowers and vegetables. Our garden, named Cottage-in-the-Meadow Gardens, is private and is listed with the Smithsonian Institution in its Archives of American Gardens. It is also on the National Register of Historic Places. We garden organically and no-till. Our vegetable garden contains a seed bank of vegetables brought to this country from Germany in the mid-1800s by my ancestors. My latest book, Gardening the Amana Way, is available at Amazon.com.

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Comments and discussion:
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I don't know... Sharon Jul 18, 2013 9:52 PM 37
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Now what do I eat? Lance Sep 11, 2011 10:43 PM 7
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We know so little pajonica Aug 28, 2011 6:40 PM 1

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