Plant perception
From Wikipedia, the free encyclopedia
Plant perception, or biocommunication in plant cells, is a belief that plants feel emotions such as fear and affection, respond to stimuli, and have the ability to communicate with other forms of life. While plants can communicate through airborne signals, and certainly have complex responses to stimuli, the belief that they possess cognitive abilities receives very little support amongst the scientific community.
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[edit] Research
The notion that plants are capable of feeling emotions was first recorded in 1848, when Dr. Gustav Theodor Fechner, a German professor, suggested the idea in his book Nanna. He believed that plants are capable of emotions, just like humans or animals, and that one could promote healthy growth by showering plants with talk, attention, and affection.[1]
One of the first to research the concept was the Indian scientist Sir Jagdish Chandra Bose, who began to conduct experiments on plants in the year 1900. He found that every plant and every part of a plant appeared to have a sensitive nervous system and responded to shock by a spasm just as an animal muscle does. One visitor to his laboratory, the vegetarian playwright George Bernard Shaw, was intensely disturbed upon witnessing a demonstration in which a cabbage had violent convulsions as it boiled to death. Bose found that the effect of manures, drugs, and poisons could be determined within minutes, providing plant control with a new precision. Bose repeated his tests on metals, administering poisons to tin, zinc, and platinum, and obtained astonishing responses which, when plotted on a graph, appeared precisely like those of poisoned animals. In addition, Bose found that plants grew more quickly amidst pleasant music and more slowly amidst loud noise or harsh sounds. He also claimed that plants can "feel pain, understand affection etc.," from the analysis of the nature of variation of the cell membrane potential of plants, under different circumstances. According to him, a plant treated with care and affection gives out a different vibration compared to a plant subjected to torture. In conclusion, he said: "Do not these records tell us of some property of matter common and persistent? That there is no abrupt break, but a uniform and continuous march of law?" [2]
Bose's experiments stopped at this conclusion, but Cleve Backster, an American scientist, conducted research that led him to believe that plants can communicate with other lifeforms. Backster's interest in the subject began in February 1966, when Backster wondered if he could measure the rate at which water rises from a philodendron's root area into its leaves. Because a polygraph or 'lie detector' can measure electrical resistance, and water would alter the resistance of the leaf, he decided that this was the correct instrument to use. After attaching a polygraph to one of the plant's leaves, Backster claimed that, to his immense surprise, "the tracing began to show a pattern typical of the response you get when you subject a human to emotional stimulation of short duration".
Led by curiosity, Backster went in search of other reactions, and decided to burn a leaf of the plant. Apparently, while he was musing upon this, there was a dramatic upward sweep in the tracing pattern. He had not moved or even touched the plant. Backster was certain that he had somehow inspired fear in the plant with his decision to burn it. He came to the resolution that, if he was correct, plants can not only feel things, but can also, in effect, read people's minds.
In the United Kingdom, the Bognor Regis Electronic Development Corporation of Sussex conducted a similar experiment. The Corporation found that their secretaries were much too busy to care for their plants, and, following the death of several of the plants through lack of water, they attached some electrodes to the plant. They reportedly discovered that the plants emitted sounds that came out through loudspeakers as mournful cries when they were in need of watering.
In 1975, three scientists (K.A. Horowitz, D.C. Lewis, and E.L. Gasteiger) published an article in Science with their results when repeating Backster's investigation of plant response to the killing of brine shrimp in boiling water. In this investigation, the researchers took into consideration control factors such as grounding the plants to reduce electrical interference and rinsing the plants to remove dust particles. Three of five pipettes contained brine shrimp while the remaining two only had water. These acted as a control because the pipettes were delivered to the boiling water at random. In addition, this investigaton used a total of 60 brine shrimp deliveries to boiling water while Backster's investigation had 13. While this experiment did show a few positive correlations, they did not occur at a rate great enough to be considered statistically viable. These experimental conditions were more rigorous and did not produce the same results.
More recently, the television show MythBusters performed an experiment aiming to either verify or disprove the concept. The tests were done by connecting plants to a polygraph's galvanometer, and then employing both actual and imagined harm upon the plants, or upon others in the plant's vicinity. The galvanometer showed some spurious readings (showing some kind of reaction about one third of the time), so a much more accurate EEG machine was used. However, when the presenters used a machine that dropped eggs randomly into boiling water, the plant had no reaction whatsoever. The show concluded that the theory was bogus.
[edit] Support and skepticism
In the scientific community as a whole, the biocommunication notion has been subjected to much criticism, and is largely regarded as a pseudoscience. Overall, there is little concrete, universally verified evidence suggesting that there is any truth to the theory, and it is therefore apt to receive a great deal of contempt among scientific circles, often disdainfully called 'the Backster Effect'. Skeptics typically criticize the fact that many experiments into 'plant perception' are not taken in controlled conditions and that therefore their results are not verifiable evidence of its existence. Many skeptics of the theory also state that, since plants lack nervous or sensory systems, they are not capable of having feelings, or perceiving human emotions or intentions, which would require a complex nervous system. [3][4] The primary emotional center in the animal brain is the limbic system which is absent in plants. [1] However, supporters of the theory say that the fact that plants do not have a limbic system does not necessarily disprove the belief that plants have emotions.
There are several reasons why plant perception investigations are considered a pseudoscience. In particular, Cleve Backster's experiments employ several of the scientific fallacies listed by Stephen S. Carey in his book "A Beginner's Guide to Scientific Method." The first fallacy in Backster’s supposition of primary plant perception is the inference of a causal link between his thoughts and the polygraph readings produced by the plants. Backster immediately assumed this causal link, however, he failed to investigate other possible explanations for the phenomenon. In making this conclusion, Backster never established evidence to support the causal link.
Another inherent flaw in Backster’s experiment is that polygraph readings are designed for humans. Polygraphs measure galvanic skin responses, resistance of skin to small electrical currents, which have been related to anxiety in humans. The use of the polygraph on plants had not been tested at the time of Backster’s experiment. He used this unsupported analogy between plant and human polygraph readings to infer that the plant was producing a stress response to his thoughts.
The theory introduced by Backster also presents an untestable explanation. After other experiments failed to support Backster’s theory that plants respond to human thoughts, he and his supporters have claimed that the plants must be “attuned” to the experimenter in order to respond. Given this ad hoc rescue, the repeatability of Backster’s experiments is limited.
Backster and Bose are not entirely alone among scientists in their view. Among the supporters of the theory are Robert B. Stone, Ph.D., a member of Mensa, and the author of The Secret Life of Your Cells, and the renowned botanist, Luther Burbank, who, in his book Training of the Human Plant, wrote that plants cannot understand the spoken word, but that they may be capable of telepathically understanding the meaning of speech.[5] Many people hold the belief that talking to their plants and showering them with attention will make them grow more speedily. These claims have been viewed with extreme skepticism.
[edit] Miscellaneous facts
English author Roald Dahl wrote a short story entitled 'The Sound Machine' dealing with the theory, in which the protagonist develops a machine that enables him to hear the sound of plants, especially when they are under pain. With the machine he hears the scream of grass being cut, and the moan of a tree when he strikes it with an axe.
[edit] References
- The Reader's Digest, Wonders of the Natural World, The Reader's Digest Association Ltd., 1975
- Stone, Robert The Secret Life of Your Cells, Whitford Press, 1994
- Jensen, D., The Plants Respond: An Interview with Cleve Backster, 2006, www.derrickjensen.org/backster.html, Accessed 30 Nov 2006
- Horowitz, K.A., Lewis, D.C, and Gasteiger, E.L. Plant 'Primary Perception': Electrophysiological Unresponsiveness to Brine Shrimp Killing, Science, New Series, Vol. 189, No. 4201 (Aug 8, 1975), pp. 478-480
- Carey, S.S. A Beginner's Guide to Scientific Method - Third Edition,Thomson-Wadsworth, 2004
- Carroll, R.T. Plant Perception (a.k.a The Backster Effect), 2005, www.skepdic.com/plants.html, Accessed 30 Nov 2006
- Tortora, Gerard J. Principles of Human Anatomy - Tenth Edition, John Wiley & Sons, Inc., 2005.
