Cleve Backster

Grover Cleveland „Cleve“ Backster Jr. (February 27, 1924 – June 24, 2013) was an interrogation specialist for the Central Intelligence Agency (CIA), best known for his experiments with plants using a polygraph instrument in the 1960s which led to his theory of primary perception where he claimed that plants feel pain and have extrasensory perception (ESP), which was widely reported in the media. These claims have been rejected by the scientific community.


Backster’s study of plants began in the 1960s, and he reported observing that a polygraph instrument attached to a plant leaf registered a change in electrical resistance when the plant was harmed or even threatened with harm. His work was inspired by the research of physicist Jagadish Chandra Bose, who claimed to have discovered that playing certain kinds of music in the area where plants grew caused them to grow faster. Bose used a crescograph to measure plant response to various stimuli and demonstrated feeling in plants. From the analysis of the variation of the cell membrane potential of plants under different circumstances, he hypothesized that plants can „feel pain, understand affection etc“ and wrote two books about it in 1902 and 1926.


In February 1966, Backster attached polygraph electrodes to a Dracaena cane plant, to measure at first the time taken for water to reach the leaves. The electrodes are used to measure galvanic skin response and the plant showed readings which resembled that of a human.


This made Backster try different scenarios, and the readings went off the chart when he pictured burning the leaf, because according to him, the plant registered a stress response to his thoughts of harming it. He conducted another similar experiment where he observed a plant’s response to the death of a brine shrimp in another room; his results convinced him that plants demonstrated telepathic awareness.


He argued that plants perceived human intentions, and as he began to investigate further, he also reported finding that other human thoughts and emotions caused reactions in plants, which could be recorded by a polygraph instrument. He termed the plants‘ sensitivity to thoughts „Primary Perception„, and published his findings from the experiments in the International Journal of Parapsychology in 1968.


Soviet scientists invited Backster to the first Psychotronic Association conference in Prague in 1973 and his paper was entitled „Evidence of Primary Perception at a Cellular Level in Plant and Animal Life“.


After 1973, he further experimented on yoghurt bacteria, eggs and human sperm and he claimed his results showed „primary perception“ could be measured in all living things.