Ever since Peter Tompkins and Christopher Bird wrote in their book The Secret Life of Plants, about an experiment of a former CIA polygraph expert, Cleve Backster, things have never been the same in people’s thinking about plant consciousness and intelligence.
Backster hooked a polygraph (lie detector) machine to a plant, sat near it and began thinking evil thoughts, like setting fire to the plant. The polygraph “went crazy”; Backster reasoned that the plant could read his mind.
Later, when others tried the same experiment and failed, he is said to have observed that you first need to develop a rapport with the plant.
Regardless, after The Secret Life of Plants, many have developed the conviction that plants could think. Some play classical music to them to make them yield better fruits.
Zoe Schlanger — a climate report at The Atlantic and author of The Light Eaters, which explores plant intelligence — has described in an interview about an extremely interesting experiment made by Heidi Appel of the University of Ohio. Knowing that plants respond to caterpillars chewing on them by sampling the caterpillar saliva and using the information to generate the exact chemical compounds that attract parasitic wasps that kill the caterpillar by injecting their eggs into it, Heidi recorded caterpillar chewing sounds and played them to the plants. The plant responded exactly as how they would if they were being chewed by real caterpillars.
A person known to this writer once teased a young creeper by moving the support all around (over many days). After a few attempts the creeper stopped following the support, leading him to conclude that creepers have “self-respect”.
Well, the evidence on plant intelligence is far from conclusive, but perhaps enough for us to be kind to plants.