Cleve Baxter’s plant experiment

A galvanometer is a machine used to detect a weak electric current. By attaching it to a human body, the change in a person’s thought or emotion can be detected through the measurement of the human body’s electrical potential, which is recorded on a graph. One day, on impulse, Cleve Backster, America’s foremost lie-detector examiner attached the electrodes of a polygraph (lie detector) to a leaf of his dracaena (a foliage plant) in his laboratory, and tried to observe any change which might occur in the galvanometer as a result of threatening the plant as he might threaten a human suspect.

To his surprise, a dramatic change occurred in the movement of the needle of the galvanometer. The dracaena perceived Backster’s threat and responded to it. Later he made the same test on more than twenty-five different varieties of plants and fruits, and all the results were the same. It is concluded, therefore, that plants are sentient. Peter Tompkins & Christopher Bird, The Secret Life of Plants (New York: Harper and Row Publishers, 1973), 3-6.