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Published: Jun.23.2012

Plant Sensitivity to Human Spontaneous Emotion
Ben Bendig (sponsored by Ken Arnette)

The question of plant consciousness made waves in the 1960s and ’70s with the publication of research by lie detector expert Cleve Backster (1968) and the popularization of his work in The Secret Life of Plants by Tompkins and Bird (1973). By measuring electrical resistance in the leaves of plants, Backster demonstrated that plants were sensitive to events in the environment, including threats to the plant, death of nearby organisms, and human interaction, particularly human emotions. The current research sought to replicate some of Backster’s findings, focusing on spontaneous emotion during human interaction. Plant electrical activity was measured with a GSR device during conversations involving the experimenter and acquaintances, using a plant that the experimenter had cared for (Schefflera Arboricola, Trinette variety), for a duration of more than two years.

Comparisons were made of activity during 4-second intervals of time with the presence of emotions (e.g., anger, surprise, embarrassment) versus 4-second intervals of no activity in the room containing the plant, revealing a highly significant difference (p < .0001). A comparison of the emotional intervals against all other human interaction intervals was also highly significant (p < .0001). Controls employed indicate that these differences are not due to temperature, sound, or movement. Movement artifacts are particularly important to control for, as nearby movement produces electrical changes in the leaves, even without contact. Interaction intervals with possible movement artifacts were excluded from the calculations.

The importance of genuine emotion in evoking these responses points to the necessity of ecologically valid and spontaneous situations for a proper scientific study of plant perceptual responses. Further work needs to be done to replicate findings about long-distance effects, as well as other “Backster effects” involving single celled organisms and human cells. Additionally, the nature of the signal and the reason for electrical manifestation of these responses are in need of further investigation.
Contact information: Ben Bendig, M.A., C.Phil, UCLA Department of Psychology, [email protected]