Ganzfeld experiment

A ganzfeld experiment (from the German words for "entire" and "field") is an assessment used by parapsychologists that they contend can test for extrasensory perception (ESP) or telepathy. In these experiments, a "sender" attempts to mentally transmit an image to a "receiver" who is in a state of sensory deprivation. The receiver is normally asked to choose between a limited number of options for what the transmission was supposed to be and parapsychologists who propose that such telepathy is possible argue that rates of success above the expectation from randomness are evidence for ESP. Consistent, independent replication of ganzfeld experiments has not been achieved, and, in spite of strenuous arguments by parapsychologists to the contrary, there is no validated evidence accepted by the wider scientific community for the existence of any parapsychological phenomena. Ongoing parapsychology research using ganzfeld experiments has been criticized by independent reviewers as having the hallmarks of pseudoscience.

Historical context

The ganzfeld effect was originally introduced into experimental psychology due to the experiments of the German psychologist Wolfgang Metzger (1899–1979) who demonstrated that subjects who were presented with a homogeneous visual field would experience perceptual distortions that could rise to the level of hallucinations. In the early 1970s, Charles Honorton at the Maimonides Medical Center was trying to follow in the footsteps of psychical researchers such as Joseph Banks Rhine who had coined the term "ESP" to elevate the discourse around paranormal claims. Honorton focused on what he thought was the connection between ESP and dreams and began exposing his research subjects to the same sort of sensory deprivation that is used in demonstrations of the ganzfeld effect, hypothesizing that it was under such conditions that "psi" (a catch-all term used in parapsychology to denote anomalous psychic abilities) might work. Honorton believed that by reducing the ordinary sensory input, "psi-conductive states" would be enhanced and "psi-mediated information" could be more effectively transmitted.

Since the first full experiment was published by Honorton and Sharon Harper in the Journal of the American Society for Psychical Research in 1974, such "ganzfeld experiments" have remained a mainstay of parapsychological research.

Experimental procedure

In a typical ganzfeld experiment, a "receiver" is placed in a room relaxing in a comfortable chair with halved ping-pong balls over the eyes, having a red light shone on them.