Research on extrasensory perception and controversial interpretations: research on the ganzfeld

Psychologists who study telepathy rejoiced in 1994 when a study published in a scientific journal seemed to confirm the existence of extrasensory perception, also known as psi perceptions. But further analysis of new research using the same protocol left thinking that this was rejoicing may be premature.


Defenders of the existence of psi and skeptics agree that the most rigorous method for studying psi is usually called the ganzfeld procedure (uniform field in German). Indeed, the skeptical psychologist Ray Hyman and Charles Honorton had drawn together in 1986 the "Joint Communique" which detailed a rigorous protocol Ganzfeld avoiding any potential bias.

In this protocol, researchers try to remove any sensory disturbance to allow the emergence of a telepathic communication between two subjects called sender (agent) and receiver (percipient).

When searching using the Ganzfeld, the receiver, which is sometimes not informed that he participates in a parapsychology experiment, described in a slightly altered state of consciousness thoughts for 30 minutes. In another room, the sender, which can sometimes hear what the receiver says, sees a target that can be a video or photo. The sender is trying to focus to transmit telepathically the target receiver. The receiver then chooses one of four targets that it seems to be closest to what he felt and saw during the previous 30 minutes.

In 1994, psychologist Daryl J. Bem of Cornell University and his colleague Charles Honorton, University of Edinburgh in Scotland, described the surprising results from a series of 11 experiments conducted by Honorton ganzfeld. They found that the receivers chose the picture corresponding to that seen by the sender more often than would the mere accident.

Then, psychologists Julie Milton of the University of Edinburgh and Richard Wiseman of the University of Hertfordhsire, England, gathered the results of 30 ganzfeld experiments using a statistical method called meta-analysis. In the July 1999 issue of Psychological Bulletin, the newspaper where Bem and Honorton had presented their results, Milton and Wiseman reported that their calculations showed that this statistical analysis did not support the existence of extrasensory perception.

"This new study fails to replicate previous research findings, but clearly we do not know why," says Milton.

This meta-analysis engendered heated debate among parapsychologists. Some argumentèrent that Milton and Wiseman had collected so irrelevant that 30 research protocols were too disparate. Milton replied that the standard statistical tests showed it was possible to treat this research as a continuum.

Bem explains "why the effect is not significant is that there are three studies which bring the whole to a level not significant, yet it turns out that these studies do not use the standard settings Ganzfed ".

Following the publication of this meta-analysis, nine new research using the ganzfeld procedure were published. Milton was agree that the psi effect became significant if the meta-analysis took into account the new research. However, she indicated that one study was performed particularly significant and that there were no effects found clearly in all research.

In 2001, Daryl J. Bem, John Palmer and Richard Broughton published a new analysis of 40 studies using the ganzfeld (the 30 already studied by Milton and Wiseman 10 and new research) and showed that significant results were obtained when the procedures used Ganzfeld standard settings. These results are currently parapsychologists in a delicate situation. They would like to explore new settings to try to make these results more reproducible, but attempts in this regard have been failures, as the Ganzfeld seems unable to lead to meaningful results if the researchers use the standard settings.