Ganzfeld experiment

The Ganzfeld experiment is a pseudoscientific technique used by advocates of parapsychology to test persons for so-called extrasensory perception (ESP). 
==Experimental conditions==
In this "experiment", a person wearing headphones is placed in a room in relaxed mood half-lying in a comfortable chair. Halved ping-pong balls are placed over his/her eyes with red light shone on them. This makes quite striking imagery for pseudoscience documentaries and is presumably only for this purpose. In the course of the "experiment", a "sender" sends information about an object ("target") to the "receiver" (the person) and the "receiver" tells what they are seeing. At the end of this process, the "experimenter" shows the "receiver" some possible "targets" from which they decide which resembled the image they saw during the "experiment".
==Studies==
The psychologist Ray Hyman (1985) reviewed forty-two studies from the ganzfeld experiment and concluded "I believe that the ganzfeld psi data base, despite initial impressions, is inadequate either to support the contention of a repeatable study or to demonstrate the reality of psi. Whatever other value these studies may have for the parapsychological community, they have too many weaknesses to serve as the basis for confronting the rest of the scientific community".Hyman, R. (1985). The Ganzfeld Psi Experiment: A Critical Appraisal. Journal of Parapsychology 49: 3–49. According to Terence Hines in his book Pseudoscience and the Paranormal (2003):
The ganzfeld studies contained serious flaws such as inadequate randomization; sensory leakage (in some cases, the receivers could hear what was going on in the sender's room next door and, it was possible for the sender's fingerprints to be visible on the target object for the receiver to see); and inappropriate statistical analysis.Dunning, B. (2013). Ganzfeld Experiments. Skeptoid Podcast. Skeptoid Media, Inc. Parapsychologists were embarrassed over this issue. 
In response, the parapsychologist Charles Honorton co-wrote a paper in 1986 with Hyman that called for additional studies with better, more precise methodologies that would help rule out nonparanormal sources of above-chance results.Hyman, R., and C. Honorton. (1986). A Joint Communique: The Psi Ganzfeld Controversy. Journal of Parapsychology 50: 350–64. Daryl Bem and Honorton (1994) published a review of ganzfield studies and concluded they were evidence for ESP.Bem, D., and C. Honorton. (1994). Does Psi Exist? Replicable Evidence for an Anomalous Process of Information Transfer. Psychological Bulletin 115: 4–18. But it turned out that there was a serious problem with their review. 
The psychologists Julie Milton and Richard Wiseman (1999) published a critique of that review and an analysis of additional new ganzfeld studies. They discovered that Bem and Honorton had counted the results of some studies as being statistically significant when they actually were not significant. This error led Bem and Honorton to conclude that the studies they reviewed had shown, overall, that ESP was operating in the ganzfeld. Milton and Wiseman reviewed thirty ganzfeld studies and they showed no effect greater than chance.Milton, J., and R. Wiseman. (1999). Does Psi Exist? Lack of Replication of an Anomalous Process of Information Transfer. Psychological Bulletin 125:387–91. Milton and Wiseman concluded:
Pseudoscientific experiments in parapsychology such as the ganzfeld studies are not evidence for psi. Consistent, independent replication has not been achieved.
==Usual outcome==
In reality, the entire "experiment" is a trick. The "experiment" is not always done in a soundproof room. The "receiver" and the "experimenter" can easily hear when videos were playing during the "experiment". Involuntary cues are given to the "receiver" during the selection procedure.
==External links==
*New Analyses Raise Doubts About Replicability of ESP Findings - Skeptical Inquirer
*Ganzfeld - Skeptic's Dictionary
==References==