Ganzfeld experiment
Encyclopedia
Parapsychology
The term parapsychology was coined in or around 1889 by philosopher Max Dessoir, and originates from para meaning "alongside", and psychology. The term was adopted by J.B. Rhine in the 1930s as a replacement for the term psychical research...
to test individuals for extrasensory perception (ESP). It uses homogeneous and unpatterned sensory stimulation to produce an effect similar to sensory deprivation
Sensory deprivation
Sensory deprivation or perceptual isolation is the deliberate reduction or removal of stimuli from one or more of the senses. Simple devices such as blindfolds or hoods and earmuffs can cut off sight and hearing respectively, while more complex devices can also cut off the sense of smell, touch,...
. The deprivation of patterned sensory input is said to be conducive to inwardly generated impressions. The technique was devised by Wolfgang Metzger
Wolfgang Metzger
Wolfgang Metzger is considered one of the main representatives of Gestalt psychology in Germany....
in the 1930s as part of his investigation into the gestalt
Gestalt psychology
Gestalt psychology or gestaltism is a theory of mind and brain of the Berlin School; the operational principle of gestalt psychology is that the brain is holistic, parallel, and analog, with self-organizing tendencies...
theory.
Parapsychologists such as Dean Radin
Dean Radin
Dean Radin is a researcher and author in the field of parapsychology. He has been Senior Scientist at the Institute of Noetic Sciences , in Petaluma, California, USA, since 2001, and is on the Adjunct Faculty in the Department of Psychology at Sonoma State University, on the Distinguished...
and Daryl Bem
Daryl Bem
Daryl J. Bem is a social psychologist and professor emeritus at Cornell University. He is the originator of the self-perception theory of attitude change, and has carried out research on psi phenomena , group decision making, handwriting analysis, sexual orientation and personality theory and...
say that ganzfeld experiments have yielded results that deviate from randomness
Randomness
Randomness has somewhat differing meanings as used in various fields. It also has common meanings which are connected to the notion of predictability of events....
to a significant
Statistical significance
In statistics, a result is called statistically significant if it is unlikely to have occurred by chance. The phrase test of significance was coined by Ronald Fisher....
degree, and that these results present some of the strongest quantifiable evidence for telepathy to date. Critics such as Susan Blackmore
Susan Blackmore
Susan Jane Blackmore is an English freelance writer, lecturer, and broadcaster on psychology and the paranormal, perhaps best known for her book The Meme Machine.-Career:...
and Ray Hyman
Ray Hyman
Ray Hyman is a Professor Emeritus of Psychology at the University of Oregon in Eugene, Oregon, and a noted critic of parapsychology.-Career:...
say that the results are inconclusive and consistently indistinguishable from null result
Null result
In science, a null result is a result without the expected content: that is, the proposed result is absent. It is an experimental outcome which does not show an otherwise expected effect. This does not imply a result of zero or nothing, simply a result that does not support the hypothesis...
s.
Historical context
The ganzfeld experiments are among the most recent in parapsychology for testing the existence of and affecting factors of telepathyTelepathy
Telepathy , is the induction of mental states from one mind to another. The term was coined in 1882 by the classical scholar Fredric W. H. Myers, a founder of the Society for Psychical Research, and has remained more popular than the more-correct expression thought-transference...
, which is defined in parapsychology as the paranormal acquisition of information concerning the thoughts, feelings or activity of another person. In the early 1970s, Charles Honorton
Charles Honorton
Charles Henry Honorton was an American parapsychologist.Honorton was born in Deer River, Minnesota on February 5, 1946....
had been investigating ESP and dreams at the Maimonides Medical Center
Maimonides Medical Center
Maimonides Medical Center is a non-profit, non-sectarian hospital located in Borough Park, Brooklyn. Maimonides is both a treatment facility and academic medical center with 705 beds, and more than 70 primary care and sub-specialty programs...
and began using the ganzfeld technique as a more efficient way to achieve a state of sensory deprivation in which it is hypothesised that psi can work. Since the first full experiment was published by Honorton and Sharon Harper in the Journal of the American Society for Psychical Research
American Society for Psychical Research
The American Society for Psychical Research is an organisation dedicated to parapsychology based in New York, where it maintains offices and a library. It is open to interested members of the public to join, and has a website...
in 1974, the ganzfeld has 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. The receiver also wears a set of headphones through which whiteWhite noise
White noise is a random signal with a flat power spectral density. In other words, the signal contains equal power within a fixed bandwidth at any center frequency...
or pink noise
Pink noise
Pink noise or 1/ƒ noise is a signal or process with a frequency spectrum such that the power spectral density is inversely proportional to the frequency. In pink noise, each octave carries an equal amount of noise power...
(static) is played. The receiver is in this state of mild sensory deprivation for half an hour. During this time, a "sender" observes a randomly chosen target and tries to mentally send this information to the receiver. The receiver speaks out loud during the thirty minutes, describing what he or she can see. This is recorded by the experimenter (who is blind to the target) either by recording onto tape or by taking notes, and is used to help the receiver during the judging procedure.
In the judging procedure, the receiver is taken out of the ganzfeld state and given a set of possible targets, from which they must decide which one most resembled the images they witnessed. Most commonly there are three decoys along with a copy of the target itself, giving an expected overall hit rate of 25% over several dozens of trials.
Early experiments
Between 1974 and 1982, 42 ganzfeld experiments were performed.Hyman's criticisms were that the ganzfeld papers did not describe optimal protocols, nor were they always accompanied by the appropriate statistical analysis. He presented in his paper a factor analysis that he said demonstrated a link between success and three flaws, namely: Flaws in randomization for choice of target; flaws in randomization in judging procedure; and insufficient documentation. Honorton asked a statistician, David Saunders, to look at Hyman's factor analysis
Factor analysis
Factor analysis is a statistical method used to describe variability among observed, correlated variables in terms of a potentially lower number of unobserved, uncorrelated variables called factors. In other words, it is possible, for example, that variations in three or four observed variables...
and he concluded that the number of experiments was too small to complete a factor analysis.
In 1986, Hyman and Honorton published A Joint Communiqué, in which they agreed that though the results of the ganzfeld experiments were not due to chance or selective reporting, replication of the studies was necessary before final conclusions could be drawn. They also agreed that more stringent standards were necessary for ganzfeld experiments, and they jointly specified what those standards should be.
Post-Joint Communiqué
In 1983 Honorton had started a series of autoganzfeld experiments at his Psychophysical Research Laboratories. These studies were specifically designed to avoid the same potential problems as those identified in the 1986 joint communiqué issued by Hyman and Honorton. Ford Kross and Daryl BemDaryl Bem
Daryl J. Bem is a social psychologist and professor emeritus at Cornell University. He is the originator of the self-perception theory of attitude change, and has carried out research on psi phenomena , group decision making, handwriting analysis, sexual orientation and personality theory and...
, both professional mentalist entertainers (magicians whose specialty is simulating psi effects) examined Honorton's experimental arrangements, and pronounced them to provide excellent security against deception by subjects. In addition to randomization consistent with the specifications of the communiqué, and computer control of the main elements of each test, these autoganzfeld experiments isolated the receiver in a sound-proof steel-walled and electromagnetically shielded room.
The PRL trials continued until September 1989. Of the 354 trials, 122 produced direct hits. This 34% hit rate was statistically similar to the 37% hit rate of the 1985 meta-analysis. These experiments were statistically significant with a z score
Standard score
In statistics, a standard score indicates how many standard deviations an observation or datum is above or below the mean. It is a dimensionless quantity derived by subtracting the population mean from an individual raw score and then dividing the difference by the population standard deviation...
of 3.89, which corresponds to a 1 in 45,000 probability of obtaining a hit rate of at least 34% by chance (mean chance expectation is 25%).
Concerning these results, Hyman wrote that the final verdict of whether psi can be demonstrated in the ganzfeld awaited the results of future experiments conducted by other independent investigators.
To see if other, post-Joint Communiqué experiments had been as successful as the PRL trials, Julie Milton and Richard Wiseman
Richard Wiseman
Richard Wiseman is Professor of the Public Understanding of Psychology at the University of Hertfordshire in the United Kingdom.Wiseman started his professional life as a magician, before graduating in Psychology from University College London and obtaining a Ph.D...
carried out a meta-analysis of ganzfeld experiments carried out in other laboratories. They found no psi effect, with a database of 30 experiments and a non-significant
Statistical significance
In statistics, a result is called statistically significant if it is unlikely to have occurred by chance. The phrase test of significance was coined by Ronald Fisher....
Stouffer Z
Z-test
A Z-test is any statistical test for which the distribution of the test statistic under the null hypothesis can be approximated by a normal distribution. Due to the central limit theorem, many test statistics are approximately normally distributed for large samples...
of 0.70.
This meta-analysis was criticised for including all ganzfeld experiments, regardless of the methods being used. Some parapsychologists considered that certain researchers had used protocols that were not part of the standard ganzfeld set up, such as targets consisting of music (traditional ganzfeld experiments use visual targets). These experiments did not return significant results. A second meta-analysis was conducted by Daryl Bem, John Palmer, and Richard Broughton in which the experiments were sorted according to how closely they adhered to a pre-existing description of the ganzfeld procedure. Additionally, ten experiments that had been published in the time since Milton and Wiseman's deadline were introduced. Now the results were significant again with Stouffer Z of 2.59.
In a 1995 paper discussing some of the challenges, deficiencies and achievements of modern laboratory parapsychology Ray Hyman said,
Contemporary research
The ganzfeld procedure has continued to be refined over the years. In its current incarnation, an automated computer system is used to select and display the targets ("digital autoganzfeld"). This overcomes many of the shortcomings of earlier experimental setups, such as randomization and experimenter blindness with respect to the targetsIn 2010, Lance Storm, Patrizio Tressoldi, and Lorenzo Di Risio analyzed 29 ganzfeld studies from 1997 to 2008. Of the 1,498 trials, 483 produced hits, corresponding to a hit rate of 32.2%. This hit rate is statistically significant with p < .001. Participants selected for personality traits and personal characteristics thought to be psi-conducive were found to perform significantly better than unselected participants in the ganzfeld condition.
Psi-conducive variables
Parapsychologists have investigated certain personality traits and characteristics as potential psi-conducive variables, suggesting that most researchers share the view that these variables play an important role in ESP performance. These factors are thought to be positively correlated with increased scores in ganzfeld experiments, as compared to unselected participants. Traits and characteristics of subjects thought to increase the chance of obtaining a successful hit rate in a psi experiment include:- Positive belief in psi; ESP
- Prior psi experiences
- Practicing a mental discipline such as meditation
- Creativity
- Artistic ability
- Emotional closeness with the sender
While there are a number of reasons that researchers avoid special participants and sample only normal populations, these factors are important considerations in future replications of ganzfeld experiment, and may be useful in predicting the outcome of these studies. An increasing number of researchers have moved towards more process-oriented experiments, and personality factors give the potential for directional, falsifiable hypotheses, a part of the scientific process that critics have argued that parapsychology lacks.
Criticism
There are several common criticisms of some or all of the ganzfeld experiments:Isolation — Richard Wiseman
Richard Wiseman
Richard Wiseman is Professor of the Public Understanding of Psychology at the University of Hertfordshire in the United Kingdom.Wiseman started his professional life as a magician, before graduating in Psychology from University College London and obtaining a Ph.D...
and others argue that not all of the studies used soundproof rooms, so it is possible that when videos were playing, the experimenter (or even the receiver) could have heard it, and later given involuntary cues to the receiver during the selection process. However, Dean Radin
Dean Radin
Dean Radin is a researcher and author in the field of parapsychology. He has been Senior Scientist at the Institute of Noetic Sciences , in Petaluma, California, USA, since 2001, and is on the Adjunct Faculty in the Department of Psychology at Sonoma State University, on the Distinguished...
argues that ganzfeld studies that did use soundproof rooms had a number of "hits" similar to those that did not.
Randomization — When subjects are asked to choose from a variety of selections, there is an inherent bias to choose the first selection they are shown. If the order in which they are shown the selections is randomized each time, this bias will be averaged out. The randomization procedures used in the experiment have been criticized for not randomizing satisfactorily.
The psi assumption — The assumption that any statistical deviation from chance is evidence for telepathy is highly controversial. Strictly speaking, a deviation from chance is only evidence that either this was a rare, statistically unlikely occurrence that happened by chance, or something was causing a deviation from chance. Flaws in the experimental design are a common cause of this, and so the assumption that it must be telepathy is fallacious
Fallacy
In logic and rhetoric, a fallacy is usually an incorrect argumentation in reasoning resulting in a misconception or presumption. By accident or design, fallacies may exploit emotional triggers in the listener or interlocutor , or take advantage of social relationships between people...
.
Controversy
In 1979, Susan BlackmoreSusan Blackmore
Susan Jane Blackmore is an English freelance writer, lecturer, and broadcaster on psychology and the paranormal, perhaps best known for her book The Meme Machine.-Career:...
visited the laboratories of Carl Sargent
Carl Sargent
Carl L. Sargent is a British author of several roleplaying game-based products and novels.-Early career:...
in Cambridge
Cambridge
The city of Cambridge is a university town and the administrative centre of the county of Cambridgeshire, England. It lies in East Anglia about north of London. Cambridge is at the heart of the high-technology centre known as Silicon Fen – a play on Silicon Valley and the fens surrounding the...
. She noticed a number of irregularities in the procedure and wrote about them for the Journal of the Society for Psychical Research.
This article, along with further criticisms of Sargent's work from Adrian Parker and Nils Wiklund remained unpublished until 1987 but were well known in parapsychological circles. Sargent wrote a rebuttal to these criticisms (also not published until 1987) in which he did not deny that what Blackmore saw occurred, but her conclusions based on those observations were wrong and prejudiced. His co-workers also responded, saying that any deviation from protocol was the result of “random errors” rather than any concerted attempt at fraud. Carl Sargent stopped working in parapsychology after this and did not respond "in a timely fashion" when the Council of the Parapsychological Association asked for his data and so his membership in that organization was allowed to lapse.