Ganzfeld experiment

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Participant of a Ganzfeld Experiment which proponents say may show evidence of telepathy.
Participant of a Ganzfeld Experiment which proponents say may show evidence of telepathy.

A ganzfeld ("total field") experiment uses audio and visual sensory deprivation to test individuals for extra-sensory perception (ESP).

Many ganzfeld experiments have yielded results that deviate from randomness to a highly significant degree, and it is claimed that these results present some of the strongest quantifiable evidence for paranormal phenomena to date.[citation needed]

The results of the Ganzfeld are controversial, sometimes even within the field of parapsychology itself. The debate is well-documented in journals such as the Journal of Parapsychology, and in articles such as those referred to below.[citation needed]

Contents

[edit] Telepathy - the search for evidence

The ganzfeld experiments are among the most recent in parapsychology for testing the existence of and affecting factors of telepathy, the ability to communicate information from one person's mind to that of another without resorting to normal means. After the initial success of the forced-choice card-guessing telepathy experiments of J. B. Rhine and his associates, researchers noted a "decline effect" where the accuracy of card guessing would decrease over time for a given subject, which some parapsychologists attributed to boredom. Some parapsychologists turned to free response experimental formats where the target was not limited to a small finite predetermined set of responses (e.g., zener cards), but rather could be any sort of picture, drawing, photograph, movie clip, piece of music, etc.

Recent surveys [citation needed] and anecdotal reports over the centuries had indicated that spontaneous psi phenomena are frequently reported in states other than normal consciousness, such as dreaming, hypnosis, meditative states, etc. In the mid-1970s, from these reports several parapsychologists, Charles Honorton, William Braud, and Adrian Parker, independently hypothesized that psi signals may in fact be available most of the time, but are masked for most people by all the cognitive or environmental "noise" that we commonly experience during the normal conscious state, while the noise is reduced in these altered states, allowing better access to the psi signals. To test this hypothesis, they developed ganzfeld experiments.

[edit] Experiments - defined

Ganzfeld experiments aim to reduce such cognitive or environmental noise through a mild form of sensory deprivation. This is done by covering the subject's eyes with a translucent mask of ping-pong ball halves, placing headphones over the subject's ears and playing a mild white noise through them, and having the subject relax on a couch or waterbed. Sometimes additional relaxation exercises are incorporated.

Once the subject has been immersed in the ganzfeld for some minutes, then the subject, acting as "receiver", is asked to access through psychic means some target. The target is typically a picture or video clip selected randomly from a large pool, which is then being viewed in a remote location by another subject acting as "sender". The subject (receiver) verbalizes his/her impressions, which are recorded and transcribed. Then the transcript, the actual target, and three other randomly chosen dummy targets are submitted in random order to independent judges. The judges are asked to rank-order the four targets against the transcript for best match. A "hit" is recorded if a judge ranks the actual target as the best match for the transcript (i.e., the actual target is ranked 1); otherwise (where the one of the three dummy targets is ranked 1) a "miss" is recorded. Over a series of such trials, a random ranking (null hypothesis) would result in an expected hit ratio of 1 in 4, or 25%. In these experiments, the subject (receiver), the judges, and the experimenter(s) working with them are to be kept "blind" as to what the actual targets are for any transcript until after judging is complete.[citation needed]

[edit] History of experiments

Claims have been made that over many such trials conducted in many labs around the world, the average hit rate has been closer to 35% rather than the 25% expected by null hypothesis (10% above chance). Such a result would be highly significant statistically.

In 1982, Charles Honorton presented a meta-analysis of the studies to date at a meeting of the Parapsychological Association, concluding that this was sufficient to establish the existence of psi phenomena. Prominent critic and skeptic Ray Hyman disagreed. This led to separate meta-analyses by each of them published in 1985 in the Journal of Parapsychology covering 42 ganzfeld studies conducted in 10 labs around the world. Honorton concluded that of the 28 studies that used similar scoring methods, 23 reported higher-than-chance hit rates, for a combined odds against chance of ten billion to one.

Honorton and Hyman's respective analyses agreed on some points, such as that something interesting was going on, and that selective reporting (the "file drawer problem" — publication bias) could not account for the results. However they disagreed on other points, most importantly as to whether the studies established the existence of psi phenomena. Specifically, Hyman pointed to potential design flaws in the experiments. This led to a joint communique between the two published in 1986 outlining more stringent standards for experimental protocols and their reporting and evaluation that they agreed should be met in order before a definitive statement could be made regarding the existence of psi phenomena in the ganzfeld.

In 1983 preceding the joint communique, Honorton and his colleagues, notably Rick Berger, designed a new series of largely automated experiments, now called the "autoganzfeld", that adhered to the new Honorton-Hyman guidelines. The experimental design was reviewed by two independent observers, both stage magicians who specialized in the simulation of psi phenomena, and they gave their stamp of approval to the security of the design as it was described.

Autoganzfeld experiments continued until 1989, when funding dried up for Honorton's lab. Over the six-year period, 11 series of tests totaling 354 sessions were conducted with a variety of subjects, with an overall hit rate of 34% (9% above chance). The odds against such results occurring by chance is 45,000 to 1, implying that (a) the experiments had proved that a parapsychology phenomena existed, (b) there was another design flaw in the experiments, (c) there were errors in the statistical analysis, or (d) there was fraud.

Since 1989, ganzfeld studies have continued at many labs, with meta-analyses published from time-to-time, both favorable and unfavorable to the psi hypothesis. One of the most recent such reviews is that of Bem, Broughton & Palmer cited below.

[edit] Criticism

The following are common criticisms of some or all of the Ganzfeld experiments:

Isolation - 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.[1]

Handling cues - Only 36% of the studies performed used duplicate images or videos, so handling cues on the images or degradation of the videos may have occurred during the sending process.[2]

Randomization - When subjects are asked to choose from a variety of selections, there is an inherent bias to not choose the first selection they are shown. If the order in which are shown the selections is randomized each time, this bias will be averaged out. However, this was often not done in the Ganzfeld experiments.[3][4]

The psi assumption - The assumption that any statistical deviation from chance is evidence for telepathy is highly controversial, and often compared to the God of the gaps argument. 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. This does not rule out, however, that it could be telepathy.[5]

[edit] See also

[edit] Notes

  1. ^ Wiseman, R., Smith, M,. Kornrot, D. (June 1996). Exploring possible sender-to-experimenter acoustic leakage in the PRL autoganzfeld experiments. Journal of Parapsychology.
  2. ^ Carpenter, S. (July 31, 1999). ESP findings send controversial message. Science News. Retrieved on 2006-06-23.
  3. ^ Hyman, Ray (1985). "The ganzfeld psi experiment: A critical appraisal". Journal of Parapsychology (49): 3-49.
  4. ^ Honorton, C (1985). "Meta-analysis of psi ganzfeld research: A response to Hyman". Journal of Parapsychology (49): 51-91.
  5. ^ Carroll, Robert Todd (2005). The Skeptic's Dictionary: Psi Assumption. Retrieved on 2006-06-23.

[edit] References

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