Summaries of the studies of linking minds through telepathy using the ganzfeld technique
Source: AN ASSESSMENT OF THE EVIDENCE FOR PSYCHIC FUNCTIONING Professor Jessica Utts, Division of Statistics, University of California, Davis. (http://anson.ucdavis.edu/~utts/air2.html
The ganzfeld technique is used to measure whether a receiver can know what a sender in a separate room is viewing. The technique uses sensory deprivation to test for telepathy. Ping-pong balls are put over the receiver's eyes and headphones over the ears. White noise is played through the headset and a bright red light in the room creates a featureless wall before the receivers eyes when seen through the ping pong balls. The receiver's eyes lose focus and have a cloudy view after a while. At the same time, the sender in another room is shown a visual stimulus such as a short video clip. The sender tries to transmit telepathically what he or she is seeing to the subject in the ganzfeld room.
The video clips or other visual stimuli are selected randomly from a large set of items. While the sender concentrates on the target, the receiver provides a continuous verbal report of what he or she seems to see in the cloudy, unfocused wall created by the halved ping-pong balls. Images the viewers describe are compared with the images seen by the subjects. Finally, at the completion of the ganzfeld period, the receiver is presented with several video clips, pictures, or objects, one of which was what the sender was actually seeing, and, without knowing which was the target, is asked to rate the degree to which each matches the image experienced during the ganzfeld period. If the receiver assigns the highest rating to the target stimulus, it is scored as a "hit." Thus, if the experiment uses judging sets containing four stimuli (the target and three decoys or control stimuli), the hit rate expected by chance is .25.
Typically, the ganzfeld experiments show a hit rate of around .35, indicating that the sender and receiver's minds were linked even when separated in different rooms.
Dr. Utts reviewed the studies using the ganzfeld technique at the request of the U.S. government to determine whether they were valid. This is the result of her research.
5.1. Conceptual Similarity: Ganzfeld Experiments
While remote viewing has been the primary activity at SRI and SAIC, other researchers have used a similar technique to test for anomalous cognition, called the ganzfeld. As noted in the SAIC Final Report of 29 Sept. 1994, the ganzfeld experiments differ from remote viewing in three fundamental ways. First, a "mild altered state is used," second, senders are [usually] used, so that telepathy is the primary mode, and third, the receivers (viewers) do their own judging just after the session, rather than having an independent judge.
The ganzfeld experiments conducted at Psychophysical Research Laboratories (PRL) were already mentioned in Section 3.4. Since the time those results were reported, other laboratories have also been conducting ganzfeld experiments. At the 1995 Annual Meeting of the Parapsychological Association, three replications were reported, all published in the peer-reviewed Proceedings of the conference.
The ganzfeld experiments differ in the preferred method of analysis as well. Rather than using the sum of the ranks across sessions, a simple count is made of how many first places matches resulted from a series. Four rather than five choices are given, so by chance there should be about 25% of the sessions resulting in first place matches.
5.2 Ganzfeld Results from Four Laboratories
In publishing the ganzfeld results from PRL, Bem and Honorton (1994) excluded one of the studies from the general analysis for methodological reasons, and found that the remaining studies showed 106 hits out of 329 sessions, for a hit rate of 32.2 percent when 25 percent was expected by chance. The corresponding p-value was .002. As mentioned earlier, the hallmark of science is replication. This result has now been replicated by three additional laboratories.
Bierman (1995) reported four series of experiments conducted at the University of Amsterdam. Overall, there were 124 sessions and 46 hits, for a hit rate of 37 percent. The hit rates for the four individual experiments were 34.3 percent, 37.5 percent, 40 percent and 36.1 percent, so the results are consistent across his four experiments.
Morris, Dalton, Delanoy and Watt (1995) reported results of 97 sessions conducted at the University of Edinburgh in which there were 32 successes, for a hit rate of 33 percent. They conducted approximately equal numbers of sessions under each of three conditions. In one condition there was a known sender, and in the other two conditions it was randomly determined at the last minute (and unknown to the receiver) that there would either be a sender or not. Hit rates were 34 percent when there was a known sender and when there was no sender, and 28 percent when there was a sender but the receiver did not know whether or not there would be. They did discover post hoc that one experimenter was more successful than the other two at achieving successful sessions, but the result was not beyond what would be expected by chance as a post hoc observation.
Broughton and Alexander (1995) reported results from 100 sessions at the Institute for Parapsychology in North Carolina. They too found a similar hit rate, with 33 hits out of 100 sessions, or 33 percent hits.
Results from the original ganzfeld work and these three replications are summarized in Table 3, along with the SRI and SAIC remote viewing results. The effect sizes for the ganzfeld replications are based on Cohen's h, which is similar in type to the effect size used for the remote viewing data. Both effect sizes measure the number of standard deviations the results fall above chance, using the standard deviation for a single session.