5X5 Episode 87
|5X5 Episode 87|
|Psi - The Ganzfeld Experiments|
|31st March 2010|
|5X5 86||5X5 88|
|S: Steven Novella|
|B: Bob Novella|
|J: Jay Novella|
|E: Evan Bernstein|
|M: Mike Lacelle|
Psi - The Ganzfeld Experiments
You're listening to the Skeptics' Guide 5x5, five minutes with five skeptics, with Steve, Jay, Rebecca, Bob and Evan.
S: This is the SGU 5x5 and tonight we are continuing our series on psi research and we are gonna talk specifically about the ganzfeld experiments. Ganzfeld, which is from the German word for "entire field", is a specific protocol of research that was developed that involves primarily sensory deprivation. So, the procedure entails using sensory deprivation on the subject, which is hypothesised to make it more likely to be receptive to ESP or to psi and then they are tasked with, for example, guessing which one of four possible targets is being projected to them.
E: And ganzfeld experiments were invented by the German psychologist Wolfgang Metzger in the late 1920s. Metzger utilised these kinds of experiments as part of his investigation into Gestalt theory. In fact, the studies of Metzger and the ganzfeld experiments were so widely read that the word "ganzfeld" was adopted as a generally accepted term. By the mid-1970s, ganzfeld experiments were being utilised by parapsychologists in an attempt to verify the existence of telepathy. Telepathy being the transfer of information on thoughts or feelings between individuals by means other the commonly known 5 senses. And it was widely believed by these parapsychologists that ganzfeld would provide a state of consciousness that might open the door to psi experiences.
J: So to go into detail about how the ganzfeld experiment works: In a typical experiment, a person called the receiver is put in an isolated room, in a chair with half ping-pong balls covering each eye. They also have a red light shone on them. This person also wears a set of headphones through which they would put in white or pink noise, which is basically static, and that blocks out any outside sounds that they might hear. The receiver is supposed to be in a state of mild sensory deprivation, as Steve said, for about a half an hour and during that time another person, who we call the sender observes a random target (as in an image) and tries to mentally send the target to the receiver. The receiver will then describe out loud what they see in their mind and the result is recorded by another person, who is blind to the other two people involved in the experiment. And then they have something they call the judging procedure. During the judging procedure the receiver is taken out of the ganzfeld state and then given or shown the set of possible targets. Like, a good example would be that one of them would be a target that was sent and three of them would be fakes. And then they have to decide which one of those most resembles the images that they witnessed. So, like I said, there's usually three decoys and one of the actual things that were being sent by one of the senders.
B: Between 1974 and 1981, 14 ganzfeld experiments were done. Charles Honorton claimed that 55% of the studies produced positive results. A meta-analysis also completed apparently showed that there was a 38% success rate with 25% being chance, so it was somewhat significant, apparently. Psychologist Ray Hyman also did a meta-analysis of these experiments and he also showed a 38% hit rate, but he also found some statistical anomalies in these early ganzfeld experiments. After examining the protocols and the experiments, he claimed that this database did not justify concluding that ESP was demonstrated. Hyman and Honorton actually were on the same page about this, regarding these early experiments. Hyman said that "both Honorton and I agree that there were sufficient problems with the original database that nothing could be concluded until further replications conducted according to specified criteria appear." So, when some of these later experiments were done Hyman noticed that the experimenter interacted with the subject during the judging phase of the experiment, and that’s a big no-no. Hyman said that this means that the judgement from trial to trial were not strictly independent. And he also discovered other experimental procedures as well. And this kinda goes on over time as more experiments are done. Hyman notices that anomalies and ultimately it comes down to the fact that Honorton was impressed with these results and claimed that they show that psi existed and Hyman was not impressed with the results and claimed that they did not show that psi exists.
M: Another major criticism comes from Susan Blackmore. In 1979, she visited Carl Sargent's lab in Cambridge where numerous ganzfeld experiments were performed and observed a number of discrepancies in the followed procedure. For example, in section number 9, the following observations were noted by Blackmore: "Sargent did the randomisation when he should not have"; "a B went missing from the drawer during the session instead of afterwards"; "Sargent came into the judging and pushed the subject towards B"; "an error of addition was made in favour of B and B was chosen" and "B was the target and the session a direct hit". Susan Blackmore wrote about the irregularities in Journal of the Society for Psychical Research in 1987. This, along with other criticisms of Sargent's work, prompted Sargent to write a rebuttal, where he did not deny that discrepancies took place, but that Blackmore's conclusions based on those discrepancies were wrong and prejudiced.
S: So, essentially, the ganzfeld experiment, which are often presented as the best or most solid evidence for psi failed to produce convincing evidence that psi is a real phenomenon. When sceptical scientists investigated the protocols, they found that they were wanting. And as the protocols were tightened, the size of the effect decreased until you ended up with a tiny, tiny effect, the kind that could easily be due to some mild statistical error in the procedure. And, when Susan Blackmore, as Mike said, went physically into a lab to see what was actually happening, she noticed that there were lots of irregularities that were not the kind of thing that you can know from the published report. So, reading the report of how the experiment was conducted isn't really sufficient to know if the experiments were tightly controlled or not. So, all the experiments, it turns out, had some significant problems and the ones that were better had the smaller effect. Whenever you see that pattern—the tighter the controls, the smaller effect until it shrinks to the noise level—below the level where you can really say anything meaningful about the experiment. So, we are left after decades and many specific experiments, without any evidence from the ganzfeld protocol being convincing that there is any anomaly going on or, specifically, any psi effect.
S: SGU 5x5 is a companion podcast to the Skeptics' Guide to the Universe, a weekly science podcast brought to you by the New England Skeptical Society in association with skepchick.org. For more information on this and other episodes, visit our website at www.theskepticsguide.org. Music is provided by Jake Wilson.