turpin@cs.utexas.edu (Russell Turpin) (08/05/88)
In article <2498@boulder.Colorado.EDU>, pell@boulder.Colorado.EDU (Anthony Pelletier) writes: > ... Randi is an expert on fraud. ... > If Benveniste or one of his associates was perpetrating an out-and-out > fraud, sleight of hand or something akin to this, Randi would be the > one to detect it. I remain unconvinced that he is qualified to comment > on the validity of an honest experiment. Randi is an expert on illusion, which includes more that intentional deception. He once investigated an ESP experiment, performed by honest and trained researchers, that seemed to show the presence of telepathy in some subjects. In the experiment, the "sender" pushed a button to turn on a light in the "receiver's" booth, to indicate that the sender was thinking of a number. The sender then registered the number with a computer using a rotary dial and then turned off the light. At this point, the receiver would enter into the computer what the receiver thought the number was. After some practice together, certain sender-receiver pairs showed a "telepathic" ability far above what chance providently allows. The experimental flaw that Randi detected is that it takes longer to dial a high number ("0" or "9") on a rotary dial than it does a low number ("1" or "2"), and that because of this, there was the possibility of some information flow from the sender to the receiver in the length of time the light was on. To test this, the numbers on the rotary dial were randomly jumbled. When this was done, the surprising results disappeared. In describing this, Randi did accused neither the experimenter nor the subjects of any deception. The subjects were supposed to try for good results -- you can hardly be expected to perform telepathy unless you give it the old college try -- and they had learned to do this, though they did not know how they were doing it. The actual results of the experiment are themselves interesting, because it provides yet another example of the surprising extent to which we can learn to perform physical feats without being aware of the physics behind what we do. Illusion is around us constantly, and not all of it is due to someone's purposely creating it. It can certainly appear in a lab when a complex experiment is performed. If a trained illusionist is called in to look for this, it does not necessarily show that fraud is suspected. Russell