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James Randi Educational Foundation

An Encyclopedia of Claims, Frauds, and Hoaxes of the Occult and Supernatural

Introduction | "R" Reading | Curse of the Pharaoh | End-of-the-World Prophecies

Index | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | Y | Z

Clever Hans phenomenon In 1900, a German named Wilhelm von Osten displayed to the public his horse, Clever Hans (Kluge Hans), who was apparently able to perform mathematical calculations. The horse was examined in 1904 by a committee headed by professor of philosophy Professor C. Stumpf, who reported that they could find no evidence of direct signaling being done by the handlers, as if that were enough to endorse the wonder. People flocked to see Hans perform. Then Dr. Albert Moll, who had examined the horse the year before——but was subsequently refused permission to see the animal again——declared that Hans was a perfectly ordinary animal who was being unconsciously (?) cued by his owner, as well as by the small movements and sounds made by observers who were standing by.


Clever Hans, a horse apparently able to perform mathematical calculations.

      An astute experimenter named Oskar Pfungst, a student of Stumpf, did the really definitive tests of Hans under Stumpf's direction, and the results of those observations gave rise to the discovery of the existence of the process of involuntary/unconscious cuing now known as the Clever Hans phenomenon. Stumpf thereupon retracted his claim of the remarkable ability he believed he'd detected in Hans.
      Hans was not the only horse (or other animal) to react to secret and/or unconscious cuing. There have been many such. In 1591, in England, a horse named Morocco became famous and made his owner rich. The horse called the totals on a pair of over-sized dice, added and subtracted, and pointed out letters and persons in the audience. The animal even showed up in Shakespeare's play Love's Labour's Lost, Act 1, Scene 2, as “the dancing horse.”
      In 1927, Dr. Joseph Banks Rhine, considered the father of parapsychology, witnessed Lady Wonder, another horse said to have psychic powers, and though he was not convinced that the horse could calculate, he did believe it was telepathic. Lady Wonder's owner used toy alphabet blocks which the horse knocked over to spell out words being thought of by the spectators, but the words were always known to the owner who handled the horse. Rhine believed he had eliminated all possibilities of trickery and error, and reported:  


      There is left then, only the telepathic explanation, the transference of mental influence by an unknown process. Nothing was discovered that failed to accord with it, and no other hypothesis proposed seems tenable in view of the results.

      Despite an investigation by Milbourne Christopher which indicated that the horse's owner was cuing Lady Wonder with movements of her whip, and a second, better designed set of tests of his own that produced no positive results, Rhine decided to stick with his original conclusion, offering the explanation that while the horse had once possessed ESP powers, it later lost them and trickery was resorted to. Such naivety in a parapsychologist is not at all rare.
      The excellent book of Ricky Jay, Learned Pigs and Fireproof Women, discusses other animals who were considered miraculous.
      See also cheating.



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