The mathematical wonders of the animal world in Elberfeld, Germany. The case was described by E. Clarapède, of Geneva University, as "the most sensational event that has happened in the psychological world."
The discovery of equine mathematical genius was made by William von Osten in 1891. The horse "Kluge Hans" (Clever Hans) was taught to count skittles (pins used in the bowling game of ninepins) by striking with his hoof as many times as there were skittles on the table. Von Osten first pronounced the numbers aloud and later wrote them on a blackboard. The results soon proved to be astonishing. The horse began to perform mathematical operations.
In 1904 von Osten invited cavalry officers to witness his experiments and exhibited the feats of Clever Hans without charge. As a result of the publicity that these performances attracted, scientists began to take an interest in the subject of animal intelligence. A scientific committee headed by C. Stumpf (director of the Institute of Psychology at Berlin University) investigated Clever Hans in 1904 and did not find trickery.
Their report was attacked by Albert Moll, a dogmatic specialist in hypnotism. Moll had visited Elberfeld and, as is often the case with unsympathetic or prejudiced observers, every experiment he made was a failure. He theorized that this proved that the animal could only perform the tasks by noting infinitesimal signs from the trainer or other persons present, and without any firm evidence Moll persuaded Stumpf to change his mind. A second committee reached a more positive conclusion concerning the horse's abilities. Thereafter, although Moll was not on either the first or second investigating committee, the myth of the "Clever Hans Error" of overlooking "unconscious signaling" passed into the psychology textbooks.
This view was reinforced by Stumpf's assistant Oskar Pfungst, who, with the permission of von Osten, conducted his own experiments with the horse. Pfungst virtually took over the horse's training, eliciting any response he desired by movements of his head, eyes, or hands. Eventually the horse paid little attention to its groom or even to its master. Pfungst's publication of his detailed experiments duly "proved" the unconscious signaling theory of Moll and gave scientific credence to the claim that animals cannot think. Even in modern times, Pfungst's work is cited as a model of reliable scientific investigation, although some years after publication of his work Pfungst himself was aware that it was not above criticism. In his book Clever Hans (1911) he writes:
"Someone could say that the horse had only been 'mechanized' and rendered useless for independent thinking by our experiments, and that previously the horse had been able to count, and simply became accustomed in my lessons to the bad habit of following my signals. But Herr von Osten never achieved results without error, as I did in my experiments."
The conclusion that, consciously or unconsciously, Pfungst retrained the horse to fit his own theories seems a likely one.
Von Osten became an irritable recluse, convinced that his lifework had been destroyed. In a newspaper article of August 1904 he states: "In spite of everything one can hardly see in these experiments more than a kind of scholarly jest which has no special value for science or practical life." He died in 1909.
The horse Clever Hans passed to Karl Krall, a jeweler in Elberfeld, who decided to continue von Osten's work and dis-prove the unconscious signaling theory. In his stables near Wuppertal, Krall taught four more horses: "Muhamed," "Zarif," "Berto," and "Hänschen." The last horse was blind and clearly unable to perceive visual signals but learned to calculate as rapidly as the other horses. Krall also put blinders on the eyes of the others during lessons so that they could only see a blackboard and not their trainer. At times he gave lessons in complete darkness. Krall improved on von Osten's training by introducing a phonetic system for language communication.
The horses not only learned the fundamental mathematical operations of addition, subtraction, multiplication, and division, but after only four months' training they extracted square and cube roots. They answered questions by stamping with their hoofs. To give the number 34, for instance, they struck three times with the left and four times with the right hoof. Krall's book Denkende Tiere (1912) stirred the world of science. Commissions and investigators from all over the world journeyed to the stables. Many scientists persisted in stubborn negations; others went away in awe and wonder. One committee of 24 scientists could not tolerate the suggestion that horses could calculate like men, which would be "subversive of the evolutionary theory." They drew up a document of protest against the facts reported earlier by the investigator Clarapède, although in fact only two of the scientists on the committee had ever seen the horses.
The famous author Maurice Maeterlinck paid a visit. The horse Muhamed, after a formal introduction, phonetically spelled out his name with his hoofs and solved almost instantaneously problems to which even Maeterlinck did not know the answer, refused to give the square root of a chance number that was afterward found to have none, and even expressed thoughts and feelings by spelling. On one occasion Muhamed complained, "The groom struck Hänschen."
Unless one is prepared to discount the evidence of Maeterlinck and the many distinguished scientists who confirmed that the horses could correctly answer questions when the answer was not even known to the inquirer, the "unconscious signaling" theory of Pfungst must be considered unproved. His own detailed experiments with Clever Hans and other animals, however consistent in results, probably proved what he expected them to prove and so cannot be considered impartial or definitive.
There are some interesting aspects about Krall's horses. Sometimes they gave messages that they were tired and would not answer. Sometimes they could not answer quite simple questions, such as the number of individuals present. If uncertain, they made a timid blow with their hoofs, and generally their intelligence and behavior appeared to be on the level of a six-to eight-year-old child.
In the experiments, care was taken to exclude the possibility of mind reading. As a precaution to prevent "unconscious signals," the questions were sometimes asked by telephone, the receiver being hung on the ear of the horse; frequently the problem was written on the blackboard and the horse left alone to solve it. Sometimes the figures were traced with a finger on the back of the animal. It is a curious fact that after six months of schooling, the horses made no further progress. They could only do what they had been taught, and they appeared to do it without any conscious effort.
No satisfactory conclusion was ever reached, although in more recent times experiments have been conducted on communication between human beings and dogs, chimpanzees, gorillas, and dolphins. Where there is a strong and friendly relationship between teacher and animal, the results indicate animal intelligence, although not amenable to formal scientific validation. An interesting development is the attempt to bypass tapping and language codes by establishing direct communication with the animal's mind, as suggested in the work of Barbara Lysedeck in the United States.
The horses of von Osten and Krall were not the first to appear to demonstrate intelligent communication. As early as 1591, in Shropshire, England, a certain Master Banks exhibited a white horse named "Morocco" that communicated by tap-ping with his hoofs, apparently able to tell how much money was in a spectator's purse. Shakespeare referred to the animal in his play Love's Labour's Lost (act 1, scene 2). It is possible that this particular case was one of fake "mind reading" similar to modern mentalist stage shows, but according to dramatist Ben Jonson, Banks and his horse were later burned at the stake for witchcraft.
In the twentieth century the "mind-reading horse 'Lady Wonder"' was investigated by parapsychologist J. B. Rhine in the winter of 1927-28. The horse gave answers to questions by touching her nose to letter or number blocks and seemed to be most successful when her owner, Claudia Fonda, was near. Rhine concluded that Lady Wonder was responding telepathically. Professional magician Milbourne Christopher believed that the horse was receiving visual cues from Fonda.
At any rate the evidence for the genuineness of the Elberfeld horses is strong, even if opposed by various scientists like Pfungst. Many scientists testified to the reality of the phenomena. Other favorable testimony came from members of the International Society of Animal Psychology.
The psychical researcher Count Cesar De Vesme speculated that the Elberfeld horses may have solved their problems in a mediumistic way, since they often spelled in the reverse order, suggesting mirror-writing, which is a characteristic of automatic scripts. De Vesme did not mean to suggest the intervention of spirits, but something like a manifestation of an equine subliminal self by motor automatism, unhampered by the limitation of the animal brain. Curiously enough, the system of communicating by tapping of hoofs is strongly reminiscent of table-turning séances.
Krall also experimented with training a young elephant, but the animal refused to learn. Since then, attempts have been made to teach dogs to communicate in a manner similar to that of Krall's horses. Between 1974 and 1975 two dogs, "Elke" and "Belam," were given some 500 lessons by Dorothy Meyer in the Berchtesgaden region of Bavaria. The dogs were owned by Hilde Meilmaier, founder of a dog school. For an account of the impressive achievement of these dogs see Maurice Rowdon's 1978 book The Talking Dogs.
Christopher, Milbourne. ESP, Seers, and Psychics. New York: Thomas Y. Crowell, 1970.
Gaddis, Vincent, and Margaret Gaddis. The Strange World of Animals and Pets. Cowles, 1970. Reprint, New York: Pocket Books, 1971.
Kindermann, Henny. Lola; or, the Thought and Speech of Animals. New York: E. P. Dutton, 1923.
Krall, Karl. Denkende Tiere. Leipzig, 1912.
Maeterlinck, Maurice. The Unknown Guest. London, 1914. Reprint, New Hyde Park, N.Y.: University Books, 1975.
Pfungst, Oskar. Clever Hans (The Horse of Mr. Von Osten): A Contribution to Experimental Animal and Human Psychology. New York, 1911. Reprint, New York: Holt, Rinehart & Winston, 1965.
Rhine, J. B. "An Investigation of a 'Mind-Reading' Horse." Journal of Abnormal and Social Psychology 23 (1929).
Rowdon, Maurice. The Talking Dogs. New York: Macmillan, 1978.
Woodhouse, Barbara. Talking to Animals. Croxley Green, England: Campions, 1970.