# The Amazing Horse Who Could Count

## The story of Clever Hans

You have probably heard of Clever Hans, the amazing horse who could count, but did you know that in addition to solving math problems, the horse could identify people, tell the time, the day of the week, and calculate the square roots of numbers? Personally, I have no difficulty – yet – with the first three but I need my calculator for the fourth.

How did this come about? I’m happy to answer my rhetorical question. Here is some history.

The teacher.  Wilhelm von Osten was a retired high school mathematics teacher who believed that animals were as intelligent as humans and could be taught. He tried to teach a cat and a bear and a horse to do simple math. The cat was indifferent, the bear was irritated, but the horse, Hans, was a brilliant student. Hans was an Arabian stallion from Russia that Wilhelm began teaching in Elberfeld, Germany in the year 1891.

The method.  Wilhelm taught Hans to count skittles – those are like bowling pins – by striking with his hoof, Hans’ hoof, not Wilhelm’s, as many times as there were skittles on the table. If there were three skittles, Hans would paw at the ground with his hoof three times. At first, Wilhem pronounced the numbers out loud. Later he wrote them on a blackboard. Soon he added the alphabet with An equal to one tap of the hoof, B equal to two taps, etc. Soon Hans graduated to more complicated operations and earned the appellation of Clever Hans (Kluge Hans in German). True - Hans was not correct 100% of the time but he was correct so often that his intellectual ability required investigation.

The testing.  Many tests of Hans took place and one individual claimed that the horse had the intellect of a 14-year old – perhaps a dubious distinction. But the first genuine scientific testing was done by Professor Carl Stumpf in 1904. That year Wilhelm had invited cavalry officers to witness the intellectual feats of Clever Hans – without charge. A writer for the New York Times also attended (see the subsequent column he wrote below).*

As a result of the publicity a committee of eminent scientists headed by Prof. Stumpf, director of the Institute of Psychology at Berlin University, tested Clever Hans and pronounced no trickery was involved – Clever Hans was indeed clever. Stumpf searched for evidence of cheating or deception but found none to explain Hans’ amazing ability. He endorsed Clever Hans as genuine – the real deal. Hans soon became a celebrity and people stood in line to witness his demonstrations. I can’t help but wonder if there were vendors peddling Clever Hans toy horses, mugs and other equine paraphernalia to the masses.

The re-testing.  Some scientists were still skeptical. One of these was Oskar Pfungst, a protégé of Stumpf (guess it helped to have a “pf” in your name) who assembled a group of thirteen researchers known as the “Hans Commission.” They tested Hans inside a large tent to avoid the distraction of numerous spectators. No evidence of trickery was found but they did find the answer to the Clever Hans phenomenon.

The testing began by using numbered flash cards that Clever Hans was familiar with. Wilhelm, his owner, saw each number before Hans did and Hans continued being clever. Then Pfungst asked Wilhelm to show Hans the cards without first looking at them himself. Now Hans’ answers became random and incorrect. What happened?

Pfungst was no pfool. He pfigured out the pfacts in a pflash. (Sorry, I got carried away). Somehow Wilhelm was giving the answers to Hans. His hypothesis was confirmed when Pfungst asked Wilhelm to stand behind Hans where the horse could not see him and again ask him to count. Again Hans failed the test. Somehow he was finding the correct answers by looking at his questioner.

Carefully observing the owner, Pfungst noted the unconscious physical cues – the non-verbal language – that was being read by Clever Hans. The owner or any other questioner would change posture subtly as Hans’ hoof-tapping was expected to begin. Then the body language would change again as the correct answer was approached.

The Conclusion.  Clever Hans was an extremely clever horse with the ability to pick up non-verbal cues but he was not a mathematician. He was providing correct answers by responding to visual cues. The psychologists realized that an animal’s or a human’s behavior can be influenced by subtle, unintentional non-verbal cues on the part of a questioner. This effect has come to be known as the “Clever Hans effect”. For further information, read this book: Oskar Pfungst: 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.

Epilogue.  Wilhelm von Osten became irritable and reclusive, convinced that his reputation and his life’s work had been defamed and destroyed. In a newspaper article in August, 1904 he is quoted: “In spite of everything one can hardly see in these experiments (the tests of Hans) more than a kind of scholarly jest which has no special value for science or practical life.” He died in 1909.

What happened to Clever Hans? He became the property of Karl Krall, a jeweler in Elberfeld who wanted to continue von Osten’s work and disprove the non-verbal signals theory. Krall owned stables in nearby Wuppertal and taught four more horses there: Muhamed, Zarif, Berto and Hanschen. The latter was blind and unable to see visual signals but learned to calculate as rapidly as the other horses.

Krall’s horses answered math questions by stamping with their hooves as Clever Hans had, but in a slightly different fashion. To give the number 34, for example, they struck the ground three times with the left hoof and four times with the right hoof.

A story is told about the renowned author, Maurice Maeterlinck, who visited Krall. After learning’ his name, the horse, Muhamed, spelled it out phonetically with his hooves. (I would have trouble spelling it, too). The horse also refused to give the square root of a chance number which was found afterward to have none, and even expressed thoughts by spelling. On one occasion, Muhamed complained that “the groom had struck Hanschen,” a fellow horse-mate.

Can we discount the experience of Maeterlinck and other distinguished scientists who confirmed that Krall’s horses could correctly answer questions when the answer was not even known to the questioner? Then the "unconscious signaling" theory of Pfungst must be considered unproved. His own detailed experiments with Clever Hans and other animals, although consistent in results, probably proved what he expected them to prove – the self-fulfilling prophecy at work – and so can not be considered impartial.

## * Berlin’s Wonderful Horse. He Can Do Almost Everything but Talk. How He Was Taught.

### "Hans is the second horse Herr von Osten has trained. He claims that any horse of fair intelligence can be so taught. Herr von Osten’s training is done purely from a scientific standpoint, and he told me that he really regretted the premature publicity given to his work. By the time this article is in print, the Kaiser who has heard with interest of this horse prodigy, will have seen the animal. – Edward T. Heyn

\B. J. Rakow Ph.D., Author, Much of What You Know about Job Search Just Ain't So." An enlightening book about job search with dynamic facts about interviewing, negotiating, networking, and creating a powerful resume.

## More by this Author

katiem2 6 years ago from I'm outta here

What an amazing story about the horse who could count. It really makes me wonder. Maybe that horse was a math teacher in a former life.

I tell ya, there are so many amazing things that just can't really be explained that have me scratching my head and the details about a horse who can count is now on the list.

Great and delightful read, thanks! Love and Peace :)

drbj 6 years ago from south Florida Author

It's funny, katie, but I had heard years ago in some psych class about Clever Hans but never really believed it was a true story and he really existed.

So I was also amazed when my research indicated it was a true story. Yes, Hans was responding to body language signals but in my view, it may take some extra equine brain cells to be able to do that.

Thank you so much for visiting and your generous comment. Love and peace to you, too, always.

PaperNotes 6 years ago

Wow, this is very interesting. No matter what, I still think that horses are intelligent animals. Yet their intelligence must not be compared to that of humans.

drbj 6 years ago from south Florida Author

Thank you for visiting, PaperNotes. I agree with you that horses are very intelligent. I believe they are ranked number three on an intelligence scale with chimps number one, and dogs number two.

Clever Hans seemed to be a cut above.

Dolores Monet 6 years ago from East Coast, United States

I so love the story about Clever Hans - this hub made me happy. But I feel so sorry for Wilhelm who believed his wonderful experiment a failure when he taught us all so much more about horses. For some reason, the story of Clever Hans brings a tear to my eyes.

drbj 6 years ago from south Florida Author

What a gracious and loving comment about Hans, Dolores. Thank you. He was a very special horse with a very special owner.

Tooba 5 years ago

The story abut Kral's horses is rather interesting and I have not come across it before, while reading upon Clever Hans. Could you please site your source?

drbj 5 years ago from south Florida Author

Hello, Tooba. Sources cited for the information about Karl Krall and his horses are: "Clever Hans and the Eberfeld Horses" by Maurice Maeterlinck and the WDR TV film regarding Karl Krall (in German) - 'Echt Wuppertal - Eine Zeitreise mit der Schwebebahn' (1999). Thanks for your visit and your interest.