I am quite sure all the horse-loving people on this site already know how sensitive and responsive these animals are, but how many of you have heard of the prodigy that was Hans The Counting Horse?

During the early twentieth century, the general public were especially interested in animal intelligence, largely due to Charles Darwin’s recent publications, such as The Origin of Species. Hans the Counting Horse, also known as Clever Hans, was an Arabian stallion in Germany in the 19th century, who was reputedly able to do arithmetic and other intellectual tasks. He was owned by Wilhelm Von Osten, a retired maths teacher, amateur horse trainer, and mystic, who pushed back many of the boundaries of psychology and science. He 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 maths. The only one he had any success with was the horse. Hans, an Arabian stallion from Russia, was a brilliant student.

Von Osten began teaching him in Elberfeld, Germany in the year 1891.  Hans was said to have learned to add, subtract, divide,multiply,work with fractions, tell the time, use a calendar, tell the difference in musical tones, read, spell and understand German!! In demonstrations, Von Osten would ask him for example: “"If the eighth day of the month comes on a Tuesday, what is the date of the following Friday?” Hans would answer by tapping his hoof a certain number of times, to indicate the required number (he had to respond by tapping his hoof, since, despite all his impressive achievements, he wasn't actually able to talk!). Hans was exhibited throughout Germany, and his trainer never charged people to see him.

As a result of all the public interest in Clever Hans, the German board of education commissioned a study on him. The commisssion concluded in 1904 that there was no trickery involved in Hans’ performance. However, after being investigated in 1907 by the psychologist Oskar Pfungst, it was deduced that the horse was not actually counting, but instead responding intuitively to involuntary cues in the body language of his trainer, Von Osten, who knew the answers to the questions. Von Osten would lean forward slightly, etc., whilst the horse was tapping, and Hans would respond to this. The trainer was completely unaware that he was giving these cues.

Using a substantial number of trials, Pfungst found that the horse could get the correct answer even if von Osten himself did not ask the questions, ruling out the possibility of fraud. However, the horse got the right answer only when the questioner knew what the answer was, and the horse could see the questioner. Both Von Osten and Hans were notoriously bad tempered and prone to rage when the horse did not perform well!. Pfungst suffered more than one bite during his investigation (from the horse, that is, not Von Osten).

Even after this official debunking, von Osten, who was never persuaded by Pfungst's findings, continued to show Hans around Germany, attracting large and enthusiastic crowds.  When Von Osten died, Hans was sold on to another trainer  who also believed that horses could learn to count, and who continued the experiments, with him and other equine pupils.

Since this time, this phenomenon of responding to subliminal bodily cues has become known as the “Clever Hans Effect” and has become well-known in psychological circles. The social communication systems of horses probably depend on the detection of small postural changes, and this may be why Hans so easily picked up on the cues given by von Osten, unconsciously.

 Interestingly, although it is not at all certain that Hans himself could actually count, more recent research suggests that horses can in fact do basic arithmetic, as this article from 2008 reports. Studies mentioned in the article have found that in tests horses consistently choose buckets containing a larger number of apples, for example.

Hans was definitely a smart horse, in any event, even if not a strictly mathematical one, and it goes to show how close to humans horses are in much of their psychology (Not a surprise to any of us here, I think!!)

I hope that you enjoyed this blog. Your votes and comments are much appreciated.

Picture courtesy of www.mathsisgoodforyou.com