In 1904, a German mathematics teacher by the name of Mr. von Osten believed that he had taught his horse, Hans, to add, subtract, multiply and divide. As if that wasn’t enough, Clever Hans, as the horse became known, could also spell, read, solve problems of musical harmony and answer personal questions, all signified by the taps of his hoof.
Mr. von Osten wasn’t in it for the money. He was so confident that he had genuinely taught his horse these things that he was quite happy to excuse himself whenever Hans was being asked questions. Needless to say, a reading, spelling, arithmetic-solving horse caused quite a stir, so much so that Clever Hans became a world-wide phenomenon. In September, 1904, even, The New York Times ran an article about Hans, “Berlin’s Wonderful Horse: He Can Do Almost Everything but Talk”. How was he taught?
As the furor about this “wonder horse” grew, the German government appointed a commission to investigate Mr. von Osten’s claims. The Hans Commission - as it was known - was led by Carl Stumpf, the philosopher and psychologist, and also included the director of the Berlin zoological gardens, a vet, a circus manager, a Cavalry officer, and a number of school teachers. In 1904, this team concluded that there was no fraud involved and that Hans the Horse could indeed do all the things his master claimed.
After the Hans Commission had finished their investigations, a man called Oskar Pfungst became intrigued by Hans and his unusual capabilities. Pfungst was an associate of Carl Stumpf, and his investigations confirmed the results of the Hans Commission insofar as he verified that there was no fraud involved. However, Oskar also noticed something that nobody else had noticed. Pfungst discovered, after many tests, that Hans could only get the correct answer, if the asker knew the answer. Once Pfungst realized this, he changed the focus of his study from the horse to the questioners, and it was here that he made some very important discoveries.
Pfungst found that the reason Hans could answer questions was that the questioners all exhibited a number of subtle, involuntary and unconscious signals that the horse could “read”. For example, a common occurrence was that as Clever Hans’ taps approached the correct answer, all questioners would display tell-tale postural and facial signs of tension that were released as the horse made the final tap. This was how Hans knew he had arrived at the correct answer. Neither consciousness of the possibility of giving these signals nor attempts to avoid giving them were successful. These are involuntary cues in the truest sense of the word.
Without fail, according to Pfungst, questioners give hints and cues that are interpreted by the respondent. This phenomenon became known as the Clever Hans Effect. Even today, comparative psychologists, those who study animal behavior, generally test animals in isolation in order to avoid this effect.
The Clever Hans effect is not restricted to animals; human beings are just as, unconsciously, susceptible to expectations as animals. There is growing evidence that our expectations of others are not just ephemeral whims hidden deep within our own psyche but rather powerful influencers of outcomes. A sobering thought...
Patricia “Trisha” Rainsford lives in Ireland and used to be a Classics teacher (amongst other things) before she became a full-time writer. She has published two novels, The Knack of Life and A Secret Place. Trisha also co-authored four other novels, which were also published, as well as having written countless other things including a TV series that was in development for a while but then cancelled (c'est la vie). Still writing today, a lot of her work is focused on the generation and application of knowledge for human development. Read more from Trisha on her blog, Creating Reciprocity.
Please feel free to comment on this article here or join the conversation on our forum.