Talented dogs that appear in television shows or monkeys that are the subject of the main news bulletin with their intelligence ... We have seen many intelligent animals until today. However, one of these animals made history with his knowledge of mathematics like poison. In the early 1900s in Germany, a horse named Smart Hans was showing its talents everywhere it went and its reputation was spreading. The owner of this Hans, whose reputation is spoken, was Wilhelm von Osten, a mathematics teacher. The owner taught Hans a lot

The most striking thing that Wilhelm von Osten taught Hans was undoubtedly the mathematical operations. Hans could do simple mathematical operations and answer these operations by hitting the ground with his hoof. For example, "What is three times four?" When asked, Smart Hans knocked his hoof to the ground 12 times. With a written message, "If eleven out of twenty, how many will be left? When asked, this time Hans knocked his hoof on the ground nine times. Besides that, Smart Hans was also communicating with the owner. He shook his head once when he wanted to say "yes", and when he wanted to say "no" he shook his head left and right.

The smart Hans's reputation crossed borders and spread as far as the Netherlands. Smart Hans, who performs many operations from multiplication to division, from addition to subtraction, is Dr. A psychologist named Oskar Pfungst came to study Dr. Oskar Pfungst initially studied both Clever Hans and his owner Wilhelm Von Osten carefully. During the demonstrations, Osten wrote the question on a cardboard and showed it to Hans. Dr. According to Oskar Pfungst's impressions, Hans's owner never gave him a clue. Not satisfied with what he saw, the psychologist wanted to ask questions himself. But Clever Hans continued to answer all questions correctly.

However, Dr. Despite the testimony of Oskar Pfrungst, scientists continued to be skeptical of Hans. In 1907, 13 scientists came together under the name of "Hans Commission" and started research. Clever Hans certainly had a talent, but scientists wanted to explore this ability. So they started testing Hans’s abilities. In the tests, Hans was asked too many questions. The answers to the questions asked were sometimes known, sometimes unknown. The distances of the questioners from Hans were different in each question. As a result of all the researches, it was determined that Hans should establish a visual contact with the person asking the question in order to give the correct answer.

In addition, another thing determined as a result of the tests was that the person asking the question should know the answer to the question in order for Smart Hans to give the correct answer. If the questioner did not know the answer to the question, Clever Hans was also unable to give the correct answer. Scientists explained that as a result of their work, those who asked the question unconsciously gave clues, while Hans read this body language.

When the clever Hans approached the correct answer, tensions rose among the audience, applause began and excitement increased. Hans observed all this and reacted accordingly. Applause was rising and Hans stopped beating his hooves to the ground, thinking he had the right answer. Psychologists realized that the behavior of a person or creature after this event can be affected by the environmental conditions and the atmosphere of the environment. This new situation discovered by psychologists has passed into the literature as the "Clever Hans Effect"