Wilhelm II's horse from Germany appeared to be able to count, name the days of the week, and even speak German. Much first thought that this was just Wihelm II telling a big hoax to get people's attention. Due to his mysterious prowess, Hans, the intelligent horse, had gained international notoriety. When William von Osten displayed his amazing horse in 1891, a large crowd of onlookers flocked to witness this extraordinary horse.
Every great pupil has a great teacher, and Herrn von Osten was one of those teachers. He was a lesser-known German mathematician who recognized promise in Hans and a chance to draw attention to the horse's skills.
The horse was attempting to communicate by pounding his foot on the ground because he was unable to talk (which would have been an experience). Hans would stomp the ground seven times if asked how much five plus two added up to; if asked what day followed following Monday, he would beat the ground once for Tuesday, twice for Wednesday, and so on.
Hans, the cleaver horse, became well-known across all of Germany, and people began to regard him as a sort of national treasure. In 1892 and 1893, he rose to such fame that people would fly in from all over the world to witness Hans do his calculations.
Was it a joke or a genuinely exceptional animal, a remarkable creature with brains to match a first-class child? Researchers said in 1904 that they had not discovered any proof that the story was a fake. However, the riddle would be ultimately solved by Professor Carl Stumpf and one of his pupils, Oskar Pfungst. They saw that Hans could very seldom provide answers to queries that his master was unable to provide, indicating that there must be some relationship between the two.
They discovered that Hans was reacting to very subtle, often unconscious, cues from his trainer through thorough testing and observations. For instance, when von Osten or the person asking the question (standing directly in front of the horse) asked Hans how much was two plus three, Hans stomped the ground five times before making a move a sixth time.
Hans closely observed the instructor, while Von Osten was extremely cautious around the animal. The trainer signaled the horse to halt by making little motions (sometimes simply a modest adjustment to facial expression or posture) each time the horse achieved the required number of indications with his foot.