The case of Clever Hans serves as an example of how easily observers can be fooled into attributing a fantastic result to the wrong cause. It also shows how good scientific methods can combat this. In the early 1900�s, Wilhelm von Osten, a retired schoolmaster in Germany, experimented with animal intelligence. He believed that animals were very intelligent, but that they were not trained adequately to exhibit it. Von Osten attempted to teach animals simple math. He had great success with a horse named Hans. After two years of training, Hans could count objects, read numbers, do math problems, tell time and do various other tasks. His answers were communicated to his trainer by pawing the ground with his hoof the correct number of times. Von Osten publicized his �thinking horse� which brought the scientific community into his stable to observe. They could not see any trickery. But, not everyone was convinced the horse could calculate square roots or that perhaps he was reading the trainer�s mind. Oskar Pfungst, a psychologist, devised a plan in which he could test Hans using controlled experiments. Pfungst was able to discern that Hans� success depended on the horse having the questioner in his view. Pfungst also discovered that Hans only got the answer correct when the questioner knew the answer as well. By careful observation, he concluded that small, nearly imperceptible cues were communicated to the horse. In anticipation of the right answer, the questioner involuntarily exhibited subtle changes in posture or facial expression that the horse perceived. He then stopped the pawing and was rewarded with food for getting the right result. Pfungst published his results in 1907 (1911 in English) as �Clever Hans (The Horse of Mr. Von Osten)�. It is a classic study of proper methodology and warns that human expectation can influence experimental results. Clever Hans exhibited that animals can be almost smarter than people in some ways � responding to very sensitive cues that humans overlook � making his cleverness appear to be magic.
- Sharon Hill (Scientist) |
Dog-Daze Training: ��