Clever Hans

The Kluge Hans (* 1895, † 1916 ) was a horse of the Orlov Trotter breed that could supposedly count and count. In the years before the First World War, the schoolmaster and mathematics teacher William of East excited with Hans ' unique skills quite a stir.

Scientific sensation or fraud

Hans answered the duties of his " teacher " with the tapping of a hoof or by nodding / shaking of the head. Such Hans could solve arithmetic tasks, and also spell and count objects or people. Apparently from the east was so convinced of his teaching profession and to his ability, that he believed his teaching methods on his horses - before the clever Hans he had owned and trained a Hans I. - to apply. In his later published book about the clever Hans the psychologist Oskar Pfungst from the east known as " astute in the teaching method and yet without an understanding of the most basic forms of scientific investigation ."

Finally, in September 1904 actually a 13-member scientific commission under the leadership of Carl Stumpf, a philosophy professor and member of the Prussian Academy of Sciences, used in the German capital to get to the bottom of the phenomenon. The Commission initially suspected a trick or fraud on the part of the math teacher, but the horse answered tasks properly, if a stranger asked the questions and from the east was absent.

Finally, Oskar Pfungst broke, who was still a student of Stumpf at that time, the riddle: Hans Although not mastered the math, but it could indicate subtle nuances in facial expression and body language of his human counterpart. Involuntarily took the questioner before the crucial "correct" Hufklopfen the horse a strained attitude, the "right answer" they expressed with their body language unintentionally from signals of relief, perceived the " Kluge Hans" in about 90 % of all cases. This worked but only if the questioner also knew the answer itself.

From the east to the completion of the investigations of the outcome was very upset. His anger directed first against the horse, so it won but soon the old confidence back and from the east allowed no further experiments. The worldview constructed by him was rapidly restored and all undeniable facts that contradicted this were ignored.

Consequences for science

The so-called "Wise -Hans effect" was an important evidence - not only of animal psychology - in scientific history, he helped the experimental psychology to break through. As Clever Hans effect is generally described as the unconscious unilateral influence the behavior of animals, particularly in the direction that the expected effect when you try to enter. The effect can be avoided by using the research design of the so-called double-blind study or of " non-intrusive measurements ." Even in social research " Kluger Hans - effect" is received as reactivity ( the respondent on behavior, appearance and imputed value systems of the interviewer as well as on the situation of the interview, see also interviewer effect).

Consequences for the " clever Hans "

Having had died from the east in 1909, the Kluge Hans went into the possession of the merchant Karl Krall, who hired more experiments with it and also trained other horses. He established a psychological laboratory in a stall of the Privy Kommerzienrates von der Heydt in Elberfeld, where he worked with a total of eleven horses, two donkeys, a pony and an elephant. From his experimental series was the 1912 book Thinking Animals forth; Furthermore, he published the magazine animal soul. However, financial success was denied him, in 1916 he gave up his work with the animals on. Hans and the other computing horses of Elberfeld were taken for use in the First World War, the fate of the prudent Hans is unknown.