Oskar Pfungst (21 April 1874 – 14 August 1932) was a German comparative biologist and psychologist. While working as a volunteer assistant in the laboratory of

Carl Stumpf Carl Stumpf (; 21 April 1848 – 25 December 1936) was a German philosopher, psychologist and musicologist. He is noted for founding the Berlin School of Experimental Psychology. He studied with Franz Brentano at the University of Würzburg ...

in Berlin, Pfungst was asked to investigate the horse known as

Clever Hans Clever Hans ( German: ''der Kluge Hans''; c. 1895 - c. 1916) was a horse that was claimed to have performed arithmetic and other intellectual tasks. After a formal investigation in 1907, psychologist Oskar Pfungst demonstrated that the horse was ...

, who could apparently solve a wide array of arithmetic problems set to it by its owner. After formal investigation in 1907, Pfungst demonstrated that the horse was not actually performing intellectual tasks, but was watching the reaction of his human observers. Pfungst discovered this artifact in the research methodology, wherein the horse was responding directly to involuntary clues in the body language of the human trainer, who had the faculties to solve each problem. The trainer was entirely unaware that he was providing such clues. In honour of Pfungst's study, the anomalous artifact has since been referred to as the Clever Hans effect and has continued to be important knowledge in the

observer effect Observer effect, observer bias, observation bias, etc. may refer to a number of concepts, some of them closely related: General experimental biases * Hawthorne effect, a form of reactivity in which subjects modify an aspect of their behavior, in ...

and later studies in

animal cognition Animal cognition encompasses the mental capacities of non-human animals including insect cognition. The study of animal conditioning and learning used in this field was developed from comparative psychology. It has also been strongly influence ...

. Pfungst never earned an advanced academic degree, though he later received an honorary MD from the University Frankfurt, where he lectured. According to Zusne (1984), Pfungst published only "about fifteen titles" in his career.

References

* Zusne, L. (1984). ''Biographical Dictionary of Psychology.'' Greenwood Press.

External links

* * * {{DEFAULTSORT:Pfungst, Oskar 1874 births 1933 deaths Animal cognition writers German psychologists