Apr 21, Oskar Pfungst: Today in the History of Psychology (21st April 1874)

Oskar Pfungst was born. A comparative psychologist renowned for his detailed study of Clever Hans, a performing horse who tapped his hoof a given number of times in order to give correct answers to complex arithmetical problems. Pfungst concluded that it was unintentional conditioning, rather than intellectual ability which explained Hans's apparent mathematical genius. He wrote: 'Hans's accomplishments are founded first upon a one-sided development of the power of perceiving the slightest movements of the questioner, secondly upon the intense and continued, but equally one-sided, power of attention, and lastly upon a rather limited memory, by means of which the animal is able to associate perceptions of movement with a small number of movements of its own which have become thoroughly habitual.' The case of Clever Hans served to demonstrate the need for rigorous methodological controls within experimental psychology and was the catalyst for research into experimenter expectancy effects.Information via:On This Day in Psychology: A Showcase of Great Pioneers and Defining Moments
Source: Forensic Psychology Blog - Category: Forensic Medicine Source Type: blogs