“The Turk” was a mechanical chess playing device which toured the globe in the 19th century. It was remarkably successful, managing able to beat almost everyone, include Napoleon. It was later revealed that there was a human hiding inside the machine operating the robot.
Clever Hans was a horse which came to public attention in Germany in the early 1900s, because of his arithmetic skills. He was able to answer questions (by stamping his hooves) such as “if the eighth day of the month comes on a Tuesday, what is the date of the following Friday?” There was so much interest in the horse that the board of education ordered an official investigation (“The Hans Commission”, only in Germany...). They actually concluded that everything was above board. However psychologist Oskar Pfungst later demonstrated that the horse was in fact picking up unconscious cues (changes in posture and facial expression) from its trainer, which were apparently entirely involuntary. Hence the use of double blind studies in social science and medicine.
