Edwin B. Twitmyer

Who was Edwin B. Twitmyer?

Edwin Burket Twitmyer was Professor of Psychology and Director of the Psychological Laboratory and Clinic at the University of Pennsylvania. He is a little-known figure in the history of psychology, but he independently discovered classical conditioning at approximately the same time as the famous Russian physiologist, Ivan Pavlov, who is normally given credit for this achievement.

Twitmyer initially studied the patellar tendon reflex, and devised an apparatus that delivered a light tap below the knees of his research subjects in order to elicit this reflex. Twitmyer warned his subjects that the tap was about to be delivered with a bell. During the course of his research, the sound of the bell was accidentally presented to one of his subjects without the tap below the knee. In a serendipitous discovery much like Pavlov's, Twitmyer realized that the auditory stimulus was sufficient to produce the now conditioned reflexive response.

Twitmyer replicated the experiment with six more subjects and found that all of them learned to associate the bell with the hammer, and would produce the response to the sound of the bell alone.