A comparative analysis of the conditional reflex discoveries of Pavlov and Twitmyer, and the birth of a paradigm.

Research on conditional reflex (CR) in Pavlov's Physiological Laboratory has preceded Twitmyer's work on conditioning at the University of Pennsylvania by 3 or 4 years. The events in Pavlov's laboratory lead toward the postulation of a new paradigm that rejected the Cartesians conceptualization of the reflex as a mechanistic response to stimuli by replacing it with the Darwinian notion of the organism's adaptation to the environmental conditions. The Pavlovian paradigm rejected the Wundtian method in favor of the objective, conditional reflex method.