Ivan Petrovich Pavlov (September 26, 1849 – February 27, 1936) was a Russian physiologist known primarily for his work in classical conditioning.
From his childhood days Pavlov demonstrated intellectual brilliance along with an unusual energy which he named “the instinct for research”.
Inspired by the progressive ideas which D. I. Pisarev, the most eminent of the Russian literary critics of the 1860s and I. M. Sechenov, the father of Russian physiology, were spreading, Pavlov abandoned his religious career and decided to devote his life to science. In 1870 he enrolled in the physics and mathematics faculty at the University of Saint Petersburg to take the course in natural science. Ivan Pavlov devoted his life to the study of physiology and sciences, making several remarkable discoveries and ideas that were passed on from generation to generation. He won the Nobel Prize for Physiology or Medicine in 1904.
Pavlov contributed to many areas of physiology and neurological sciences. Most of his work involved research in temperament, conditioning and involuntary reflex actions. Pavlov performed and directed experiments on digestion, eventually publishing The Work of the Digestive Glands in 1897, after 12 years of research. His experiments earned him the 1904 Nobel Prize in Physiology and Medicine. These experiments included surgically extracting portions of the digestive system from animals, severing nerve bundles to determine the effects, and implanting fistulas between digestive organs and an external pouch to examine the organ’s contents. This research served as a base for broad research on the digestive system.
Further work on reflex actions involved involuntary reactions to stress and pain. Pavlov extended the definitions of the four temperament types under study at the time: phlegmatic, choleric, sanguine, and melancholic, updating the names to “the strong and impetuous type, the strong equilibrated and quiet type, the strong equilibrated and lively type, and the weak type.” Pavlov and his researchers observed and began the study of transmarginal inhibition (TMI), the body’s natural response of shutting down when exposed to overwhelming stress or pain by electric shock. This research showed how all temperament types responded to the stimuli the same way, but different temperaments move through the responses at different times. He commented “that the most basic inherited difference. .. was how soon they reached this shutdown point and that the quick-to-shut-down have a fundamentally different type of nervous system.”
The concept for which Pavlov is famous is the “conditioned reflex” (or in his own words the conditional reflex) he developed jointly with his assistant Ivan Filippovitch Tolochinov in 1901. He had come to learn this concept of conditioned reflex when examining the rates of salivations among dogs. Pavlov had learned then when a buzzer or metronome was sounded in subsequent time with food being presented to the dog in consecutive sequences, the dog will initially salivate when the food is presented. The dog will later come to associate the sound with the presentation of the food and salivate upon the presentation of that stimulus. Tolochinov, whose own term for the phenomenon had been “reflex at a distance”, communicated the results at the Congress of Natural Sciences in Helsinki in 1903. Later the same year Pavlov more fully explained the findings, at the 14th International Medical Congress in Madrid, where he read a paper titled The Experimental Psychology and Psychopathology of Animals.