On this date in 1849, Ivan Petrovich Pavlov was born in Ryazan, Russia. He enrolled in Ryazan Ecclesiastical Seminary in the 1860s. In 1870, he dropped out in order to study natural sciences at the University of St. Petersburg. He graduated in 1875, and went on to attend the Academy of Medical Surgery. Pavlov became a professor of pharmacology at the Military Medical Academy in 1890 and director of the department of physiology at the Institute of Experimental Medicine in 1891, where he studied the physiology of the digestive system, often using dogs as research subjects. He wrote books about his research, including Work of the Digestive Glands (1897), Psychopathology and Psychiatry (1962) and Conditioned Reflexes (1960). In 1904, he earned the Nobel Prize in Physiology and Medicine for his work with digestive organs. Pavlov married his wife, Serafima, in 1881.
Despite Pavlov’s influential research on the digestive system, he is most famous for his discovery of classical conditioning: teaching an animal to associate a reflex with an unrelated stimulus. Pavlov made the discovery while researching the salivary glands of dogs, after he noticed that dogs salivated when they anticipated food in addition to when they began eating. This led Pavlov to condition the dogs to begin salivating when they saw or heard a variety of stimuli – most famously, bells. He accomplished this by ringing a bell every time he fed the dogs, making them associate bells with food.
Pavlov described himself as an atheist who lost his faith when he was a seminary student. “In regard to my religiosity, my belief in God, my church attendance, there is no truth in it; it is sheer fantasy,” Pavlov told his student Evgenii Mikhailovich Kreps in the 1920s, according to the article “Pavlov’s Religious Orientation” by George Windholz (published in Vol. 25 of the Journal for the Scientific Study of Religion, 1986). He continued: “I was a seminarian, and like the majority of seminarians, I became an unbeliever, an atheist in my school years.” Windholz also quoted Pavlov as saying, “There are weak people over whom religion has power. The strong ones – yes, the strong ones – can become thorough rationalists, relying only upon knowledge, but the weak ones are unable to do this.” D. 1936