Pavlov, Ivan Petrovich 1849-1936

Russian physiologist.

Pavlov was a Nobel Prize-winning physiologist, whose research into the process of the conditioned reflex is considered a landmark discovery in both modern physiology and behavioral psychology. Pavlov was recognized by the Nobel Committee for his work with mammalian digestion; however, later experiments with canine salivation led to his theorization of the learned or conditioned reflex—a physiological response to associated but otherwise unrelated stimuli. Pavlov observed that dogs presented with some additional stimulus that accompanied regular feedings, such as a flash of light, could be made to salivate when only the additional stimulation, and no food, was offered. From these and similar experiments, Pavlov established the physiological basis of certain types of learned behavior. In theory, Pavlov also applied his discovery of the conditioned reflex to human beings. In addition to his study of digestion and higher nervous activity, Pavlov is remembered for his work with the physiology of blood circulation and as an accomplished scientific administrator.

Biographical Information

Pavlov was born on 26 September 1849 in Ryazan, Russia. He was educated at Ryazan Ecclesiastical High School and later attended the Ryazan Ecclesiastical Seminary, where he exhibited considerable interest in the natural sciences. In 1870 Pavlov opted to leave the seminary and to continue his studies at St. Petersburg University. There Pavlov began working with the physiologist Elie de Zion and honing his surgical skills. After graduation in 1875, Pavlov entered medical school at the Military Medical Academy in St. Petersburg, and served as a laboratory assistant to Zion, who had recently been named chair of the academy's physiology department. Pavlov later transferred for two years to the Veterinary Institute following Zion's dismissal, and in 1877 traveled to Breslau, Germany (now Wroclaw, Poland) to study digestion under Rudolf Heidenhain. Pavlov was honored with a scholarship for postdoctoral study after earning his medical degree in 1879 and returned to Germany to further his research into circulation and digestion. In 1895 Pavlov was named chairman of physiology at the St. Petersburg Institute for Experimental Medicine and remained in this position for much of his subsequent career. For his continued studies into the process of mammalian digestion he was awarded the Nobel Prize for Medicine or Physiology in 1904. By this time, Pavlov had begun his experiments on conditioned reflexes in laboratory dogs. Following the Bolshevik Revolution in 1917, Pavlov occasionally spoke out against the Soviets, but was nevertheless given preferential treatment by the Communist Party, which hoped to use his experiments with the conditioned reflex for political ends. In 1935 the Soviet government built Pavlov an extensive, state-of-the-art laboratory where he could continue his work. He died of pneumonia shortly thereafter on 27 February 1936 in Leningrad (now St. Petersburg).

Major Works

Few of Pavlov's works are available in English translation and, in addition, critics discern that most of the writings attributed to him represent to some degree the combined efforts of Pavlov and his many laboratory assistants—though it is clear that Pavlov is the principal intellectual force behind all of the following texts. The Work of the Digestive Glands (1902) contains the culmination of Pavlov's experiments on the alimentary canal of dogs performed in the late 1880s and 1890s. Pavlov and his fellow researchers studied digestion by surgically altering laboratory dogs, principally by modifying canine stomachs to create a "Pavlov pouch," into which gastric juices could be separated for observation and testing. Pavlov's later and more well-known work on the conditioned reflex is available to English-speaking audiences in Lectures on Conditioned Reflexes (1923) and Conditioned Reflexes: An Investigation of the Physiological Activity of the Cerebral Cortex (1960). These texts record the results of Pavlov's further experimentation with dogs. Again using surgical procedures, Pavlov and his team studied the relationship between the higher nervous system and the action of the salivary glands. By associating certain unrelated stimuli—such as the presence of a lab assistant, the ring of a bell, or a flash of light—with the routine feeding of the dogs, Pavlov was able to demonstrate the performance of conditioned reflexes. This he succeeded in doing by stimulating salivation without actually offering food, through the simple recreation of those stimuli (bell, light, assistant's presence) that had been related to feeding. Drawing from these experiments, Pavlov theorized the existence of a physiological component to psychological processes, and differentiated between the mechanisms of innate and conditioned reflexes. Pavlov's collected works, including a significant number of scientific articles and research essays, appear in the five-volume Russian compilation Polnoe sobranie trudov (1940-49).

Critical Reception

Critics have observed that Pavlov's discovery of the conditioned reflex has been quite influential in the scientific community, particularly in Russia, where research into Pavlovian physiology has continued, uninterrupted, through the end of the Soviet regime and of the twentieth-century. Since Pavlov's death, however, many reassessments of Pavlovian theory have occurred. Contemporary scientists have uncovered a number of errors within the details of Pavlov's thought. Critics likewise have acknowledged that Pavlov's failure to satisfactorily explain the true mechanism of the conditioned reflex represents a serious limitation. Nevertheless, scholars have continued to see Pavlov as a pioneering figure in the study of physiology and have observed the tremendous influence his work with the conditioned reflex has exerted on the modern field of behavioral psychology.