Ivan Petrovich Pavlov was a Russian physiologist known primarily for his work in classical conditioning. He was a pioneer in the study of circulation, digestion, and conditioned reflexes.
Background
Pavlov was born on September 26, 1849 in Ryazan, Russia. He was the oldest of eleven children, six of which died during childhood. His father, Peter Dmitrievich Pavlov, was a priest and teacher of Greek and Latin. His mother, Varvara Ivanovna Uspenskaya, was the daughter of a priest, yet was herself illiterate. Pavlov’s grandfather and great-grandfather were sextons and farmers. His great-great-grandfather, Mokey Pavlov, was the son of a serf who had no surname and whose Christian name, Pavel, became the family name of succeeding generations.
Education
Pavlov was enrolled in the second grade of the First Ryazan Parochial School in 1860, at the age of 11 (an injury caused by a fall had delayed his formal schooling), and in the Ryazan Theological Seminary in 1864. He attended the seminary at a time of great liberal fermentation following the freeing of the serfs, when enlightenment was the keynote of the day. In 1870 he left the seminary to enter the Department of Natural Sciences of the Physicomathematical Faculty of the University of St. Petersburg where he studied chemistry and physiology.
After graduating from the university in 1875, Pavlov spent four years at the Military Medical Academy. He graduated from the academy in 1879 with the unusual record of 11 scientific publications, only two of which were collaborations and seven of which appeared in Pflugefs Archiv. He stayed at the academy for postgraduate research. His 77-page doctoral thesis, “Tsentrobezhnye nervy serdtsa” (“Efferent Nerves of the Heart”), appeared in 1883. After completing his dissertation, he won a two-year traveling fellowship, which he spent studying abroad with such leading scientists as Emil Du Bois-Reymond in France, and Johannes Müller, Muller, Carl Ludwig, and Hermann von Helmholtz in Germany.
Upon his return to Russia, Pavlov began independent research on cardiac physiology in the Saint Petersburg laboratory of the physiologist Sergei P. Botkin who soon entrusted the direction of his laboratory to Pavlov. This allowed Pavlov to devote all of his time to research. He involved himself thoroughly in all details of an experiment and even in his earliest experimental work regarded it as essential to work with the intact organism in order to maintain as far as possible the natural conditions of the physiological systems he chose to study.
In 1890 Pavlov was appointed professor of pharmacology at the Military Medical Academy in St. Petersburg, and in 1896 he also was made the head of the Department of Physiology. He held this post until his resignation in 1924. In the meantime (1890), he was given a second and concurrent assignment: to organize and direct the Department of Physiology in the new Institute of Experimental Medicine.
At the turn of the century, he began his work on the physiology of the higher parts of the brain, using the experimental methods of the conditioned reflex. In laboratory experiments on dogs and apes, and in clinical studies of mental patients, Pavlov founded and developed what he called "the science of higher nervous activity." He developed "the chronic method" in which he trained animals to lie on the operating table and without anesthesia undergo elaborate and lengthy experiments. In this manner he was able to study the functions of the animal under more natural conditions. With this method Pavlov discovered a number of important laws concerning the reflex regulation of the digestive glands, and developed his "theory of nervism." He summarized his findings in the only book he ever wrote, Work of the Digestive Glands, published in 1897.
The next phase of Pavlov's work grew out of these investigations of digestion. He had found that saliva and gastric juices were secreted by the experimental dogs not only when food was introduced into the mouth, but also at the sight of food, at the sound of the footsteps of the person doing the feeding, and at the rattling of dishes in the preparation of the food. Pavlov ignored these reactions as long as he could. As his work on digestion proceeded, however, the psychic stimulation of the gastric and salivary glands interfered with the experiments to such an extent that he could no longer ignore them. For this purpose he employed a sound-proof, scent-proof, windowless experimental chamber with elaborate equipment designed to present controlled stimuli to the experimental animals. From these experiments he found that any stimulus - sound, sight, or scent - could act as a signal calling forth the same response as the actual presence of the object signalized.
Thus, Pavlov found that many stimuli evoked salivary responses. As he collected experimental facts and made generalizations in the form of "laws of functioning" of the higher parts of the brain, a new science gradually took shape, the science of higher nervous or psychic activity. The basis of this science was the division of reflexes into two types - unconditioned and conditioned reflexes. This science of the functioning of the brain was based largely on the interaction between two processes - excitation and inhibition.
In addition to the investigation of normal animal activity, Pavlov experimented with higher nervous illnesses in dogs and apes and the nature of sleep. He found that sleep is a form of inhibition which diffuses over the entire cortex of the brain and penetrates more or less deeply into the lower parts of the brain. He called sleep a form of "protective inhibition" in which the inhibition spreads unchecked by its opposite - excitation. With regard to nervous breakdowns in animals, Pavlov finally arrived at a point where he could, at will, induce "mental illness" in dogs and apes, and equally at will, cure it. He came to the conclusion that higher nervous functional illness in animals was caused by overpowering or clashing stimuli, or by problems which overtax the higher nervous system. He called these laboratory breakdowns, "experimental neuroses."
Pavlov was keenly aware that he could not apply to human beings his work with animals until he first determined at what level the animal and human cerebral activity are the same and at what level they are different. In his study of the higher nervous activity of man, Pavlov found that in healthy human beings the two lower systems were subordinate to and regulated by the highest system. In mental illness, however, the three systems tend to be dissociated in such a manner that the highest system ceases to one extent or another to play the decisive and regulatory role.
In 1935, at the age of 86, Pavlov presided at the sessions of the XV International Physiological Congress held in Saint Petersburg and Moscow. He worked in his Saint Petersburg laboratory unshortly before his death of pneumonia in February 1936.
Pavlov was opposed to extreme political positions of any kind. He did not welcome the Russian Revolution of 1917, which destroyed the old system of the czars, or Russian supreme rulers, and replaced it with a Communist system. He was hostile to the new Communist system. Even so, Lenin signed a special decree in 1921, assuring that Pavlov would have support for his scientific work. In 1930 the government built him a laboratory.
By 1935 Pavlov had become reconciled to the Communist system, he declared that the "government, too, is an experimenter but in an immeasurably higher category."
Views
Quotations:
"What can I wish to the youth of my country who devote themselves to science? Thirdly, passion. Remember that science demands from a man all his life. If you had two lives that would not be enough for you. Be passionate in your work and in your searching. "
Membership
In 1907 he was elected to membership in the Russian Academy of Sciences.
Royal Society
1907
Personality
In 1881 Pavlov married Serafima Karchevskaia, a woman with profound spiritual feeling, a deep love for literature, and strong affection for her husband. In her later years, she suffered from ill health and died in 1947. Sara's first pregnancy ended in a miscarriage. When she conceived again, the couple took precautions, and she safely gave birth to their first child, a boy whom they named Mirchik; she became deeply depressed following Mirchik's sudden death in childhood. Ivan and Sara eventually had four more children. Their youngest son, Vsevolod, died of pancreatic cancer in 1935, only one year before his father.
Connections
In 1881 Pavlov married Seraphima (Sara) Vasilievna Karchevskaya who was a teacher and the daughter of a doctor in the Black Sea fleet. He was so impoverished that at first they had to live separately. His wife was a domestic, religious, and literary woman, who devoted her life to his comfort and work. She first had a miscarriage supposedly caused by having to run after her very fast-walking husband. Later they had a son, Wirchik, who died very suddenly as a child. Following Wirchik, they had three sons, Vladimir, Victor and Vsevolod. Vsevolod became a very well known physicist and professor of physics at Leningrad in 1925. They also had a daughter named Vera.