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Ivan Petrovich Pavlov
(1849 - 1936)
Russian physiologist known chiefly for his development of the concept
of the conditioned reflex. In a now-classic experiment, he trained a
hungry dog to salivate at the sound of a bell, which was previously
associated with the sight of food. He developed a similar conceptual
approach, emphasizing the importance of conditioning, in his pioneering
studies relating human behaviour to the nervous system. He was awarded
the Nobel Prize for Physiology or Medicine in 1904 for his work on digestive
secretions.
Life.
Pavlov, the first son of a priest and the grandson of a sexton, spent
his youth in Ryazan in central Russia. There, he attended a church school
and theological seminary, where his seminary teachers impressed him
by their devotion to imparting knowledge. In 1870 he abandoned his theological
studies to enter the University of St. Petersburg, where he studied
chemistry and physiology. After receiving the M.D. at the Imperial Medical
Academy in St. Petersburg (graduating in 1879 and completing his dissertation
in 1883), he studied during 1884-86 in Germany under the direction of
the cardiovascular physiologist Carl Ludwig (in Leipzig) and the gastrointestinal
physiologist Rudolf Heidenhain (in Breslau).
Having worked with Ludwig, Pavlov's first independent research was on
the physiology of the circulatory system. From 1888 to 1890, in the
laboratory of Botkin in St. Petersburg, he investigated cardiac physiology
and the regulation of blood pressure.
He became so skillful a surgeon that he was able to introduce a catheter
into the femoral artery of a dog almost painlessly without anesthesia
and to record the influence on blood pressure of various pharmacological
and emotional stimuli. By careful dissection of the fine cardiac nerves
he was able to demonstrate the control of the strength of the heartbeat
by nerves leaving the cardiac plexus; by stimulating the severed ends
of the cervical nerves, he showed the effects of the right and left
vagal nerves on the heart.
Pavlov married a pedagogical student in 1881, a friend of the author
Fyodor Dostoyevsky, but he was so impoverished that at first they had
to live separately. He attributed much of his eventual success to his
wife, a domestic, religious, and literary woman, who devoted her life
to his comfort and work. In 1890 he became professor of physiology in
the Imperial Medical Academy, where he remained until his resignation
in 1924. At the newly founded Institute of Experimental Medicine, he
initiated precise surgical procedures for animals, with strict attention
to their postoperative care and facilities for the maintenance of their
health.
During the years 1890-1900 especially, and to a lesser extent until
about 1930, Pavlov studied the secretory activity of digestion. While
working with Heidenhain, he had devised an operation to prepare a miniature
stomach, or pouch; he isolated the stomach from ingested foods, while
preserving its vagal nerve supply. The surgical procedure enabled him
to study the gastrointestinal secretions in a normal animal over its
life span. This work culminated in his book Lectures on the Work of
the Digestive Glands in 1897.
Laws of conditioned reflex.
By observing irregularities of secretions in normal unanesthetized animals,
Pavlov was led to formulate the laws of the conditioned reflex, a subject
that occupied his attention from about 1898 until 1930. He used the
salivary secretion as a quantitative measure of the psychical, or subjective,
activity of the animal, in order to emphasize the advantage of objective,
physiological measures of mental phenomena and higher nervous activity.
He sought analogies between the conditional (commonly though incorrectly
translated as "conditioned") reflex and the spinal reflex.
According to the physiologist Sir Charles Sherrington, the spinal reflex
is composed of integrated actions of the nervous system involving such
complex components as the excitation and inhibition of many nerves,
induction (i.e., the increase or decrease of inhibition brought on by
previous excitation), and the irradiation of nerve impulses to many
nerve centres. To these components, Pavlov added cortical and subcortical
influences, the mosaic action of the brain, the effect of sleep on the
spread of inhibition, and the origin of neurotic disturbances principally
through a collision, or conflict, between cortical excitation and inhibition.
Beginning about 1930, Pavlov tried to apply his laws to the explanation
of human psychoses. He assumed that the excessive inhibition characteristic
of a psychotic person was a protective mechanism--shutting out the external
world--in that it excluded injurious stimuli that had previously caused
extreme excitation. In Russia this idea became the basis for treating
psychiatric patients in quiet and nonstimulating external surroundings.
During this period Pavlov announced the important principle of the language
function in the human as based on long chains of conditioned reflexes
involving words. The function of language involves not only words, he
held, but an elaboration of generalizations not possible in animals
lower than the human.
Opposition to Communism.
Pavlov's relationships with the Communists and the Soviet government
were unique not only for the Soviet Union but also for the history of
science. Although he was never a politician, he spoke fearlessly for
what he considered the truth. In 1922, during the distressing conditions
in the aftermath of the Revolution, he requested permission from Vladimir
Lenin to transfer his laboratory abroad. Lenin denied this request,
saying that Russia needed scientists such as Pavlov and that Pavlov
should have the same food rations as an honoured Communist. Although
it was a period of famine, Pavlov refused: "I will not accept these
privileges unless you give them to every one of my collaborators!"
In spite of many honours granted him by Soviet officials, he upbraided
them openly. After returning from his first visit to the United States
in 1923 (the second was in 1929), he publicly denounced Communism, stated
that the basis for international Marxism was false, and said that "For
the kind of social experiment that you are making, I would not sacrifice
a frog's hind legs!" In 1924, when the sons of priests were expelled
from the Military Medical Academy in Leningrad (the former Imperial
Medical Academy), he resigned his chair of physiology announcing, "I
also am the son of a priest, and if you expel the others I will go too!"
In 1927, distressed that his was the only negative vote in the Academy
of Sciences against the newly recommended "red professors,"
he wrote to Joseph Stalin, protesting that "On account of what
you are doing to the Russian intelligentsia--demoralizing, annihilating,
depraving them--I am ashamed to be called a Russian!" In the late
1920s, as an anti-Communist gesture, he refused Nikolay Bukharin, the
Soviet commissar of education, admission to his laboratory, though the
laboratory was supported by government funds administered by Bukharin.
During the last two years of his life, Pavlov gradually ceased these
excoriations and even stated that he hoped to see the success of the
government at the helm of his country. This change of heart may have
been a result of increased government support of science and of his
own feelings of patriotism when war with Japan seemed imminent. He was
never a Communist, however, nor was he responsible for the technique
of brainwashing that has sometimes been ascribed to him.
In personal habits Pavlov was extremely punctual, never missing an
appointment, it was claimed, and arriving on time in the laboratory
even when there was revolutionary activity on the streets. To a collaborator,
who explained his 10-minute delay as a result of the shooting, Pavlov
exclaimed, "What difference does a revolution make when you have
experiments to do in the laboratory!" He was a bold, vehement nonconformist
both in science and in his personal life; he fiercely took up the cudgel
for what he believed regardless of the force of his opposition. Although
Pavlov held to scientific agnosticism, he considered true religion beneficial;
he said that he envied no one anything except his wife her devout religious
faith.
Assessment.
Pavlov's method of studying the normal, healthy animal in natural conditions
made possible his contributions to science. He was able to formulate
the idea of the conditioned reflex because of his ability to reduce
a complex situation to the simple terms of an experiment. Recognizing
that in so doing he omitted the subjective component, he insisted that
it was not possible to deal with mental phenomena scientifically except
by reducing them to measurable physiological quantities.
Although Pavlov's work laid the basis for the scientific analysis of
behaviour, and notwithstanding his stature as a scientist and physiologist,
his work was subject to certain limitations. Philosophically, while
recognizing the preeminence of the subjective and its independence of
scientific methods, he did not, in his enthusiasm for science, clarify
or define this separation. Clinically, he accepted uncritically psychiatric
views concerning schizophrenia and paranoia, and he adopted such neural
concepts as induction and irradiation as valid for higher mental activity.
Many psychiatrists now consider his explanations too limited, and some
neurophysiologists have taken greater interest in other developments,
such as electrophysiology and biochemistry. In contrast to Sherrington,
he has had few prominent students outside Russia. His method of working
with the normal, healthy, unanesthetized animal over its entire life
has not been generally accepted in physiology.
BIBLIOGRAPHY.
Boris Petrovich Babkin, Pavlov: A Biography (1949, reissued 1971), based
on personal and professional knowledge of the author, one of Pavlov's
oldest pupils, is the most complete and reliable account until World
War I; in dealing with Pavlov's later life Babkin depends upon other
sources, including the memoirs of his widow. A more recent study of
his life and career is Jeffrey A. Gray, Ivan Pavlov (1980). W. Horsley
Gantt, Russian Medicine (1937, reprinted 1978), shows the relation of
Pavlov to prominent Russian figures in medicine; see also W. Horsley
Gantt, L. Pickenhain, and Ch. Zwingmann (eds.), Pavlovian Approach to
Psychopathology (1970).
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