Pavlov’s conceptualization of unconditional reflexes,or instincts,within the framework of the theory of higher nervous activity

According to I. P. Pavlov’s theory of higher nervous activity, the establishment and dissolution of conditional reflexes enhances the higher organism’s adaptation to the external environment. Pavlov asserted that, ontogenetically, conditional reflexes are based upon innate, unconditional reflexes (UR) or instincts. Pavlov did not distinguish between URs and instincts, but he preferred the former term. Phylogenetically the URs emerged out of well-established conditional reflexes during the development of higher organisms. An outgrowth of the experimental conditioning procedure, developed during the second decade of this century, was the observation and delineation of new URs. While studying human nervous and psychiatric disorders in the 1930s, Pavlov elucidated other URs. Pavlov identified 13 major URs, but he failed to formulate an exhaustive classification scheme of URs.     

Pavlov’s position toward konorski and miller’s distinction between pavlovian and motor conditioning paradigms

Two Warsaw medical students, Jerzy Konorski and Stefan Miller, having read I. P. Pavlov’s works on conditional reflexes, informed him in a 1928 letter that they had discovered a new type of conditioning. A previously neutral stimulus preceded the passive lifting of a dog’s paw which then was followed by feeding; this stimulus then evoked the spontaneous raising of that paw. Pavlov responded informing them that their conditioning of motor responses expanded his theory of higher nervous activity, but that their conditioning paradigm—that they named CRII—did not differ fundamentally from the Pavlovian conditioning paradigm. The replication of the Warsaw experiment in Pavlov’s laboratory failed to provide unequivocal results. From 1931 to 1933, Konorski, working in Pavlov’s Leningrad laboratory, further explored the parameters of CRII. Pavlov insisted that the conditioning of motor movements differs from the conditioning of other sensory analyzers only in that, on the neural level, the motor analyzer is both afferent, that is, perceptive, and efferent, that is, responsive. Konorski was not convinced, and he subsequently maintained that the two conditioning paradigms were fundamentally different.     

The second signal system as conceived by Pavlov and his disciples

Pavlov clearly formulated his ideas on thesecond signal system (specifically, language) in the 1930s. This occurred in conjunction with his interest in interspecies differences and in the study of human neuroses. Pavlov proposed that conditional reflexes signal concrete reality while symbolic-language provides abstractions of reality. Phylogenetically, language emerged in the humans because this form of communication had survival value to the species. Pavlov’s disciples L. A. Orbeli and N. I. Krasnogorskii had considered the ontogenetic development of language. The experimental investigation of A. G. Ivanov-Smolenskii extended Pavlov’s empirical study of the function of language in psychopathology. Notwithstanding a sustained interest in language, Pavlov did not develop a theory of language acquisition based upon the conditioning principle. Pavlov’s conceptualization of language may not have been original, nor did it contribute significantly to modern linguistics. It is now mainly of historical interest. It was, nevertheless, important to the conceptualization of neuroses within the context of the theory of higher nervous activity and it had far-reaching political implications for Soviet psychology in the immediate post-World War II period.     

Trends in the psychophysiology of individual differences

Pavlov’s typology of higher nervous activity was the first systematic approach to the psychophysiology of individual differences. Pavlov’s theory has been further developed by Teplov, Nebylitsyn and their pupils in the Institute of Psychology in Moscow. In particular, Nebylitsyn has delineated a new property of the nervous system and has shown that it is different from strength of nervous system. In the Western research context we can compare the relationship between these two parameters to that between arousal and conditioning level. Eysenck’s theory of the physiological bases of extraversion/introversion is discussed in relation to Nebylitsyn ’s theses and Gray’s conception of arousability. Finally, it is suggested that future work in the psychophysiology of individual differences should stress the study of the ontogenetic development of the physiological variables.     

Schilder and Pavlov’s theory of higher nervous activity

In the late 1920s, the Viennese psychoanalyst Paul Schilder, after performing a conditioning experiment with human subjects, criticized I. P. Pavlov’s concept of “experimental neurosis.” Schilder maintained that subjective reports by conditioned human subjects were more informative than the objectively observed behavior of conditioned dogs. In 1932, Pavlov published a rejoinder to Schilder’s critique in theJournal of the American Medical Association. Pavlov maintained that Schilder misunderstood the value and implications of the scientific, objective method in the study of experimental neurosis. In 1934, Schilder subjected Pavlov’s theory of higher nervous activity to an incisive critique in a 1935 article inImago. Schilder objected to Pavlov’s narrow, reductionist conceptualization of the conditional reflex. Schilder reiterated his view that the psychological, subjective explanation of the conditional reflex is preferable to the physiological, objective explanation, and that the inference of cortical phenomena from experimental findings might be improper. Neither Pavlov nor any of his disciples replied to Schilder. The author provides an apology for the Pavlovian position, suggesting that Schilder was unfamiliar with early and late writings of Pavlov.     

Pavlov’s position on the effects of decortication on conditional reflexes

This paper examined D. Joravsky’s (1989) hypothesis that I.P. Pavlov dogmatically refused to acknowledge that classical conditioning can be mediated by subcortical regions of the large cerebral hemispheres. Decortication literature from 1901 to 1936 was reviewed. The early studies available to Pavlov, who died in 1936, showed that decortication does not allow the establishment of new or retaining of old conditional reflexes (CRs). G.P. Zelenyi’s later experiments(1930) suggested that the establishment of primitive CRs in decorticated dogs was possible. Pavlov never denied this possibility but cautioned that Zelenyi’s experiments could have been methodologically flawed. Although Joravsky’s original hypothesis on Pavlov’s position on the relation between decortication and the establishment of CRs is by and large accepted, it must be stressed that Pavlov’s theory of higher nervous activity was primarily concerned with the function of the brain in the higher organism’s struggle for existence. Within this context the cortical, rather than subcortical, processes play the decisive role in the organism’s adaptation to the changing external environment.     

Hypnosis and inhibition as viewed by heidenhain and pavlov

About 1880, Rudolf Heidenhain, then Professor of Physiology and Histology at the University of Breslau, experimentally studied hypnotic phenomena. Heidenhain explained hypnosis physiologically, in terms of cortical inhibition. Subsequently, I. P. Pavlov, who in 1877 and again in 1884 was Heidenhain’s student at Breslau, encountered hypnotic phenomena during conditional reflex experiments. In 1910, Pavlov described hypnotic states and explained them (as had Heidenhain three decades earlier), in terms of partial inhibition of the cortex. As the concepts of inhibition and excitation are cornerstones of Pavlov’s theory of higher nervous activity, it is of historical interest to search for influences that led Pavlov to incorporate the concept of inhibition into his theory. It is most likely that Pavlov first encountered the concept of central inhibition in the 1860s when reading I. M. Sechenov’sThe Reflexes of the Brain (1863/1866) and that the importance of the concept was augmented by Heidenhain’s use of it in explaining hypnotic phenomena.     

Pavlov's position on the effects of decortication on conditional reflexes.

This paper examined D. Joravsky's (1989) hypothesis that I.P. Pavlov dogmatically refused to acknowledge that classical conditioning can be mediated by subcortical regions of the large cerebral hemispheres. Decortication literature from 1901 to 1936 was reviewed. The early studies available to Pavlov, who died in 1936, showed that decortication does not allow the establishment of new or retaining of old conditional reflexes (CRs). G.P. Zeleny?'s later experiments(1930) suggested that the establishment of primitive CRs in decorticated dogs was possible. Pavlov never denied this possibility but cautioned that Zeleny?'s experiments could have been methodologically flawed. Although Joravsky's original hypothesis on Pavlov's position on the relation between decortication and the establishment of CRs is by and large accepted, it must be stressed that Pavlov's theory of higher nervous activity was primarily concerned with the function of the brain in the higher organism's struggle for existence. Within this context the cortical, rather than subcortical, processes play the decisive role in the organism's adaptation to the changing external environment.     

Schilder and Pavlov's theory of higher nervous activity. A critique and apologia

In the late 1920s, the Viennese psychoanalyst Paul Schilder, after performing a conditioning experiment with human subjects, criticized I. P. Pavlov's concept of "experimental neurosis." Schilder maintained that subjective reports by conditioned human subjects were more informative than the objectively observed behavior of conditioned dogs. In 1932, Pavlov published a rejoinder to Schilder's critique in the Journal of the American Medical Association. Pavlov maintained that Schilder misunderstood the value and implications of the scientific, objective method in the study of experimental neurosis. In 1934, Schilder subjected Pavlov's theory of higher nervous activity to an incisive critique in a 1935 article in Imago. Schilder objected to Pavlov's narrow, reductionist conceptualization of the conditional reflex. Schilder reiterated his view that the psychological, subjective explanation of the conditional reflex is preferable to the physiological, objective explanation, and that the inference of cortical phenomena from experimental findings might be improper. Neither Pavlov nor any of his disciples replied to Schilder. The author provides an apology for the Pavlovian position, suggesting that Schilder was unfamiliar with early and late writings of Pavlov.     

Pavlov and the mind-body problem

I. P. Pavlov claimed that the mind-body problem would ultimately be resolved by empirical methods, rather than by rational arguments. A committed monist, Pavlov was confronted by dualism in the case of an hysterical person. Under normal conditions, her body's left side was insensitive to pain, but when she was hypnotized, there was a reversal of her sensitivity to pain, with the right side becoming insensitive. Pavlov acknowledged that the divergence between stimulation and response suggested dualism, yet condemned his disciple G.P. Zelenyî as well as Charles S. Sherrington, for their dualistic tendencies. Pavlov's continuous adherence to monism is attributed to the influence of popular scientific books that he read during his adolescence. The books maintained that science was based upon monism. Pavlov proposed that by introducing the concept of emotions, an hysterical person's condition could be explained within the framework of his theory of higher nervous activity, thereby obviating the need to change his paradigm.     

Pavlov’s “higher nervous activity”

The term higher nervous activity was introduced by Pavlov about 1909 to replace what he previously called “psychical” or “mental.” In Russia “higher nervous activity” is now used for what we often designate as psychophysiological or psychosomatic. “Higher nervous activity” was not a synonym in Pavlov’s use for psychical or mental; it indicates what physiology can deal with and measure as opposed to our subjective feelings and representations. The philosophical differences underlying Pavlov’s concepts, as well as the philosophical basis for distinguishing between what we measure physically and the subjective correlates, are discussed.     

Pavlov's conceptualization of learning.

Introductory texts in psychology create the misleading impression that I. P. Pavlov was concerned solely with conditioned reflexes. In fact, influenced by Woodworth's Contemporary Schools of Psychology (1931), Pavlov also became interested in learning. Pavlov proposed a two-factor learning theory according to which all learning was based on association, but conditioning and trial and error learning had specific functions. According to Pavlov, conditioned reflexes were temporary and unstable and therefore more flexible in the interaction of higher organisms with the changing environment. Trial and error learning provided knowledge and was relatively more stable. Scientific discovery was based on facts obtained by trial and error; valid relations were reinforced by experimental results, whereas incorrect relationships were extinguished. Some suggestions are made that would allow authors of introductory texts to describe more informatively the contributions of Pavlov to modern psychology.     

A comparative analysis of the conditional reflex discoveries of pavlov and Twitmyer,and the birth of a paradigm

Research on conditional reflex (CR) in Pavlov’s Physiological Laboratory has preceded Twitmyer’s work on conditioning at the University of Pennsylvania by 3 or 4 years. The events in Pavlov’s laboratory lead toward the postulation of a new paradigm that rejected the Cartesians conceptualization of the reflex as a mechanistic response to stimuli by replacing it with the Darwinian notion of the organism’s adaptation to the environmental conditions. The Pavlovian paradigm rejected the Wundtian method in favor of the objective, conditional reflex method.     

The impact of Pavlov on the psychology of learning in English-speaking countries

The translation of Pavlov's lectures (Pavlov, 1927) provided English-speaking psychologists with access to the full scope of Pavlov's research and theoretical ideas. The impact this had on their study of the psychology of learning can be assessed by examining influential books in this area. This reveals that Watson (1924) had been highly effective in promoting the misleading idea that Pavlov was a fellow S-R theorist. This assumption was not questioned by Tolman (1932), Hilgard and Marquis (1940) or by Hull (1943). However, this mistake was not made by Skinner (1938), who also provided the strongest arguments against Pavlov's belief that behavioral effects required explanation in terms of physiological processes. Post-1927 most learning research in the English-speaking countries continued to use instrumental, rather than Pavlovian, conditioning procedures. Nevertheless, many of the issues addressed by this research were ones that Pavlov had been the first to raise, so that his major influence can be seen as that of defining a research program for subsequent students of learning.     

Pavlov's position toward American behaviorism

Pavlov's development of the conditional reflex theory coincided with the rise of American behaviorism. Substituting an objective physiology for a subjective psychology, Pavlov saw in the rise of American behaviorism a clear confirmation of his method and theory. But in the early 1930s, Lashley attacked Pavlov's theory of specific cerebral localization of function, proposing instead the concept of an internal cerebral organization; Guthrie objected to Pavlov's centralist interpretation of conditioning, proposing instead a peripheralist interpretation; while Hull challenged Pavlov's theory of sleep and hypnosis as the manifestations of inhibition. Pavlov replied with critiques of Lashley's, Guthrie's, and Hull's views, and, convinced that Lashley and Guthrie misunderstood his position, repeated his method's and theory's basic propositions. Yet, Pavlov never gave up the expectation that American behaviorism would accept his conditional reflex theory and saw in Hunter's 1932 statements a support of his assumptions.     

I.P. Pavlov vs. N.I. Bukharin: The critical mind and the arrogance of power

In 1923, Pavlov criticized the Marxist theses and the policy of the Soviet regime. In 1924, N.I. Bukharin, a Marxist theoretician and member of the Soviet government, responded to Pavlov’s passionate speech with a sarcastic diatribe. I suggest that Pavlov’s speech and Bukharin’s article represent a conflict between a scientist critical of the Marxist pseudotheory and a journalist’s abusive response to the realization that his theory was without much merit.     

The importance of I.P. Pavlov for the development of neuroscience.

By his experimental and theoretical work on the physiology and pathophysiology of the higher nervous activity I.P. Pavlov significantly influenced the development of Neuroscience. During the 1950 Pavlovian Conference in Moscow, Stalin and the Communist Party tried to dogmatize his and his pupils' fundamental theories. But the Pavlovian ideas were developed by his pupils in open discussions with representatives of other schools in a very creative way, opening the doors for a systemic approach to understanding the integrative functional systems of brain and behavior. Pavlov emphasized the high plasticity of the central nervous system, investigated the complex functional systems within the brain and between the organism and its environment, and designed models for pathological deviations of the higher nervous activity. During his last years, he freed himself from the strong deterministic view and characterized the organism and its environment as a self-organizing system.     

Pavloviana in the USA: Archives of the history of American psychology,university of Akron

This paper represents one step in the effort to locate, examine, and make generally available archival materials related to the life and work of I. P. Pavlov and held outside the Soviet Union, in particular in the United States. The Archives of the History of American Psychology contain fairly extensive correspondence among American psychologists, with informative references to Pavlov, including letters written by K. S. Lashley, R. M. Yerkes, and J. B. Watson. References to Pavlov are also located in a variety of other sources, including reminiscenses of psychologists and R. M. Yerkes’“Obituary” of Pavlov written in 1916. Pictures of Pavlov and his close associates are reproduced from still photographs and motion picture films.     

Pavlovvs. Köhler

During the 1920s, I. P. Pavlov’s scholarly interests broadened to consider problem-solving. Distrusting Wolfgang Köhler’s Gestalt explanation of the problemsolving process and its interspecies aspects, Pavlov performed, from 1933 to 1936, a number of experiments, including a replication of Köhler’s building experiment, using chimpanzees as subjects. Confirming Köhler’s findings, Pavlov explained the problemsolving process in terms of unconditional reflexes and the establishment, by Pavlovian conditioning and the Thorndikian method of trial and error, of temporary neural connections identical, on the psychological level, to associations. In contrast to Köhler’s “structural” explanation, Pavlov emphasized the processes of analysis and synthesis. According to Pavlov insight is achieved progressively—as the result of the organism’s problem-solving behavior—contradicting Köhler’s thesis of a sudden subjective reorganization of the environmental situation. Pavlov explained interspecies differences among higher organisms in terms of the range of a species behavior, with the second signal system as the main distinguishing characteristic between human and nonhuman species.     

The importance of I. P. Pavlov for the development of neuroscience

By his experimental and theoretical work on the physiology and pathophysiology of the higher nervous activity I.P. Pavlov significantly influenced the development of Neuroscience. During the 1950 Pavlovian Conference in Moscow, Stalin and the Communist Party tried to dogmatize his and his pupils’ fundamental theories. But the Pavlovian ideas were developed by his pupils in open discussions with representatives of other schools in a very creative way, opening the doors for a systemic approach to understanding the integrative functional systems of brain and behavior. Pavlov emphasized the high plasticity of the central nervous system investigated the complex functional systems within the brain and between the organism and its environment, and designed models for pathological deviations of the higher nervous activity. During his last years, he freed himself from the strong deterministic view and characterized the organism and its environment as a self-organizing system. Lecture at the Annual Meeting of the Pavlovian Society, November 1, 1998, Dusseldorf, Germany.