Pavlov as a psychologist

American psychologists are informed on Pavlov’s work on conditional reflexes but not on the full development of his theory of higher nervous activity. This article shows that Pavlov’s theory of higher nervous activity dealt with concepts that concerned contemporary psychologists. Pavlov used the conditioning of the salivary reflex for methodological purposes. Pavlov’s theory of higher nervous activity encompassed overt behavior, neural processes, and the conscious experience. The strong Darwinian element of Pavlov’s theory, with its stress on the higher organisms’ adaptation, is described. With regard to learning, Pavlov, at the end of his scholarly career, proposed that although all learning involves the formation of associations, the organism’s adaptation to the environment is established through conditioning, but the accumulation of knowledge is established by trial and error.     

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.     

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.     

Learning: Association or Computation? Introduction to a Special Section

The fundamental nature of learning is a central problem in psychology. Traditionally, psychologists have assumed that learning must involve the formation of associations. Early last century, the pioneering work of Pavlov on conditioned learning in animals seemed to put this assumption beyond doubt. More recently, many psychologists came to believe that a different kind of process must underlie complex learning, such as language learning in humans, and that this process must be described as computational rather than associative. Whether complex human learning is associative or computational continues to be a subject of intense research. The articles in this Special Section turn this debate on its head by asking whether simple animal learning is associative or computational. Surprisingly, the question is still very much open, and excitingly, it appears quite tractable.     

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.     

Eponymy,obscurity, Twitmyer,and Pavlov

The discovery of the conditioned reflex is generally credited to Ivan P. Pavlov. So closely is Pavlov associated with this phenomenon that it is commonly referred to as the Pavlovian conditioned reflex. Edwin B. Twitmyer independently discovered the conditioned reflex at approximately the same time and reported the finding in 1904 at the meeting of the American Psychological Association. Unlike Pavlov's, Twitmyer's data had little impact on psychology. There have been various hypotheses to explain the failure of the field to recognize Twitmyer's discovery. These explanations are criticized and modified to reflect an emphasis on Twitmyer's and Pavlov's respective social and intellectual contexts.     

Pavlov and the Pavlovians in the laboratory

The general character of the Pavlovians and their role in the experimental investigation of conditioned reflexes is discussed. From 1897 to 1936, Ivan P. Pavlov had at least 146 co-workers and he was closely involved in their experimental work. The social background, nationality, and gender of the Pavlovians are described together with the daily routine in the laboratories. It is pointed out that, despite Pavlov's authoritarian style, the Pavlovians characterized him as the epitome of a scholar and an admirable human being. It is concluded that the work in the laboratories was truly a cooperative effort between Pavlov and his co-workers.     

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.     

Interaction of dominant focus and conditional reflex as a functional unit of behavior organization

The interaction of two fundamental phenomena—the dominant focus and the conditional reflex—discovered and introduced by A. A. Ukhtomsky and I. P. Pavlov lay at the basis of behavior. According to E. A. Asratyan, the backward conditioned connection is a specialized dominant focus in the functional structure of the consolidated conditional reflex. It makes the behavior goal-directed and active. The dominant focus and conditioned reflex play the same role in the adaptive behavior of the individual as does variability and selection in the process of evolutional adaptation. That is why it is impossible to agree with Popper and Eccles that hypothesis theory has to replace Pavlov’s theory of the conditional reflex. Imprinting and psychonervous activity by images (I. S. Beritashvili) are two special exemplars of conditional reflexes after one coincidence. The so-called “elementary reasoning activity of animals” (according to L. V. Krushinsky) is a kind of the instinctive inherited behavior.     

Pavlov and the demise of the influence of Gestalt psychology in the Soviet Union

Summary The demise of the influence of the classical Gestalt psychology in the Soviet Union has been linked to I.P. Pavlov's negative stance toward Gestalt tenets. Actually, Pavlov's attitude toward Gestalt psychology was by no means uniform. Pavlov was receptive to, as well as critical of a number of substantive issues. He acknowledged the Gestalt interpretation of transposition, but criticized the Gestalt rejection of association and learning by trial and error. Pavlov's strongest objection to Gestalt psychology centered on the philosophical issues of causality, methodology, and on the problem of mind and body. Despite these objections, no direct evidence links Pavlov's criticism of Gestalt theses to the weakening of their influence on Soviet psychology. Instead, the demise of classical Gestalt psychology in the Soviet Union should be attributed to political exigency. Soviet authorities, in a period of political crises, were intent upon the elimination of all traces of bourgeois psychologies.     

A pavlovian approach to psychiatry

The basic scientific discovery made by Pavlov, namely the differentially associated paired system comprising related positive and negative conditioned signals based upon inborn reflex systems, has been applied to normal, neurotic and psychotic states. A hypothesis is suggested as to the causation of neurotic and psychotic disorder. The differentially associated paired systems based upon the reproductive reflexes have to be reversed at puberty in the course of maturation and this disrupts normal function. This is not incompatible with Freudian ideas where “unconscious incestuous wishes, drives and guilt” are believed to be potent factors in the production of functional disorders. Freudian “life instincts” are equated with normal differentially associated paired systems and “death instincts” are equated with those paired systems in a state of reversal (ultraparadoxical phase).     

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.     

The place of the conditioned reflex in psychology and psychiatry: Reply to reese,dykman, and peters

Razran’s “The Place of the Conditional Reflex in Psychology and Psychiatry” delivered at GAP Symposium No. 9 traced historically the influence of Russian physiology on American behavior systems, first in the classical Watson period and then in present-day Neobehaviorism. The address collated Pavlovianism and Behaviorism, and mentioned recent Soviet emphasis of interoceptive, semantic, and compound-stimulus conditioning. Within the limits of time, it dealt with group developments and not with individual contributions. And it assumed that a behavior system comprises both normal and abnormal aspects; that is, the basics of both psychology and psychiatry. The assertion by Reese, Dykman and Peters that “Psychiatrists tend to avoid contributions of experimental psychologists and vice versa” is not shared by Razran, nor, he believes, by American psychiatry and experimental psychology as such. And the assertion is contrary to the Pavlovian tradition. Pavlov’s first, 1903, publication on conditioned reflexes was entitled “Experimental Psychology and Psychopathology in Animals” which he later renamed “the physiology and pathology [or pathophysiology] of higher nervous activity.”     

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.     

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.     

Effects of incidental pictorial and verbal adjuncts on text learning

In this study, college students read and studied texts on historical figures in psychology, which were supplemented by drawings and/or brief biographies of these persons. In Experiment 1, a 2 x 2 between-groups design was conducted in which students received one adjunct with each text, both adjuncts, or neither. In Experiment 2, a single group of students received a within-subjects manipulation of the same adjunct conditions. In the between-groups comparison, students receiving biographies learned less of the target text passages, with the group receiving illustrations and biographies performing least accurately. In the within-subject conditions, texts accompanied by an illustration were better learned, with these students doing best on the text with both picture and biography. The results suggest that adjuncts may emphasize some texts, at the expense of learning from the other texts, but that too much adjunct material interferes with the learning of the target passages.     

Behaviorism, latent learning, and cognitive maps: needed revisions in introductory psychology textbooks

This paper critically assesses the scholarship in introductory psychology textbooks in relation to the topic of latent learning. A review of the treatment of latent learning in 48 introductory psychology textbooks published between 1948 and 2004, with 21 of these texts published since 1999, reveals that the scholarship on the topic of latent learning demonstrated in introductory textbooks warrants improvement. Errors that persist in textbooks include the assertion that the latent learning experiments demonstrate unequivocally that reinforcement was not necessary for learning to occur, that behavioral theories could not account for the results of the latent learning experiments, that B. F. Skinner was an S-R association behaviorist who argued that reinforcement is necessary for learning to occur, and that because behavioral theories (including that of B. F. Skinner) were unable explain the results of the latent learning experiments the cognitive map invoked by Edward Tolman is the only explanation for latent learning. Finally, the validity of the cognitive map is typically accepted without question. Implications of the presence of these errors for students and the discipline are considered. Lastly, remedies are offered to improve the scholarship found in introductory psychology textbooks.     

Opioid receptors mediate direct predictive fear learning: evidence from one-trial blocking

Pavlovian fear learning depends on predictive error, so that fear learning occurs when the actual outcome of a conditioning trial exceeds the expected outcome. Previous research has shown that opioid receptors, including μ-opioid receptors in the ventrolateral quadrant of the midbrain periaqueductal gray (vlPAG), mediate such predictive fear learning. Four experiments reported here used a within-subject one-trial blocking design to study whether opioid receptors mediate a direct or indirect action of predictive error on Pavlovian association formation. In Stage I, rats were trained to fear conditioned stimulus (CS) A by pairing it with shock. In Stage II, CSA and CSB were co-presented once and co-terminated with shock. Two novel stimuli, CSC and CSD, were also co-presented once and co-terminated with shock in Stage II. The results showed one-trial blocking of fear learning (Experiment 1) as well as one-trial unblocking of fear learning when Stage II training employed a higher intensity footshock than was used in Stage I (Experiment 2). Systemic administrations of the opioid receptor antagonist naloxone (Experiment 3) or intra-vlPAG administrations of the selective μ-opioid receptor antagonist CTAP (Experiment 4) prior to Stage II training prevented one-trial blocking. These results show that opioid receptors mediate the direct actions of predictive error on Pavlovian association formation.     

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.