Pavlov knew but one way to battle his Beast of Doubt: more experiments, which would produce pravil’nye results and bring him closer to the underlying laws that, he remained confident, underlay the crushing “mass of details demanding explanation.” After he had completed his monograph, his lab pursued various lines of investigation, but he was himself most engaged in the one that seemed most fruitful in this respect—the analysis of nervous types, which promised not only to reconcile conflicting experimental data, but also to provide the missing piece in his grand quest, to join the results of CR experiments to observable personalities and other psychological phenomena among dogs and humans.1
So 1926 and 1927 found Pavlov and Petrova again sitting side by side in their semiprivate experimental station on the second floor of the Towers of Silence, again exploring the nervous types of dogs, and again trying to correlate the animals’ differential responses to CR experiments with their personalities and the Hippocratic typology. The veteran, excitable Postrel was now joined by Bek, who was chosen to replace the fallen Milord because he fit Pavlov’s definition of a sanguinic—lively, curious, and prone to sleeping on the experimental stand.
Pavlov’s diagnosis of the nervous constitution of the sanguinic (like that of all the Hippocratic types) was based on metaphorical reasoning about how strong and weak excitatory and inhibitory processes, in various combinations, might be expressed in various behaviors and personalities. He had diagnosed sanguinics as having both an extreme imbalance toward excitation and weak excitatory cortical cells. Thus, he reasoned, they were very lively when free to seek out a wide range of different stimuli, but when their cortical cells were subject to the constant stimulation of any single stimulus (for example, in the experimental stand), the cells soon approached exhaustion, protective inhibition kicked in, and the dog fell asleep. Similar reasoning led him to conclude that the extremely inhibited melancholic also had a weak nervous system. In this case, because the excitatory material in his cortical cells was quickly depleted, the nervous system of the melancholic responded to excitation with an almost immediate protective inhibitory impulse to spare the cells exhaustion and damage. The result was an inhibitory—and thus melancholic—response to all stimuli and events.
Such metaphorical reasoning always underlay Pavlov’s reasoning from the salivary results of CR experiments to his conceptual map of the nervous system and, finally, to behavior and personality. The word “weak” referred simultaneously to a presumed shortage or deficiency of excitatory materials in the cortical cells, to a nervous imbalance between excitation and inhibition, and to a set of behaviors and personal traits (such as cowardice).
Pavlov and Petrova now sought to assess the strength of Bek’s nervous system by attempting to break him. Petrova induced a sharp confrontation between excitation and inhibition by the lab’s now-favored method. First, she established the stimulation of the skin in one place as a CS and stimulation of another place as a CI. Then, she rapidly alternated stimulation of the two spots. Strong (that is, balanced) dogs could endure this clash of excitatory and inhibitory impulses without disturbance, while weak (imbalanced) ones “fall into a pathological state toward either excitation or inhibition.” The experimenters monitored both the dog’s behavior and his baseline reaction to other established CRs. During six days of trials, Petrova reported, the rapid alternation of CS and CI indeed proved difficult for Bek. The dog’s salivary reactions to established CSs wavered, and he moved about “uneasily,” breathing loudly—but he did not break. So, they concluded, sanguinic dogs did not have a weak nervous system, but rather “a strong one, which, so to speak, is efficient in its own way.” The sanguinic’s tendency to fall asleep on the stand actually attested to the strength of this nervous type: “When work is demanded, they give the maximum of energy; if there is no demand for work, they are characterized by inhibition, quickly passing into drowsiness and sleep.” (Here, “strength” has acquired yet another meaning—the efficient use of resources.)2
How, then, did the sanguinic Bek’s nervous system compare to that of the excitable Postrel? Petrova compared the dogs’ performance in three experiments that tested the relative strength and interaction of their excitatory and inhibitory processes. For example, using a test that became routine in such diagnoses, she explored how quickly each dog could turn a CS into a CI, and vice versa. Before this series of trials, Postrel had for eight years responded to the metronome beating 144 times per minute as a CS (generating 17 to 19 drops of saliva) and at 66 times per minute as a CI (generating 0 drops). If M66 was now repeatedly reinforced with feeding, how quickly would the dog begin salivating at its beat? On the very first day, Postrel began salivating to M66 and did so “without the slightest tension.” For the experimenters, this rapid transformation indicated the great relative strength of Postrel’s excitatory process. The reverse process, turning M144 into a CI by ceasing to accompany it with feeding, proved much more difficult for him. Only on the sixth day did Postrel’s salivary response to this longstanding CS decline—and it fluctuated between 6 and 16 drops (rather than reaching 0), which, like the dog’s panting, Petrova interpreted as the reflection of a difficult “struggle” between the dog’s excitatory and inhibitory processes. Only after three weeks (on the forty-sixth repetition) did Postrel respond to M144 with zero salivation—but even this belated success was accompanied by a decline in the dog’s salivary response to other CSs. This, the experimenters concluded, was further evidence of Postrel’s highly unbalanced excitatory constitution.
The pattern with sanguinic Bek was much different. The dog “easily” turned his former CS into a CI (on the fourth day of trials), but transformed his CI into a CS more slowly and with obvious difficulty (he panted and yelped). Bek also outperformed Postrel on two other experimental tests (for example, the ability to form a delayed reflex) that measured the strength of the inhibitory process. Petrova and Pavlov concluded, then, that Postrel was the more excitable type, while the sanguinic Bek was better balanced. This diagnosis was fortified by the experiments of another coworker upon the “Napoleonic” dog Pingel’, whose behavior, affect, and response to similar experiments (like Bek, the animal could not be broken) established his bona fides as a sanguinic.3
Based on these experiments, Pavlov reversed the position of the sanguinic and choleric. He now adopted the nervist description of the Hippocratic types that he would invoke thereafter: the choleric (represented by Postrel) was the most extremely excitable type, the sanguinic (Bek and Pingel’) leaned toward excitation but was more balanced, the phlegmatic leaned toward inhibition but was also basically balanced, and the melancholic was extremely inhibited.
Addressing the Society of Russian Physicians in December 1927, he spoke confidently about the personalities and subjective experiences that resulted from these differing nervous constitutions:
For the melancholic, obviously, every phenomenon of life becomes an inhibitory agent, as he believes in nothing, hopes for nothing, in everything sees and expects only bad, danger. The choleric type is manifestly a militant type, easily and quickly irritated. And at the golden mean stand the phlegmatic and sanguinic temperaments—balanced and therefore healthy, stable, and truly lively nervous types, however different, and even opposite, representatives of these types might appear. The phlegmatic is calm, always equable, a persistent and stubborn laborer at life. The sanguinic is fervent, a very productive activist, but only when he has many interesting missions, that is, when there is constant excitation. When such a mission is lacking he becomes bored, listless, precisely like our sanguinic dog (as we usually call them) who is very lively and active when the setting excites him but then sleeps in the absence of such excitations.4
Having so thoroughly anthropomorphized his dogs, he had no hesitation in concluding, “Obviously, these types are that which we term temperaments in people. Temperament is the most general characteristic of each separate person, the most basic characteristic of his nervous system, and this puts its stamp upon the entire activity of every individual.”5
This nervous typology also provided the basis for a preliminary analysis of mental illnesses in humans. Individuals of the central types remained “more or less untouched amidst the choppiness and storms of life’s sea,” but cholerics broke toward excitation, as manifested in neurasthenia, and melancholics broke toward inhibition, which was expressed as hysteria. Circular psychosis and schizophrenia were, “by their physiological mechanism, a higher phase of these same illnesses.” Neurasthenics could sometimes function quite well—“many great people were neurasthenics”—but their periods of intense work alternated with periods of depression. Thus circular psychosis. In both lab dogs and humans, excessive strains upon a weak cortex resulted in hypnotic states—that is, deeply inhibited states intermediate between wakefulness and sleep. The dynamics of these hypnotic states held the key to severe mental illness. For example, the extreme form of hysteria was schizophrenia, in which the inhibition of cortical functions led to loss of cortical control and so to the “predominance, the uncontrolled excitation, of the most complex unconditional reflexes (aggression, passive-defensive, and other reflexes that are functions of the subcortical centers).”6 In identifying mental illness with hypnotic states, Pavlov was relying upon leading European authorities. The turn toward psychiatry would preoccupy him during the 1930s.7
In his Croonian Lecture to the Royal Society in London, delivered six months later in May 1928, Pavlov delivered a more cautious, less explicitly anthropomorphic version of this same speech. Claiming that his typology of nervous types was “constantly verified” by lab investigations, he conceded in passing that “of course, there are certain gradations among these basic types.” He emphasized the extreme plasticity of the nervous system and expressed his hope that his research would help guide upbringing and self-education. “In any event, looking at these experiments I myself have made clear many things both about myself and others.”8
This last intriguing comment went unmentioned in the breathless report by the New York Times’ Walter Duranty about Pavlov’s “triumphant visit to England.” Under the headline “Dr. Pavlov Defines Causes of Insanity,” Duranty informed readers that the Russian had enunciated “a sensible and scientifically exact classification of the human types. Where the Freudians guess, Pavlov defines positively by experiment, giving the first rational explanation of nervous diseases and insanity.”9
By decade’s end, the chief had assigned numerous coworkers to perform typological analyses. One subgroup studied “inhibited, cowardly” dogs. Their reports illustrate Pavlov’s goal of mapping the results of CR experiments upon behavioral and personality attributes, the difficulties in doing so, and the way that these difficulties fueled an ever-expanding research program.10
Nikolai Vinogradov inherited the “weak, inhibited” female Umnitsa in 1926, after Pavlov had already discussed her extensively in his monograph as the archetypical cowardly animal. Born and raised in the lab—where, chief and coworker always added, she had never been mistreated—Umnitsa was “awkward” and “fearful,” with “an extremely expressed orientational reflex.”11
Subtle differences in the nature of this orientational (or investigative) reflex had become an important indicator of a dog’s nervous type. The basic orientational reflex, colloquially termed the “What is it?” reflex, was considered the animal’s initial excitatory response to any new stimulus. In some dogs, this was followed by a second, inhibitory phase—the “passive-defensive reflex”—that rendered the animal immobile. For Pavlov, each phase reflected the precise adaptation of the organism to its environment and served a specific purpose in the struggle for existence: the excitatory phase set the animal’s entire sensory apparatus searching for the nature and significance of a new stimulus. “In humans, this reflex has progressed greatly, finally manifesting itself in the form of the curiosity that creates science, which promises and provides us with the greatest, unlimited orientation to the world around us.” The second, inhibitory phase immobilized the animal, “making it less noticeable to an enemy and eliminating or moderating the aggressive reaction of a powerful competitor.” Therefore, any change in the environment elicited two reflexive responses: “a positive investigative [reflex] and, so to speak, an inhibitory reflex of caution.”12
Over time, in the usual process of metaphorical stretching, this notion of a passive-defensive reflex expanded to include a wide range of responses to an initial exciter that, although they did not immobilize the animal, seemed to express an inhibited, cautious, and fearful attitude toward the unknown. It became a generalized “reflex of caution.” With the growing attention to nervous types in the 1920s, this response to novelty became an identifier of an overly inhibited, cowardly dog.
Despite her fearfulness in daily life, Umnitsa had proved a good experimental animal, adjusting well to experimental work and producing CRs with “great precision.” Like Speranskii’s dog Avgust, however, she was traumatized by the Leningrad flood and no longer produced pravil’nye CRs when secluded in the Towers of Silence. After resting for about one year, Umnitsa was assigned to coworker Nikolai Vinogradov for a detailed experimental analysis of “the weak inhibited type of nervous system.”13
Vinogradov’s results greatly complicated the laboratory view of what, exactly, made a “weak” dog weak. Pavlov had previously defined weakness as a presumed lack of high-quality excitable material in the cortical cells. Weak dogs, then, inclined toward inhibition (and therefore cowardice). In his book, Pavlov had even termed them “specialists in inhibition.” But Vinogradov’s experiments indicated that Umnitsa’s excitatory and inhibitory processes were both weak. That is, the dog’s ability to form CRs and CIs was equally unimpressive. She required many trials to form a CR, and even then produced a paltry amount of salivation in response. Yet if the experimenter ceased to reinforce an existing CS, this CR vanished only very slowly—which testified to a weak inhibitory process. Nor did the dog respond to CIs with the total lack of salivation that a strong inhibitory process would produce. Furthermore, it proved impossible to extinguish Umnitsa’s orientational reflex to an indifferent agent. This was also true of decerebrated dogs, which had led the lab to the conclusion that the orientational reflex was a UR originating in the subcortex. By this logic, Umnitsa’s inability to inhibit her orientational reflex reflected a “great weakness of the cortex, which therefore could not inhibit the automatism of the subcortex.” So Vinogradov (and Pavlov) revised the longstanding lab view of a “weak” dog, now adopting the position that the weak cortical cells of such dogs resulted in a deficiency in both excitation and inhibition. This, of course, complicated the earlier view of a direct relationship between cowardice and the predominance of inhibition.14
Vinogradov’s experiments also highlighted the importance of two dimensions of higher nervous activity that would acquire increasing importance in coming years: the role of experience (or training) and that of the “social exciter.” Due to Umnitsa’s weak nervous system, for example, she could not initially form a CR to the electrical buzzer—presumably because this strong exciter elicited an extreme and immobilizing passive-defensive reflex. So Vinogradov lessened the strength of the buzzer by muffling it, trained Umnitsa first to accomplish the less demanding task of forming a CR to this gentler stimulus, and eventually succeeded in eliciting a CR to the buzzer at full strength. “For the successful formation of conditional reflexes in animals with a weak nervous system,” he concluded, “the method of training and extreme gradualness is indispensable.” Using this same approach, he managed also to extend the length and intensity of Umnitsa’s workday.15
As he attempted to improve Umnitsa’s performance, Vinogradov also noticed the importance of the social exciter in the form of “the constant friendly presence of the experimenter-master.” Umnitsa performed poorly in an isolated chamber, but if the experimenter instead sat beside her (conducting experiments by what became known as the “greenhouse” method) she could work longer and respond more precisely to a much more varied group of exciters. Vinogradov concluded that the social exciter raised the general tonus of the higher nervous system, which was particularly important for such weak animals as Umnitsa.16
Coworker Stanislav Vyrzhikovskii experimented on another “inhibited, weak” creature, Zheltyi (Yellow). Zheltyi’s behavior, too, demonstrated the importance of the social exciter for animals of a weak type, and Vyrzhikovskii’s interpretation gave this a dishonorable, even sinister twist:
When free, Zheltyi is a very mobile animal. He needs to become acquainted with everything: to inspect and sniff.... Zheltyi’s attitude toward the people and dogs he encountered was not always identical. It depended on whether or not the experimenter or attendant was near—that is, a familiar person from whom he could expect help if necessary...If so, he was braver, throwing himself upon passers-by, but the smallest motion in his direction—and often even a glance—sufficed to send him hiding behind the back of his “friend,” from which he continued to bark. In relation to dogs, in the same circumstances Zheltyi was a coarse bully, but of course only within certain bounds. In the presence of his “protector” he would bravely, with a militant demeanor, approach a strange dog, as if just about to fight. But with the very first sign of his opponent’s superiority he would flee to put his “protector” between himself and his enemy....
If unaccompanied by a protector during an unavoidable encounter with an unknown [person or dog], Zheltyi by all means possible demonstrates his friendly intentions, his devotion, and so forth—wagging his tail, fawning, lying on his back—ingratiating himself with man or dog. This is the source of his sociability.17
Clearly not enamored with this creature, Vyrzhikovskii described him as an opportunistic sycophant: “Zheltyi knows how to ‘serve.’ This ‘service’ is hardly random; to the contrary, it always seems to have some goal. For example, he serves if in his presence another dog is given food or if addressed in a strict tone.”18
Zheltyi’s unappealing character was mirrored by his performance in experiments. His responses to both CSs and CIs were weak and unstable—indeed, he was just as likely to salivate in response to a CI as to a CS, and in roughly the same amount. Like Umnitsa, Zheltyi was unable to form a CR to a strong stimulus such as an electrical buzzer—which instead, presumably through negative induction, caused his other CRs to decline. He performed much better when aided by the “social exciter,” but Vyrzhikovskii’s attitude toward this was unforgiving: “One must, then, recognize Zheltyi as a cowardly animal, constantly needing social help.”19
The final, decisive proof of Zheltyi’s extreme inhibitedness and cowardice was his failure to mount even the unintimidating Umnitsa. The two were left alone in a room when Umnitsa was in heat. “There was a mutual disposition: they played, licked each other, and so forth.” Yet even this “powerful sexual excitation” could not spur Zheltyi to action. The faintest sound, or even the slightest wagging of Umnitsa’s tail, sent Zheltyi scurrying away to the far corner of their quarters or lying cravenly on his back. “All this confirms the weakness of Zheltyi’s nervous system and his need for the social exciter. The absence of a ‘protector’ sends him into an inhibited state from which he cannot be extracted even by the sexual reflex.”20
Vinogradov’s and Vyrzhikovskii’s research changed the longstanding definition of “weak”—revising it from a predominance of inhibition over excitation to a deficiency in both nervous processes—and, for Pavlov, highlighted the need to study further the role of the social exciter.
Two other studies of cowardly dogs further complicated the attempt to connect the results of CR experiments neatly with behavioral and personality attributes. Dmitrii Kuimov’s dog Felix possessed all the behavioral attributes of a highly inhibited type. “Cowardly and submissive,” with a highly developed passive-defensive reflex, the animal responded to a person’s approach by rolling on the ground, yelping, and “sometimes urinating.” Yet Felix was always “energetic in the stand and worked marvelously.” He formed positive CRs easily and differentiated quickly between M132 and M66. He clearly possessed “a balanced nervous system.” How, then, to explain the animal’s cowardice? This, Kuimov concluded—no doubt at the suggestion of the chief, who was observing his experiments—was “probably the result of the dog’s earlier training. In his early youth, one must conclude, the dog aroused his master’s hope that he would become a show dog. To this happy past testifies the pup’s clipped tail (participation in a course for purebreds?).” The implication here is that, chosen for pampered “show dog” status, Felix was spared the interactions with other dogs and the rigorous demands from humans that might have toughened him up to the level his inborn qualities made possible.21
Psychiatrist-coworker Alexander Ivanov-Smolenskii’s dog Garsik seemed similarly paradoxical. Garsik, too, exhibited a strong passive-defensive reflex—and so was presumably an “inhibited type with a weak cerebral cortex.” Yet he formed both positive and negative CRs quickly, accomplished such difficult tasks as the formation of a delayed reflex easily, and emerged unscathed from the same challenges that broke weak dogs. How, then, to explain Garsik’s powerful passive-defensive reflex?Intrigued, Pavlov worked closely with Ivanov-Smolenskii on Garsik’s case, and the pair concluded that the contradictory indications resulted from the animal’s upbringing. Garsik had been born and raised in the laboratory kennel—“that is, in conditions of unfreedom, in a ‘jailhouse’ regime”—which had encouraged caution, broken his spirit, and produced submissive behaviors that masked his true nervous character. This raised the question of “the influence of upbringing, together with nervous type, on the animal’s behavior.” As Felix’s case also presumably illustrated, a precise understanding of nervous types—and the successful mapping of experimental results upon observable behaviors and personalities—required an understanding of yet another variable: the animal’s life experiences. According to Pavlov’s close associate Viktor Rikman, Garsik’s case convinced the chief to convert his rural dog nursery in Koltushi into a center for the study of this variable. Two words that had been previously used interchangeably now acquired distinct meanings: inborn “temperament” and environmentally influenced “character”—and a new line of investigation on the relationship between nature and nurture was born.22
Conferring with his coworkers at their Wednesday meeting a few years later, Pavlov spoke directly about Garsik’s pivotal role in the lab’s research. By that time (1930), another dog, Mampus, had also manifested a striking divergence between his performance in CR experiments, which indicated a weak nervous system, and his calm, strong personality. Clearly, Mampus was a weak type who had been “brought up in a propitious setting in which he had nothing to fear, and his size won him the respect of other dogs, and so there developed in him peaceful, measured manners.” Garsik was an opposite case, “a cowardly animal by his behavior, who turned out in experiments to be a strong type. Apparently, as opposed to Mampus, Garsik’s surroundings were unfavorable—he was beaten often—and as a result there appeared cowardly manners in a strong type of nervous system.”23 By 1933 the relationship of nature and nurture had become central to research at Pavlov’s Koltushi lab in the countryside, and Garsik had become a classical case illustrating a general truth—that life experience influenced the animal’s ability to temper his reflex of caution and develop a bolder, more inquisitive relationship to his environment.24
Investigations of cowardly dogs illustrate the general direction of Pavlov’s research on nervous types in the latter part of the 1920s. Numerous coworkers prepared detailed studies of individual dogs in the hope of establishing a clear typology. But this resulted not in an increasingly definitive schema that linked experimental results to observable behaviors and personalities (let alone to the Hippocratic types) but rather in the multiplication of variant data, the constant invocation of new variables, and the continual discovery of new subjects for future research.
The Hippocratic typology would always provide a colloquial terminology for lab discussions, and it became enshrined in Pavlov’s iconic image, but it never provided more than a crude and problematic framework for grouping lab animals. According to Pavlov’s daughter Vera, most animals defied that typology. Having herself attempted to type the dog Tom, she later explained: “Dogs with a classically strongly expressed type of higher nervous activity are encountered relatively rarely. Most animals with which [the experimenter] deals represent various intermediate forms between one basic type and another.” Yet the doctrine of nervous types became central to Pavlov’s investigations—to his attempts to systematize the mountains of contradictory data generated by experiments—and in the 1930s he expanded his efforts to find the additional variable or two that might render his typology coherent.25
He was increasingly troubled about the prospects for doing so. In the early days of his investigations, he had relied largely on the two basic processes of excitation and inhibition for his typology; hence, dogs were overexcited, balanced, or overinhibited. Then a second variable—balanced or unbalanced—permitted him to use the Hippocratic foursome (the choleric was unbalanced and excitable, the sanguinic was reasonably balanced with a tendency toward excitation, the phlegmatic was reasonably balanced with a tendency toward inhibition, and the melancholic was unbalanced and inhibited). Not only did this typology fail to contain the experimental data (as Vera testified in the citation above), but experiments and other lines of investigation continually revealed additional properties of the nervous system, and so new variables for any typology. For example, the relative “strength” of cortical material emerged as a variable independent of the balance between excitation and inhibition. Coworkers also concluded that the “lability” of nervous processes varied independently from their “strength” or “weakness”—that a dog might have labile excitation and inert inhibition—and so forth. Pavlov always remained optimistic and forward-looking in his public pronouncements, acknowledging that some individual dogs evaded his typological categories but insisting upon the reality of those categories themselves.
Privately, however, he pondered the situation unhappily. Attempting to take stock sometime between 1928 and 1930, he entitled a single sheet of paper “Possible types of central nervous system,” identified the three most important nervous qualities that influenced a dog’s responses to an experiment (and so defined its nervous type), and began combining these qualities systematically, sometimes provisionally identifying these combinations with the name of a dog. He began:
1. Strong, balanced, labile.
2. Strong, balanced, inert excitation and inhibition.
3. Strong, balanced, inert excitation, labile inhibition.
4. Strong, balanced, inert inhibition, labile excitation.
5. Strong, unbalanced with a relative dominance of excitation, labile.
6. Strong, unbalanced with a relative dominance of excitation, inert excitation and inhibition.
Working out the various combinations, he listed twelve possible “strong” types before reaching “13. Weak, balanced, labile (passive-defensive),” and delineating twelve possible varieties of weak dogs, identifying one of the lab’s notable cowards provisionally within one of these: “22. Weak, relative dominance of inhibition, inert excitation and inhibition (Umnitsa?).” Then came “25. Middling, balanced, labile,” but, now headed for at least thirty-six possible types, and with very few of his some 150 dogs identified with any of them, he ended his list with the desultory recognition “and so forth.”26 The distance to the horizon remained undiminished.
* * *
Pavlov frequently commented about himself during experiments with dogs, observing similarities between the animals’ responses and his own sensations and experiences. “That which I see in dogs,” he explained to one reporter as he made the rounds in his lab, “I immediately transfer to myself, since, you know, the basics are identical.”27
This constant analogizing between dog and self was both a way to understand the experiments themselves—of reasoning from observable patterns of salivation to the unseen higher nervous processes that lay behind them and the subjective experiences that they produced—and an effort to understand himself scientifically. This only made good sense for somebody seeking a scientific approach to psychological and psychiatric phenomena, to the mysteries of the human psyche.
As he grew older, Pavlov often commented about changes in his own higher nervous activity as a result of aging—for example, the loss of short-term memory and the lessening “reactivity of my cortex.” In 1923, Anrep found him using the language of CRs to ponder the influence of aging—and the fading overseer of inhibition—upon his thinking: “It is so amusing to watch myself growing old and to observe which faculty diminishes and disappears first. Old age has such a lot of advantages; I feel that I have now acquired an extraordinary freedom in thinking, a great faculty of arriving rapidly at conclusions, making plans, discovering relationships, and analyzing intricate experiments. My mind has become much freer than it ever was before. Of course, I know that this is all due to the fact that I am rapidly losing the faculty of self-criticism; inhibition is so much more delicate a process than excitation; we see it every day in [conditional] reflexes, and now I am observing it on myself.’”28
What, then, did Pavlov mean when he confided in 1928 to the distinguished audience that gathered for his Croonian Lecture to the Royal Society in London that experiments on nervous types had illuminated much about himself? He was at the time preoccupied with Ivanov-Smolenskii’s experiments on Garsik—that “cowardly animal by his behavior, who turned out in experiments to be a strong type”—and he seems to have been thinking specifically about the divergence between that dog’s inborn nervous type and its outward behavior and personality. He may well have been puzzled about a similar divergence in himself, since Pavlov must have considered himself an unlikely nervous type to become a successful scientist. Garsik, there is good reason to believe, solved this riddle for him.
Pavlov believed that only a good balance between excitation and inhibition allowed an organism to perceive reality correctly. A dog with a strong, balanced nervous system could differentiate accurately between similar stimuli and remain unbroken during trials that precipitated neurosis in weaker, poorly balanced animals. That same balance, he explained in his speeches of 1918, was the physiological basis for the great successes of England and Germany in science and self-government, and its absence—the predominance of excitation—underlay Russians’ woeful performance in those same arenas.
But Pavlov himself was hardly a strong, balanced type. His mother had been emotionally unstable and his two uncles self-destructively erratic. He himself had been extremely high-strung from childhood. In his first year at college, he had been sent home with “neurosismus,” and in the late 1880s (by his own later diagnosis) he had suffered from neurasthenia or hysteria. Famously explosive, he considered himself “an unrestrained choleric.” He was perhaps describing his own feelings during his seemingly uncontrollable outbursts when he stated confidently that if an overexcitable dog could speak, it would report “that it cannot restrain itself from doing what it should not.”29
How, then, could this unbalanced choleric become such a successful scientist? At the turn of the century, Pavlov had enjoyed thinking about his scientific style, and discussing it with coworkers, in terms of Ostwald’s classification of thinkers as “romantics” or “classicists.” By the 1920s it was natural to adopt instead the terminology of nervous types. Pavlov’s longtime associate Iosif Rozental’ was no doubt drawing upon such discussions when in 1929 he addressed that subject in an article for Physician’s Gazette on the occasion of Pavlov’s eightieth birthday. Rozental’ explained that Pavlov’s difficult life before 1890 had developed in him “strong self-control” that balanced his “inborn excitability.” The result was “a personality possessing both powerful excitatory and inhibitory processes.” This was the physiological basis of Pavlov’s style of creative scientific work, which combined a powerful excitatory phase (featuring free and even “fantastic” theorizing) with an equally powerful inhibitory phase (featuring “all-sided critical analysis” of these hypotheses). Devoted to Pavlov and intimately familiar with his temper, Rozental’ would never have published such a revelation, let alone in a celebratory article, without approval from the chief himself.30
Pavlov’s abilities and achievements, like Garsik’s, were not, then, the simple result of inborn nervous temperament, but rather of the interaction of nature and nurture. His elliptical comment in the Croonian Lecture about enhanced self-knowledge was almost certainly an allusion to this resolution of a mystery in his own biography through his always profoundly anthropomorphic and self-referential research on nervous types.