"In the West, [Ivan Pavlov] has often been taken to have adopted an extremely mechanistic stimulus–response model of mental processing. He himself played his part in constructing this image, not least through the anthropomorphism of much of his research on dogs. But, as [recent biographer Daniel P.] Todes notes, the biggest contribution to this misapprehension was made by his first translators, who erroneously rendered his key experimental concept as “conditioned” rather than “conditional” reflex. In combination with the stereotype of dogs salivating to bells, this has made Pavlov come across as a narrow determinist and as a scientist preoccupied with external phenomena rather than underlying causes. In America, he has been domesticated as a variety of behaviourist. But this is a very misleading view.
One part of the stereotype is correct: Pavlov and his co-workers spent a great deal of their time getting dogs to salivate (though their preferred stimuli were the buzzer and the metronome, not the bell). But, as Todes shows in an exposition both lucid and nuanced, that was merely the starting point. Dogs for Pavlov were experimental subjects rather than machines for replicating results. He and his colleagues developed close working relationships with their animals (even as they tortured them). Control groups were unthinkable: all the dogs were individuals. This allowed Pavlov to conduct elaborate sequences of experiments on the same dog, with multiple combinations of stimuli, but quickly forced him to confront an inconvenient fact: dogs, like human beings, were different. Excitation and inhibition were not universal mechanisms, but varied in their intensity and interrelations from one animal to the next. By 1924, Pavlov enjoyed excellent lab conditions, including the purpose-built “Towers of Silence” where dogs could be isolated from extraneous stimuli, but even this apparently most neutral of environments affected dogs in profoundly different ways. A psychiatrist, perhaps, would have welcomed this evidence of irreducible psychic variation, but a physiologist and determinist, such as Pavlov always remained, badly needed to find a way of accounting for it. The second half of Pavlov’s life may be regarded as one long search for a way of embracing the complexity without abandoning core mechanistic positions.
The underlying irony was that, from approximately the mid-point of his life, this world-renowned physiologist was in fact going after the psyche. Even if he still thought nervous impulses the best way of explaining the mind’s functioning, he was starting to push against the limits of his earlier explanatory models. In earlier days, he had taken “conditional reflexes” as a synonym for what the psychologists called “associations”. He attempted to prove the point by establishing in dogs longer chains of reflexes: not just light-equals-meat, but also metronome-equals-light-equals-meat. But these experiments did not yield satisfactory results: Pavlov had to admit that associations were broader than reflexes, and that the cumulative study of individual reflexes could not account for the “systematicity” of the nervous system.
In the last decade of his life, as he came to acknowledge that the psychic whole was more than the sum of its nervous parts, his work took a distinctly psychiatric turn. No doubt this was partly the result of intellectual one-upmanship: he wanted to use his physiological toolkit to show the established specialists in the human mind the limits of their own aetiological speculations. But Pavlov’s interest in psychiatric abnormalities was also born of the sheer opportunism of any good researcher. Quite simply, a number of his dogs were nervous wrecks. In 1924, at least a couple of the animals were traumatized by their narrow escape from drowning during the Leningrad flood. Others were broken by the programme of experiments to which they were subjected – vivisection, isolation, electric shocks, jarring sounds. Earlier in his career, Pavlov might have discarded such animals as no longer “normal” and fit for purpose. Now they had become his most intriguing subjects: he analysed mental illness as a “break” caused by intolerable burdens on the nervous system. He was also more explicitly extrapolating from animals to humans. In the mid-1930s, he held court at “Clinical Wednesdays”, where he examined two or three patients [human or canine?] and then delivered a diagnosis, with psychiatrists in silent and sceptical attendance.
Pavlov’s dogs also drew him into the nature-versus-nurture debate. It was plausible to suppose that variation in dogs’ nervous types could be explained by heredity and by their different life experiences before entering the clutches of his lab assistants. In the early 1920s, Pavlov endorsed research on mice that seemed to demonstrate the inheritance of acquired characteristics, only later to have to retreat from this position when the experimental results were shown to be flimsy. A few years later, with the creation, thanks to Bolshevik largesse, of a bucolic experimental station outside Leningrad, he had the opportunity to investigate heredity in a more controlled and convincing manner. Dogs could be reared in controlled environments as “free” or “imprisoned”, and multiple generations could be studied to investigate inherited characteristics."