Conventional wisdom has it that Ivan Pavlov made dogs salivate to the sound of a bell, discovered the conditioned reflex, and laid the foundations for behaviourism, an austere creed that ruled the mind to be off limits for science. Almost all of this is false. Pavlov’s bell was in fact a sophisticated adjustable buzzer. The ‘conditioned reflex’ is a mistranslation: reflexes are instead ‘conditional’, occurring only under certain conditions. Pavlov, no behaviourist, saw his scientific work as a pathway to understanding ‘our consciousness and its torments’. His goal was not to reduce mind to mechanism but to use the tools of digestive physiology to comprehend the complexity of psychological functions and individuality. As the distinguished medical historian Daniel Todes writes in this superb biography, the salivary glands were to Pavlov a window into the psyche.

The only correct feature of the popular image of Pavlov is the iconic dogs. He dabbled in other creatures during his long career, including a disastrous involvement with mice and a more positive experience with a pair of chimpanzees. At one point he resisted a recommendation from Alfred Nobel to study giraffes. But Pavlov always returned to his faithful dogs, which he regarded with unrestrained anthropomorphism. As Todes astutely notes, Pavlov had ‘a long-standing practice of interpreting dogs as people and people as dogs’. A keen student of canine temperament, he observed that dogs came in many distinct ‘nervous types’, but they were all members of a species that was uniquely suited to his mode of experimentation.