But Pavlov never held such views, according to “Ivan Pavlov: A Russian Life in Science” (Oxford), an exhaustive new biography by Daniel P. Todes, a professor of the history of medicine at Johns Hopkins School of Medicine. In fact, much of what we thought we knew about Pavlov has been based on bad translations and basic misconceptions. That begins with the popular image of a dog slavering at the ringing of a bell. Pavlov “never trained a dog to salivate to the sound of a bell,” Todes writes. “Indeed, the iconic bell would have proven totally useless to his real goal, which required precise control over the quality and duration of stimuli (he most frequently employed a metronome, a harmonium, a buzzer, and electric shock).”