The “Pavlovian bell” (a conditional stimulus or CS) was made famous by this 1926 footage of “Mechanics in the brain” as well as a 1906 Science article quoting a Huxley lecture at Charing Cross Hospital in London. It was also mentioned in 1923 publications of The Scientific Monthly & the Quarterly Journal of Experimental Physiology. In it’s March 1928 issue Time magazine further popularized it by describing this movie
“The process of changing unconditioned reflex into a conditioned reflex was clearly demonstrated to an audience of psychiatrists at the Academy of Medicine last week in a cinema titled “the Mechanics of the Brain.” The cinema showed dogs which dripped saliva at the sound of a bell…
The film was directed by the famous Vsevolod Pudovkin. The movie itself shows experiments involving conditioned reflexes of a child that were conducted by Prof. Krasnogorskii in the 1st paediatric clinic of the Leningrad Medical Institute. At the time of this production Ivan Pavlov was the director of the Institute of Physiology. Recordings of children in ordinary conditions were performed by Prof. A Durnov. The other physiological experiments and demonstrations were performed by Prof. D. Fursikov in the laboratory of Ivan Pavlov and in the Institute of Brain of the Academy of Sciences of USSR. The recording of animals was performed in the Leningrad Zoo with the assistance of it’s director I.Banilov.
It was claimed that “this film was prepared under the direction of Ivan Pavlov and was projected by him at the 14th International Consists of Physiology in Rome in 1932.” It is true that after the congress, Pavlov donated the film to Carla Fab who was then Professor and Chairman of the Department of Physiology at the University of Milano Medical School and that the film was used in Foil’s course of medical physiology in Milano and in Son Paulo, Brazil until his retirement. It is also true that given the political climate in the Soviet Union at the time, Pavlov’s liberties were restrained and he had to comply to the demands of those in power (the Bolsheviks, a Marxist faction founded by Vladimir Lenin).
In his biography, Daniel Todes presents us with evidence that suggests that Pavlov needed funding to run his laboratories from the Bolsheviks and endured some of their demands. This movie was tolerated by him but in fact, he did not routinely use the bell. Most often he used a “buzzer, black square, mechanical stimuli, rotating object, “hooter”, whistle, lamp flash, electric shock, or the more exacting sound of a beating metronome. But rarely ever —a bell.