Oil on canvas hand drawn coloured painting of Russian physiologist Ivan Petrovich Pavlov born on 14 September 1849. Pavlov experimented on dogs and came up with the theory of conditioned response (the "Pavlovian response"). Pavlov's experiments showed that when a bell was rung at the same time as food was being presented to the dog in consecutive sequences, the dog will initially salivate when the food is presented. Later, the dog will come to associate the ringing of the bell with the presentation of the food and salivate upon the ringing of the bell. Bells were not the only stimuli he used to elicit this response and his writings record the use of a wide variety of stimuli, including electric shocks, whistles, metronomes and tuning forks. He was awarded The Nobel Prize in Physiology or Medicine 1904 "in recognition of his work on the physiology of digestion, through which knowledge on vital aspects of the subject has been transformed and enlarged". He is depicted here together with a dog and two bells.
