Russian physiologist and father of behaviourist psychology. As Director of the Leningrad Institute of Experimental Medicine (1913) his work was concerned with the main areas of physiology, the circulatory system, the digestive system and his theory of higher nervous activity. In 1904 he was awarded the Nobel Prize in Physiologyfor research into the digestive system. His great contribution to psychological knowledge is his theory on the basic model of mental activity ¨~?? the 'conditioned reflex' or learning through association. In his study of the digestive process in dogs, he showed that if a bell is sounded every time food is presented to a dog, it is likely, in anticipation, to have started to salivate even if no food appears.