1-157-350 - Ann Ronan Picture Library/Heritage-Images

Diagram of Pavlov's findings on conditioned salivary reflex. D: organ of touch and temperature; N: 1-6 analysers; S: salivary gland; Q: saliva secreting centre in the medulla oblongata; M: muscle; R: motor centre in the spinal cord. Ivan Pavlov (1849-1936) was a Russian physiologist who carried out famous research in the 1890s and 1900s into conditioned reflexes in dogs. He found that a dog trained to associate food with the sound of a bell would salivate when the bell sounded even when no food was forthcoming.