Ivan Pavlov was a Russian psychologist who was known for his development of conditioned response. One of his more well known experiments showed the principles of conditioned response. Pavlov surgically created openings in the digestive tracts of dogs. He noted that dogs would salivate upon seeing their owner, in anticipation of being fed. According to his system of conditioned response, when offered an unconditioned stimulus produced a response. This is shown when a dog is offered food, they salivate. This response is caused by the creation of new reflexive pathways created in the cortex of the brain by the conditioning process. Excitation promotes conditioned responses, and inhibition suppresses them. Testing the dog's ability to differentiate between stimuli led to mental neuroses, similar to mental breakdowns in humans.
Pavlov won the Nobel Prize for Physiology and Medicine in 1904 as a result of this research. He applied these concepts to psychiatry, and is considered one of the founding leaders of psychiatry. Although Pavlov never considered himself a psychologist, he is considered an important aspect of the behaviorist school in the America.