John B. WATSON 9 January 1878 – 25 September 1958

He was an American psychologist and founder of the school of behaviorism. He was one of the most influential environmental psychologists in American psychology. He modeled Pavlov's views on conditional reflex. He argued that if a dog could be conditioned, then a baby could also be conditioned and that the babies were raised through conditioning. Watson did not speak of reinforcement or reward in learning. According to him, the response to a stimulus is the last and most frequently repeated response to that stimulus. This principle was named The Last and Most Frequent Response principle.