The discovery was accidental. Pavlov was doing research on digestion and on the central nervous system. For his research, he collected saliva from the animals in his laboratory. To get the saliva, he had an experimenter put meat powder in the laboratory dogs’ mouths. The meat powder was a stimulus to get the dogs’ mouths to water. Soon he noticed that the dogs’ mouths watered even before they got the meat powder. In fact, their mouths began to water at the sight of the experimenter. The experimenter had become the stimulus