Classical conditioning is based on research done by physiologist Ivan Pavlov in the 1890’s. He researched salivation in dogs in response to being fed. Pavlov predicted the dogs would salivate in response to the food placed in front of them, but he also noticed that his dogs would begin to salivate whenever they heard the footsteps of his assistant who was bringing them the food. When Pavlov discovered that any object or event which the dogs learned to associate with food (such as the lab assistant) would trigger the same response, he realized that he had made an important scientific discovery. He devoted the rest of his career to study this type of learning. To further illustrate the effects of classical conditioning- if I were to say the word “calm” it would most likely have a neutral effect or you would associate it to a feeling of tranquillity. Now if every time I said “calm” and fired a gun into the air beside you , eventually that word would cause physiological changes in your body- like tension in your muscles, elevated heartrate ,and perhaps even cause you to become startled in anticipation of the gunshot just by saying the word. As you see anything you are able perceive through sound ,sight, or even smell is capable of eliciting any reaction you are able to make.