Pavlov, when he started this research, had no interest at all in learning. He was interested in saliva. And to get saliva he had to have dogs. And he had to attach something to dogs so that their saliva would pour out so he could study saliva. No idea why he wanted to study saliva, but he then discovered something. What he would do is he’d put food powder in the dog’s mouth to generate saliva. But Pavlov observed that when somebody entered the room who typically gave him the food powder, the dog–the food powder saliva would start to come out. And later on if you–right before or right during you give the dog some food – you ping a bell – the bell will cause the saliva to come forth. And, in fact, this is the apparatus that he used for his research.