John Waston (1878) raised the banner of behavioral psychology for the first time in 19 13. He was the first person in the United States to take Pappu's research results as the basis of learning theory. In his view, learning is a process of establishing conditioned reflex with one stimulus instead of another. According to Watson, there are only a few conditioned reflexes (such as sneezing and knee jumping) and emotional reactions (such as fear, love and anger). ) As soon as human beings are born, all other behaviors are formed by establishing a new stimulus-response (S-R) connection through conditioned reflex.

Watson used the principle of conditioned reflex to do an experiment of fear formation. Because animals are associated with stimuli that cause fear, babies are afraid of that kind of animal.

Before conditioned reflex, the child approached the rabbit without fear. Later, after the rabbit appeared, there was a noise, which scared the children. After conditioned reflex, rabbits alone can scare children. In the worst case, children will be afraid of anything hairy, such as mice, stuffed animals and even bearded people. The fear that was originally confined to rabbits has now been extended to similar stimuli.

In practical education, many students' attitudes are acquired through classical conditioning. For example, many students may dislike foreign languages because they associate them with unpleasant experiences, such as asking for loud translation of sentences in class. Being asked difficult questions (CS) in class causes anxiety (UR), and students form a conditioned reflex of foreign language fear, which may sum up their fear of other courses or school institutions. Similar learning processes also occur in other school experiences.