Answer: Behaviorism
Explanation: Behaviorism is a current of psychology interested in how stimulus condition responses. There was an experiment with dogs, conducted by Pavlov where he made a bell ring everytime his dogs were going to be fed, resulting on them to salivate when the bell rang even though they hadn't seen the food yet.
This proves that a stimuli like a bell produces a response conditionated by previous exposure to such stimuli.