This is also known as Schachter's Two-Factor Theory of Emotion, after Stanley Schachter. Schachter proposed that human emotions contain two factors or parts: physical arousal and a cognitive label. According to Schachter, both of these elements must be present for you to experience an emotion. Some form of arousal occurs (e.g., increased heart rate, perspiration, etc.), you then put some label on this arousal, and then experience the emotion. For example, imagine playing a physically demanding game like basketball. As soon as you are done with the game (and you are hot, your heart is racing, etc., which is the state of arousal) someone gives you some bad news. In response, you get angry (label the emotion as anger), and feel that anger. The question is, would you have gotten less angry about this news if you were not aroused from playing basketball? According to Schachter, you are probably going to be more angry in the aroused state than if you got the news in a less aroused state.