Schachter and singer's (1962) experiment in which participants were injected with epinephrine--allegedly as part of a study of the effects of a vitamin compound on vision--is one of the most famous studies in social psychology because the experiment showed that

The experiement showed how arousal and contextual cognition plays a role in emotions. their popular theory is called two factor theory of emotion. it shows that people makes sense of their emotion based on clues in their environment and that arousal alone does not make sense when it is the source of emotion.