He is best known for his contributions to the Two-factor theory of emotion.

The misattribution of arousal study tested the two-factor theory of emotion.

The two-factor theory of emotion, or Schachter-Singer theory, states that emotion is a function of both cognitive factors and physiological arousal.

Stanley Schachter and Jerome Singer proposed a theory also known as the two-factor theory of emotion, which implies emotion have two factors: physical arousal and cognitive label.

Schachter's cognitive labeling theory thus identifies "cognitive attribution," the mind's attempt to pair the feeling of arousal with its (inferred) causal pattern in the environment as the second factor in the Two-factor Theory of Emotion.