What Is Two-factor Theory of Emotion?

The ability to infer another person’s emotional state is a fundamental component of successful social interaction and, as such, is a critical component in the theory of mind. The two-factor theory of emotion proposes that both cognitive and physiological mechanisms are involved in the experience of emotions.

What Is the Two-factor Theory of Emotion?

Two-factor theory of emotion is a psychological hypothesis that suggests that emotion is not on an independent feedback loop with physiological sensations but rather that these two systems are intertwined. In other words, when you’re feeling a certain way, the physiological sensation experienced simultaneously is interpreted by your brain as your body’s response to that particular emotion.

Schachter and Singer developed the two-factor theory of emotion in 1962. According to this theory, Two-factors are involved in emotion. These two factors are physiological arousal and cognitive appraisal. In other words, the Two-factor theory of emotion states that emotions occur as a result of:

  • A situation or event that causes physiological arousal
  • A person’s interpretation of this event

For example, if you get into a car accident with someone and you believe it was their fault, you might experience anger. If you think it was your fault, you might feel guilt instead. Physiological responses are physical reactions like increased heart rate or sweating when we experience an emotion.

Related Read: What Are Mixed Feelings?

Schachter and Singer’s Experiment

Schachter and Singer’s experiment is a classic study in psychology that examined the relationship between emotion and cognition. It was conducted by Stanley Schachter and Jerome E. Singer and published in their book ‘Cognitive, Social, and Physiological Determinants of Emotional State’ (1962).

To start with the experiment, the participants were told they were being injected with a new drug called Suproxin to test their eyesight. However,  they were injected with epinephrine or a placebo.

The experiment involved four groups:

  • Epinephrine informed: This group was told they could feel side effects such as shaking hands, heart pounding, and warm and flushed face.
  • Epinephrine ignorant: The subjects in this group were not informed of what symptoms they might experience during the experiment.
  • Epinephrine misinformed: The subjects in the epinephrine misinformed group were told that they would probably feel their feet go numb and have an itching sensation over parts of their body, along with a slight headache.
  • A control group: The control group was injected with a placebo (a substance that produces no physiological effects) and was informed of no potential side effects.

A confederate was included to interact with the participants after receiving an injection. The confederate either acted euphoric or angry when interacting with them. The researchers found that the confederate’s impact varied between participants in different conditions.

Those participants who had not been informed about the effects of the injection reported feeling one of two emotions—happiness or anger—more often than those who had been informed. When participants were exposed to confederate with europhic emotion, they reflected signs of happiness. When they were exposed to an angry confederate, however, they expressed signs of anger.

Criticism of Two-factor Theory

Although some studies have supported the two-factor theory, research in this area has produced both wholly and partially contradictory results.

Marshall and Zimbardo’s Experiment

Marshall and Zimbardo replicated Schachter and Singer’s euphoria conditions by injecting participants with epinephrine and a placebo and were divided into four groups as follows:

  • Epinephrine-injected. They were exposed to a neutral confederate.
  • Placebo-injected. They were exposed to arousal symptoms.

The other two groups were injected with epinephrine based on their body weight.

The results showed that the euphoria confederate did not significantly increase the euphoria in the subjects. Their induced euphoria was no more significant than that experienced by the neutral confederate. The subjects who received epinephrine did not react differently from the placebo group regarding susceptibility to emotional manipulation.

Maslach’s Experiment

Maslach’s study was designed to replicate Schachter and Singer’s study but used hypnotic suggestion as the arousal source instead of epinephrine. In the experiment, subjects were hypnotized and told to become aroused in response to a cue. After being aroused without knowing why, the subjects were told to forget the source of their arousal.

The experimenter hypnotized the participants and instructed them either to follow the cue or not. A confederate was added who began to exhibit either euphoric or angry behavior. Later, two other subjects were added to the experiment, both hypnotized, aroused, and exposed to a euphoric confederate.

While one group of participants was informed about the source of their arousal, the other group was not. The findings indicated that unexplained physical arousal was more likely to generate negative emotions regardless of whether participants were exposed to the angry or euphoric confederate.

Two-factor Theory of Emotion vs. James Lange Theory 

As discussed before, the two-factor theory states that both an individual’s physiological arousal and cognitive interpretation of this arousal must occur for an emotion to be experienced. In other words, a person cannot feel an emotion unless they experience both a physiological response and think about it.

In contrast to this theory, James Lange proposed that emotions are directly caused by certain stimuli (i.e., seeing a snake). Under his theory, when someone sees a snake, they interpret this object as dangerous (the cognitive component), resulting in an emotional response (i.e., fear).

Final Thoughts

The two-factor theory contends that the feeling of emotion is not just a subjective experience but is also a result of what the person thinks about their situation. We don’t feel surprised because it’s raining; we feel surprised because we thought it wouldn’t rain. Because of this, much of our emotional experience can be manipulated by increasing or decreasing our expectations of a situation.


  • Marshall, G. D., & Zimbardo, P. G. (1979). Affective consequences of inadequately explained physiological arousal. Journal of Personality and Social Psychology, 37(6), 970–988. 
  • Schachter, S., & Singer, J. (1962). Cognitive, social, and physiological determinants of emotional state. Psychological Review, 69(5), 379–399.
  • ​​Cotton, J. L. (1981). A review of research on Schachter’s theory of emotion and the misattribution of arousal. European Journal of Social Psychology, 11(4), 365–397. 
  • Maslach, C. (1979). Negative emotional biasing of unexplained arousal. Journal of Personality and Social Psychology, 37(6), 953–969. 

Hi, I am Happy. I'm a professional writer and psychology enthusiast. I love to read and write about human behaviors, the mind, mental health-related topics, and more.