The Schachter-Singer Two-Factor Theory of Emotion

According to the Schachter-Singer theory of emotion, developed in 1962, there are two key components of an emotion: physical arousal and a cognitive label. In other words, the experience of emotion involves first having some kind of physiological response which the mind then identifies.

Many cognitive theories of emotion emerged during the 1960s, as part of what is often referred to as the "cognitive revolution" in psychology. One of the earliest of these cognitive theories was one proposed by Stanley Schachter and Jerome Singer, known as the two-factor theory of emotion.

What Is the Two-Factor Theory?

The two-factor theory of emotion focuses on the interaction between physical arousal and how we cognitively label that arousal. In other words, simply feeling arousal is not enough; we also must identify the arousal in order to feel the emotion.

So, imagine you are alone in a dark parking lot walking toward your car. A strange man suddenly emerges from a nearby row of trees and rapidly approaches. The sequence that follows, according to the two-factor theory, would be much like this:

1. I see a strange man walking toward me.
2. My heart is racing and I am trembling.
3. My rapid heart rate and trembling are caused by fear.
4. I am frightened!

The process begins with the stimulus (the strange man), which is followed by the physical arousal (rapid heartbeat and trembling). Added to this is the cognitive label (associating the physical reactions to fear), which is immediately followed by the conscious experience of the emotion (fear).

What would happen if you were walking toward your car on a bright sunny day and an elderly woman began to approach you? Rather than feeling fear, you might interpret your physical response as something like curiosity or concern if the woman seemed to be in need of assistance. 

Schachter and Singer’s Experiment

In a 1962 experiment, Schachter and Singer put their theory to the test. A group of 184 male participants was injected with epinephrine, a hormone that produces arousal including increased heartbeat, trembling, and rapid breathing.

All of the participants were told that they were being injected with a new drug to test their eyesight. However, one group of participants was informed of the possible side-effects that the injection might cause while the other group of participants was not. Participants were then placed in a room with another participant who was actually a confederate in the experiment.

The confederate either acted in one of two ways: euphoric or angry. Participants who had not been informed about the effects of the injection were more likely to feel either happier or angrier than those who had been informed.

Schacter and Singer had hypothesized that if people experienced an emotion for which they had no explanation, they would then label these feelings using their feelings at the moment.

The results of the experiment suggested that participants who had no explanation for their feelings were more likely to be susceptible to the emotional influences of the confederate.

Examples of the Two-Factor Theory

The following are everyday examples in which the Schachter-Singer theory may be applied:

• Your boss calls you into their office. They don't tell you why. You start sweating, and you label what you're feeling as "anxious." However, when you meet with them, they say they want to give you a raise. You are already physically aroused, but now, you cognitively label this feeling "excitement" as a result of the good news.
• You see a friend while you're out shopping. You haven't spoken to this friend because the two of you had a fight. You experience a physical response of a rapid heart rate. You cognitively label this feeling "nervous." Then, you feel the emotion, and perhaps leave the store to avoid seeing them.
• You just finished shopping and you're walking by yourself to your car. It's dark outside. You hear someone walking behind you. Their footsteps are the stimulus that create a physical response in you—you begin trembling, and label this feeling "fearful." It turns out, it was just a store employee walking to their car after their shift.

Each example demonstrates a stimulus (being called into your boss's office, seeing an old friend, and walking to your car, respectively) that results in a physical response based on your assessment of the situation (sweating, rapid heart rate, and trembling).

As you can see, cognitive labeling is open to interpretation, depending on the context. You might be anxious about speaking with your boss, until you realize they have good news. You might be fearful about hearing footsteps in the parking lot, until you realize you aren't in danger.

Criticism of the Two-Factor Theory

While Schachter and Singer's research spawned a great deal of further research, their theory has also been subject to criticism. Other researchers have only partially supported the findings of the original study and have at times shown contradictory results. 

In another study by Maslach, hypnotic suggestion was used to induce arousal rather than injecting epinephrine.

The results suggested that unexplained physical arousal was more likely to generate negative emotions no matter which type of confederate condition they were exposed to.

Other criticisms of the two-factor theory include, sometimes emotions are experienced before we think about them. Other researchers have supported James-Lange's initial suggestion that there are actual physiological differences between emotions.

Other Theories of Emotion

It may be helpful to consider other popular theories of emotion that came before the Schacter-Singer theory. The James-Lange theory of emotion, developed by William James and Carl Lange in the 1880s, takes a different approach.

Similar to the Schacter-Singer theory, the James-Lange theory proposes that an emotion occurs as a result of arousal. In other words, if we aren't physically aroused, our emotional response will be weakened.

However, unlike the Schacter-Singer theory, The James-Lange theory posits that different types of arousal create different emotional experiences.

For instance, many people experience rapid heart rate and sweating when they're scared. But other physical responses, such as a slowed heart rate and relaxed muscles, indicate other emotions such as peacefulness and relaxation.

The Schacter-Singer theory, on the other hand, maintains that it is not the specific physical response that dictates the emotions that are felt—it is the cognitive label that we put on our response to stimuli that ultimately determines the emotion.

The Cannon-Bard theory of emotion was developed in response to the James-Lange theory. Created by Walter B. Cannon and Philip Bard in 1927, the theory posits that emotion and physical arousal occur at the same time.

In other words, if someone cuts you off in traffic and you almost hit them, you'll experience sweating and a rapid heart rate at the exact same time as you experience the emotion of fear.