Schachter and Singer’s Two-factor Theory of Emotion

Two-factor Theory freeway interchange

The Two-factor Theory of Emotion stands as a notable concept that explains emotions through a dual-component process, necessitating both physiological arousal and cognitive appraisal to experience emotion. Researchers Stanley Schachter and Jerome E. Singer proposed the theory in a 1962 publication.

Their theory postulated that physiological arousal is non-specific in terms of emotion, meaning the body’s actual physiological state does not correspond to a particular emotional experience. It is the cognitive interpretation, or what one thinks about the arousal, that shapes the emotional experience.

Schachter and Singer’s work emerged amidst the prevalence of the James-Lange Theory and the Cannon-Bard Theory, which were influential in setting the stage for the emergence of the Two-factor Theory.

The James-Lange Theory proposed that physiological arousal precedes emotional experience, suggesting that one feels emotion after the body reacts to an event. Conversely, the Cannon-Bard Theory argues that emotional experience occurs simultaneously with physiological responses, not as a result of them. Schachter and Singer recognized aspects of these theories but diverged by emphasizing the role of cognitive appraisal in the emotional process.

The work of William James and Carl Lange was foundational for Schachter and Singer’s theory. James and Lange had posited that emotions are the perception of bodily changes. Building upon their perspective, Schachter and Singer argued the significance of context in interpreting these bodily changes. For instance, a racing heart might be interpreted as excitement in one context or fear in another, depending on the situation and cognitive appraisal.

Furthermore, Philip Bard’s contribution to the understanding of emotion, particularly his part in the Cannon-Bard Theory, underpinned the idea that the thalamus sends signals simultaneously to the cortex and the body, provoking emotional experience and physiological reactions concurrently. Schachter and Singer’s theory acknowledges this physiological component but adds the crucial layer of cognition.

The Schachter-Singer Experiment

In 1962, Stanley Schachter and Jerome E. Singer conducted an investigation to see how people use environmental cues to explain physiological changes. They had three hypotheses for the experiment.

First, if a person encounters a state of arousal for which they have no immediate explanation, they will identify it and describe their feelings using the cognitions that are available to them at that time.

Second, if a person is in a state of arousal for which they have a suitable explanation, they are unlikely to identify their feelings using the alternative cognitions available.

Third, if a person is placed in a circumstance that would normally cause them to feel an emotion, they will only react or experience feelings if they are in a state of physiological arousal.


Participants were told they would be injected with a new medicine named “Suproxin” to test their vision. The subjects were injected with either epinephrine (which raises blood pressure, heart rate, and respiration) or a placebo.

Participants were randomly assigned to one of four conditions: epinephrine informed (where participants were told they would experience effects similar to epinephrine), epinephrine ignorant (where participants were not told about side effects), epinephrine misinformed (where participants were told the wrong side effects), or a control group (where participants were injected with a placebo and not told about any side effects).

Following the injection, a confederate interacted with the students while seeming either furious or ecstatic. The experimenters observed the subjects through a one-way mirror and graded their state on a three-category scale.

The participants were subsequently given a questionnaire, and their heart rates were recorded. Participants in the epinephrine misinformed group reported the most euphoria, followed by the ignorant, placebo, and informed groups. In contrast, those in the uninformed group were the most angry, followed by the placebo and informed groups.

The findings indicate that participants who had no reason for why their body felt the way it did were more vulnerable to the confederate, validating the three hypotheses.

Arousal Misattribution

A subsequent study on misattribution of arousal put Schachter and Singer’s two-factor theory of emotion to the test. Psychologists Donald G. Dutton and Arthur P. Aron intended to employ a natural setting to elicit physiological arousal. In this experiment, male volunteers walked across two distinct types of bridges.

One bridge was a terrifying (arousing) suspension bridge that was extremely thin and suspended above a deep ravine. The second bridge was considerably safer and more stable than the first.

At the end of each bridge, an attractive female experimenter greeted the [male] volunteers. She handed out a questionnaire to the participants, which included an unclear picture to describe and her phone number to contact if they had any additional questions.

The purpose of this study was to determine which group of males were more likely to call the female experimenter and to assess the sexual content of the stories the men wrote after crossing one of the bridges.

They discovered that men who traveled across the terrifying bridge were more likely to contact the woman to follow up on the study, and their stories were more sexual in nature. According to the two-factor hypothesis, this is because they transferred (misattributed) their arousal from fear or anxiety on the suspension bridge to higher degrees of sexual attraction to the female experimenter.

Interpretation and Appraisal

The two-factor theory of emotion posits that the emotional experience is a result of a cognitive process of interpretation followed by an appraisal of the environment. This process determines the type and intensity of the emotional response.

Cognitive interpretation is the first step in the emotional process as described by the two-factor theory. It involves the mind as it assesses an event, determining the nature of the emotional response. A person’s previous experiences, beliefs, and expectations influence this interpretation of the immediate event.

This aspect is crucial because it forms the foundation upon which emotions are built. For instance, an accelerated heartbeat could lead to panic if interpreted as a health threat or excitement if associated with a positive challenge.

Appraisal heavily relies on environmental cues. Individuals interpret these cues from their immediate environment.

The context includes anything from physical location to social setting, and it is critical because it affects the appraisal and subsequent emotional response. The evaluation of these cues, whether they are a threatening growl in a dark alley or the welcoming smile of a friend, helps to assess the situation’s significance, tailoring emotions appropriately.

Role of the Autonomic Nervous System

The autonomic nervous system plays a crucial role in the two-factor theory. It is divided into two parts: the sympathetic and the parasympathetic nervous systems. During emotional arousal, it is the sympathetic nervous system that is primarily activated, preparing the body for a swift response to stimuli.

Sympathetic activation leads to various physiological changes that are often perceived as the physical component of emotion. Example changes include:

  • Increased heart rate
  • Elevated blood pressure
  • Accelerated breathing

These automatic responses are part of the ‘fight or flight’ mechanism that elicits a reaction even before the brain has fully processed the event cognitively.

In the context of positive emotions, like euphoria, the body might also exhibit signs of arousal, such as a feeling of energy or warmth, attributed to similar sympathetic nervous system activity. The physical and mental health domains interlink closely through these emotional responses, highlighting why emotional health is recognized as an integral part of overall healthcare.

Labelling of Emotion

The process of labelling emotions is fundamentally tied to cognitive appraisal. Individuals interpret physiological responses to stimuli by assigning emotional labels, which in turn mediate their emotional states.

For example, the same sensation of increased heart rate could be labelled as either excitement or anxiety, depending on the cognitive interpretation of the context. Schachter’s research highlights the importance of this cognitive factor, as emotions are not solely derived from bodily changes but also the interpretation of those changes.

Extension to Other Emotional States

The two-factor theory of emotion has been broadened to encompass both positive and negative emotional states, as well as more nuanced complex emotions. This extension explores the theory’s applicability across a diverse range of emotions.

Emotions like joy and love are approached differently in the extended theory compared to negative emotions such as anger and depression. Positive emotions generally follow a similar pattern of arousal and subsequent cognitive labelling, leading an individual to identify specific pleasant or gratifying emotions.

Conversely, negative emotions are often linked with an undesirable physiological state which, when coupled with a negative cognitive appraisal, can result in feelings such as sadness or fear. For example, the experience of anxiety arises from a heightened state of arousal that, when paired with thoughts of uncertainty or danger, solidifies the emotion.

Complex emotions, such as those involved in interpersonal relationships, including love, often require an intricate blend of cognitive appraisal and physiological arousal. The two-factor theory suggests that the emotional experience of love encompasses both an intense physiological arousal and a deeper cognitive appraisal, recognizing the value and significance of the relationship.

Beyond basic arousal, love involves long-term attachment and a cognitive understanding of deep affection and connection.

The expansion of the two-factor theory posits that cognitive theories of emotion are crucial in differentiating among various emotional states, whether they are straightforward or multifaceted. It is the cognitive aspect that helps an individual discriminate between feeling ecstatic or composed, irritated or simply unenthusiastic.

Two Factor Theory Criticism

Criticism of the two-factor theory has been substantive, particularly concerning the notion of undifferentiated arousal. Researchers argue that physiological responses may be more emotion-specific than previously understood.

Leon Festinger, associated with the development of cognitive dissonance theory, has influenced the critical approach toward the two-factor theory, invoking the cognitive aspects of emotion processing as quite distinctive and complex.

In 1979, Christina Maslach designed a study to replicate and expand on the Schachter and Singer investigation. Instead of injecting epinephrine, the administration employed hypnotic suggestions to determine the source of arousal.

The subjects were either hypnotized or employed as controls (similar to the placebo effect in the Schachter and Singer trial). Participants that were hypnotized were told to become aroused at the presentation of a cue and not to remember the source of their arousal.

Right after the subjects were hypnotized, a confederate began acting euphorically or angrily. Later in the experiment, the participants were exposed to two additional euphoric confederates. One confederate had to keep track of the cause of the arousal, while the other confederates instructed the individuals to expect various arousal symptoms.

The findings revealed that all subjects, based on self-reports and observation, believe that unexplained arousal promotes undesirable outcomes. Subjects remained furious despite the joyful confederate.

Maslach argued that a lack of explanation for an arousal will result in a negative feeling, such as wrath or fear. However, Maslach acknowledged a limitation: there may have been more negative emotions self-reported because there are more phrases referring to negative emotions than good ones.

Another critique is that the Schachter-Singer Theory focuses exclusively on the autonomic nervous system and makes no mention of the emotional process within the central nervous system other than to indicate the significance of cognitive variables. This is significant given the importance of particular brain areas in regulating emotional experience (for example, fear and the amygdala).

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