Two factor theory of emotion

The Two Factor Theory of Emotion is a social psychology theory that views emotion as having two components (factors): physiological arousal and cognition. According to the theory, cognitions are used to interpret the meaning of physiological arousal in a particular situation. Because cognitions are influenced by the situation, the theory predicts that elements of a person's environment can have a significant impact upon their emotional state, provided that the reasons for any physiological arousal are ambiguous.

The adrenaline study
In 1962 psychologists Stanley Schachter and Jerome Singer gave 184 college students one of two types of injections: adrenaline (also called epinephrine) or a placebo. All experimental subjects were told that they were given vitamins to test their vision. The adrenaline injection caused a number of side-effects including increased heart rate, increased breathing, and increased blood flow to the muscles and brain. The saline injection had no side effects.

Some subjects were told about the side-effects of the adrenaline while others were misled and told that it would produce a dull headache and numbness. A third group of subjects received no information at all.

After the injections the subjects waited in a room with another subject who was actually a confederate of the experimenter. The confederate behaved one of two ways: playful or angry.

Subjects who were misled or naive about the injection's side-effects behaved similarly to the confederate, taking cues from the situation to interpret their arousal level to determine their emotional state. Subjects who knew what to expect, on the other hand, did not manifest emotion mirroring the confederate.

The high bridge study
Social Psychologists A. Aron and D. Dutton used a natural setting to induce physiological arousal in their test of the Two Factor Theory of Emotion. In their study, an attractive female experimenter asked male passersby to complete a brief survey. She intercepted potential subjects either at the end of a bridge or on the bridge itself. The footbridge used was long, narrow, and spanned a deep ravine. Following the survey interview, the experimenter gave the subjects her telephone number in case they had further questions. The dependent variable in this experiment was the number of telephone calls received from the subjects after the experiment.

The theory predicted that more subjects would call if they were interviewed on the bridge itself. By being in a state of arousal (due to the bridge height) at the time of the interview, it was predicted that subjects would misattribute their physiological response as an attraction to the experimenter. This is exactly what was found. Approximately 50% of the male subjects telephoned the experimenter if they were interviewed on the bridge while approximately 15% of the subjects interviewed on the side actually called.

Papers

 * Schachter, S., & Singer, J., Cognitive, Social, and Physiological Determinants of Emotional State, Psychological Review, 1962, 69, 379-399.
 * Dutton, D. G. and Aron, A. P. (1974) Some evidence for heightened sexual attraction under conditions of high anxiety, Journal of Personality and Social Psychology, 30, 510-517