Two factor theory of emotion

The two-factor theory of emotion, states that emotion is based on two factors: physiological arousal and cognitive label. The theory was created by researchers Stanley Schachter and Jerome E. Singer. According to the theory, when an emotion is felt, a physiological arousal occurs and the person uses the immediate environment to search for emotional cues to label the physiological arousal. This can sometimes cause misinterpretations of emotions based on the body's physiological state. When the brain does not know why it feels an emotion it relies on external stimulation for cues on how to label the emotion.

Stanley Schachter and Jerome E. Singer (1962) performed a study that tested how people use clues in their environment to explain physiological changes. Their hypotheses were:

Participants were told they were being injected with a new drug called "Suproxin" to test their eyesight. The participants were actually injected with epinephrine (which causes respiration, an increase in blood pressure and heart rate) or a placebo. There were four conditions that participants were randomly placed in: epinephrine informed, epinephrine ignorant, epinephrine misinformed and a control group. The epinephrine informed group was told they may feel side effects including that their hands would start to shake, their heart will start to pound, and their face may get warm and flushed. This condition was expected to use cues to explain their physiological change. In the epinephrine ignorant group, the experimenters did not explain to the subjects what symptoms they might feel. This group was expected to use cues to explain their physiological change. The epinephrine misinformed group was told that they would probably feel their feet go numb, and have an itching sensation over parts of their body, and a slight headache. This group was expected to use cues around them for their physiological change. The control group was injected with a placebo and was given no side effects to expect. This group was used as a control because they were not experiencing a physiological change and have no emotion of label. After the injection, a confederate interacted with the students, who was either acting euphoric or angry. The experimenters watched through a one way mirror and rated the participants' state on a three category scale. The participants were then given a questionnaire and their heart rate was checked.

The researchers found that the impact of the confederate was different for the participants in the different conditions. From high to low euphoria their ranking was as follows: epinephrine misinformed, epinephrine ignorant, placebo, epinephrine informed. In the anger condition the ranking was: epinephrine ignorant, placebo, epinephrine informed. Both results show that those participants who had no explanation of why their body felt as it did, were more susceptible to the confederate. These findings are considered to support the researchers' hypotheses.

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