Schachter & Singer (1962)

Aim To test the Two Factor Theory of Emotion. To research whether given a state of physiological arousal with no explanation, cognitive factors would help in describing feelings.


  • To test the Two Factor Theory of Emotion.
  • To research whether people turn to cognitive factors to help in describing feelings if provided a state of physiological arousal with no explanation.

Cognition – mental process of acquiring and processing knowledge.
Emotion – the body’s adaptive response to a particular situation.
Metacognition – thinking about thinking.

Cognition interprets our physiological state so that we can label our emotional responses. During physiological arousal, your heart and respiration rate increase, pupils dilate, and adrenaline is released.
Schachter & Singer developed the Two-Factor Theory of Emotion. They suggested that emotional experiences come from a combination of physical arousal and cognition that makes the best sense of the person's situation.

Research Method, Design and Variables
It was a highly standardised laboratory experiment. Participants were exposed to the same environment with scripted responses from the stooge.
The research design used was the independent measures design.

Independent variable:

  • Knowledge about the injection symptoms (informed, misinformed, or ignorant).
  • The emotional situation following the injection (euphoria or anger). There was a control group that was injected with a saline solution rather than epinephrine.

Dependent variable:

  • Observational data was recorded by two observers through a one-way mirror during the emotional arousal. The observer had to measure to what extent the participant acted in a euphoric or angry way.
  • The self-report that participants completed following the emotional arousal.


The 185 participants were male college students taking introductory psychology at the University of Minnesota. They received course credit. Their health records were checked priorly to ensure that no harmful effects would result from the injection. The sampling method employed was self-selecting sampling.

When participants arrived at the lab, they were told that the aim was to test the effects of the vitamin supplement ‘Suproxin’ on vision. Participants were asked for informed consent to inject the vitamin. Participants were deceived and actually injected with either adrenaline or a placebo (saline solution). They would experience side effects within 3 to 5 minutes which would last for an hour.

  1. Participants in the informed conditions were told the correct side effects of the injection, ‘your hand will start to shake’. Participants would have an explanation for any feelings.
  2. Participants in the misinformed condition were told the wrong side effects of the injection, ‘your feet will feel numb’. Participants would not have any explanation for the actual side effects they would experience. This group was introduced as a control.
  3. Participants in the ignorant condition were told that they would experience no side effects. They would not have an explanation for the actual side effects they would experience.

Right after the participants' injection, the doctor left, and the experimenter returned with a stooge who was introduced as another participant. The experimenter said that both had taken the Suproxin injection and would take 10 minutes for absorption, after which they would both be given the same tests of vision. Participants were then exposed to one of two emotional states: euphoria or anger. The stooge never knew which condition any participant was in.

In the euphoria condition, the experimenter added that they could use the stationary if they needed to. The waiting room had been in a state of disarray and the stooge made icebreaker comments and played with the items. The stooge suggested that the participant join in, and the stooge played with the things. In the euphoria condition, the category ‘initiates new activity’ was operationalized by the criteria that a euphoric behaviour outside the stooge’s routine must be initiated. The behaviour had to be one the participant had never seen before. Examples of newly initiated activities: opening the window, throwing paper basketballs, and hula hooping.

In the anger condition, the experimenter explained that they had to wait 20 minutes to absorb the Suproxin. Participants had to complete a questionnaire during this time. The stooge was instructed to create a feeling of anger in the room. Comment made: ‘this really irritates me.’ Comments increased in intensity as the questions became more personal. The stooge crumpled up the questionnaire at the end and stomped out of the room.

The experimenter returned to the room and told them to complete one final questionnaire relating to their physical responses to the Suproxin. They were debriefed and told the reason for the deception. The experimenter swore participants to secrecy to protect future runs.

All participants gave consent. The injection was administered by a trained doctor to protect participants. The participants were deceived, but this was necessary to prevent demand characteristics therefore, it improves the validity of the study.


  1. If a person is aroused with no immediate explanation, they will describe their feelings in terms of the cognitions available.
  2. When an individual is aroused and has an explanation, they won't label their feelings in terms of the cognition available.
  3. If an aroused person is in a situation which in the past could have made them emotional, they would be emotional again.


  • 1 participant did not agree to the injection. 11 people had their data excluded due to suspicion. 5 had no physiological arousal to the injection so their data was excluded, and in the end, there were 169 participants left.
  • Participants who received adrenaline were significantly more sympathetically aroused (showed by pulse rate and self-rating) compared to the placebo participants. The misinformed group only took part in the euphoria condition as it was a control. Making them take part in just the euphoric condition still allows us to make an evaluation of the impacts, plus, it helps save time.
  • In all the adrenaline conditions, participants’ pulse rate increased, whereas the pulse rate for the placebo group decreased.
  • From the self-report measure, the euphoric misinformed group was the happiest. Euphoria ignorant group was the second happiest. The informed group was the least happy as they had an explanation for what they were feeling. Participants in the anger ignorant condition were the angriest, and those in the placebo group were the second angriest. They were susceptible to the stooge as they had no explanation. Their behaviour was observed through a one-way mirror and the behaviour matched their self-report.

An aroused person with no explanation for the arousal describes their feelings in terms of the cognition available. The study is useful in treating people with anxiety or panic attacks as they can identify the environmental triggers that cause them to be aroused.

Individuals do not explain arousal by only looking at the behaviour of those around them. They use past experiences to explain arousal.

Strengths and Weaknesses

  • It was a highly controlled laboratory experiment, as the same experimental rooms were used, and the stooge had given scripted responses. Participants were randomly allocated to different conditions. All participants were deceived, and the double-blind technique was used.
  • The sample consisted of university students so participant variables may distort findings. This makes results less valid.
  • The sample only had male participants thus, the study is less generalisable as females may experience emotions differently.
  • Adrenalin does not affect everyone in the same way due to individual differences.
  • No assessment was made of the participant's mood before the injection; thus, it reduces validity.
  • Questionnaires helped operationalise the dependent variables, therefore the data is standardised. Quantitative data collected can be easily analysed and used to compare results across two conditions. Weakness – > questionnaire does not give participants the same freedom to express feelings as discussions would. However, other measures such as observation were useful as the results matched the data in the self-reports.

Nature vs. Nurture
Our emotional responses can be accounted for by both, differences in nature (hormone levels) and nurture (experiences).

Individual vs. Situational Explanations
Situational factors do matter in our expression of emotions however, individual differences are present as well. For example, the extent to which participants were affected by the mood of the stooge.