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Schachter, S.  & Singer, J.E.   (1962).  

Cognitive, Social and Physiological Determinants of Emotional State.



Schachter and Singer developed the two-factor theory of emotion.  The two-factor theory suggests that emotion comes from a combination of a state of arousal and a cognition that makes best sense of the situation the person is in.  For example, the two-factor theory of emotion argues that when people become aroused they look for cues as to why they feel the way they do.



  The aim of the study is to test the two-factor theory of emotion.

  From the aim three propositions (or hypotheses) were devised:

1.   If a person experiences a state of arousal for which they have no immediate explanation, they will label this state and describe their feelings in terms of the cognitions available to them at the time. 

2.   If a person experiences a state of arousal for which they have an appropriate explanation (e.g.  ‘I feel this way because I have just received an injection of adrenalin’), then they will be unlikely to label their feelings in terms of the alternative cognitions available.  

3.   If a person is put in a situation, which in the past could have made them feel an emotion, they will react emotionally or experience emotions only if they are in a state of physiological arousal.



The participants were 184 male college students, taking classes in introductory psychology at Minnesota University.  90% of which received two extra points on their final exam for every hour they served as subjects.  The subjects’ health records were checked to make sure that the adrenalin would not have an adverse effect.

The method used was a laboratory experiment with independent measures.  There were two independent variables.   The information about the adrenalin injection given to the subjects, and the situation they are put in (euphoria situation or anger situation).

The first independent variable (information about the adrenalin injection given to the subjects) was manipulated in the following way

As soon as the participant arrived, he was taken to a private room by the experimenter and told that the aim of the experiment was ‘to look at the effects of vitamin injections on visual skills’, and was asked if he would mind having an injection of ‘Suproxin’ (made up name). 

184 out of 195 subjects agreed to the injection.  They were given an injection (by a doctor) of either adrenalin (epinephrine) or a placebo, which was actually a saline solution, which has no side effects at all.  The effects of the adrenalin are very similar to the effects of arousal of the sympathetic division of the autonomic nervous system (as in the fight or flight syndrome) - increasing in blood pressure, heart rate, blood sugar level, respiration rate, and blood flow to the muscles and brain, with an accompanying decrease in blood flow to the skin.  This is often experienced as palpitations, tremors, flushing and faster breathing.  The effects begin after three minutes and last from ten minutes to an hour. 

The subjects were then put in one of four experimental conditions:

1.    Adrenalin Ignorant - subjects were given an adrenalin injection and not told of the effects of the drug.

2.   Adrenalin Informed - subjects were given an adrenalin injection and warned of the ‘side effects’ of the drug (hand shake, heart pounding, dry mouth etc.).  The subjects were therefore prepared for the effects of the adrenalin (although they thought they were to do with the suproxin).

3.    Adrenalin Misinformed - subjects were given an adrenalin injection and told to expect side effects but were told these would be numb feet and headache.  These subjects would, therefore, not be expecting the effects of the adrenalin.

4.    Control Group - Placebo - subjects were given an injection that would have no effect and were given no instructions of what to expect.


The second independent variable (the situation they are put in - either euphoria situation or anger situation) was manipulated in the following way.

Immediately after the subject’s injection, the doctor left the room and the experimenter returned with a stooge.  The stooge was introduced as another subject and the experimenter stated that both had had the Suproxin injection and that they had to wait for 20 minutes while the Suproxin was absorbed into the bloodstream, after which they would both be given the same tests of vision.

The participant was placed in either the euphoria situation or anger situation.

The euphoria situation

The waiting room had been deliberately put into a state of mild disarray and as the experimenter was leaving, he apologetically added that, if they needed any rough paper, rubber bands or pencils they should help themselves.  As soon as the experimenter left the room the stooge introduced himself again, made a few icebreaker comments and then began his routine which consisted of playing with items (paper, rubber bands, pencils, folders and hula hoops) left in the room.  The stooge encouraged the participant to join in while he played with the objects.  The routine was standardised as far as was possible. The stooge never knew which condition any particular subject was in.

The anger situation

The participants in this situation were placed with a stooge and were asked to spend the 20 minutes waiting time answering questionnaires.  Before looking at the questionnaires, the stooge told the subject that he thought it unfair to be given injections, and that they should have been told when they first called.

The five-page questionnaire started innocently enough, but then grew increasingly personal and insulting (e.g. ‘How many times each week do you have sexual intercourse?’)  The stooge, sitting opposite the subject, paced his own answers so that at all times they were both working on the same question.  At regular points, the stooge made a series of standardised comments about the questions, starting off innocently enough, but growing increasingly discontented and finally he ends in a rage.

This routine again was standardised and the stooge never knew which condition any particular subject was in. 

[The adrenalin misinformed condition was not run in the anger sequence because it was originally conceived as a control condition, and that its inclusion in the euphoria sequence would suffice as a means of evaluating any artifactual effects of the adrenal informed instructions]

Overall, the study ran seven conditions as shown in table below


The conditions in the Schachter and Singer experiment  

Euphoria Anger
Informed   Informed
Ignorant Ignorant
Placebo Placebo


The researchers then made observational measures of emotional response through a one-way mirror, and also took self-report measures from the subjects.  The self-report questionnaire contained of a number of mock questions but the crucial ones to measure mood and emotion are shown below in the table. 


 The self-report rating scale used by Schachter and Singer.

1. How irritated, angry or annoyed would you say you feel at present?

I don’t feel at all irritated or angry

I feel a little irritated and angry

I feel quite a lot irritated and angry

I feel very irritated and angry

I feel extremely irritated and angry


2. How good or happy would you say you feel at present?

I don’t feel at all happy or good

I feel a little happy and good

I feel quite a lot happy and good

I feel very happy and good

I feel extremely happy and good


When the subjects had completed the questionnaires, the experimenter announced that the experiment was over, explained the deception in detail, answered any questions and swore the subjects to secrecy.  Finally, subjects answered a questionnaire about their experiences, if any, with adrenalin and their suspicion about the experimental set-up.  None knew anything about the experiment beforehand, but 11 were so extremely suspicious that their data was automatically discarded.

For the score of self-reported emotion, the anger score was subtracted from the happiness score.

The scale is a measure of happiness minus anger (i.e. the higher the positive value, the happier the subject reports himself feeling),




The subjects who received the injections of adrenalin showed significantly more sympathetic arousal (as measured by pulse rate and self-ratings on palpitation, tremor, numbness, itching and headache) in comparison to the placebo subjects. 

[However, five subjects showed no relevant symptoms to the adrenalin and thus, were excluded from the study]

In the euphoria condition the misinformed participants were feeling happier than all the others.  The second happiest group was the ignorant group.  This demonstrates that these participants were more susceptible to the stooge because they had no explanation of why their bodies felt as they did.  The informed group felt the least happy because they understood why they felt as they did.

In the anger condition, the ignorant group felt the angriest.  The second angriest group was the placebo group.  The least angry group were those who were informed.  Again this shows that participants were more susceptible to the stooge because they had no explanation of why their body felt as it did.

The behaviour (which was observed through a one way mirror) matched their self-reports.



Schachter and Singer argue that their findings support their two-factor theory of emotion.   The two-factor theory of emotion states that the physiological arousal in different emotion is entirely the same and we label our arousal according to the cognitions we have available.

They argue that all three propositions were supported.  


Evaluation of Procedure/Method

The main strength of the method used by Schachter and Singer is the amount of control they had of their procedure.  For example they were able to randomly allocate different participants to the different conditions, they were able to deceive the participants of the real nature of the experiment and standardise the procedure as much as possible.  They even ensured that the stooge did not know which condition the participant was in.

However there are many weakness of the method used by Schachter and Singer.  

The experiment definitely lacked ecological validity.  We do not usually experience emotions in the way in which Schachter and Singer induced them.  We are often aware of events before the onset of arousal and this gives us information we can use to interpret out physical cues. 

The sample used in the experiment can also be criticised.   The sample was all male college students, taking classes in introductory psychology at Minnesota University.   We could criticise the use of students or males.   It could be, for example that males do not always experience emotions in the same way as females.  The sample is certainly not representative.

The study can also be questioned on ethical grounds.  Even though the participants were given health checks before the experiment began, and were thoroughly debriefed, they were considerably deceived. 

The results were definitely not as impressive as expected.  All the participants in the euphoria and anger situation were not actually angry.  If they were angry they would have got minus scores.  It seems that the experimenters were only able to make participants less happy but not angry. 

We can also question the assumption that all participants would react in the same way to the adrenaline.  Adrenalin does not affect everyone in the same way, for example five of Schachter & Singer’s subjects were excluded from analysis because they experienced no physiological symptoms.

A further problem with the procedure is that no assessment was made of subjects’ mood before the injection - presumably, a subject in a better mood to begin with might respond more positively to a playful stooge.

Finally, perhaps because people wanted to believe the theory, and perhaps because of the complexity of the experiment, no attempt at replication was made until 1979 when Marshall and Zimbardo failed to obtain the same results as the original study. 


Evaluation of Explanation


The two-factor theory of emotion has been an influential theory of emotions.  However subsequent work has shown that the relationship is more complex than the two-factor theory predicts.

For example psychologists now argue that peoples efforts to understand an unexplained state of arousal is more extensive than a quick examination of cues in the surrounding environment.  When we seek to explain a state of arousal, we don’t merely use others’ behaviour but call on many other sources of information as well, particularly our own past history - we search for prior occasions on which we felt this arousal state to explain its occurrence now.  



Schachter, S  & Singer, J.E. (1962) Cognitive, social and physiological determinants of emotional state.  Psychological Review, 69, 379-99.





GROSS, R. (1999) Key Studies in Psychology, 3rd Edition. London: Hodder and Stoughton

BANYARD, P. AND GRAYSON, A. (2000) Introducing Psychological Research; Seventy Studies that Shape Psychology, 2nd Edition. London: Macmillan