Experiments in Intergroup Discrimination - Tajfel (1970)


To investigate the minimal conditions in which prejudice and discrimination can occur. To demonstrate that merely putting people into groups is sufficient for people to discriminate in favor of their own group and against members of the other group


1st Experiment: 64 boys (between the ages of 14 and 15), who attended a comprehensive school in a suburb of Bristol. 2nd Experiment: 48 new boys

Research Method

Experiment 1

  • 64 boys (14-15 years old) who attended a comprehensive school in a suburb of Bristol.
  • Came to the lab in separate groups of eight.
  • All were from the same ‘House’ in their school so they all knew each other.
  • In the first part of the experiment the boys were brought together into a lecture room and were told that the researchers were interested in the study of visual judgement
  • Forty different clusters of dots were flashed on a screen and the boys were asked to estimate the number of the dots and then record it.
  • Afterwards, they were told they were being grouped into ‘over-estimators’ and ‘under-estimators,’ although their grouping was really random.
  • They were given the following task: they would have to give the other participants (although they would no know the identity of the other participants; they were all given a code number) points which would then which would then be converted into real money at the end of the experiment
  • They were brought into a room (separately) where they were given a booklet. On each page there were two rows with 14 boxes each (the two rows were for two different people). One row was labeled # of over estimator, the other # of under estimator.
  • They were not giving money to themselves
  • The participants had to check one column
  • After they were finished, they were brought back into the first room where they were awarded the points the other people had given them
  • The value of each point was a tenth of a penny.
  • They then had to make three types of choice. In-group: both rows represented members of the same group as the boy. Out-group: both rows represented members of a different group of the boy. Inter-group: one row represented a member of the same group, the other row represented a member of a different group.

  • Experiment 2

  • 48 new boys broken into three groups of 16
  • They were shown 12 slides of paintings (6 by Paul Klee, 6 by Wassily Kandinsky) and asked to say which one they preferred, although they didn’t know which was which
  • Afterward, they were told that they were being divided into those who preferred Klee and those who preferred Kandinsky, but it was really random.
  • They were told to allocate points again using the matrix, by picking one of the columns.
  • Tajfel wanted to assess three things: Maximum joint profit, which gives the largest profit to both groups, maximum in-group profit, which gave the largest profit for the in-group, and maximum different, which gave the largest possible difference in gain between the two groups, in favor of the in-group.
  • The data collected in the study was quantitative and was gathered through the self-reports done by the participants when they were asked to record their answers.
  • Findings

    Experiment 1

  • With the inter-group choices most of the participants awarded more points to members of their own group.
  • When the choices were all in-group or out-group points were awarded according to maximum fairness.

  • Experiment 2

  • Tendency to use the maximum difference technical in favor of in-group profit.
  • Maximum joint profit had little to no effect on the points.
  • Maximum In-group Profit and Maximum difference showed a strong effect on the points awarded.
  • Participants gave the in-group members as much points as possible while costing the out-group.
  • For choices between two in-group members maximum joint profit was displayed more than when the choice was between two out-group members.

  • Weaknesses

  • This study was in a lab setting, while prejudice is a social phenomenon
  • The tasks asked to be completed were unusual.
  • Bias may be present. This is because they were divided into groups the participants may have felt they were suppose to discriminate.

  • Ecological Validity

    The validity is low because it was conducted in a lab setting. While prejudice is a social phenomenon, it is hard to study accurately in a lab. While also the tasks asked to be completed were unusual.


    Experiment 1

  • Discrimination occurred due to the simple designating of in and out group membership. (categorization)
  • Choices between both groups(inter-group) were not made to maximize everyone’s winnings, but instead the increase the group profit.

  • Experiment 2

  • The process of categorizing participants into groups caused in-group favoritism and out-group discrimination.
  • This study showed that discrimination was easy to create.
  • People would much rather show out-group discrimination and suffer at the expensive of in group gain. Therefore creating social distance among the groups. Taijfel uses the Social Identity Theory to explain this inter-group discrimination displayed.

  • Strengths

  • There was high levels of control in this study.
  • There was no confounding variables that would affect group membership.
  • There was no social interaction.
  • The behaviors could be attributed to categorization and not pre existing prejudice.

  • Ethics

    Deception was used when categorizing the participants in order to create the in and out-group and study discrimination.

    Tajfel (1970)

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