Intergroup Discrimination Experiments
Henri Tajfel (1970)

In 1970 Henri Tajfel and others conducted experiments in intergroup discrimation in the English city of Bristol. This study was conducted with the participation of sixty-four schoolboys aged between fourteen and fifteen years. These boys already knew each other to some extent as the all attended the same school and indeed were members of the same year group and school "house."

The participants were divided into groups of eight, allegedly on the basis of how they scored in a series of tests where they were told their visual judgement was to be gauged according to their individual estimate of the numbers of dots flashed onto a screen, but actually randomly. The boys found themselves variously categorised as "overestimators" and "underestimators" or as being "accurate" or "inaccurate" and were then presented with distributing rewards to their own and other groups.

The numbers in the matrices shown below represent units of 1/10 of a penny.

In one condition the top row of the matrices represented the amounts that could be allocated to a fellow group member. The bottom row referred to amounts available for allocation to another member of the in-group. A participant was not allowed to award money to himself. The subject also did not know the identity of any member of either group. In another condition the subjects awarded amounts to two different members of the outgroup. In a third condition, the main experimental condition, in half the trials the top row represented the amount to be awarded to another in-group member, and the bottom row represented the amount to be awarded to an outgroup member. In the other trials the groups were switched around for both rows. There were six matrices, repeated three times; one for each of the three conditions. Note that each box within a matrix forces the subject to favour one boy over another; there is no box that allows equal amounts to be given. It should be noted that for each box, within the matrix, there was another that held its inverse. It is claimed that the subjects are presented with a "clear alternative to discriminating against the outgroup." In making their Intergroup choices, a large majority of the subjects allocated significantly more points to their in-group compared to the amount allocated to the outgroup. In the other two conditions the points were distributed fairly.

In the second experiment, the experimenters are interested in the strategy adopted by the boys, when allocating points. The boys could allocate for maximum joint profit (MJP), or for maximum profit for the in-group (MIP), or for maximum difference (MD) between the points allocated for one group compared to the other. In this experiment, the groups were randomly allocated to two groups after the boys had judged 12 paintings by two "foreign painters." The groups were labelled the "Klee group" and the "Kandinsky group" being named after the actual painters whose work had been shown. This time the matrices consisted of 13 boxes, and were designed to facilitate the use of any one of the three strategies, mentioned above. In the centre of the matrices was a box with either 13 or 17 points in both the top and bottom rows, allowing for an equal allocation. Towards the ends of the matrices a choice could be made that would help to maintain maximum joint profit, maximum ingroup profit or the maximum difference in amounts allocated between the two groups (see image below).

The results demonstrated that when the boys had the choice between maximising the profit for all and maximising the profit for their own group, they chose the latter. Even more interestingly though, the boys were found to be more concerned with creating as large a difference as possible between the amounts allocated to each group (in favour of their own group), then in gaining a greater amount for everybody, across the two groups. Tajfel points out that this last finding is blatant discrimination caused by categorising the boys into meaningless groups.