People all over the world believe that their own nation, culture, language, and religion are better and more deserving than others. Part of the reason for that is even more basic than real or perceived competition for finite resources. Rather, it stems from something more subtle and psychological. A classic study of high school boys in Bristol, England, conducted by Henri Tajfel and his col- leagues (1971) begins to reveal this point. The boys in this study were shown a series of dotted slides, and their task was to estimate the number of dots on each. The slides were presented in rapid-fire succession so that the dots could not be counted. Later, the experimenter told the participants that some people are chronic “overestimators” and that others are “underestimators.” As part of a second, entirely separate task, participants were divided into two groups—one that was said to consist of overestimators and the other of underestimators. (In fact, they were divided randomly.) Participants were then told to allocate points to other participants that could be cashed in for money.
This procedure was designed to create minimal groups in which people are categorized on the basis of trivial, minimally important similarities. Tajfel’s over- estimators and underestimators were not long-term rivals, did not have a history of antagonism, were not frustrated, did not compete for a limited resource, and were not even acquainted with each other. Still, participants consistently allo- cated more points to members of their own group than to members of the other group. This pattern of discrimination, called ingroup favoritism, has been found repeatedly in studies in many countries and using a variety of different measures, although there are some factors that make the effect more or less likely to occur