Not surprising, you might say. After all, this is the reason why football supporters beat each other up every so often before and after games between their clubs. And yet, this is not the full story. Nearly two decades later, Henri Tajfel, then Professor of Social Psychology at Bristol University (United Kingdom), and colleagues conducted a series of studies that called into question the assumption that competitive goals are a necessary condition for the development of intergroup hostility (Tajfel, Billig, Bundy, & Flament, 1971). Participants in these studies were 14‐ to 15‐year‐old schoolboys, who all knew each other well and came to the psychology laboratory in groups of eight to participate in an experiment (see Chapter 2) on visual perception. Their task was to estimate the number of dots that were flashed onto a screen. After completion of this task, they were told that they would also participate in a second experiment and, for the ease of coding, would be divided on the basis of the dot estimates they had just made. Half the boys were then (randomly) assigned to the ‘under‐estimators’ group, the other half to the ‘over‐estimators’ group. (In later studies, boys were often divided on the basis of their alleged preference for paintings by Klee or Kandinsky, an equally irrelevant criterion for boys of that age.) The boys then had to assign rewards to other individuals in real money. They did not know the identity of the other individuals, but only their code numbers and their group membership.