Read “The Power of Us: Harnessing Our Shared Identities to Improve Performance, Increase Cooperation, and Promote Social Harmony” or visit the Book Website, where this study and topic is explained in more detail.

Read more about Social Identity Theory.

Check out this primary source for Tajfel and colleagues’ minimal group experiments: Social categorization and intergroup behaviour

This Business Insider article digs deeper into the Adidas and Puma rivalry, and provides more information about what the rivalry is like today.

Even young children (ages 5-8) exhibit in-group preferences when they are assigned to minimal groups. Discriminatory preferences remain even when researchers work really hard to make sure the kids know the groups are meaningless. Indeed, the chance to affiliate makes the groups meaningful! See this article for more details.

Research suggests that people prefer minimal ingroups over outgroups because they expect these shared identities to facilitate cooperation within the group. They represent an opportunity for cooperation, that both children and adults are quick to seize upon.

This article by Rupert Brown (who recently published a biography of Henri Tajfel) provides an in depth account of the history of the minimal group paradigm.