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Psychologists Muzafer and Carolyn Sherif, in a classic experiment in the 1950s, divided a group of 12-year-old white, middle-class boys at a summer camp into the “Eagles” and the “Rattlers.” At first, when the boys did not know one another, they formed a common social category as summer campers. But as time passed and they began to consider themselves to be either Eagles or Rattlers, these 12-year-old boys formed two distinct social groups.
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In the beginning, the Eagles and Rattlers were friendly, but soon their games evolved into intense competitions. The two groups began to call each other names, and they raided each other's cabins, hazed one another, and started fights. In other words, loyalty to the in-group led to antagonism and aggression toward the out-group, including fierce competitions for the same resources. Later in the same experiment, though, Sherif had the boys work together to solve mutual problems. When they cooperated with one another, the Eagles and Rattlers became less divided, hostile, and competitive.
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Members use titles, external symbols, and dress to distinguish themselves from the out-group.
Members tend to clash or compete with members of the out-group. This competition with the other group can also strengthen the unity within each group.
Members apply positive stereotypes to their in-group and negative stereotypes to the out-group.
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