Robbers' Cave study

n. A study carried out by Muzafer Sherif in which groups of 11-year-old boys were first put in groups and allowed to develop group cohesion and ritual, then placed in competition, and finally presented with an urgent problem which required both groups to solve in Robber’s Cave State Park in Oklahoma. The main findings of the study were that group situation tended to determine individual feelings and actions toward others, which were positive toward in-group members and negative toward out-group members in the competitive situation and then positive toward everybody in the group cooperation 
situation.