One of the most famous social psychology experiments was Muzafer Sherif's Robber's Cave experiment. The experiment involved two groups of twelve-year-old boys at Robber’s Cave State Park in Oklahoma.
The twenty-two boys involved did not know each other before-hand and came from similar backgrounds. They were put into two groups and encouraged to bond as separate groups. The two groups soon were at odds with each other and had very negative feelings toward each other. They were then encouraged to work out their differences.
As a result of the study, which of the following concepts was found to BEST help reduce tension between groups?