Sherif's (1966) robber's cave state park study demonstrated that conflict can be created simply by randomly assigning people into competing groups. he later demonstrated that he could reduce conflict by having campers work together to achieve some mutual interest (e. g., fixing a broken truck, restoring the camp's water supply). sherif's study demonstrates how foster cooperation.

The correct answer is superordinate goals.

Superordinate goals refer to refer to goals that involve the cooperation and coming together of two or more individuals or groups in order to achieve a mutual goal. Superordinate goals are usually major and important enough for different individuals or groups to put aside their differences or disagreements and work together in order to achieve the same outcome.