the summer camp but could only be achieved with both groups working together, such as obtaining water during a water shortage or procuring a film that both groups wanted to see but did not have enough money for. Sherif found that these goals encouraged cooperation between the boys, which reduced conflict between the groups, increased positive beliefs about boys from the other group, and increased cross-group friendships. Background Superordinate goals are most often discussed in the context of realistic conflict theory, which proposes that most intergroup conflicts stem from a fight over scarce resources, especially in situations that are seen as zero-sum. Under realistic conflict theory, prejudice and discrimination are functional, because groups are tools used to achieve goals, including obtaining scarce resources that would be difficult to get as an individual. In this case, groups see other groups with similar goals as threats and therefore perceive them negatively. Groups that are both competing for the same limited resource are said to have a negative interdependence. On the other hand, there are groups that benefit from working together on goals that are not zero-sum. In this case, these groups are said to have a positive interdependence. In order to remove competition between different factions under realistic group conflict theory, it is necessary to have non-zero sum goals that create a positive interdependence within groups rather than a negative interdependence. Superordinate goals can create positive interdependence if they are seen as desirable by both groups but are not achievable by each faction independently. Psychological Mechanisms Work in social psychology suggests that superordinate goals differ from single group goals in that they make the larger group identity more salient and increase positive beliefs about everyone in the larger superordinate group. Cooperation and Interdependence Superordinate goals differ from smaller group goals in that they cannot be achieved by a single small group, and thus force multiple groups to work together, encouraging cooperation and penalizing competition. This encourages each group to consider the other group positively rather than negatively, as the other group is instrumental to achieving the common goal. This fosters a sense of positive interdependence rather than negative interdependence. Superordinate Goals and Identity In addition to increasing positive interdependence, having two groups work together on a single superordinate goal makes the larger group identity more salient. In effect, superordinate goals make it more likely that both groups will consider themselves as part