Recall that sherif and his colleagues (1951) created conflict between two groups of boys in a summer camp. once in-group cohesiveness was established, they set up a series of competitive situations such as tug-of-war and other competitive games. conflict between the two groups escalated. sherif and his colleagues were only successful in reducing conflict and hostility when they brought the groups together in neutral situations. leaders endorsed a truce between the two rival groups. they constructed situations that fostered mutual interdependence. groups were punished for behaving with hostility. 10 points