There are also techniques for reducing prejudice that utilize interdependence between two or more groups. That is, members across groups have to rely on one another to accomplish some goal or task. In the Robbers Cave Experiment, Sherif used this strategy to reduce conflict between groups. Elliot Aronson’s Jigsaw Classroom also uses this strategy of interdependence. In 1971, thick racial tensions were abounding in Austin, Texas. Aronson was brought in to examine the nature of this tension within schools, and to devise a strategy for reducing it (so to improve the process of school integration, mandated under Brown v. Board of Education in 1954). Despite strong evidence for the effectiveness of the "jigsaw classroom," the strategy was not widely used (arguably because of strong attitudes existing outside of the schools, which still resisted the notion that racial and ethnic minority groups are equal to Whites and, similarly, should be integrated into schools).