Some believe that social structure is naturally developed, caused by larger systemic needs (e.g. the need for labour, management, professional, and military classes), or by conflicts between groups (e.g. competition among political parties or elites and masses). Others believe that this structuring is not a result of natural processes, but of social construction. In this sense, it may be created by the power of elites who seek to retain their power, or by economic systems that place emphasis upon competition or cooperation.