Dependency theory developed in the late 1950s led by Raul Prebisch to explain why economic growth in wealthy nations did not necessarily lead to growth in poorer countries. It argues that poorer nations are dependent on wealthy nations for resources, markets, and obsolete technology, which prevents self-sustaining development. Wealthy nations also actively maintain this state of dependence through economic, political, and cultural means. Dependency theory aimed to explain the persistent underdevelopment and inequality between nations as an intrinsic result of the patterns of interaction and trade within the global economic system.