Dependency theory argues that European development was based on actively underdeveloping non-European societies by extracting their resources and surplus value through colonialism and unequal trade relations. This created a global hierarchy with wealthy core nations and poorer peripheral nations. Dependency theorists believe underdevelopment was generated by the development of capitalism itself, not due to the periphery's isolation or internal failings, and that true development can only be achieved by breaking from the capitalist world system. World-systems theory shares similarities in analyzing global core-periphery relations but emphasizes long-term comparative analysis of societies within the global system.