Dependency theory
One alternative model on the left is [(Dependency theory)]. It emerged in the 1950s and argues that the underdevelopment of poor nations in the Third World derived from systematic imperial and neo-colonial exploitation of raw materials. Its proponents argue that resources typically flow from a "periphery" of poor and underdeveloped states to a "core" of wealthy states, enriching the latter at the expense of the former. It is a central contention of dependency theorists such as Andre Gunder Frank that poor states are impoverished and rich ones enriched by the way poor states are integrated into the "world system".