World-Systems theory

Meaning: World-systems theory, associated with Immanuel Wallerstein, explains global inequality by treating the world as one interdependent capitalist economy instead of separate countries developing on their own. Nations hold one of three positions. Core nations are wealthy and industrialized, with strong states and high-skill production. Peripheral nations supply raw materials and low-wage labor and tend to have weaker states. Semi-peripheral nations sit between: they are industrializing, still dependent on the core, and draw resources from the periphery. Wealth tends to flow from periphery to core, so inequality is built into the structure.

On the MCAT: A passage may describe a multinational firm moving factories to a low-wage country, or a nation exporting raw materials and importing manufactured goods. You may be asked to classify the country or to choose which theory explains the pattern. Contrast it with modernization theory, which says countries develop in stages by adopting technology and institutions, so poverty is mainly due to internal factors, and with dependency theory, which stresses exploitation of poorer nations by richer ones.

Common confusion: Dependency theory has two tiers (core and periphery); world-systems theory adds the semi-periphery. Core and periphery describe economic roles, not map position, and a country can move between them over time.