The Theory of Cumulative Causation (Gunnar Myrdal) argues that regions with an initial economic advantage attract more investment, workers, and infrastructure, creating a self-reinforcing cycle of growth, while surrounding regions lose resources through backwash effects and fall further behind.
The Theory of Cumulative Causation says development is a snowball, not a ladder. Once a region gets a head start (a port, a factory cluster, a resource), that advantage attracts investment, skilled workers, and infrastructure. Those new resources make the region even more attractive, which pulls in even more growth. Success feeds success.
The flip side is just as important. As the growing core sucks in capital and labor, surrounding regions get drained of their best workers and investment money. Geographers call these losses backwash effects. The result is a widening gap between a prosperous core and a struggling periphery, which is why cumulative causation is one of the structuralist explanations for spatial variations in development you study in Topic 7.5, alongside dependency theory and Wallerstein's World System Theory.
This term lives in Topic 7.5 (Theories of Development) in Unit 7: Industrial and Economic Development Patterns and Processes, supporting learning objective AP Human Geography 7.5.A: explain different theories of economic and social development. The CED's essential knowledge (EK SPS-7.E.1) names Rostow, Wallerstein, dependency theory, and commodity dependence as theories that explain spatial variations in development, and cumulative causation is the mechanism behind the structuralist ones. It answers the question Rostow's stages can't: why don't all regions climb the development ladder at the same pace? Because growth concentrates where growth already exists. If you can explain that feedback loop, you can explain core-periphery patterns at every scale, from neighborhoods to the global economy.
Keep studying AP Human Geography Unit 7
Backwash Effects (Unit 7)
Backwash effects are the other half of cumulative causation. While the core gains, the periphery actively loses workers, capital, and businesses to it. One theory, two directions of flow.
Core-Periphery Model (Units 6-7)
Cumulative causation is the engine that builds core-periphery patterns. The model describes the uneven map; cumulative causation explains why the unevenness keeps getting worse instead of evening out.
Agglomeration Economies (Unit 7)
Agglomeration is cumulative causation at the scale of a city or industrial cluster. Firms locate near other firms to share suppliers and skilled labor, which attracts more firms, which is exactly the self-reinforcing loop Myrdal described.
Dependency Theory (Unit 7)
Both are structuralist theories that reject Rostow's idea that every country develops the same way. Dependency theory blames the core for exploiting the periphery; cumulative causation focuses on the snowball logic of growth concentrating where growth already is.
No released FRQ has used "cumulative causation" verbatim, but it sits squarely inside Topic 7.5, which the exam tests heavily through compare-and-contrast questions on development theories. Multiple-choice stems often describe a scenario (a booming city pulling investment and migrants away from rural areas) and ask which theory or concept explains it. On FRQs, this term is most useful as an explanation tool. If a prompt asks you to explain why regional inequality persists or why development is spatially uneven, describing the self-reinforcing cycle (initial advantage → investment and migration toward the core → backwash effects on the periphery → widening gap) earns explanation points that a simple definition won't. Always pair the concept with a directional claim about what flows where.
Both theories explain why poor regions stay poor, but the mechanism differs. Dependency theory says periphery countries are poor because core countries deliberately structure trade to exploit them (often a legacy of colonialism). Cumulative causation doesn't require exploitation at all. It says growth naturally concentrates where advantages already exist, and the periphery falls behind simply because investment and talent flow toward the core. Dependency theory is about power; cumulative causation is about momentum.
Cumulative causation says an initial economic advantage attracts more investment, workers, and infrastructure, creating a self-reinforcing cycle of growth in the core region.
Backwash effects are the cost of this cycle, as the periphery loses capital and its most skilled workers to the growing core.
The theory predicts that regional inequality widens over time without intervention, which contradicts Rostow's assumption that all places move through the same stages of growth.
It supports AP Human Geography 7.5.A by explaining spatial variations in development at multiple scales, from city neighborhoods to the global core and periphery.
On FRQs, use cumulative causation as a cause-and-effect explanation for uneven development, not just a vocabulary word, by tracing what flows from periphery to core and why.
It's Gunnar Myrdal's idea that regions with an early economic advantage attract more investment, workers, and infrastructure, creating a self-reinforcing growth cycle while nearby regions lose resources through backwash effects and fall further behind.
No, that's the opposite of its prediction. Unlike Rostow's stages model, which assumes every region can climb the same development ladder, cumulative causation predicts the gap between core and periphery widens over time because growth keeps concentrating where it already exists.
Dependency theory says the core deliberately exploits the periphery through unequal trade relationships, often rooted in colonialism. Cumulative causation doesn't require exploitation; it says investment and skilled labor naturally flow toward already-successful regions, so the periphery falls behind through momentum rather than malice.
Backwash effects are the negative consequences for peripheral regions as a core grows, including loss of skilled workers to out-migration, capital flight toward core investments, and local businesses being outcompeted. They're the draining half of the cumulative causation cycle.
It falls under Topic 7.5 (Theories of Development) and learning objective AP Human Geography 7.5.A, so it can appear in multiple-choice scenarios about regional inequality and is a strong explanatory tool for FRQs about uneven development, even though the CED's essential knowledge names Rostow, Wallerstein, and dependency theory explicitly.
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