ABSTRACT
This chapter formulates the theoretical explanation of the historical evolution of world-systems. This theory combines the idea of iterations of a basic model with transformations in modes of accumulation. The chapter's basic model represents the main processes that are involved in hierarchy formation and technological intensification. The model contains six other variables: population growth, environmental degradation, population pressure, emigration, circumscription, and conflict. The stress approach formulated by Brian Hayden to explain technological intensification contends that ecologically marginal regions experience population pressure more strongly and are more likely to implement technological changes. The causal elements in the iteration model affect older core regions and semiperipheral regions differently and this constitutes an important world-system modification of the Harris-Carneiro-Cohen model. The world-system unit of analysis is important at every level because of the phenomenon of semiperipheral development and because circumscription does not happen within societies but only in intersocietal systems.
