3. HIGHLIGHTING COMPLEXITY: ECONOMICS - SYSTEM DYNAMICS - FUZZY LOGIC

The third phase of lateral pressure modeling builds on exploratory system dynamics modeling for the period from 1970s onward, and introduces investigations based on fuzzy logic. Early system dynamics models of lateral pressure such as Choucri et al. (1972)1 addressed the interconnections among the master variables that create internal sources of external conflict. Extending this work, Choucri and Bousefield (1978)2 developed a model of the economy anchored in the master variables, and then located sources of lateral pressure and propensities toward modes of external behavior.

Later, in a comparative analysis of 20 countries (industrial and developing) Wils et al. (1998)3 extended the analysis of internal sources of international conflict, and examined the nature of the feedback effects, namely how international conflict in turn influences and even alters the master variables of the state and changes the internal sources of conflict as well as propensities for particular modes of external behavior.  Subsequently, Lofdahl (2002)4 modeled the relationship between internal dynamics of growth and development rooted in the master variables, on the one hand, and propensities toward particular patterns of international trade and their environmental impacts, on the other. Lofdahl’s work departed from previous investigations by adopting a worldwide perspective and positing the all-encompassing global system

This phase concentrates on basic changes in the master variables across states and over time -- and implications for international relations. Introducing the use of fuzzy logic, the analysis generated empirically based distributions of states both within and across profile groups (Wickbolt and Choucri, 2006)5. The use of fuzzy logic facilitates more systematic and more accurate specifications of the distribution of states throughout the international system. This could be an important step in visualizing shifts in state “location” over time and, to some extent, helping to anticipate conflict-prone behavior.


  1. Choucri, N. M., Laird, M., & Meadows, D. L. (1972). Resource scarcity and foreign policy: A simulation model of international conflict. Cambridge, Mass: Center for International Studies, Massachusetts Institute of Technology.
  2. Choucri, N., & Bousefield, M. (1978). Alternative futures: An exercise in forecasting. In Choucri, N., & Robinson, T. W. (1978). Forecasting in international relations: Theory, methods, problems, prospects. San Francisco: W.H. Freeman.
  3. Wils, A., Kamiya, M., & Choucri, N. (January 01, 1998). Threats to sustainability: simulating conflict within and between nations. System Dynamics Review, 14, 129-162.
  4. Lofdahl, C. L. (2002). Environmental impacts of globalization and trade: A systems study. Cambridge, Mass: MIT Press.
  5. Wickboldt, Anne-Katrin, & Choucri, N. (2006). Profiles of States as Fuzzy Sets: Refinement of Lateral Pressure Theory. International Interaction, 32, 153-181.