Papua New Guinea, or the north west Pacific coastlines of North America. Also for example, the formation of some early states in East Africa, Sri Lanka, and Polynesia do not easily fit with Carneiro's model. Hence Claessen's school developed a "complex interaction model" to explain early state formation, in which factors such as ecology, social and demographic structures, economic conditions, conflicts, and ideology become aligned in ways which favour state organisation. Later development and revision Carneiro has since revised his theory in various ways. He has argued that population concentration can act as a lower level impetus for tribal conflict than geographic circumscription. He has also argued that, in addition to the necessities of conquest, a more important reason for creation of chiefdoms was the rise of war chiefs who use their military loyalists to take over a group of villages and become paramount chiefs. The theory also has since been applied to many other contexts. One of leading experts on world-system theory, Christopher Chase-Dunn, noted in 1990 that the circumscription theory is applicable for the global system. Since the modern world system, being global, is completely circumscribed, the factor of circumscription is supposed to bring about the political unification of the world as it had done on regional scales on numerous occasions in the past. The thesis was further developed by historian Max Ostrovsky who widely used the circumscription theory in his book. The works of Chase-Dunn and Ostrovsky linked the circumscription theory with Carneiro's other theory of the political unification of the world. In the "Foreword" to Ostrovsky's book Carneiro acknowledges that he unjustly "abandoned" the circumscription theory in the Bronze Age. Carneiro's later interview contains his answer on the intriguing question, "Are we circumscribed now?" References Bibliography Carneiro, R. L. The Muse of History and the Science of Culture. New York: Kluwer Academic/Plenum Publishers, 2000. Lewellen, Ted C. 1992. Political anthropology: An Introduction, Second Edition. Westport Connecticut, London: Bergin and Garvey, pp. 54–55. Claessen, H. J. M, Structural change; evolution and evolutionism in cultural anthropology. Leyden: CNWS, 2000 External links Video on Carneiro's Circumscription Theory Cultural anthropology Historical determinism Political theories Theories of history Anthropological theories Political anthropology Environmental humanities Geopolitics