Endogenous versus Exogenous Origins of Crises, an essay by D. Sornette
By analyzing precursory and aftershock properties of shocks and ruptures in finance, material rupture, earthquakes, amazon.com sales and other natural and social systems, we find ubiquitous power laws similar to the Omori law in seismology that allow us to distinguish between external shocks and endogenous self-organization.
Robust dynamic classes revealed by measuring the response function of a social system, R. Crane and D. Sornette, submitted to Proc. Nat. Acad. Sci. USA (2008)
- Our work addresses fundamental questions concerning the application of physical concepts to societal dynamics, and is one of the first such studies to uncover rules governing collective human activity. Searching for general principles underlying the internal organization of complex systems has been stifled by the lack of an established general framework for designing, testing, and analyzing empirical data. Our work on collective human activity provides a consistent theoretical framework and a set of tools that can be easily and generically extended to other studies of complex systems.
- Using this novel framework, we have discovered how to robustly classify human dynamics, and we find a surprising emergent law that has its theoretical basis in the physics of fluctuation phenomena. Our work can be used for prediction of complex systems, and as a footnote, our findings have major implications for questions of search and marketing. Furthermore, this work is based on a unique and massive data set collected from the fourth largest website raising its visibility and making it appealing to a broad cross-section of people.
- This work has the potential to revolutionize the study of collective human behavior, provide a new framework for research into the dynamics of complex systems, and appeal to a very broad audience of scientists and general public alike.
Endogenous versus Exogenous Events in the Global War on Terror, P. Meier, D. Sornette and R. Woodard (PDF, 454 KB), paper presented at the 49th International Studies Association Annual Convention, San Francisco,CA, March 26-29, 2008