EMERGENT EXTREMISM IN A MULTI‐AGENT MODEL OF RELIGIOUS CLUBS

I. INTRODUCTION Religious extremism is as old as religion itself, but the tendency to promote militancy and terrorism from within extremist religions appears to be much more common now than in times past (Juergensmeyer 2001, Stern 2003, Wiktorowicz 2005). (1) Today's terrorists routinely frame their objectives in religious terms and organize their activities within religious movements. This shift is not due to increased militancy within religion as a whole, not even within the stricter subset of religious groups commonly labeled "sectarian" or "fundamentalist" (Bromley and Melton 2002, Marty and Appleby 1995). Rather, groups with militant objectives are increasingly leveraging the latent potential for violence within extremist religion. Krueger and Maleckova (2003) and Krueger (2007) have shown that, contrary to popular hypotheses regarding the salience of poverty and education, it is instead institutional conditions such as civil liberties that contribute to the origination of terrorists within a country. Religious extremism has been shown to be a potentially powerful input into the production of terrorism (Berman 2004), (2) and the origination of terrorists has been empirically connected to civil liberties. We seek to complete the triangle and connect religious extremism to social conditions in an extension of existing theory, and test the predictions of the model in an empirical context, with an eye toward civil liberties. This paper extends previous models of religious clubs to better account for observed patterns of extremism across different settings and test policies most likely to reduce the appeal of extremism. Economists, at first blush, should have trouble explaining the survival of groups that demand large sacrifices from their members. Successful religious groups, however, routinely impose all sorts of apparently unproductive costs on their members. Iannaccone (1992) introduced a formal model of religious clubs within which apparently irrational "sacrifice and stigma" enhances the individual and collective utility. His model demonstrated the feasibility of extremist groups, but does less to explain the relative prevalence of extremism across time and place. Further, the original model allows for only corner solutions, and as such, the viability of extreme groups is indistinguishable from the viability of the more moderate groups they must compete with for members in the religious marketplace. In Section II we revisit, analyze, and extend the club model of religion. We push the analysis of the original model, exploring sacrifice, substitutability of club and private goods, and their relationships to member commitment and the viability of extremist groups. In this preliminary analysis, we illustrate not only the potential insights of the club theory of religion into the strength and viability of extremist groups, but also the limitations inherent to the representative agent model. We proceed by extending the model in a multi-agent (MA), computational framework. This framework permits us to analyze the distributions of agents and clubs that make up a religious economy. The computational nature of the model is critical because it allows for sufficient heterogeneity of agents and clubs, and given this heterogeneity, agent decision making absent closed-form solutions via Nash equilibria. Extremists' groups emerge as just one segment (the high-cost tail) of a distribution of religious clubs that range across the full spectrum of potential (group-imposed) sacrifice and stigma. Extremism is identifiable and comparable in the model because it exists within a full spectrum of clubs. By varying the parameters of the model that control the distribution of (secular) wages across agents and the degree of substitutability between religious and secular commodities, we can better explain where and when religious extremism is most popular, its strength relative to more moderate groups, and which economic policies reduce its prevalence. …