How Terrorism Spreads: Information, Emulation, and the Diffusion of Ethnic and Ethno-religious Terrorism Sara M. T. Polo University of Essex smtpol@essex.ac.uk PRIO 8 May 2014
Outline Introduction Theory Research Design Results Conclusion
Research Question How does terrorism diffuse? How does the use of terrorist tactics spread between ethnic and ethno-religious groups?
Research Question Very little is known about whether and how terrorism diffuses between groups as well as countries. Ethnic and ethno-religious terrorism have represented the largest component of global terrorism over the past 40 years. Hot-spots of transnational terrorism. Evidence that ethnic conflict is contagious. But what about the tactics that groups use? (terrorism within as well as outside civil wars) Focus on specific mechanisms of diffusion of ethnic and ethno-religious terrorism.
Introduction Theory Research Design Results Conclusion Ethnic and Ethno-Religious Terrorism 1970-2009 No Terrorism Terrorism How Terrorism Spreads Sara M. T. Polo University of Essex
Summary of the Argument Decision to resort to terrorism not just a function of a group s domestic situation, motives and resources but likely to be influenced by the behaviour of similar groups abroad or in the same country. Choice of terrorist tactics social emulation between groups. Structural similarity between groups (focus on similar political marginalization/exclusion). Geographic proximity (communication, direct interactions between groups, spread of information and tactics).
The Geography of Terrorism Diffusion of transnational leftist terrorism in Latin America and Western Europe (Midlarsky et al. 1980). Country-level hot-spots of transnational terrorism (Braithwaite and Li, 2007). Diffusion of terrorism along civilizational lines (Neumayer and Pluemper, 2010).
The Diffusion of Ethnonationalist Conflict Relevance of ethnic conflict abroad: Ethnification, Ethnic Dissimilation, and Demonstration Effects (Kuran, 1998). Ethnicity becomes politically salient. Ethnic groups become more aware of their own situation relative to that of others (group comparison). Groups may have incentives to make more extreme demands. Events abroad may change directly the ethnic balance of power at home (e.g. refugee flows, Salehyan and Gleditsch, 2006). Ethnic conflict abroad may lead groups to update their beliefs about the costs of protest and, ultimately, violence and their probability of success. (Hill, Rothchild, and Cameron, 1998).
Outline Introduction Theory Research Design Results Conclusion
The External Determinants of Terrorism Determinants of terrorism: the transnational dimension of grievances and opportunities. Groups can use different tactics and strategies (violent and non violent) to voice their grievances and achieve their political objectives. Terrorism (indirect targeting) is only one of the tactics groups can adopt. Use of terrorism by one group may generate a potential bandwagon among other groups which perceive themselves as similar in their political or economic situation to that group and can therefore draw inspiration from its activities. Terrorism by neighbouring groups affects cost-benefit calculations and perceptions of feasible tactics.
Emulation and Proximity Use of terrorism by a politically marginalized group may produce emulation effects among other politically marginalized ethnic groups. Demonstration effects can trigger or increase perception of grievances and heighten domestic salience of ethnic issues and discrimination. Peer group effect: identification requires some connection between the groups, such as similarity in ethnic mix, cultural affinity, or direct interactions. Connections define the reference groups whose behaviour is relevant for the actions of a particular group.
Emulation and Proximity Similarity and identification more likely to occur at regional rather than global level. Unlike peaceful mass protests and demonstrations, terrorism is a more costly and risky strategy which requires specific skills and resources. Having a neighbouring group that uses terrorism may facilitate training and planning of operations as well as allow for the establishment of alliances between groups (more resources, specific evidence for this). Diffusion of ethnic and ethno-religious terrorism as an inherently asymmetric process (politically included groups and countries with only included groups are relatively immune from this phenomenon).
Mechanism of Diffusion Geographic Proximity Political Similarity Communication/Information Identification Gating Factors Emulation
Hypotheses H1a: A politically excluded ethnic group i is more likely to use terrorist tactics if other similarly excluded groups j in neighbouring regions also use terrorism. H1b: A politically excluded ethnic group i is more likely to use terrorist tactics if other similarly excluded groups in neighbouring countries j also use terrorism. H2a: An ethnic group i is more likely to adopt terrorist tactics if its kin in neighbouring country j also uses terrorism. H2b: An ethnic group in country i is more likely to adopt terrorist tactics if its kin in neighbouring country j also uses terrorism and they have a similar political status.
Outline Introduction Theory Research Design Results Conclusion
Research Design Group-level analysis; all politically relevant ethnic groups 1970-2009 (EPR v. 2.0, Cederman et al. 2010). Dependent variable: new dataset on terrorist attacks per ethnic group-year (additional source Global Terrorism Database, 2011). Spatial lag of terrorism by neighbouring ethnic group with similar political status. NT NT block diagonal matrix (distance based on Geo EPR, Wucherpfennig et al. 2011, political status based on EPR). Spatial lag of terrorism by neighbouring kin group with similar political status (temporally lagged). TEK data from Cederman et al. 2013.
Research Design Control variables: Group characteristics (EPR v. 2.0, Cederman et al. 2010); Country-level covariates: media density (Warren 2014), real GDP per capita (Gleditsch 2005), level of democracy (Polity IV; Freedom House); Time dependence (Carter and Signorino 2010). Bayesian Spatial Probit (Wilhelm and Godinho de Matos, 2013) and model with observational spatial lag.
Outline Introduction Theory Research Design Results Conclusion
Terrorism obs. lag (NB country) t 1 Terrorism obs. lag (NB group) t 1 Terrorism TEK t 1 Table: Empirical Results Model 1 Model 2 Model 3 2.025 (0.154) 4.110 (0.620) 2.124 (0.238) Regional Autonomy 0.557 0.742 1.693 (0.344) (0.349) (0.456) Powerless 0.888 0.952 0.850 (0.302) (0.312) (0.412) Discriminated 1.241 1.739 1.260 (0.321) (0.298) (0.372) Separatist 1.847 2.352 1.894 (0.483) (0.435) (0.477) Media Density 0.00399 0.00234 0.00261 (0.00277) (0.00220) (0.00690) N 16575 15502 7629 Clustered standard errors in parentheses + p < 0.10, p < 0.05, p < 0.01, p < 0.001
Terrorism obs. lag (NB country) t 1 Terrorism obs. lag (NB group) t 1 Terrorism TEK t 1 Table: Empirical Results Model 4 Model 5 Model 6 1.936 (0.133) 4.280 (0.580) 1.932 (0.227) Regional Autonomy 0.700 0.711 1.753 (0.281) (0.280) (0.355) Powerless 0.653 0.622 0.434 (0.237) (0.243) (0.353) Discriminated 1.069 1.460 1.203 (0.243) (0.231) (0.313) Separatist 1.305 1.784 1.442 (0.404) (0.351) (0.402) Democracy 0.0702 0.0902 0.0863 (0.00971) (0.00975) (0.0149) N 23513 21875 11145 Clustered standard errors in parentheses + p < 0.10, p < 0.05, p < 0.01, p < 0.001
Table: Bayesian Spatial Probit, 5000 iterations, burn-in = 100 (1) (2) w/o TEK w TEK Excluded 0.202 + 0.061 (0.124) (0.129) Group size -0.028-0.439 (0.267) (0.337) Terrorism TEK 1.141 (0.328) Constant -0.667-0.672 (0.147) (0.153) ρ 0.531 0.514 (0.092) (0.087) N 623 623 Coefficients represent posterior means + p < 0.10, p < 0.05, p < 0.01, p < 0.001
Substantive Effects Discriminated Groups Terrorism Probability 0.00 0.10 0.20 No Terrorism NB Terrorism NB
Outline Introduction Theory Research Design Results Conclusion
Conclusion and Improvements Importance of looking at external factors as relevant determinants of terrorism. Structural similarity, identification, and proximity as components of a diffusion mechanism of ethnic terrorism. Future improvements to the project: estimate Bayesian spatial probit with all years/decades, compare estimated coefficients using alternative methods (e.g. PMLE, GMM) better integrate role of non-relational channels (i.e. media) in the diffusion of terrorist tactics.
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