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From Isolation to Radicalization: Anti-Muslim Hostility and Support for ISIS in the West

  • TAMAR MITTS (a1)


What explains online radicalization and support for ISIS in the West? Over the past few years, thousands of individuals have radicalized by consuming extremist content online, many of whom eventually traveled overseas to join the Islamic State. This study examines whether anti-Muslim hostility might drive pro-ISIS radicalization in Western Europe. Using new geo-referenced data on the online behavior of thousands of Islamic State sympathizers in France, the United Kingdom, Germany, and Belgium, I study whether the intensity of anti-Muslim hostility at the local level is linked to pro-ISIS radicalization on Twitter. The results show that local-level measures of anti-Muslim animosity correlate significantly and substantively with indicators of online radicalization, including posting tweets sympathizing with ISIS, describing life in ISIS-controlled territories, and discussing foreign fighters. High-frequency data surrounding events that stir support for ISIS—terrorist attacks, propaganda releases, and anti-Muslim protests—show the same pattern.


Corresponding author

*Tamar Mitts, Assistant Professor, School of International and Public Affairs, Columbia University,


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I thank Susanne Baltes, Eli Berman, Abhit Bhandari, Christopher Blattman, Jasper Cooper, Lindsay Dolan, Page Fortna, Grant Gordon, Guy Grossman, Kolby Hanson, Macartan Humphreys, Sarah Khan, Sung Eun Kim, Egor Lazarev, Summer Lindsey, Joshua Mitts, Suresh Naidu, Jacob Shapiro, Kunaal Sharma, Jack Snyder, Camille Strauss-Kahn, Lauren Young, and the Journal’s editor and anonymous reviewers for their helpful feedback. I also benefited from comments from seminar participants at Brown, Chicago, Columbia, Dartmouth, Emory, Michigan, Northwestern, NYU, Stanford, and Vanderbilt. I thank Geffen Huberman for her research assistance. Replication files are available at the American Political Science Review Dataverse:



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Adida, Claire L., Laitin, David D., and Valfort, Marie-Anne. 2016. Why Muslim Integration Fails in Christian-Heritage Societies. Cambridge, MA: Harvard University Press.
Allport, Gordon W. 1979. The Nature of Prejudice. New York, NY: Basic Books.
Backstrom, Lars, Sun, Eric, and Marlow, Cameron. 2010. “Find Me if You Can: Improving Geographical Prediction with Social and Spatial Proximity.” In Proceedings of the 19th International Conference on World Wide Web. Raleigh, NC: ACM, 61–70.
Barrett, Richard, Berger, Jack, Ghosh, Lila, Schoenfeld, Daniel, el-Shawesh, Mohamed, Skinner, Patrick M., Sim, Susan, and Soufan, Ali. 2015. “Foreign Fighters: An Updated Assessment of the Flow of Foreign Fighters into Syria and Iraq.” The Soufan Group.
Bartlett, Jamie, and Birdwell, Jonathan. 2013. “Cumulative Radicalisation between the Far-Right and Islamist Groups in the UK: A Review of Evidence.” Demos (3–15).
Bass, Loretta. 2014. What Motivates European Youth to Join ISIS? Syria Comment: University of Oklahoma.
Bayman, Daniel, and Shapiro, Jeremy. 2014. “Be Afraid. Be a Little Afraid: The Threat of Terrorism from Western Foreign Fighters in Syria and Iraq.” Foreign Policy at Brookings.
Benmelech, Efraim, and Klor, Esteban F.. 2018. “What Explains the Flow of Foreign Fighters to ISIS?Terrorism and Political Violence, 1–24. Published online 31 October 2018.
Berger, J. 2015. “The Metronome of Apocalyptic Time: Social Media as Carrier Wave for Millenarian Contagion.” Perspectives on Terrorism 9 (4): 61–71.
Berger, J., and Morgan, Jonathan. 2015. “The ISIS Twitter Census: Defining and Describing the Population of ISIS Supporters on Twitter.” The Brookings Project on US Relations with the Islamic World 3: 20.
Biggs, Michael, and Knauss, Steven. 2012. “Explaining Membership in the British National Party: A Multilevel Analysis of Contact and Threat.” European Sociological Review 28 (5): 633–46.
Borum, Randy. 2011. “Radicalization into Violent Extremism I: A Review of Social Science Theories.” Journal of Strategic Security 4 (4): 7.
Bryan, Jennifer. 2005. “Constructing ‘The True Islam’ in Hostile Times: The Impact of 9/11 on Arab Muslims in Jersey City.” In Wounded City: The Social Impact of 9/11, ed. Foner, Nancy. New York, NY: Russel Sage Foundation, 133–162.
Burrows, Thomas. 2016. “Islamophobic Hate Crimes in London Have Nearly Doubled in the Last Two Years as Muslims Say They Are ‘Very Conscious of Keeping Your Head Down’.” The Daily Mail.
Carter, Joseph A., Maher, Shiraz, and Neumann, Peter R.. 2014. “# Greenbirds: Measuring Importance and Influence in Syrian Foreign Fighter Networks.” The International Centre For the Study of Radicalisation and Political Violence.
Crone, Manni. 2016. “Radicalization Revisited: Violence, Politics and the Skills of the Body.” International Affairs 92 (3): 587–604.
Cunningham, Daniel, Everton, Sean F., and Schroeder, Robert. 2017. “Social Media and the ISIS Narrative.” White Paper. Monterey, CA: Defense Analysis Department, Naval Postgraduate School.
Dabiq. 2015. “The Extinction of the Grayzone.” Dabiq 7: 54–66.
Dalgaard-Nielsen, Anja. 2010. “Violent Radicalization in Europe: What We Know and what We Do Not Know.” Studies in Conflict & Terrorism 33 (9): 797–814.
Dancygier, Rafaela M., and Laitin, David D.. 2014. “Immigration into Europe: Economic Discrimination, Violence, and Public Policy.” Annual Review of Political Science 17: 43–64.
della Porta, Donatella. 2018. “Radicalization: A Relational Perspective.” Annual Review of Political Science 21: 461–74.
Eatwell, Roger. 2006. “Community Cohesion and Cumulative Extremism in Contemporary Britain.” The Political Quarterly 77 (2): 204–16.
European Social Survey Round 7. 2014. “European Social Survey Round 7 Data (2014).” Data File Edition 2.1. NSD - Norwegian Centre for Research Data.
Fernandez, Alberto M. 2015. “Here to Stay and Growing: Combating ISIS Propaganda Networks.” The Brookings Project on U.S. Relations with the Islamic World U.S.-Islamic World Forum Papers 2015.
Flaig, Joseph. 2016. “Khola Hasan from Theydon Garnon Says She Has Experienced Increased Islamophobia in Epping Forest.” The Guardian.
Frenett, Ross, and Dow, Moli. 2016. “One to One Online Interventions: A Pilot CVE Methodology.” Institute for Strategic Dialogue.
Friedman, Jerome, Hastie, Trevor, and Tibshirani, Robert. 2010. “Regularization Paths for Generalized Linear Models via Coordinate Descent.” Journal of Statistical Software 33 (1): 1–22.
Front National. 2017. “The National Front Platform (In French).”
Goldenberg, Jacob, and Levy, Moshe. 2009. “Distance Is Not Dead: Social Interaction and Geographical Distance in the Internet Era.” arXiv preprint arXiv:0906.3202.
Golder, Matthew. 2016. “Far Right Parties in Europe.” Annual Review of Political Science 19 (1): 477–97.
Gould, Eric D., and Klor, Esteban F.. 2016. “The Long-run Effect of 9/11: Terrorism, Backlash, and the Assimilation of Muslim Immigrants in the West.” The Economic Journal 126 (597): 2064–114.
Greenberg, Karen J. 2016. “Case by Case: ISIS Prosecutions in the United States.” Center on National Security, Fordham University School of Law.
Grimmer, Justin, and Stewart, Brandon M.. 2013. “Text as Data: The Promise and Pitfalls of Automatic Content Analysis Methods for Political Texts.” Political Analysis 21 (3): 267–97.
Gurr, Ted R. 1970. Why Men Rebel. Princeton, NJ: Princeton University Press.
Hainmueller, Jens, and Hopkins, Daniel J.. 2014. “Public Attitudes toward Immigration.” Annual Review of Political Science 17: 225–49.
Hall, Ellie. 2015. “Gone Girl: An Interview with an American in ISIS.” Buzzfeed News.
Hegghammer, Thomas. 2010. “The Rise of Muslim Foreign Fighters: Islam and the Globalization of Jihad.” International Security 35 (3): 53–94.
Holland, Joshua. 2016. “Islamic Extremism Is Not the Root Cause of Europe’s Terror Problem.” The Nation (March 30).
Horgan, John G. 2015. “De-Radicalization Programs Offer Hope in Countering Terrorism.” Los Angeles Times.
Horowitz, Donald L. 1985. Ethnic Groups in Conflict. Oakland, CA: University of California Press.
Humphreys, Macartan, and Weinstein, Jeremy M.. 2008. “Who Fights? the Determinants of Participation in Civil War.” American Journal of Political Science 52 (2): 436–55.
Inge, Sophie. 2013. “Nazi Graffiti and Pig’s Head Left at Mosque Site.” The Local.
Isaac, Mike. 2016. “Twitter Steps up Efforts to Thwart Terrorists’ Tweets.” New York Times.
Jamal, Amaney. 2008. “Civil Liberties and the Otherization of Arab and Muslim Americans.” In Race and Arab Americans before and after 9/11: From Invisible Citizens to Visible Subjects, eds. Jamal, Amaney A. and Naber, Nadine. Syracuse, NY: Syracuse University Press, 114–30.
James, Gareth, Witten, Daniela, Hastie, Trevor, and Tibshirani, Robert. 2013. An Introduction to Statistical Learning. Vol. 112. New York: Springer.
Jurgens, David. 2013. “That’s what Friends Are for: Inferring Location in Online Social Media Platforms Based on Social Relationships.” ICWSM 13: 273–82.
Jurgens, David, Finethy, Tyler, McCorriston, James, Xu, Yi Tian, and Ruths, Derek. 2015. “Geolocation Prediction in Twitter Using Social Networks: A Critical Analysis and Review of Current Practice.” In Proceedings of the 9th International AAAI Conference on Weblogs and Social Media (ICWSM), eds. Quercia, Daniele and Hogan, Bernie. Palo Alto: AAAI Press, 188–97.
Karam, Nicoletta. 2012. The 9/11 Backlash: A Decade of US Hate Crimes Targeting the Innocent. Pennsauken, NJ: BookBaby.
Kent Online. 2015. “MP Gareth Johnson Contacts Police over Britain First “Anti-halal Operation” in Dartford.” Kent Online.
King, Gary, and Zeng, Langche. 2001. “Logistic Regression in Rare Events Data.” Political analysis 9 (2): 137–63.
Lubbers, Marcel, and Scheepers, Peer. 2002. “French Front National Voting: A Micro and Macro Perspective.” Ethnic and Racial Studies 25 (1): 120–49.
Lyons-Padilla, Sarah, Gelfand, Michele J., Mirahmadi, Hedieh, Farooq, Mehreen, and van Egmond, Marieke. 2015. “Belonging Nowhere: Marginalization and Radicalization Risk Among Muslim Immigrants.” Behavioral Science & Policy 1 (2): 1–12.
Malet, David. 2013. Foreign Fighters: Transnational Identity in Civil Conflicts. Oxford, UK: Oxford University Press.
Marans, Daniel. 2015. “What You Need to Know about Syrian Refugees Who Have ‘Positive’ Views of ISIS.” The World Post.
McCaul, Michael, Thompson, Bennie, Katko, John, Sanchez, Loretta, Loudermilk, Barry, Vela, Filemon, Ratcliffe, John, Payne, Donald, Hurd, Will, and McSally, Martha. 2015. “Final Report of the Task Force on Combating Terrorist and Foreign Fighter Travel.” Homeland Security Committee.
McGee, Jeffrey, Caverlee, James A., and Cheng, Zhiyuan. 2011. “A Geographic Study of Tie Strength in Social Media.” In Proceedings of the 20th ACM International Conference on Information and Knowledge Management, eds. Berendt, Bettina, de Vries, Arjen, Fan, Wenfei, Macdonald, Craig, Ounis, Iadh, and Ruthven, Ian. Glasgow: ACM, 2333–6.
McGee, Jeffrey, Caverlee, James, and Cheng, Zhiyuan. 2013. “Location Prediction in Social Media Based on Tie Strength.” In Proceedings of the 22nd ACM International Conference on Conference on Information & Knowledge Management. eds. He, Qi and Iyangar, Arun. San Francisco: ACM, 459–468.
Mousseau, Michael. 2011. “Urban Poverty and Support for Islamist Terror: Survey Results of Muslims in Fourteen Countries.” Journal of Peace Research 48 (1): 35–47.
Naber, Nadine. 2008. “Introduction: Arab Americans and U.S. Racial Formations.” In Race and Arab Americans before and after 9/11: From Invisible Citizens to Visible Subjects, eds. Jamal, Amaney A. and Naber, Nadine. Syracuse, NY: Syracuse University Press, 1–45.
Neumann, Peter R. 2013. “The Trouble with Radicalization.” International Affairs 89 (4): 873–93.
Norris, Pippa. 2005. Radical Right: Voters and Parties in the Electoral Market. New York, NY: Cambridge University Press.
Nussio, Enzo. 2017. “The Role of Sensation Seeking in Violent Armed Group Participation.” Terrorism and Political Violence, 1–19.
Office for National Statistics. 2016. Census Geography.
Petersen, Roger D. 2001. Resistance and Rebellion: Lessons from Eastern Europe. New York, NY: Cambridge University Press.
Rabasa, Angel, Pettyjohn, Stacie L., Ghez, Jeremy J., and Boucek, Christopher. 2010. Deradicalizing Islamist Extremists. Technical Report, RAND Corp Arlington VA National Security Research Div.
Raghavan, Sudarsan. 2016. “Two of Her Daughters Joined ISIS. Now She’s Trying to Save Her Two Younger Girls.” The Washington Post.
Reuters, . 2016. “Anti-islam Movement PEGIDA Stages Protests across Europe.” Reuters.
Robinson, Belinda. 2015. “ISIS Supporter, 17, Is Sentenced to 11 Years in Prison for Tweeting 7,000 Messages Backing the Terror Group and Helping a Friend to Join Fighters in Syria.” Daily Mail.
Rydgren, Jens. 2008. “Immigration Sceptics, Xenophobes or Racists? Radical Right-Wing Voting in Six West European Countries.” European Journal of Political Research 47 (6): 737–65.
Scacco, Alexandra. 2018. Anatomy of a Riot: Why Ordinary People Participate in Ethnic Violence. WZB Berlin Social Science Center.
Sedgwick, Mark. 2010. “The Concept of Radicalization as a Source of Confusion.” Terrorism and Political Violence 22 (4): 479–94.
Shane, Scott, Apuzzo, Matt, and Schmitt, Eric. 2015. “Americans Attracted to ISIS Find an ‘Echo Chamber’ on Social Media.” New York Times.
Stack, Liam. 2015. “American Muslims under Attack.” New York Times.
Takhteyev, Yuri, Gruzd, Anatoliy, and Wellman, Barry. 2012. “Geography of Twitter Networks.” Social Networks 34 (1): 73–81.
The Atlantic. 2017. “The ‘First Lady of ISIS’.” The Atlantic.
Van Zeller, Mariana. 2016. “Radicals Rising.”
Victoroff, Jeff, Adelman, Janice R., and Matthews, Miriam. 2012. “Psychological Factors Associated with Support for Suicide Bombing in the Muslim Diaspora.” Political Psychology 33 (6): 791–809.
Vidino, Lorenzo, and Hughes, Seamus. 2015. “ISIS in America: From Retweets to Raqqa.” George Washington University: Program on Extremism.
Walter, Barbara F. 2017. “The Extremist’s Advantage in Civil Wars.” International Security 42 (2): 7–39.
Wiktorowicz, Quintan. 2005. Radical Islam Rising: Muslim Extremism in the West. Lanham, MD: Rowman & Littlefield Publishers.
Wildman, Sarah. 2017. “Meet the Far-Right Party That’s Bringing Racism and Xenophobia Back to Germany.” Vox.
Wilner, Alex S., and Dubouloz, Claire-Jehanne. 2010. “Homegrown Terrorism and Transformative Learning: An Interdisciplinary Approach to Understanding Radicalization.” Global Change, Peace & Security 22 (1): 33–51.
Wilson, Lydia. 2015. “What I Discovered from Interviewing Imprisoned ISIS Fighters.” The Nation.
Wood, Elisabeth Jean. 2003. Insurgent Collective Action and Civil War in El Salvador. New York, NY: Cambridge University Press.
Worley, Will. 2016. “Thousands Take Part in Anti-islam Pegida Protests across Europe.” The Independent.
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Mitts Dataset

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Mitts supplementary material 1

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