Radicalization is the change in beliefs, feelings, or actions toward increased support for one side of an intergroup conflict. Extremism refers to beliefs, feelings or actions that go against the political status quo. A minority of radicals or extremists move to violent action, including the violence against civilians that is called terrorism.

Clark McCauley and I are on record asserting that the psychology of radicalization has been the same for hundreds of years1. In our book, Friction: How Conflict Radicalizes Them and Us (2016), we described twelve psychological mechanisms that can move individuals, small groups and mass publics to more radical opinions and actions. Case studies for each mechanism came from modern radical movements and 19th-century anarchist movement, with striking similarities across time, space and ideology.

What are the mechanisms of radicalization?

On the individual level, personal or political grievance can radicalize, regardless of who is perceived as the culprit: the Russian czarist government, the Western apostates, or the Israeli government. Similarly, individuals could be led down a slippery slope of radical action (from smaller, less radical acts like delivering messages to more radical actions like driving a getaway vehicle, to planting explosives or shooting people), whether the group facilitating this transition is the 19th-century Russian People’s Will or the 21st-century’s Islamic State (ISIS). Zarqawi became radicalized for the thrill and status of political violence, the same way as Russian-born Barannikov did in the 1870s and as many Western-born youths did, traveling to Iraq and Syria to join ISIS. For love, Sonya Perovskaya followed her boyfriend into the terrorism of People’s Will, as the Bali bomber followed his brother into Al Qaeda. Unfreezing from normal life’s rules and attachments (brought about by war, repressions, or personal troubles) creates an opening for radicalization that religious cults and terrorist groups exploit, offering lost souls a home and a community while indoctrinating them into a radical ideology.

On the level of small groups, Polarization of heated group debates marked the transition from peaceful activism to radical action for 19th-century Russian students who became People’s Will terrorists as well as for 20th-century American students who became Weather Underground terrorists. The threat of persecution and isolation as the group goes underground, as well as competition with the state or with rival radical groups, are also hallmarks of group radicalization across the history of terrorism.

On the level of mass publics, hate, including essentialization (“they are all the same”) and dehumanization (“roaches/vermin/animals”) of the enemy, such as in 1930s Germany mass opinion against Jews and Communists, was a radicalizing force for rightwing terrorists responsible for attacking a Pittsburg synagogue2, a New Zealand mosque,3 and a Charleston African-American church4. Jujitsu is a tactic terrorist groups employ to goad their powerful opponents into an over-reaction bound to produce recruits and sponsors to the terrorists’ cause, as Al Qaeda did when they attacked the U.S.A on 9/11, baiting the U.S. into wars in three Muslim countries, each with numerous civilian casualties. Finally, martyrs inspire followers to kill and die for their cause, whether that cause is ancient or modern, religious or political.

In short, the same twelve mechanisms that moved Russian anti-czar terrorists in the late 1800s can be identified in present-day Islamist terrorists in Syria and Iraq as well as in Rightwing terrorists in the U.S.A. But while psychological mechanisms remain the same, the means for radicalizing have undergone dramatic changes.

How has radicalization evolved?

Before, radicalization of an individual or a group required serious investments of time (traveling to targets of radicalization and disseminating radicalizing materials), talent (painting posters and printing proclamations, and smuggling these past police), and money (paying for safe houses, printing presses, and travel expenses of those carrying radical messages and materials). Nowadays, anyone with a computer and an internet connection can put together a website, complete with links to videos, photos, and audio tracks. The cost of radicalizing communications has plummeted.

The risks of engaging in radicalizing efforts have gone down as well. Based in Syria and Iraq, ISIS has taken responsibility for attacks around the world, carried out by individuals who received inspiration and instruction over the Internet5.

Individuals can receive radicalizing messages sitting in front of their computers at home. They can download instructional videos or manuals for building home-made bombs. They can identify with a radical group and carry out attacks in its name without ever interacting with any other group members.

Radical feelings, thoughts, and behaviors have changed little over time. But the Internet and social media platforms such as Facebook and Twitter have introduced new ways to move people toward radicalization. As a result, the audience for radicalizing ideas and actions has greatly expanded. Not only would-be terrorists but also “ordinary people” are now targets of remote radicalization efforts designed to weaponize their frustrations. Through social media, Russia appealed to internal divisions between racial and social groups in the U.S.A., radicalizing opinions to affect the 2016 presidential elections.6 As of January 2019, U.S. intelligence officials state that Russia continues to evolve tools for mass radicalization, plotting another election interference for the 2020 elections.7

What’s new about radicalizing media today?

Radicalizing media are faster-paced than ever before. It took Zarqawi several years and thousands of miles tracked across Afghanistan to get to his goal: meeting Osama bin Laden.8 Today, that journey may take only weeks. Those seeking radical groups and individuals can get to them by clicking on the right websites, following certain Gab, Instagram, or Twitter handles, or by watching certain YouTube channels. Speed is one thing that’s different about radicalizing media today.

Breadth is another media advance. Billions of people around the world use the internet and participate in social media platforms. Even if the proportion susceptible to radicalization is small, with the greater efficiency of communication and lower cost of commitment, the number radicalized is much greater now.

What can be done to contain mass radicalization?

After the terrorist attacks of 9/11, the U.S. government-sponsored research initiatives linking academics with security practitioners. As a result, we now know a lot more about terrorists than we knew on 9/11. This knowledge helps the FBI and the police to track potential perpetrators and thwart most terrorist attacks before they endanger people’s lives.

Internet social media has proven to be a powerful vehicle for mass radicalization. Paid trolls or internet bots (computer programs that amplify a particular political message by retweeting, “liking,” or reposting it) can aid a political campaign, help incite a rally, or popularize a political issue. This power to interfere in our political system requires oversight.

Political candidates in the U.S. are not allowed to accept campaign donations from foreign sources, and Americans lobbying for foreign governments must register with the U.S. government. But, through social media, foreign governments can interfere in U.S. politics, including U.S. elections. Even for U.S. political players, social media open doors to voters’ minds in a new form of influence that is not subject to campaign limitations or reporting requirements. Existing laws are not enough to control foreign or domestic political manipulation in the age of the Internet. We must write new laws that would reduce the public’s vulnerability to manipulation through the social media–especially foreign-origin politicking, especially foreign-origin politicking disguised as domestic voices. 

As demonstrated by Russian efforts on social media, Americans are vulnerable to radicalization along existing fault lines.9 Russian propaganda emphasized our internal conflicts, inflaming passions of Whites against Blacks, immigrants against native-born, gays against straights, Christians against Muslims, and Democrats against Republicans.10 Russian internet interventions aimed to exploit these divisions.

This is a new form of warfare.11 Other countries will try to do what the Russians tried to do. We should work toward reducing the divisions that give enemies an opening. One way to achieve this goal is for the government to sponsor large-scale projects that bring different factions together for the common good. The challenges looming on our collective horizon are serious––climate change, increasing inequality, mass migrations driven by poverty and crime, aging population, health-care crises.  These issues require collective action. Government-led initiatives to address these major challenges could bring us together, and fortify us against hybrid warfare whose battlefield is the Internet and whose trophies are our hearts and minds.

Read the full series “Extremism in Historical and Evolutionary Perspective”:

  1. Introduction by Anthony Lopez and Hammad Sheikh
  2. The Virtue of Extremism is its Enhancement of the Ordinary by David Barash
  3. Extremism as Defense by Rose McDermott
  4. Why Extremism Isn’t the Real Issue by Mark Sedgwick
  5. What is Radicalization? by Sophia Moskalenko
  6. Conservative Extremists Are Afraid of Threats That Don’t Exist by Colin Holbrook and Jennifer Hahn-Holbrook
  7. Extremist Violence Has Its Roots in Morality, Not Ideology by Clark McCauley
  8. In the Eye of the Beholder: Parochial Altruism, Radicalization, and Extremism by Zoey Reeve
  9. Hidden Figures: The Untold Story of Terrorist Recruiters by John Horgan and Katerina Papatheodorou
  10. Why Terrorists Are Misunderstood by Max Abrahms
  11. Why Religious Extremism is Maladaptive by Richard Sosis
  12. The Extremist in Historical Perspective: Lessons from the Era of Anarchist Terrorism by Randall Law
  13. Terrorism and the Apocalyptic by Charles B. Strozier
  14. Extremist Groups Require the Greatest Trust Among Members by Melissa McDonald
  15. Moral Rigidity Evolved to Strengthen Bonds Within Groups by Antoine Marie
  16. Sacred Values, Social Identities, and Extremist Violence by Nafees Hamid


[1] McCauley, C. R., & Moskalenko, S. (2016). Friction: How Conflict Radicalizes Them and Us. Oxford University Press.

[2] Andone, D., Hanna, J., Sterling, J., & Murphy, P. P. (2018). “Hate Crime Charges Filed in Pittsburgh Synagogue Shooting That Left 11 Dead,” Turner Broadcasting System, Inc.

[3] Besley, T., & Peters, M. A. (2019). “Terrorism, Trauma, Tolerance: Bearing Witness to White Supremacist Attack on Muslims in Christchurch, New Zealand,” Educational Philosophy and Theory, DOI: 10.1080/00131857.2019.1602891

[4] Sanchez, R., & Payne, E. (2016). “Charleston Church Shooting: Who is Dylann Roof?” CNN. com16.

[5] https://www.cnn.com/2015/12/17/world/mapping-isis-attacks-around-the-world/index.html

[6] Jamieson, K. H. (2018). Cyberwar: How Russian Hackers and Trolls Helped Elect a President What We Don’t, Can’t, and Do Know. Oxford University Press.

[7] https://www.washingtonpost.com/world/2019/01/30/us-intelligence-chiefs-de-facto-message-allies-around-world-youre-right-trump-is-wrong/?utm_term=.b36890161930

[8] Brisard, J.-C. with Martinez, D. (2005). Zarqawi. Other Press, New York.

[9] https://www.dailymail.co.uk/sciencetech/article-5207017/Did-fall-Russian-propaganda-Facebook-tell-you.html

[10] Jamieson, K. H. (2018). Cyberwar: How Russian Hackers and Trolls Helped Elect a President What We Don’t, Can’t, and Do Know. Oxford University Press.

[11] Arquilla, J., & Ronfeldt, D. (1993). “Cyberwar is Coming!” Comparative Strategy12(2), 141-165.

Published On: January 8, 2020

Sophia Moskalenko

Sophia Moskalenko

Sophia Moskalenko received her Ph.D. in psychology from the University of Pennsylvania in 2004. Her research on terrorism and radicalization has been presented in scientific conferences, government briefings, radio broadcasts, and international television newscasts. As a research fellow at the National Consortium for the Study of Terrorism and Responses to Terrorism (NC-START) she has worked on research projects commissioned by the Department of Defence, Department of Homeland Security and Department of State. With Clark McCauley, she has co-authored the award-winning Friction: How Conflict Radicalizes Them and Us, and The Marvel of Martyrdom: The Power of Self-Sacrifice in the Selfish World.

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