Review Essay: Twenty Important Journal Articles and Reports on Radicalisation to, and De-Radicalisation from, Terrorism

Review Essay: Twenty Important Journal Articles and Reports on Radicalisation to, and De-Radicalisation from, Terrorism

by David C. Hofmann

Keeping up-to-date with new research on terrorism can be challenging for both academic and non-academic researchers, with a multitude of books, articles and reports of varying degrees of quality being produced continuously. Andrew Silke noted that the publication of books on terrorism nearly jumped tenfold after 9/11, from 150 titles in 2000 to 1108 the following year, and 1767 in 2002 [1]. If one searches for books on terrorism with one decade later, one gets over 30,000 results and the sub-genre ‘radicalisation’ already produces in excess of 300 books. Research on radicalisation took off in 2004 in response to the blowback from the American intervention in Iraq the year before. The London bombings in 2005 generated further interest in the phenomenon of “homegrown terrorism”, where apparently self-starting cells of radicalising individuals mobilized against their host countries with little or no material support from foreign terrorist entities. This has created a whole new field of empirical inquiry.

Wading through the sea of literature can be daunting. As a starting point for those interested in studying radicalisation processes, this review essay covers twenty articles and reports that are, in this writer’s opinion, particularly helpful for a better understanding of the phenomenon. No books are discussed here as this would expand this text beyond the patience of most readers. A bibliography subsequent to this review lists, however, books as well. Terrorism Studies is an interdisciplinary field and the present review of articles covers texts from anthropology, psychology and political science. This selection leans toward articles and reports that have some degree of synergy with this writer’s own discipline – sociology.

The approach taken in reviewing the selected articles and reports is akin to a miniature literature review or an annotated bibliography. Its purpose is to provide the reader with a concise summary of the content of each article/report that goes beyond a cursory glance an abstract can offer. The most salient arguments and aspects of each article or report are highlighted, and occasionally supplemented, with this reviewer’ opinions on the importance and impact of the item under  review. As so often in the social sciences, there is no consensus on the definition of radicalisation in these articles. However, the following definition by Alex P. Schmid captures many elements that can be found in them:

Radicalisation: an individual or collective (group) process whereby, usually in a situation of political polarisation, normal practices of dialogue, compromise and tolerance between political actors and groups with diverging interests are abandoned by one or both sides in a conflict diad in favour of a growing commitment to engage in confrontational tactics of conflict-waging. These can include either the use of (non-violent) pressure and coercion, various forms of political violence other than terrorism or acts of violent extremism in the form of terrorism and war crimes. The process is, on the side of rebel factions, generally accompanied by an ideological socialization away from mainstream or status quo-oriented positions towards more radical or extremist positions involving a dichotomous world view and the acceptance of an alternative focal point of political mobilization outside the dominant political order as the existing system is no longer recognized as appropriate or legitimate.” [2]

The twenty articles and reports selected for review here are listed in alphabetical order:

  • Ashour, O. (2010). Online de-radicalisation? Countering violent extremist narratives: Message, messenger and media strategy. Perspectives on Terrorism, 4 (6), 15-19.

With the Internet playing a crucial function in homegrown terrorist radicalisation, it has become an increasingly important security issue to devise strategies to counter jihadist online narratives. To this effect, Omar Ashour outlines a three-pillared strategy for the implementation of online counter-narratives. The first pillar is the message, which requires the creation of multi-layered and attractive counter-messages to terrorist group ideology that are tailored to individual groups (e.g. a counter-narrative for a Right-Wing terror group like Kahane Chai would not be congruent for the IRA, and vice-versa). The second pillar focuses on the messengers, who must appear to have some sort of legitimacy or credibility with the target group. Ashour notes that there is currently a critical mass of former jihadist militants to tap into as a resource for delivering counter-narrative messages. The third and final pillar is the media, which requires careful publication and dissemination of the counter-narrative message.

  • Atran, S. (2003). Genesis of suicide terrorism. Science, 299, 1534-1539.

 Anthropologist Scott Atran’s article on the genesis of suicide terrorism is now somewhat dated but it touches upon some crucial elements of terrorist radicalisation. The article asserts that the most effective way of defending against future suicide attacks is combating the process of radicalisation which is capitalised upon by suicide-bomber recruiting organizations. Notably, the radicalisation and recruitment of suicide bombers is identified as an institutional-level phenomenon. Atran argues that preventing radicalisation of potential suicide bombing recruits requires macro-level solutions, such as applying the right amount of pressure and inducements to undermine communal support for suicide bombing, empowering moderates, and addressing grievances and humiliation in the Muslim community. Elements of Atran’s conclusions are evident in subsequent theories of terrorist radicalisation, and this short but informative article serves as an ideal starting point for those interested in exploring root causes of radicalisation.

  • Barlett, J., & Miller, C. (2012). The edge of violence: Towards telling the difference between violent and non-violent radicalisation. Terrorism and Political Violence, 24 (1), 1-21.

In this article focused on homegrown terrorism, Jamie Bartlett and Carl Miller report the findings of a two-year fieldwork study in the UK, Canada, Denmark, France and the Netherlands. Their research is divided into two parts. The first is focused on addressing a gap in the current literature: the lack of studies that simultaneously look at control groups. This article does so by comparing “permissive factors” between radicals who become terrorists, and radicals who do not engage in violence. The second part of the article examines the process of radicalisation, and differentiates between types of radicalisation that escalate to violence and those that do not. The authors identify four elements of radicalisation that are often overlooked, but have the potential to help understand how radicalisation can lead to violence for some, but not others: (1) the emotional pull to act in the face of injustice, (2) thrill, excitement, and coolness, (3) status and internal code of honour, and (4) peer pressure.

  • Borum, R. (July 2003). Understanding the terrorist mindset. FBI Law Enforcement Bulletin, 72 (7),7-10.

This FBI report outlines forensic psychologist Randy Borum’s four-stage heuristic model of terrorist radicalisation. Borum’s model begins with the recognition by the pre-radicalised individual or group that an event or condition is wrong (“It’s not right”). This is followed with a framing of the event or condition as selectively unjust (“It’s not fair”). The third step occurs when others are held responsible for the perceived injustice (“It’s your fault”). The final step involves the demonization of the ‘other’ (“You’re evil”). While somewhat dated and replaced by newer and more complex theories, Borum’s model is a very good example of an early heuristic attempt at systematising and understanding processes of terrorist radicalisation.

  • Crone, M., & Harrow, M. (2011). Homegrown terrorism in the West. Terrorism and Political Violence, 23(4), 521-536.

Manni Crone and Martin Harrow’s article takes an interesting position by attempting to address certain ambiguities surrounding the definition of homegrown terrorism. They suggest that homegrown terrorism can be reduced to two dimensions: belonging and autonomy. Within these dimensions, the authors propose four ideal types of Western homegrown terrorism: (1) internal autonomous, (2) internal affiliated, (3) external autonomous, and (4) external affiliated. Four illustrative cases of Danish homegrown terrorists are used to highlight the characteristics of each ideal type. This is then followed by a quantitative analysis of Islamist terrorism from 1989-2008, examining whether Western terrorism has seen a shift towards homegrown attacks. The authors find that since 2003 there has been a rise in both internal and autonomous acts of terrorism, but that most internal attacks have some form of external affiliation.

  • Dalgaard-Nielsen, A. (2010). Violent radicalisation in Europe: What we know and what we do not know. Studies in Conflict and Terrorism, 33, 797-814.

In her review of the current state of literature on violent radicalisation in Europe, Anja Dalgaard-Nielsen identifies three major research trends: French sociology, social movement/social network theory, and empirical case studies. She summarizes the strengths and weaknesses of each approach in order to qualitatively assess the state of the literature on radicalisation. While the summary of the identified major research trends on radicalisation is helpful, the strength of this article lies in its critical examination of the state of radicalisation research. Dalgaard-Nielsen echoes the often-repeated criticism that radicalisation research lacks a solid empirical foundation, advocating for the increased use of control groups to properly account for changes in radicalisation. She also points out that despite an increasing trend of focusing on leadership figures in terrorist radicalization processes, there is a paucity of data on their motivations and on what separates them from other terrorists in the organization or cell. The author concludes with pertinent and useful suggestions on how to circumvent such gaps in gathering empirical data on terrorist radicalisation.

  • Dawson, L. L. (2010). The study of new religious movements and the radicalisation of home-grown terrorists: Opening a dialogue. Terrorism and Political Violence, 22 (1), 1-21.

This article by Lorne Dawson, a sociologist of religion, focuses on the conspicuous and somewhat puzzling lack of dialogue between research on homegrown radicalisation  to terrorism and joining sects of new religious movements (NRMs). Dawson begins the analysis by stating the reasons why opening lines of communication between NRM and terrorism research would be fruitful, why it never came to pass, and the grounds with which to begin this dialogue. He notes and delineates three primary points of contact between both subject areas: (1) who, how and why people join NRMs and terrorist groups, (2) how both types of groups maintain and intensify member commitments, and (3) why some NRMs become violent. Dawson’s article concludes with six ‘lessons learned’ from this preliminary comparative analysis between joining NRMs and terrorist radicalisation, which can serve as basis for future collaborative research into ideologically charged groups of a religious or political nature that capture their members and try to cut them off from the rest of society.

  • King, M., & Taylor, D. M. (2011). The radicalisation of homegrown jihadists: A review of theoretical models and social-psychological evidence. Terrorism and Political Violence, 23 (4), 602-622.

In this article, psychologists Michael King and Donald Taylor review five major radicalisation models, highlighting their commonalities and the discrepancies. The authors identify and discuss three common elements found to be important to the process of radicalisation that appear in each model: the phenomenon of relative deprivation, struggles over identity, and the presence of certain personality characteristics. Among the discrepancies, King and Taylor point out the differing formats and portrayals of the radicalisation process (emergent vs. linear progression) across the five models. They then carry the analysis further with discussions on the role of extremist organizations in fomenting radicalisation and the role of individual characteristics in the radicalisation process. The article concludes with three major suggestions for avenues of future research related to the common elements they found in the models, namely, more research on: (1) the affective reactions to group relative deprivation, (2) the management of identities, and (3) the relevant personality characteristics.

  • Kirby, A. (2007). The London Bombers as “Self-Starters”: A case study in indigenous radicalisation and the emergence of autonomous cliques. Studies in Conflict & Terrorism, 30, 415-428.

The London bombings of 2005 caused a partial shift in radicalisation research from the external threat of Al-Qaida, to the internal issue of homegrown terrorist radicalisation. In a case study of the London Bombers, Aidan Kirby argues that previous conceptions of terrorist radicalisation which framed radicalisation as a series of networks connected to a formal and organized jihad is not nuanced enough to explain the dynamics of self-starting homegrown terror cells. To further his argument, Kirby points to the analytical confusion that emerged after the London bombings as to whether the perpetrators were connected formally with Al-Qaida, or acted on their own. Kirby draws heavily on Marc Sageman’s Understanding Terror Networks [3] in his argument that new paradigms focused on social dynamics are necessary in order to understand how homegrown terror cells emerge autonomously. He concludes his argument by highlighting the importance of the Internet as a tool allowing for self-starting homegrown terrorism cells to radicalise and obtain operational knowledge. Since the article was written, evidence has surfaced that the London bombers (especially those involved in the failed attempt of 21/7) were not as autonomous as originally thought, given the links found to Al-Qaeda Core in Waziristan.

  • Kleinmann, S.M. (2012). Radicalisation of homegrown Sunni militants in the United States: Comparing converts and non-converts. Studies in Conflict & Terrorism, 35 (4), 278-297.

This article addresses an important question that has been overlooked in the research on terrorist radicalisation: is the radicalisation process the same for converts and non-converts to Islam? Scott Matthew Kleinmann’s research focuses on Sunni homegrown terrorism in the US from 2001 to 2010, and his data were coded to examine individual, group, and mass factors influencing radicalisation. The research findings show that individual/internal forces play a greater role in the radicalisation of Sunni converts, and group level processes (e.g. ties of kinship and friendship) affect both Sunni converts and non-converts in a similar fashion. Kleinmann’s findings provide a unique insight into differing radicalisation processes and he identified an important sub-category for comparative analysis – the convert who is under pressure to show his commitment to the new cause more than the non-reborn believer.

  • McCauley, C., & Moskalenko, S. (2008). Mechanisms of political radicalisation: Pathways toward terrorism. Terrorism and Political Violence, 20 (3), 415-433.

At the time of the writing of this review, psychologists Clark McCauley and Sophia Moskalenko’s article on the mechanisms of political radicalisation ws the most frequently accessed online article in the leading journal Terrorism and Political Violence. This article served also as a basis for Friction: How Radicalisation Happens to Them and Us [4], an influential book on radicalisation written by the same authors. In the article, the authors identify twelve mechanisms of radicalisation across three levels of analysis: individuals, groups and mass publics. Of the twelve identified mechanisms, the authors note that only two are autonomous, while the remaining ten are reactive. This leads them to make an important argument that current research on radicalisation is focused too much on the individual actors, and not enough on the dynamics of inter-group conflict.

  • Moghaddam, F. M. (2005). A staircase to terrorism: A psychological exploration. American Psychologist, 60 (2), 161-169.

Fathhali M. Moghaddam’s article is a good example of a theory that treats radicalisation as a linear process that progresses along a pathway leading to extreme violence. Moghaddam explains radicalisation as a metaphorical ascent up a narrowing staircase from a ground floor to five higher floors each with different levels of commitment. Individual perceptions of injustice, relative deprivation, and morality are central to his explanation of why certain people ascend the staircase right up to the top floor (representing terrorism) while millions of others experiencing more or less the same starting conditions do not progress very far towards the top. His metaphor begins with a ground floor from which those individuals suffering acutely from feelings of relative deprivation ascend to the first floor of radicalisation. The first floor is populated by all those who seek greater justice for conditions of injustice, relative deprivation and shame. Individuals climbing further up on the staircase are those who feel that in the existing political system their upward social mobility is blocked as their voices of protest are silenced and they are allowed no participation in public decision-making - they ascend to the second floor. On the second floor, Moghaddam explains, one can find those who are inclined to believe leaders who redirect feelings of anger and aggression onto an external enemy. Having been radicalized in mosques or other meeting places they will climb to the third floor where they will disengage from society and are drawn towards  a moral engagement with a terrorist  creed. The fourth floor involves the concretization of a dualistic world-view of “you are either with us or against us”. Those who rose so far  begin to be incorporated into the  structures of terrorist organisations. Some are recruited to take the last steps on the staircase and commit acts of terrorism; they have reached the top floor. For those interested in further reading, Moghaddam expands upon this article in his book From the Terrorists’ Point of View [5].

  • Mullins, S. (2012). Iraq versus lack of integration: understanding the motivations of contemporary Islamist terrorists in Western countries. Behavioral Sciences of Terrorism and Political Aggression, 4 (2), 110-133.

Sam Mullin’s article is a review piece that covers some of the important ‘driving forces’ behind home-grown terrorist radicalisation. While Mullins offers little innovation on the subject, the article’s strength lies in its concise coverage of some of the major ‘hot’ topics surrounding research on Western homegrown terrorism. More specifically, he reviews the research on: (1) psychological abnormality, (2) individual adversity, (3) Western material and political conditions, (4) comparative conditions between the US and Europe, (5) identity crises, (6) Western foreign policy in Iraq, (7) the influence of Islamism, (8) the role of religion, and (9) social motives. Mullins does a fair job covering each topic, and his article is a good place for the reader interested in quickly absorbing some of the major issues and debates surrounding research on homegrown terrorism. The article concludes with a discussion on theoretical and counter-terrorism implications surrounding the state of current research on homegrown terrorism.

  • Rinehart, C. S. (2009). Volatile breeding grounds: The radicalisation of the Egyptian Muslim Brotherhood. Studies in Conflict & Terrorism, 32(11), 953-988.

This case study on the radicalisation of the Egyptian Muslim Brotherhood addresses an often-overlooked factor in the radicalisation process: the dynamics of leadership within the radicalisation process. Christine Sixta Rinehart argues that there are three major factors which contributed to the radicalisation of the Brotherhood: (1) the influence of a charismatic leader, (2) the radicalisation over time of the Brotherhood’s leadership, and (3) frustration at the failure of the Brotherhood to radicalise the population at large. Rinehart’s research utilizes theories like frustration-aggression and Weber’s work on charismatic authority as the basis of her analysis. She concludes that when combined, the three aforementioned factors are what motivated the Brotherhood to commit acts of terrorism.

  • Silber, M. D., & Bhatt, A. (2007). Radicalisation in the West: The homegrown threat. New York: NYPD Intelligence Division.

This influential and often-quoted report by two members of the NYPD Intelligence Division puts forth a model for explaining the home-grown terrorist radicalisation of Islamic jihadists.  Written in a terse and explanatory style for law enforcement practitioners, the NYPD report focuses on a comparative study of five international cases of home-grown jihadi terrorist groups and attempts to create a conceptual framework explaining the home-grown radicalisation process. The authors describe a four step process:  (1) pre-radicalisation – focusing on the environmental and social factors promoting terrorism; (2) self-identification – marking the beginning of  the exploration of the Salafi Islamist worldview, due to  some personal crisis or cognitive event; (3) indoctrination – involving an intensification of radical beliefs and a belief in action to further the Salafist cause; and (4) jihadization – the self-identification of members of a group  as holy warriors, and the commencement of operational planning for a terrorist attack. Among their findings, the authors present a number of key implications which continue to influence the study of home-grown terrorism, such as Al-Qaeda’s inspirational role, the failure to adequately integrate 2nd and 3rd generation immigrants, the futility of profiling home-grown terrorists, and so on. Readers might also wish to look at one of the author’s volume: Mitchell D. Silber. The Al Qaeda Factor. Plots Against the West. Philadelphia: University of Pennsylvania Press, 2012.

  • Silke, A. (2008). Holy warriors: Exploring the psychological processes of Jihadi radicalisation. European Journal of Criminology, 5 (1), 99-123.

The aim of Andrew Silke’s article is to review and assess the quality of psychological research evidence on jihadi radicalisation. Before systematizing the available literature, Silke begins by criticizing the lack of primary research and the overreliance on newspaper reports and secondary material in current psychological research. Adopting the general view that terrorist radicalisation is a gradual process, Silke identifies and discusses a number of common but complex inter-meshing factors found in the backgrounds of terrorists: (1) age and gender, (2) education, career and marriage, (3) social identity, (4) marginalization and discrimination, (5) catalytic events and perceived injustice, (6) status and personal rewards, and (7) opportunity and recruitment. Silke concludes with a discussion of how these common factors go against the common perception of the terrorist as “mentally-ill”, stressing how radicalisation occurs in small groups of like-minded individuals who gradually commit themselves more and more to a radical cause. He argues that the focus for psychologists of terrorism should be on small-group dynamics and psychological processes, and less on the psycho-pathological or crime-like aspects of terrorist radicalisation.

  • Taylor, M. & Horgan, J. (2006). A conceptual framework for understanding psychological process in the development of the terrorist. Terrorism and Political Violence, 18 (4), 585-601.

As the title suggests, this article presents Max Taylor and John Horgan’s conceptual framework for understanding and addressing the psychology of terrorism. Much like the main argument in Horgan’s book, The Psychology of Terrorism [6], the authors argue an important point – that radicalisation and engagement in terrorism is a gradual, step-by-step process, which cannot be explained by reverting to theories about a psycho-pathological state of mind. The article continues with a discussion of pathways into and out of terrorism, where three critical process variables are identified: (1) setting events, (2) personal factors, and (3) social, political and/or organizational contexts. The authors conclude that future research should focus on understanding factors such as decisional contexts, individual choices and the implications of involvement in terrorist activities.

  • Thompson, R. L. (2011). Radicalisation and the use of social media. Journal of Strategic Security, 4 (4), 167-190.

Robin Thompson’s article is a policy piece that focuses on explaining how and why social media sites (Facebook, Twitter, etc.) are effective radicalisation tools. She argues that the use of social media in terrorist radicalisation is not a transient phenomenon, and it can pose a real threat to national security by encouraging homegrown terrorism. The article presents its case with three observations: (1) the ubiquity and reach of social media, (2) arguing that social media is the “perfect voice” for radicals trying to rally supporters to a cause, and (3) an analysis of how social media played a role in the 2011 Arab Spring uprisings. The article concludes with policy suggestions aimed at implementing a response to the potential radicalisation effects of social media. Notably, Thompson argues that the intelligence and the national security communities need to become more involved in social media themselves in order to better understand its potential as a medium for radicalisation.

  • Useem, B. & Clayton, O. (2009) Radicalisation of U.S. prisoners. Criminology & Public Policy, 8 (3), 561-592.

Bert Useem and Obie Clayton’s article addresses a still understudied aspect of terrorism research: the radicalisation of prisoners. In interviews with 210 American prison officials and 270 American inmates, the authors set forth to gauge whether the social environment in correctional institutions is conducive for radicalisation into jihadi terrorism. While there are a number of methodological issues with the sample that hinder obtaining comprehensive results, the authors conclude that there is a low level of radicalisation among US inmates. They identify four reasons why this might be: (1) the increase of order in prisons, (2) institutional boundaries between inmates and outside radical communities, (3) anti-radicalisation initiatives executed by agency leadership, and (4) the low levels of education of inmates in comparison to other terrorists. The authors conclude by arguing that prison life has a very low level of effect on whether or not an American inmate will become radicalised to jihadi terrorism.

  • Vidino, L. (2009). Homegrown jihadist terrorism in the United States: A new and occasional phenomenon? Studies in Conflict & Terrorism, 32 (1), 1-17.

Lorenzo Vidino’s main argument in this article is that homegrown terrorism has a long history within the US, despite the widespread view that it is mainly a recent and mostly European phenomenon. Vidino points to violent acts by African American Muslim organizations, the 1993 Landmarks plot, travelling jihadi fighters in the 1990’s, the post 9/11 boom, and a number of lone wolf terrorists as examples of this long tradition of homegrown US terrorism. He argues that the failure to recognize this situation stems from a ‘delayed awareness’ in the pre-9/11 days because intelligence communities had greater legal and cultural impediments to monitoring internal terrorist threats. The London bombings in 2005 further catalyzed the interest of US authorities in detecting and neutralizing homegrown terrorist threats. Vidino continues by identifying four reasons why there is a divergence between the comparatively low levels of homegrown radicalisation amongst Muslims in the US than in Europe: (1) better economic conditions, (2) geographic dispersion, (3) immigration patterns, and (4) tougher immigration policies. The article concludes with a brief analysis of the history of the US government’s response to homegrown terrorism.


Acknowledgements: The author would like to thank Dr. Lorne L. Dawson for his helpful comments and advice.

About the Reviewer: David C. Hofmann is a doctoral candidate in Sociology and Legal Studies at the University of Waterloo, Canada. His current research interests include terrorist radicalisation and charismatic authority. He can be reached at [email protected]


[1] A. Silke (2008). “Research on Terrorism: A Review of the Impact of 9/11 and the Global War on Terrorism”, in: H. Chen, E. Reid, J. Sinai, A. Silke and B. Ganor (Eds.) Terrorism Informatics: Knowledge Management and Data Mining for Homeland Security. New York: Springer,pp. 27-49.

[2] Alex P. Schmid. Radicalisation, De-Radicalisation, Counter-Radicalisation: where do Terrorism Studies stand in Understanding Mobilisation to, and Demobilisation from, Islamist Violent Extremism and Jihadist Terrorism? The Hague: International Centre for Counterterrorism (ICCT), 2012 (Unpublished Literature Review), p.17. 

[3] M. Sageman (2004). Understanding Terror Networks. Philadelphia: University of Pennsylvania Press.

[4] Clark McCauley & Sophia Moskalenko (2011). Friction: How radicalisation happens to them and us. New York: Oxford University Press.

[5] F. M. Moghaddam (2006). From the terrorists’ point of view: What they experience and why they come to destroy. Westport, CT: Praeger Security International.

[6] John Horgan (2005). The psychology of terrorism. London and New York: Routledge.

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