Radicalization (or radicalisation) is a process by which an individual or group comes to adopt increasingly extreme political, social, or religious ideals and aspirations that (1) reject or undermine the status quo or (2) reject and/or undermine contemporary ideas and expressions of freedom of choice. For example, radicalism can originate from a broad social consensus against progressive changes in society. Radicalization can be both violent and nonviolent, although most academic literature focuses on radicalization into violent extremism (RVE). There are multiple pathways that constitute the process of radicalization, which can be independent but are usually mutually reinforcing.
Radicalization that occurs across multiple reinforcing pathways greatly increases a group’s resilience and lethality. Furthermore, by compromising its ability to blend in with non-radical society and participate in a modern, globalized economy, [clarify] serves as a kind of sociological trap that gives individuals no other place to go to satisfy their material and spiritual needs.
Western Counterterrorism and Law Enforcement Agencies' Definitions of Radicalization 
United States 
According to the U.S. National Counterterrorism Center (NCTC), The grievances that fuel radicalization are diverse and vary across locations and groups. Radicalization frequently is driven by personal concerns at the local level in addition to frustration with international events.
NYPD: In 2007 The New York Police Department Intelligence Division released a document that focused on the Islamist radicalization process entitled, Radicalization in the West: The Homegrown Threat. The report was co-authored by Mitchell D. Sibler and Arvin Bhatt, who are both Senior Intelligence Analysts for the NYPD. The report researched and analyzed several famous case studies from abroad as well as from the United States to collect the needed data to create their step by step explanation of radicalization. The cases examined included: the London, England 7/7 attack, 2004 Madrid train bombings, the Toronto 18 case, Herald Square Bomb Plot, the Lackawana Six plot, and the Al Muhajiroun Two plot. The NYPD report breaks down the radicalization process into four steps with each step including its own key indicators and triggers. The four steps to radicalization are their key indicators are:
- Pre-radicalization: Individual's ordinary life prior to radicalization
- Key indicators: Individuals background and current environment. Other indicators from the study included being a 2nd or 3rd generation immigrant to the U.S., having a college or even advanced degree, and being a recent convert.
- Self-identification: The individual comes to identify with radical movements
- Key indicators: 1) A crisis event occurs progressing the individual towards Salafi Islam. 2) Regular attendance at a Salafi mosque 3) Change in personal behavior that may include: giving up vices such as gambling, drinking alcoholic beverages, and smoking, as well as becoming involved in social activism pertaining to Islam
- Indoctrination: Individual intensify and focus their beliefs
- Key indicators: 1) Individual takes on political worldview and relating all things back to Salafi Islam and its teachings 2) Withdrawal from mosque and movement towards a small group or "cluster" where radical ideas are espoused and shared 3) Politicalization of new Salafi beliefs
- Jihadization: Individual start to take actions based on their beliefs
- Key indicators: 1) Decision to travel abroad to countries involved in conflict for training 2) Preparation for an “act of furtherance” by way of internet research, physical surveillance of possible targets, and visiting jihadi websites for words of encouragement prior to an attack 3) Acquiring materials needed for explosives or other means of attack i.e. guns, vehicles, bomb components
Similar to other radicalization reports that have been created the NYPD report also includes several key assumptions:
- There is no single pathway to extremism. All cases take very different paths of radicalization
- If an individual goes through all or even some of the steps of radicalization that does not mean that they will commit an act of terrorism. Several cases exist where an individual radicalized (wholly or partially) and never committed any acts of terrorism
- The NYPD report also cites that the Internet as a key driver of radicalization and includes it in several sections of the report.
United Kingdom 
The UK Home Office, MI5’s parent agency, bluntly defines radicalization as “The process by which people come to support terrorism and violent extremism and, in some cases, then join terrorist groups.” The MI5 report closes by saying that no single measure will reduce radicalization in the UK and that the only way to combat it is by targeting the at risk vulnerable groups and trying to assimilate them into society. This may include helping young people find jobs, better integrating immigrant populations into the local culture, and effectively reintegrating ex-prisoners into society.
The Royal Canadian Mounted Police defines radicalization as “the process by which individuals — usually young people — are introduced to an overtly ideological message and belief system that encourages movement from moderate, mainstream beliefs towards extreme views. While radical thinking is by no means problematic in itself, it becomes a threat to national security when Canadian citizens or residents espouse or engage in violence or direct action as a means of promoting political, ideological or religious extremism. Sometimes referred to as “homegrown terrorism,” this process of radicalization is more correctly referred to as domestic radicalization leading to terrorist violence.”
The Dutch AIVD defines radicalization as “Growing readiness to pursue and/or support - if necessary by undemocratic means - far reaching changes in society that conflict with, or pose a threat to, the democratic order.”
The Danish Security and Intelligence Service (PET) defines radicalization as “A process by which a person to an increasing extent accepts the use of undemocratic or violent means, including terrorism, in an attempt to reach a specific political/ideological objective.”
The Radicalization Process 
Despite being composed of multifarious pathways that lead to different outcomes and sometimes diametrically opposed ideological purposes, radicalization can be traced to a common set of pathways that translate real or perceived grievances into increasingly extreme ideas and readiness to participate in political action beyond the status quo. To quote Shira Fishman, a researcher at the National Consortium for the Study of Terrorism and Responses to Terrorism, "Radicalization is a dynamic process that varies for each individual, but shares some underlying commonalities that can be explored."" Though there are many end products of the process of radicalization, to include all manner of extremist groups both violent and nonviolent, a common series of dynamics have been consistently demonstrated in the course of academic inquiry.
Radicalization and Mutual Aid 
Eli Berman's 2009 book Radical, Religious, and Violent: the New Economics of Terrorism applies a rational choice model to the process of radicalization, demonstrating that the presence of mutual aid networks increase the resilience of radical groups. When those groups decide to use violence, they also enjoy a heightened level of lethality and are protected from defection and other forms of intervention by states and outside groups.
All organizations insofar as they include the possibility of free riders by extension experience defection constraints. Within the context of a violent extremist organization, defection means either defection to a counterintelligence or security apparatus, or defection to a non-radical criminal apparatus. Both of these outcomes spoil specific plans to exercise violence in the name of the group at large. The “defection constraint” is similar to a threshold price-point in that it denotes what rewards would justify the defection of any one individual within the context of an organization. Berman uses the example of a Taliban protection racket for convoys of consumer goods moving through Afghanistan: checkpoints are set up at several points along a trade route, and each checkpoint’s team is given a small percentage of the convoy’s total value if it arrives safely at its destination. The incentive for any one checkpoint’s team deciding to simply hijack a convoy as it passes through, sell the goods off, and escape, increases as the value of the convoy increases. The same dynamic applies to attacks; while an individual in a terrorist group may not feel drawn by the reward of alerting the police to an impending low level crime, the reward for alerting the police to an impending high profile attack, such as a mass bombing, becomes more attractive. While non-radicalized and criminal organizations can only rely on organizational cohesion through a calculus of greed, fear, and perhaps familial loyalty, Berman argues that religious radicalization greatly increases the defection constraints of radical terrorist organizations by requiring outsized demonstrations of commitment to the cause prior to recruiting operatives.
Mutual aid is the voluntary and reciprocal exchange of goods within an organization. Examples in various religious antecedents include Judaic Tzedakah, Islamic Zakat, and various Christian institutions of charity, as described in the Acts of the Apostles. Berman argues that religious organizations experience economic risks by extending mutual aid to all alleged believers - theological assent is cheap, action can be costly. By imposing a series of outwardly visible social rules, such as restrictions (or prescriptions) on dress, diet, language, and social interactions, groups impose a cost on entering into a mutual aid partnership, diminishing the occurrence of free riding.
These restrictions have a dual effect in radical groups. Not only do they ensure that an individual is committed to the cause, but they also diminish individual’s access to consumption opportunities and social interaction that might persuade them to distance themselves from the cause. As individuals become more involved with radical activities, their social circles become more constrained, which diminishes contact with non-radicalized persons and further entrenches radicalized thinking. For example, when a young man spend several years in a Yeshiva in order to establish himself within a Haredi community, he foregoes future earnings that would be accessible should he choose a secular education. To quote Berman “As consumption opportunities are limited, work for pay becomes less appealing, freeing up even more time for community activities.” This sunk cost figures into future calculations, and raises the defection constraint in a way that non-radicalized group dynamics cannot. Going back to the Taliban convoy example, not only have the two footsoldiers in question have been vetted by demonstrating commitment to the cause, they also have had their exterior options limited such that it would be difficult to blend into a new environment for lack of skills and cultural understanding. As such, the threshold price point to defect, as represented by the value of the convoy, increases to include both the price of losing their existing support network and non-quantifiable factors such as friends, family, safety, and other goods over the course of their lives.
Individual Pathways 
While the overall arch of radicalization usually involves multiple, reinforcing processes, scholars have identified a series of individual pathways to radicalization. Clark McCauley and Sofia Mosalenko’s 2009 book Friction: How Radicalization Happens to Them and Us identifies the following sociological and psychodynamic pathways:
Individual-Level Factors 
Radicalization Due to Personal Grievance: This pathway emphasizes revenge for real or perceived harm inflicted upon oneself by an outside party. This initial offense triggers other psychodynamic mechanisms, such as thinking in more stark in-group and out-group terms, lowered inhibitions to violence, and lessened incentives to avoid violence. Chechen “Shahidka” also known as Black Widows, women who have lost husbands, children, or other close family members in conflict Russian forces are a good example.
Radicalization due to group grievance: “Group grievance” radicalization dynamics are similar to those that are primed by personal grievances; the difference is that the subject perceives harm inflicted on a group that she belongs to or has sympathy for. This pathway accounts for the larger portion of political and ethnic radical violence, in which action is taken on behalf of the group at large rather than as an act of personal revenge. Radicalization out of sympathy for an outgroup is rarer, but can be observed in the Weather Underground's attempted alignment with the Black Panthers and Viet Cong. The tie between radicalization into violent extremism through group grievance and suicide bombing has also been quantifiably demonstrated: perceived threats to proximal identity such as the presence of foreign troops or invasion accounts for the majority of suicide bombings.
Slippery Slope: The “Slippery Slope” represents gradual radicalization through activities that incrementally narrow the individual’s social circle, narrow their mindset, and in some cases desensitize them to violence. This has also been called the “True Believer” syndrome, as a product of which one becomes increasingly serious about their political, social, and religious beliefs as a product of “taking the next step”. One can begin by participating in nonviolent activities such as mutual aid, wherein the best way to raise one’s in-group social status is to demonstrate seriousness about the cause and increase the level of commitment in terms of beliefs and activities. As an individual commits act after act, sunk costs are developed. Even if activity is initially only ideological or only criminal, the process of radicalization conflates the two such that criminal acts are justified for intellectually radical purposes, and radical purposes are invoked to justify what are ultimately criminal acts.
Love: Romantic and familial entanglement is often an overlooked factor in radicalization. Several violent extremist organizations, especially at their origin, owe their structure to a tight-knit group of friends who share religious, economic, social, and sexual bonds. While this example is evident in more extreme cases, such as those of Charles Manson's "Family" and other radical cults, it also applies radicalization in secular and orthodox religious environments. Love can serve as a connection between influential figures, connecting their networks of followers through a combination of attraction and loyalty. This particular force was especially notable in New Left radical groups, such as the American Weather Underground and the German Red Army Faction. The connections between Bill Ayers and Bernardine Dohrn, or between Gudrun Ensslin and Andreas Baader served as the organizational and intellectual nucleus of these groups.
Risk and Status: Within a radical group, high-risk behavior, if successful, offers a pathway to status insofar as it becomes re-construed as bravery and commitment to the cause. As such, violence or other radical activity provides a pathway to success, social acceptance, and physical rewards that might otherwise be out of reach.
"Disproportionate involvement in risk taking and status seeking is particularly true of those young men who come from disadvantaged family backgrounds, have lower IQ levels, are of lower socioeconomic status, and who therefore have less opportunity to succeed in society along a traditional career path. These young men are more likely to be involved in gang activity, violent crime, and other high-risk behavior."
Unfreezing: Loss of social connection can open an individual to new ideas and a new identity that may include political radicalization. Isolated from friends, family, or other basic needs, individuals may begin to associate with unlike parties, to include political, religious, or cultural radicals. This is especially noted in prison radicalization, where individuals bind together over racial, religious, and gang identity to a greater degree than in the outside world and often bring their newfound radical identity beyond prison to connect with radical organizations in the populace at large.
Group-Level Factors 
Insofar as a group is a dynamic system with a common goal or set of values it is possible that the group’s mindset as a whole can affect individuals such that those individuals become more radical.
Group Polarization: Discussion, interaction, and experience within a radical group can result in an aggregate increase in commitment to the cause, and in some cases can contribute to the formation of divergent conceptions of the group’s purpose and preferred tactics. Within a radical group, internal dynamics can contribute to the formation of different factions as a result of internal disillusionment (or, conversely, ambitions) with the group’s activities as a whole, especially when it comes to a choice between violent terrorism and nonviolent activism. The Weather Underground’s split with Students for a Democratic Society is one of many examples. The dynamics of group polarization imply that members of this larger group must either commit to one faction and demonstrate their loyalty through further radicalization, or leave the group entire.
Group Isolation: Isolation reinforces the influence of radical thinking by allowing serious and or persuasive members of the group to disproportionately define the body’s agenda. When an individual only has access to one in-group social environment, that group gains a totalizing influence over the individual - disapproval would be tantamount to social death, personal isolation, and often a lack of access to the basic services that mutual aid communities fulfill. As an isolated minority, Islamic groups in the West are especially vulnerable to this form of radicalization. Being cut off from society at large through language barriers, cultural difference, and occasionally discriminatory treatment, Muslim communities become more vulnerable to additional pathways of radicalization
Group Competition: Groups can become radicalized vis-a-vis other groups as they compete for legitimacy and prestige with the general populace. This pathway emphasizes increased radicalization in an effort to outdo other groups, whether that increase is in violence, time spent in religious ritual, economic and physical hardship endured, or all four.
Religious movements and the terrorist elements that form in their name display this characteristic. While in some cases there may be doctrinal or ethnic differences that motivate this kind of competition, its greatest outward sign is an increased demand by the group for commitment to radical actions.
Mass Radicalization 
Also called “the logic of political violence”, Jiujitsu politics is a form of asymmetrical political warfare in which radical groups act to provoke governments to crack down on the populace at large and produce domestic blowback that legitimates further violent action. The primary purpose of a radical group using this tactic is not to destroy the enemy outright, but to make the enemy strike at political and ideological moderates, such that the existing political order loses its claim on legitimacy while the radical group gains legitimacy. By destroying moderates, radical groups encourage a bifurcated society and use state's reactions to violence as a justification for further violence. Al-Qaeda's strategy of luring the West, specifically the United States, into ground wars in Islamic states that polarize the Ummah against the West while avoiding engagements that would allow the American military to draw on its technical superiority is an example of jiujitsu politics. David Kilcullen, Counterinsurgency advisor to David Petraeus during the Iraq Surge, has called this the "Accidental Guerilla" syndrome.
Hatred: In protracted conflicts the enemy is increasingly seen as less human, such that their common humanity does not readily trigger natural inhibitions against violence. This involves "essentializing" both the self and enemies as respectively good and evil entities. The Islamist use of Takfirism, or (apostasy), to justify the murder of non-radical Muslims and nonbelievers (Kafir - "pagans") is an example of this. Hannah Arendt, in The Origins of Totalitarianism outlines a similar dynamic that contributed to the ideologies of pan-slavism, Nazism, and antisemitism, where an in-group constructs an exalted self identity for political purposes and mobilizes against out-groups in order to solidify that identity. This dynamic of hatred is not unique to rightist groups. The Weathermen and Red Army Faction often characterized police officers and government officials as “pigs” worthy of death and subhuman treatment.
Martyrdom: Martyrdom implies that the person in question died for a cause or is willing to die for a cause. The symbolic impact of martyrdom varies across cultures, but within the field of radicalization the act or pursuit of martyrdom denotes the absolute value of a radical’s way of life.
Poverty: The association between radicalization and poverty is a myth. Many terrorists come from middle-class backgrounds and have university-level educations, particularly in the technical sciences and engineering. There is no statistical association between poverty and militant radicalization. As outlined above, poverty and disadvantage may incentivize joining a mutual aid organization with radical tendencies, but this does not mean that poverty proper is responsible for radicalization.
Mental Illness: though personal psychology does play a significant part in radicalization, mental illness is not a root cause of terrorism specifically or ideological radicalization broadly. Even in the case of suicide terrorism, psychological pathologies, such as sociopathy and schizophrenia are largely absent.
See also 
- Political radicalism
- Islamic extremism in the United States
- Martyrdom video
- Moderation theory
- Terrorist cell
- Terrorist network
- National Consortium for the Study of Terrorism and Responses to Terrorism
- The International Centre for the Study of Radicalisation and Political Violence
- Violent Radicalization and Homegrown Terrorism Prevention Act of 2007
- U.S. counter violent extremism strategy
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- McCauley, C., Mosalenko, S. "Mechanisms of political radicalization: Pathways towards terrorism," Terrorism and Political Violence (2008). 416
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