Are there objective criteria that we can use to discern if an act of violence constitutes terrorism, or is such labeling always a subjective and political decision? Wherein lies the boundary between domestic versus international terrori and is that a meaningful distinction to make? How do individuals get radicalized, and how do they reach the point of committing violent acts? In this chapter, we tackle these questions (and others) and the issue of terrorism in international security. There are no easy, agreed upon answers to most of them, and terrorism continues to be a highly contested and politically charged concept, while constituting a very real and pressing security threat in many countries around the world. But that is even more reason to look closely at the controversies surrounding its definition, its historical evolution and patterns, and its contemporary manifestations in the twenty-first century as well as approaches to countering terrorism and attempts at international cooperation.

The global resurgence of violent extremism punctuated by recent acts of politically motivated violence necessitates a detailed examination of the factors that contribute to the radicalization process. Here, we argue that relative deprivation, or the perception that one’s in-group is unfairly deprived of material or symbolic goods relative to other groups, often elicits support for violent extremism. Because relative deprivation theory emphasizes perceived, rather than actual, experiences of injustice, the concept helps explain why members of both structurally disadvantaged and advantaged groups sometimes turn to violent extremism – especially when they believe that their in-group cannot redress their perceived grievances through normative mechanisms (i.e., when group efficacy is low). After demonstrating that relative deprivation can foster support for extremist violence and introducing an integrative model of group-based relative deprivation and violent extremism, we propose solutions to the growing threat of radicalization including the need to (a) reduce inequality, (b) develop productive ways for the disenfranchised to establish meaning in their life, (c) foster belongingness, and (d) build inclusive democracies that provide legal means to redress real or perceived grievances. By taking such proactive measures, practitioners and policymakers can mitigate the threat of violent extremism and make the world a safer place.

This chapter examines how emotions contribute to the development of violent extremism, drawing on research into emotional drivers of violent intergroup behavior. We first introduce the concept of emotion and explain the role of cognitive appraisals of events in shaping emotions. Then, to position emotions within the context of hostile intergroup relations, we demonstrate how social identities and group processes impact emotional experience. In the main section of this chapter, we consider the roles of several discrete emotions that motivate distinct types of behaviors relevant to violent extremism. Using a broad framework of the radicalization process, we suggest that: (1) humiliation, shame, and anger in response to self- or group-relevant experiences are pertinent pre-radicalization as they create a desire to reestablish a positive self- or group-image and to restore a sense of justice; (2) contempt, disgust, and hatred, as emotions that exclude their targets from moral consideration and motivate their eradication, develop during active radicalization; and (3) positive emotions, such as love, joy, and pride, which increase commitment and motivate others, characterize the engagement stage. We draw out implications of our analysis for policymakers, stressing the importance of responding to the unfulfilled emotional needs that motivate violent extremism.

Historical records and recent events suggest that conspiracy theories and violent extremism are closely associated. However, empirical research examining this link has only recently gained momentum. The present chapter provides an overview of this fast-growing research field. We first discuss theoretical explanations of the link between conspiracy theories and violent extremism, as well as the hypothetical mechanisms underpinning it. Next, we summarize the empirical evidence so far along three main research lines: (a) evidence from radicalized groups and individuals; (b) evidence from general population studies focusing on support for, and intentions to engage in, violent extremism; (c) evidence from the general population focusing on extreme political attitudes. We conclude by formulating recommendations for policy and practice.

Previous research has underscored the significance of intergroup threat perceptions in fostering prejudice and hostility toward out-groups. Nevertheless, the degree to which different types of threats – symbolic, realistic, numerical, existential, and meta-threat – remains insufficiently explored. This chapter provides a theoretically informed review of the role of these diverse threat types and synthesizes recent empirical studies demonstrating that perceptions of threat can precipitate extreme forms of out-group hostility, including violent extremism. The evidence suggests that threat perceptions not only incite violent hostility across various cultural contexts but also provoke violent defensive reactions among both majority and minority groups aiming to protect their valued traditions, scarce resources, and societal status and to avoid the perceived dread of extinction. We further discuss how cultural narratives, media portrayals, and political rhetoric shape these threat perceptions, which may fuel the process of radicalization and lead to a spiral into violent extremism. Our objective is to present a detailed analysis that can lay the groundwork for devising strategies to alleviate perceived threats leading to violent extremism. Accordingly, we propose prevention and intervention strategies designed to diminish perceived threats and curtail their violent ramifications.

This chapter examines the effects that international military interventions and foreign military occupations have on violent extremism with a particular focus on how interventions and occupations foster psychological processes associated with radicalization and patterns of political violence. The chapter begins by providing definitions for the key terms and then surveys the main strands of literature on how international interventions and foreign occupations may provoke violent extremist responses. In particular, the chapter discusses evidence that military interventions and occupations enhance grievances and feelings of national humiliation among affected populations, prompting them to support political violence. International military interventions and occupations can also foster violent extremism by facilitating othering of foreigners, by worsening human rights standards, and by producing a strategic environment conducive to political violence. The chapter also examines how interventions and occupations may foster vicarious radicalization outside of the intervened-in or occupied country, thereby increasing the threat of political violence globally. The discussion of the literature is expanded to acknowledge that certain studies in the literature depict a relationship of greater complexity or nuance. It discusses some key limitations in the literature on international military interventions, foreign occupations, and violent extremism. Finally, it concludes with implications for scholars and practitioners.

This chapter characterizes violent extremism as an ideology, and associated communication-based or overt behavior, that protects, promotes, advances, and defines a group’s social identity, and is implicitly or actually violent. It presents a social identity theory and, primarily, an uncertainty-identity theory account of how normal social identity-based group and intergroup behaviors can become violently extreme. Social identity processes are driven by people’s motivation to (a) secure a favorable sense of self though belonging to high status groups, and (b) reduce uncertainty about themselves and who they are through identification with distinctive groups with unambiguously defined identities. In the former case, people strive to protect or improve their group’s status relative to other groups, and when moderate nonviolent strategies are continuously thwarted, they can reconfigure their group’s identity to incorporate and promote violent extremism. In the latter case, people strive to resolve feelings of self-uncertainty by identifying with distinctive groups, and when intergroup distinctiveness is blurred and their group’s social identity becomes fuzzy they are attracted to ethnocentrism, populist ideology, autocratic leaders, and ultimately violent extremism. The chapter ends by identifying warning signs of radicalization and intervention principles.

This chapter examines the complex relationship between religious fundamentalism and violent extremism, focusing on the socio-cognitive processes involved in radicalization. In the central part of our analysis, we explore how religious fundamentalism may contribute to violent extremism. Our investigation reveals that the relationship between these two variables is mediated by some group-related factors and ideologies (e.g., out-group hostility, perceived superiority, collective narcissism, ideological extremism, and extremist networks). Importantly, religious fundamentalism does not always lead to violent extremism; it is moderated by some situational and contextual factors (e.g., perceived injustice, perception of threat, and group tightness). We then discuss the implications of these findings for counter-violent extremism programs. We argue for a comprehensive approach, advocating for integrated interventions that combine ideological, psychological, and economic strategies. This assertion stems from the recognition that the drivers of violent extremism extend beyond religious narratives to include psychological factors and subjective and economic deprivation. As such, we caution against an approach that disregard nonideological aspects, as it may weaken the effectiveness of interventions.

The role of poverty in violent extremism is best explained by moving away from reductionism and adopting a “from societies to cells” perspective. We explain terrorism, an important kind of violent extremism, by using the metaphor of a staircase to terrorism, which proposes the conditions in which there is an increased probability of individuals moving up the staircase, and eventually participating in terrorist actions on the final floor. Each floor of the staircase is characterized by particular psychological processes, but common to all these experiences is the primacy of subjectivity. While actual material conditions do not explain individual propensities to climb up the staircase to terrorism, feelings of relative deprivation and injustice increase the probability of this action. Although social class and poverty do not explain individuals moving up the staircase, they do influence the location of terrorist specializations on different levels of the staircase. Terrorist specializations have been ignored, but they are of vital practical importance. Nine different terrorist specializations are identified, and a schematic representation is presented, locating the specializations on the staircase to terrorism. Implications for policymakers and practitioners are discussed.

This chapter explores the multifaceted role of gender within extremist ideologies and examines manifestations of masculinity, femininity, and misogyny in various extremist contexts. It shows how different scholarly approaches explain the ways in which gendered narratives shape recruitment, radicalization, and participation in extremist activities. Different explanations of male violence emphasizing the sociocultural construction of masculinity within extremist milieus is discussed and the notion of the “manosphere” and its subcultures like incels is introduced thereby showing how online spaces foster misogynistic ideologies that can escalate into violence. Furthermore, the roles women play within extremist groups, from active participation in violence to providing crucial support functions, are also highlighted. Finally, the implications of gender dynamics for prevention efforts are discussed. Ultimately, the chapter advocates for a nuanced understanding of gender dynamics to inform more effective prevention strategies and policymaking in the fight against violent extremism.

Terrorism, radicalization, and (violent) extremism are all contested concepts, referring to specific political labels, ideologies, and related actions. The oldest of the three is “terrorism,” which, as a term, has been around since the late eighteenth century. “Radicalization” is derived from “radicalism” which has its roots in the progressive programs of nineteenth-century political parties that fought, inter alia, for secularism and democracy. “Extremism” is a term first associated with totalitarian movements emerging in the twentieth century in the wake of the First World War. “Violent extremism” is a construct that surfaced only at the beginning of the twenty-first century, referring initially to Islamist ideologies but became subsequently extended to acts of violence by secular groups, especially those on the far right as well. The three concepts are sometimes used wrongly interchangeably, as quasi equivalents. In this chapter some of their characteristics and relationships are explained. Practical and policy implications on countering (violent) extremism, based on the opposite of extremism – moderation – are outlined at the end.

This chapter constructs five ideal types of participants who undergo quite diverse processes of joining and leaving violent extremist groups: “ideologists,” “followers,” “adventurers,” “misfits,” and “traditionalists”. These five types tend to be influenced by relatively distinct combinations of push, pull, and barrier factors. The implications of this analysis are that to prevent recruitment into and engagement in violent extremism, push and pull factors should be reduced, and barriers to participation should be reinforced. Likewise, to facilitate disengagement from violent extremism, push and pull factors should be reinforced, and barriers to disengagement and reintegration should be reduced. Importantly, to be relevant and effective, preventive interventions should be targeted to the specific type of person in question, addressing their specific drivers or needs.

This chapter explores the psychological impact of authoritarian cult involvement and the therapeutic strategies beneficial for recovery. Cults often employ intense coercive persuasion, resulting in significant psychological distress, including symptoms of dissociation, anxiety, depression, and, in some cases, psychosis. The chapter also highlights the importance of psychoeducation as a crucial component of treatment. Some fundamental psychotherapeutic approaches and strategies are briefly reviewed, calling for further research to identify the most effective interventions. There are unique challenges in treating former cult members – those born or raised in cults as well as those recruited. Extrinsic and intrinsic barriers to treatment include the availability of resources, limited understanding and appreciation of cultist phenomena among clinicians, and indoctrinated distrust of mental health professionals. The chapter concludes that while cult involvement can lead to severe psychological distress, therapeutic interventions have the potential to support recovery.

This chapter highlights the importance of military aggression by the Nazis and their allies for radicalization of violence; explains key Axis war aims in East and West and methods used to achieve them (”pacification”); exemplifies the key role of the Wehrmacht for mass killing of civilians in the Balkans and “the East”; recaps historiography on the myth of the “clean Wehrmacht” and its persistence in public perception and German family memory.

The Introduction introduces broader structural aspects: the importance of war, process development and its determinants, the differences and similarities between Axis partners concerning the “Jewish question,” the fluidity of victim groups as defined or perceived by perpetrators; the links and variations among German/Axis mass atrocities (”final solution,” “euthanasia,” “ethnic cleansing,” Soviet POWs, “pacification”). It addresses controversies over the meaning of a “perpetrator” (referring also to the multiplicity of historic manifestations, functions, and usages introduced in the volume) and approaches to “becoming perpetrators”; it introduces correlation with other (partly artificial or otherwise problematic) categories such as “bystander,” “complicity,” and “rescuer” and their constructive engagement by the chapter authors.- outlines the organization of the volume into sections, the sequence of chapters, and raises to attention some of the key points to be considered in the different contributions.

In the conclusion, we review the book’s chapters and argue that Latin America has experienced a resurgence of conservative forces in recent years. We analyze the supply and demand of a broad set of conservative alternatives, paying special attention to the processes of party-building, adaptation, and rebranding. We find that new right-wing forces often have weak organizations, but have been able to mobilize voters along noneconomic cleavages, including security, gender politics, and reproductive rights. The adoption of a highly conservative profile has allowed parties to access lower-class constituencies and mobilize mass support among them. The politicization of cultural issues, such as LGBT rights and religious identities, has contributed to polarization and the rise of populist radical right parties. These parties have flourished within the context of political and economic shocks and benefited from cultural backlashes and the crises of traditional right-wing parties. In these situations, politics becomes a zero-sum game and the stakes get higher. Democratic stability in the region is arguably at its most tenuous state since the age of military dictatorships. Interrupted presidencies have become realities in many countries over the past fifteen years, raising concerns about democratic stability and potential threats to democratic institutions.

This chapter argues that throughout history many religions have proved themselves capable of sparking and fueling hostility toward outsiders and even toward people in the same faith who are viewed as unacceptable for one reason or another. We examine recent manifestations of extremism in Christianity, Hinduism, Buddhism, Judaism, and Islam, explaining that analysts often disagree about the extent to which religious beliefs and institutions are causally important. Key terms such as religious extremism, fundamentalism, radicalization, and terrorism are defined, noting the crucial importance of maintaining a distinction between the religious extremist and the extremely religious. Though we suggest researchers face many methodological challenges, we explore a broad range of empirical studies on related topics. The chapter also reviews theory and research on why and how people become religious extremists. We further draw on the psychology of radicalization, arguing that nowadays most scholars believe that there are cognitive and behavioral processes at work. Some people may move directly to carrying out terrorist deeds without acquiring much group ideology or religious belief.

Radicalization is most often seen as a gradual process that may or may not lead to radical or extreme behaviors such as terrorism. Theories on the radicalization process often highlight the potential role of social exclusion in the propensity for radicalization. We here present some of the major radicalization theories and discuss exclusion as a common denominator that could trigger a radicalization process. We then describe the research on personality and individual differences in relation to radicalization briefly, before discussing individual differences that are connected to exclusion in more depth. We go through the available empirical evidence supporting the notion that some individual level differences, such as rejection sensitivity, could moderate the effect of exclusion on radicalization. We further discuss other potential individual differences that relate to exclusion such as need to belong and entitlement.