Extremism has recently been described as one of the most pressing problems in contemporary society (Reference Littler and LeeLitter & Lee, 2023). The burst of extremism in today’s world has happened as the hodgepodge of different ideologies replaced the hegemonic ideological blocks of the Cold War (Reference UgarrizaUgarriza, 2009) and the rise of digital technologies catalyzed this change (Reference Littler and LeeLitter & Lee, 2020). In order to propose policies or interventions to reduce or eliminate extremism, it is necessary to understand its causes. What is clear is that extremism results from a multitude of causes, not just one. In this volume, we will focus on one specific contributor which has received relatively little attention in the past: social exclusion.
Social exclusion – being kept apart from others physically or emotionally – is a powerful event per se. It is known from previous research that social exclusion can be an extremely painful experience associated with threats to fundamental human needs like control and meaningful existence (see Reference WilliamsWilliams, 2009). That extremism can be triggered as a result from this threatening event does not seem implausible. At the same time, social exclusion is very common. A diary study, for example, recorded about an ostracism episode a day for the average person (Reference Nezlek, Wesselmann, Wheeler and WilliamsNezlek et al., 2012), and other research also shows that exclusion is something we all experience (Reference Bernstein, Neubauer, Benfield, Potter and SmythBernstein et al., 2021). Because of this fact alone, it should not be assumed that every excluded person will become extremized. Instead, exclusion seems to be one ingredient in a lethal cocktail that contributes to the likelihood of extremism. Thus, moderators are likely to be at work, driving the connection between exclusion and extremism in certain constellations.
To explore the exclusion–extremism link in depth and gather empirical evidence, this volume will provide an overview of the existing body of research for the first time. The book is organized into three parts, spanning the core effect, underlying mechanisms, and associated concepts.
In Part I, we look at the basic link between exclusion and extremism. Hales, Wood and Williams (Chapter 1) review the temporal need-threat model of ostracism and apply it to the question of how ostracism could lead to extremism: Various needs that are threatened by ostracism could be met through extreme groups. They also examine empirical investigations of this possibility and consider whether participating in extreme groups might lead to further ostracism. Renström and Bäck (Chapter 2) address exclusion and radicalization, and here specifically the role of individual differences. They show that exclusion-related traits such as rejection sensitivity and need to belong are relevant moderators of the relationship between exclusion and radicalization. Pfundmair (Chapter 3) focuses on terrorism, the violent endpoint of radicalization that will not occur in every case of radicalization but is associated with the most serious consequences. She presents theories and findings that outline how exclusion and terrorism are linked. The remaining chapters of Part I look at two special cases of extremism and how they relate to exclusion: White extremism and extremism among incels. Graupmann and Wesselmann (Chapter 4) examine how perceived threats of marginalized status among White individuals has led to White extremism. They emphasize the role of social identity and the self in understanding the psychology behind this process, and through this lens, they consider possible productive ways to promote more healthy racial identity. Rousis and Swann (Chapter 5) deal with incels, the so-called involuntary celibates, men who aspire to romantic or sexual partners but fail to obtain them. They outline their radicalization processes, including the role of exclusion.
In Part II, we explore factors that drive the exclusion–extremism link. The first chapters deal with important mediators of the link between exclusion and extremism. Ellenberg and Kruglanski (Chapter 6) examine how extremism could arise from a motivational imbalance. They examine how a quest for significance – which could be activated by exclusion – can motivate individuals to make extreme sacrifices and engage in otherwise unacceptable actions to fulfill that need. Wagoner and Hogg (Chapter 7) take a detailed look at the influence of identity uncertainty, that is, the feeling of being uncertain about oneself and one’s own identity, how this feeling can be potentiated under exclusion and contribute to joining extremist groups. Doosje, Feddes, and Mann (Chapter 8), on the other hand, address the group as an important driver of extremism. They show how social identity processes – processes known to be elevated under exclusion – promote nonnormative developments. The remaining chapters of Part II look at relevant moderators of the link between exclusion and extremism. Möring and Pratto (Chapter 9) elaborate status indignity, i.e., the resentment that one’s own group is perceived to be lower than it deserves and that can be linked to perceptions of social exclusion. Chinchilla and Gómez (Chapter 10) investigate how these processes could play out across different cultural and psychological contexts. They examine in particular the process of identity fusion, in which people become profoundly identified with a group or ideology, and how this could motivate fighting on its behalf.
The final part of the book, Part III, explores related concepts that are relevant to better understand the link between exclusion and extremism. Kowalski and Leary (Chapter 11) explore how people react to interpersonal rejection and examine five forms of extreme aggression that sometimes result (school and mass shootings, intimate partner violence, hazing, retaliative suicide, and cyberbullying). Riva and Marinucci (Chapter 12) address how chronic exclusion, which has already led to resignation, can fuel the radicalization process. And, finally, Imhoff (Chapter 13) presents an overview of the psychology of conspiracy beliefs and examines the evidence for a possible link between social exclusion experiences and increased belief in conspiracies.
All in all, the findings presented in this volume can be integrated into a comprehensive framework (see Figure 0.1). According to this, extremism – i.e., the development into a norm deviation – arises from certain antecedents, for example, in the case of terrorist radicalization, a cognitive opening for radical ideas, and ends with certain outcomes. It should be borne in mind that a violent endpoint like terrorism is a possible outcome; however, it is not inevitable. Most people who embrace extreme or even extremist ideas act accordingly only in the rarest of cases (Reference BorumBorum, 2011). Both the antecedents for and a progression into extremism are driven by a wide variety of factors. One of these factors is social exclusion. The pathway from exclusion to extremism is likely not direct, but occurs indirectly through the consequences of exclusion – such as an increased search for significance, the avoidance of uncertainty, or intensified group processes. Moreover, the link between exclusion and extremism is made more likely by certain boosters – for example, increased rejection sensitivity, a sense of status indignity, or a particular cultural context.
In gathering together a collection of chapters written by leading social psychologists, we not only aim to shed further light on the theoretical concepts of extremism and social exclusion but would also like to contribute to the development of preventive and interventive measures that could take a potent starting point in the promotion of social inclusion. Because, as Jesse Jackson said, “inclusion is not a matter of political correctness, it is the key to growth” (Reference DanielsDaniels, 2007).
