John G Horgan

Georgia State University | GSU · Department of Psychology

Many high-profile societal problems involve an individual or group repeatedly attacking another - from child-parent disputes, sexual violence against women, civil unrest, violent conflicts and acts of terror, to current cyber-attacks on national infrastructure and ultrafast cyber-trades attacking stockholders. There is an urgent need to quantify th...

Attempts to profile terrorists have failed resoundingly, leaving behind a poor (and unfair) impression of the potential for a sound psychological contribution to understanding the terrorist. However, recent work in the area has delivered promising and exciting starting points for a conceptual development in understanding the psychological process a...

In social science research on terrorism, there is a continued lack of individual-level, data-driven evidence to test hypotheses, build reliable case studies, and support the emergence of new theories about the psychological process in the development of the terrorist. To help redress this deficiency, this article calls for explicit discussion of re...

Violent extremism (VE; i.e., terrorism) is an issue of increasing relevance in school settings. Worldwide, terrorist actors have increasingly targeted youth in schools both for victimization via attacks as well for radicalization and recruitment to their ranks. Although violent extremism as an ideologically motivated act can be distinguished from m...

Since its inception as a modern and evolving discipline, psychology has been concerned with issues of human security. This think piece offers an initial conceptualisation of human security as a broad security concept that encompasses a range of interrelated dimensions that have been responded to by different sub-disciplinary domains within psycholo...

Terrorism is a diverse form of violence, and terrorists are also diverse in terms of their characteristics, motivations for participating, and the roles they take within terrorism. Though terrorism studies have mostly focused on developing broad theories of why people participate in terrorism in general, some scholars have advocated for research th...

In Western democracies, Muslim converts are overrepresented in Islamist terrorism compared to born-and-raised Muslims. Consequently, researchers have begun to consider how the process of conversion to Islam might influence participation in terrorism, yet empirical data are lacking. To explore these connections, the present study measured the conver...

This article adds to the growth in data‐driven analyses seeking to compare samples of violent extremists with other violent populations of interest. While lone‐actor terrorists and public mass murderers are frequently treated as distinct offender types, both engage (or attempt to engage) in largely public and highly publicized acts of violence and...

In popular culture, converts are thought to be more zealous than those brought up in the same religion (i.e., nonconverts). This is particularly relevant in the context of Islam in Western countries, where outsiders sometimes view conversion to Islam as a harbinger of religious violence rather than a legitimate expression of a search for meaning an...

A response to Marc Sageman's article "On Recidivism"

Perceived peer attitudes (PPA) often influence young men’s violent attitudes and behaviors, although people with higher social network diversity (SND) are less likely to adopt their close peers’ attitudes. There is currently limited research examining this role of peer networks in the development of violent extremism (VE). Consequently, the current...

Muslim converts are overrepresented in Islamist terrorism compared to non-convert Muslims – Why? To explore possible explanations, we probed aspects of radicalism and Islamic religiousness within relevant populations. Specifically, we surveyed 356 American Muslim adults, of which 177 were self-identified converts, with the Activism and Radicalism I...

This article responds to Clark McCauley's commentary on our Attitudes-Behaviors Corrective (ABC) Model of Violent Extremism, in which he contrasts our framework with his own two pyramids model (developed with Sophia Moskalenko). In particular, we focus on further distinguishing between the "core" and "optional extra" elements of our ABC model, elab...

Research suggests that lone-actor terrorists and mass murderers may be better conceptualized as lone-actor grievance-fueled violence (LAGFV) offenders, rather than as distinct types. The present study sought to examine the extent to which these offenders could (or could not) be disaggregated along dimensions relevant to the threat assessment of bot...

Research pays little attention to the diverse roles individuals hold within terrorism. This limits our understanding of the varied experiences of the terrorist and their implications. This study examines how a terrorist’s role(s) influence the likelihood of and reasons for disengagement. Using data from autobiographies and in-person interviews with...

Muslim converts tend to be overrepresented in terrorist activity compared to fellow nonconvert Muslims. However, due to the low base rate of terrorism activity, there is a significant risk that this overrepresentation is a “false positive.” We therefore tested the prevalence of far more common, but potentially antecedent, cognitions to terrorism—ac...

Progress in understanding and responding to terrorism and violent extremism has continued to stall in part because we often fail to adequately conceptualize the problem. Perhaps most notably, much of our terminology (for instance, “radicalization”) and many variants of our existing models and analogies (including conveyor belts, staircases and pyra...

An enduring bugbear in the study of terrorism is conceptualizing the role ideology plays for individuals involved in such activities. Explanations range from presenting ideology as a key determinant to those who argue that it is often barely relevant at all. In this article we seek to reconcile competing notions of ideology in the emergence of terr...

Research pays little attention to the diverse roles individuals hold within terrorism. This limits our understanding of the varied experiences of the terrorist and their implications. This study examines how a terrorist’s role(s) influence the likelihood of and reasons for disengagement. Using data from autobiographies and in-person interviews with...

Recent interest in terrorist risk assessment and rehabilitation reveals the likelihood and risk factors for terrorist reengagement and recidivism are poorly understood. Informed by advances in criminology, this study develops a series of theoretical starting points and hypotheses. We test our hypotheses using data on 185 terrorist engagement events...

Although much is now known about religious conversion in general, there is still relatively little known about how and why conversion to Islam takes place in the United States. Expanding on previous research, the current study examines types of conversions among United States Muslim converts. Seventy-three converts to Islam, all United States resid...

Religious conversion is the process by which a person commits to the beliefs of a new religious tradition and shifts away from their previously held religious beliefs (Stark and Finke 2000). Religious conversion and its mechanisms have been studied for millennia (Zinnbauer and Pargament in Journal for the Scientific Study of Religion, 37(1), 161–18...

Gatekeepers are those in a position to recognize, in others, potentially problematic presenting issues, and who are willing and able to connect those persons to relevant service providers. In the domain of violence prevention, they represent a network of those who can serve as ‘first responders’ with respect to helping those in need. Therefore, it...

Scholars have urged a shift in research on mass murder from the creation of typologies to theoretically rich, data-driven comparative examinations of the phenomenon. We seek to redress such calls in two ways. First, we analyze a unique sample of public mass murderers through the multistage explanatory model of cumulative strain theory. Second, we u...

Utilizing a sample drawn to represent the general U.S. population, the present study experimentally tested whether a call-center’s disclaimer regarding limits to caller confidentiality (i.e., that operators would be required to refer calls to law enforcement if callers were to discuss anyone who was a danger to themselves or others) affected disclo...

Not unlike early criminology, terrorism research currently ignores or minimizes the issue of behavioral variation between and across individuals convicted of terrorist crimes. Consequently, our understanding of what constitutes involvement per se, and what involvement means for those who participate, remains limited. In turn, our ability to provide...

The litany of public mass murders, from Aurora, Newtown, Charleston, Las Vegas, and Parkland to less well-known incidents that occur yearly, has focused national attention on federally mandated mental health background checks of prospective gun purchasers. The call has been to put more gun-disqualifying mental health records into the Instant Crimin...

The idea that identifiable behaviors presage violence is a core concept in the threat assessment literature. Especially meaningful from an operational perspective is “leakage” which concerns whether offenders intentionally or unintentionally reveal insights into their thoughts or feelings that suggest impending targeted violence. Previous research...

What would motivate someone to willingly enter frontline combat against the Islamic State? New research finds three compelling reasons: commitment to some sacred values, forsaking commitment to their own kin for those same values, and belief in the spiritual strength of one’s own group compared to that of the enemy.

Islamic State in Iraq and Syria (ISIS) online recruitment has been the subject of considerable interest by journalists and technology writers, but there has been no scholarly work to date exploring ISIS Telegram channels and chat rooms. Telegram has played an important role in recruitment and coordination in recent ISIS/terror attacks in Europe. Fu...

Historically, terrorists have overwhelmingly been young adults. Direct involvement in terrorist attacks is associated with people in their 20s and 30s, with those in leadership positions slightly older (30s and 40s). The composition of the so-called Islamic State, however, defies the idea of even a generic demographic profile. While the Islamic Sta...

A deeper understanding of terrorist disengagement offers important insights for policymakers and practitioners seeking to persuade individuals to leave these groups. Current research highlights the importance of certain “push” and “pull” factors in explaining disengagement. However, such studies tell us very little about the relative frequencies at...

Despite the extraordinary social and political consequences often associated with terrorist violence, as well as our responses to it, psychological research on terrorist behavior is conspicuously underdeveloped. This special issue of American Psychologist presents a series of articles that showcase new conceptual, theoretical, and empirical advance...

Recent interest in terrorist risk assessment and rehabilitation reveals the causes of terrorist recidivism are poorly understood. Informed by advances in criminology, this study develops a series of theoretical starting points and hypotheses about the factors associated with terrorist re-engagement and recidivism. We test our hypotheses using data...

This paper applies the distance-to-crime approach to the case of Improvised Explosive Device (IED) and shooting attacks conducted by the Provisional Irish Republican Army (PIRA) during the Northern Ireland conflict, 1970–1998. The aim is to (a) measure the typical ‘distance to crime’ (b) detect whether a distance-decay effect is noticeable and (c)...

Research Summary Public interest and policy debates surrounding the role of the Internet in terrorist activities is increasing. Criminology has said very little on the matter. By using a unique data set of 223 convicted United Kingdom–based terrorists, this article focuses on how they used the Internet in the commission of their crimes. As most sam...

This paper outlines the socio-demographic, developmental, antecedent attack, attack preparation and commission properties of 115 mass murderers between 1990 and 2014. The results indicate that mass murderer attacks are usually the culmination of a complex mix of personal, political and social drivers that crystalize at the same time to drive the in...

This paper outlines the sociodemographic, developmental, antecedent attack, attack preparation, and commission properties of 115 mass murderers between 1990 and 2014. The results indicate that mass murderer attacks are usually the culmination of a complex mix of personal, political, and social drivers that crystalize at the same time to drive the i...

A burgeoning literature exists on indicators associated with lone-actor terrorism, spree shooters, mass murders and other forms of targeted violence. Such studies of low- likelihood, high-impact crimes largely suffer from 2 interrelated problems: low base rates and long observational periods. These studies largely fail to consider whether risk fact...

Using the Islamic State (ISIS) as a case study, we explore the process by which children evolve from novice recruits to fully-fledged members of a violent extremist movement. From currently available data, we propose six stages of child socialization to ISIS – Seduction, Schooling, Selection, Subjugation, Specialization, and Stationing. Furthermore...

The study found little to distinguish these two violent offender types in their socio-demographic profiles. Their behaviors, on the other hand, differed significantly in the degree to which they had interacted with co-conspirators, their antecedent event behaviors, and the degree to which they lacked information prior to their attack. Unlike lone t...

Also available here: https://www.ncjrs.gov/pdffiles1/nij/grants/249936.pdf

A popular stereotype is that women will play more minor roles than men as environments become more dangerous and aggressive. Our analysis of new longitudinal data sets from offline and online operational networks [for example, ISIS (Islamic State)] shows that although men dominate numerically, women emerge with superior network connectivity that ca...

Counterterrorism strategies involving the killing of terrorists are a prominently used but controversial practice. Proponents argue that such strategies are useful tools for reducing terrorist activity, while critics question their effectiveness. This article provides empirical insight into this strategy by conducting a series of negative binomial...

The centenary of the 1916 Rising marks a time of peaceful commemoration, across the island of Ireland. However, several violent dissident republican groups wish to seize it as an opportunity to re-organise in an attempt to bolster and legitimise their sustained paramilitary campaign. This study seeks to provide a greater understanding of how this p...

Involvement in terrorism has traditionally been discussed in relatively simplistic ways with little effort spent on developing a deeper understanding of what involvement actually entails, and how it differs from person to person. In this paper, we present the results of a three-year project focused on 183 individuals associated with the global jiha...

This article presents a case study of one individual's trajectory through violent right-wing extremism in the USA. Drawing on an in-depth in-person interview conducted with ‘Sarah', we trace the influences affecting the nature and extent of her involvement, engagement and disengagement. We focus on delineating the complexity of Sarah's disengagemen...

Refugee studies have examined both resilience and adverse outcomes, but no research has examined how different outcomes co-occur or are distinct, and the social-contextual factors that give rise to these diverse outcomes. The current study begins to address this gap by using latent profile analysis to examine the ways in which delinquency, gang inv...

Despite widespread recognition that the use of counternarratives is an important strategic component of countering violent extremism, to date, there are no comprehensive guidelines on how to develop and distribute counternarratives to effectively reduce support for terrorism. To redress this, we offer communication and psychology theory-based proce...

Who would be the first to notice, and able to intervene, with individuals considering acts of violent extremism? Study 1 found evidence that those best positioned to notice early signs of individuals considering acts of violent extremism might be those individuals’ friends: perhaps more so than school counselors, clergy, or family members. Furtherm...

Although research on violent extremism traditionally focuses on why individuals become involved in terrorism, recent efforts have started to tackle the question of why individuals leave terrorist groups. Research on terrorist dis- engagement, however, remains conceptually and theoretically underdeveloped. In an effort to enhance our under- standing...

This article examines key setting events and personal factors that are associated with support for either non-violent activism or violent activism among Somali refugee young adults in the United States. Specifically, this article examines the associations of trauma, stress, symptoms of posttraumatic stress disorder (PTSD), posttraumatic growth (PTG...

Using stochastic methods we illustrate that the Provisional Irish Republican Army's (PIRA) network is clustered along three primary dimensions: (a) brigade affiliation, (b) whether the member participated in violent activities, and (c) task/role within PIRA. While most brigades tended to foster connections within the brigade (that is, “closure”), t...

This paper presents an analysis of the Provisional Irish Republican Army's (PIRA) brigade level behavior during the Northern Ireland Conflict (1970-1998) and identifies the organizational factors that impact a brigade's lethality as measured via terrorist attacks. Key independent variables include levels of technical expertise, cadre age, counter-t...

This paper presents an analysis of the Provisional Irish Republican Army's (PIRA) brigade level behavior during the Northern Ireland Conflict (1970-1998) and identifies the organizational factors that impact a brigade's lethality as measured via terrorist attacks. Key independent variables include levels of technical expertise, cadre age, counter-t...

This article analyzes the sociodemographic network characteristics and antecedent behaviors of 119 lone-actor terrorists. This marks a departure from existing analyses by largely focusing upon behavioral aspects of each offender. This article also examines whether lone-actor terrorists differ based on their ideologies or network connectivity. The a...

This article presents an empirical analysis of a unique dataset of 1240 former members of the Provisional Irish Republican Army (PIRA). We highlight the shifting sociological and operational profile of PIRA's cadre, and highlight these dynamics in conjunction with primary PIRA documents and secondary interview sources. The effect of these changes i...

Modeling behavior related to radicalization and terrorism is extremely complex. Consequently, the development of computational approaches to support an understanding of behavioral underpinnings that lead up to radicalization is a significant undertaking and necessitates either a decomposition of behavioral activity into smaller, more manageable beh...

Terrorist organizations are both imitative and innovative in character. While the drivers of imitation have been extensively modeled using concepts such as contagion and diffusion, creativity and innovation remain relatively underdeveloped ideas in the context of terrorist behavior. This article seeks to redress this deficiency by presenting a conc...

Terrorism has returned to Northern Ireland. In the years after the Real IRA bombing of Omagh in 1998, violent Republican groups have re-emerged as a major security threat to a region that has for too long been denied peace, stability, and prosperity. Those responsible have many names. They are dissidents, breakaways, splinter factions, spoilers, "r...

Despite the growth of terrorism literature in the aftermath of the 9/11 attacks, there remain several methodological challenges to studying certain aspects of terrorism. This is perhaps most evident in attempts to uncover the attitudes, motivations, and intentions of individuals engaged in violent extremism and how they are sometimes expressed in p...

Social networks are said to facilitate learning and adaptation by providing the connections through which network nodes (or agents) share information and experience. Yet, our understanding of how this process unfolds in real-world networks remains underdeveloped. This paper explores this gap through a case study of al-Muhajiroun, an activist networ...

Recent, and welcome, interest in the subject of terrorist disengagement and de-radicalization has revealed that the causes of terrorist recidivism are poorly understood. Studies of terrorist recidivism are virtually non-existent, which is surprising given that most critiques of terrorist de-radicalization programs are anchored in debates about the...

The conceptualization of terrorist groups as networks is increasingly common to terrorism studies, although methods of analysis vary widely. Contrary to common understandings, the integration of computational and qualitative methods is possible even with limited (small-n) data. The triangulation of different methods can produce insights overlooked...

Modelling behaviour related to the perpetration of improvised explosive devices is extremely complex. Behavioural aspects range from those who create a plan to those who gather supplies for developing the devices to those who passively look the other way. Developing computational approaches to understanding such behaviour necessitates either a deco...

Since the advent of the Good Friday peace agreement, violence associated with dissident Irish Republican groups continues to present major security challenges. While there has not been a tragedy on the scale of the 1998 Omagh bombing, the level of violent dissident Republican (VDR) activity has risen steadily in frequency since then, and in 2010 re...

This research note provides a descriptive content analysis of contemporary definitions of improvised explosive device (IED) before offering a systematic and comprehensive alternative definition. The analysis of existing definitions identifies significant differences across a number of dimensions, including whether IEDs can be characterized in terms...

The chapter discusses vulnerabilities of al-qa’ida related to ideology, framing, strategic objectives and decision making, and resource mobilization efforts, all of which can be exploited.

There is widespread agreement among scholars and practitioners that terrorism scholarship suffers from a lack of primary-source field research [1]. The absence of solid ethnographic research has yielded studies that suffer from a lack of rigorous analysis and often result in opinion masquerading as analysis. This dearth of field work stems in part...

This article seeks to answer the question of who were the women of the Provisional IRA and to assess any demographic patterns of PIRA involvement. We use a multi-method approach to describe the many roles and functions of female members of the Provisional Irish Republican Army from 1970 to 1998. Drawing on a sample of 61 convicted or deceased PIRA...