Blurred Boundaries of Lone-Actor Targeted Violence: Similarities in the Genesis and Performance of Terrorist Attacks and School Shootings

Abstract

Over the past 5 years, Europe has witnessed an increasing number of attacks by “lone actors,” whose definition and classification presents challenges to the existing premises of violence research. These cases appear to combine elements from both rampage killings (school shootings) and terrorism. Research has to date treated school shootings and lone-actor terrorism as distinct phenomena, although no clear and unequivocal definitions have been formulated for either. In terms of execution and developmental path, school shooters and lone-actor terrorists appear to have a great deal more in common than previously thought. Against the background of the current state of research, we derive hypotheses about the differences and similarities in the genesis of both phenomena. In relationship to execution, this applies to the planned mode of assassination and the communicative significance attached to both phenomena. In connection with the development path, we find that similar processes of progressive cognitive transformation (toward a polarized and violent interpretative framework) occur in a context of experienced grievances and crises, whereby both groups tend to exhibit functional processing of reality. Processes of identification with biographically and culturally compatible worldviews and interpretative frameworks lead to a redefinition of the perpetrator's self-concept, and in turn to cognitive escalation and changes in behavior. The path toward violent action is supported by social mechanisms arising out of the necessity to keep this cognitive and behavioral escalation process secret. Finally, similar trigger events are observed for both phenomena. In this context, we describe school shootings and acts of terrorism as demonstrative targeted violence.

Introduction

Over the past 5 years Europe has witnessed an increasing number of attacks by “lone actors,” whose definition and classification presents challenges to the existing premises of violence research. These cases appear to combine elements from both rampage killings (school shootings) and terrorism. The events of August 26, 2015 at Smith Lake, Virginia, are paradigmatic: During a live television broadcast, former reporter Vester Lee F. shot two ex-colleagues. He filmed the homicide using an action camcorder and disseminated the video footage in social networks. In addition, he faxed a prepared statement to the TV station, his former employer. It refers to the Virginia Tech Shooter Cho S. and the Columbine shooters Eric H. and Dylan K. As his motive, he named personal experience of workplace bullying and revenge for the Charleston massacre of June 17, 2015, where a 21-year-old gunman shot dead nine Black Americans in a church (Shear et al. 2015).¹

Research has to date treated school shootings and lone-actor terrorism as distinct phenomena, although no clear and unequivocal definitions have been formulated for either. School shootings (also rampage shootings) are generally understood as targeted attacks committed by (former) school students, where the school is deliberately selected as the location and lethal weapons are used with the intention to kill. They are driven by personal motives associated with the school context and normally understood as personal revenge for experiences of humiliation (e.g., Bondü et al. 2011; Scheithauer and Bondü, 2011; Vossekuil et al. 2004). The term terrorism, on the contrary, defines acts of violence directed against a political or societal order and embedded in a communication strategy (Crenshaw 1981)². Terrorism is expected to be much more embedded in terrorist organization.

The differences between the two phenomena are, according to the current state of research, found in the different locations targeted and above all in individual and social motives: tending to be personal in the case of school shooters, political/ideological, or religious in the case of terrorist violence (Capellan 2015; Lankford 2013; Malkki 2016). They are each also associated with different research traditions, exhibiting few points of contact to date. Only most recently, following a spike in lone-actor terrorist attacks, has a discussion concerning the similarities begun, with a growing number of comparative studies now conducted.

First Comparative Studies of School Shootings and Terrorist Attacks

The first comparison of school shootings and terrorist incidents was conducted by Lankford and Hakim (2011), who compared American school shooters with Palestinian suicide bombers. Their study is based on the observation that both groups are homicidal-suicidal. Lankford and Hakim criticize the general dichotomy that regards school shooters as psychologically unstable, but suicide bombers as extremist but rational actors. They argue that the differences between the two groups are cultural rather than personal in nature. Lankford an Hakim find strong similarities in terms of psychological constitution and motivation. The perpetrators share many common characteristics, such as a highly troubled childhood, relative deprivation, and low self-esteem. In both cases, personal crises form the starting point for the turn to violence, with the underlying motive of avenging injustice, and also acquiring fame and repute.

As the starting point for their comparative analysis of school shooters and politically motivated attackers, McCauley and colleagues (2013) note that in both cases the perpetrators plan their actions in advance, usually act alone, and draw their motivation more from emotional/social than material or instrumental needs. They find that both groups exhibit high levels of mental health issues. The biographies in both groups are characterized by depression, despair, and suicidal tendencies. McCauley and Moskalenko find significant differences in relationship to age and marital status at the time of the crime: Politically motivated attackers were considerably older and more likely to be married.

Malkki (2014) also argues that elements of political communication are inherent to certain school shootings, above all from the perspective of the perpetrators themselves. She identifies shared political elements in 28 school shootings in Europe, the United States, and Canada between 1999 and 2011. Malkki distinguishes three types: cases with open political communication (type 1), cases with references to earlier shooters (type 2), and isolated cases (type 3). In terms of the motivational structure, both type 1 and type 2 appear comparable with acts of terrorism, with the perpetrators' actions orientated on cultural scripts such as the “revolution of the dispossessed” and legitimized through ideological elements.³

Sandberg and colleagues (2014) approach the connection between the two phenomena from the terrorism end. Their study of the writings of Anders B., who carried out the July 2011 Norway attacks in Oslo and Utøya, shows that the attacker was influenced not only by the rhetoric of right-wing Islamophobic groups but also by the cultural script of school shootings. The execution of his attack on the Workers' Youth League summer camp on the island of Utøya and the developments leading up to it thus demonstrate strong parallels with school shootings. In advance of the attack, B. withdrew almost completely and restricted his social life to the online context. His preparations for the attacks were comprehensive, and he drafted numerous statements, in which—like various school shooters before him—he justified his actions and presented himself as the defender of European culture.

Research Question

Studies conducted to date have already described numerous similarities between school shootings and lone-actor terrorism; but no systematic comparison of execution and the developmental pathways has yet been conducted. In the following, we therefore formulate questions and theses on fundamental similarities—and possible differences—between the two phenomena in relationship to execution and development path. We focus here on the social mechanisms that influence the developmental path and ultimately also the execution of attacks, concentrating in particular on the following questions:

What phenotypical similarities and differences in execution are observed between school shootings and acts of terrorism?

Which processes and mechanisms are associated with the initiation, consolidation or execution of a specific type of attack?

We base our arguments on findings from our own research of a German sample of school shootings and terrorist attacks, as well as the international case studies and research literature on both phenomena. Within the interdisciplinary project TARGET (Act and Case Analyses of Expressive Violence), funded by the German Federal Ministry of Education and Research (BMBF) from 2013 to 2016⁴, we conducted comparative case studies of school shootings, terrorist attacks, and attack planning, and other multiple homicides by young people in Germany between 2000 and 2012, with the aim of analyzing the specificity of multiple homicides. This project was notable for its combination of different perspectives on serious violence: social and developmental psychology, sociology, criminology, and forensic psychiatry.

Situations of Demonstrative Violence

Departing from other work on serious acts of targeted violence, which concentrate primarily on the genesis and motives of the attack, we begin our exploration by examining the violent act (attack) itself and working back from there to aspects of the developmental path. Many strands of violence research convey an impression that the act of violence is an automatic consequence of antecedent processes and mechanisms, but does not itself merit attention. Only in more recent approaches that explicitly address the microsociology of situations of violence (e.g., Collins 2008), is the act of violence treated as a process in its own right.

First assumption: school shootings and lone-actor terrorism exhibit diverse phenotypical similarities in terms of violent action

The overarching similarity between school shootings and lone-actor terrorist attacks is that they are (1) planned and prepared acts. The perpetrators take weapons to a targeted location with the clear intention of conducting a lethal attack. Neither the choice of place nor the sequence of events is accidental; both are planned and prepared clandestinely, to produce an asymmetry of power during the attack: while planned with the utmost precision by the perpetrator, the violence is sudden and unexpected for all others (Collins 2014; Leuschner 2016; Sofsky 1997). For both school shootings and lone-actor terrorism, we can differentiate variations in execution, in particular in relationship to the degree of physical proximity between perpetrator and victims. This observation is supported by a study of active shooter incidents in the United States between 2000 and 2013 (Federal Bureau of Investigation 2013).

Proximal attacks such as knife attacks or use of small arms represent the archetype for the lone-actor attacks under discussion here. This is the mode frequently observed in both school shootings and in acts of terrorism by small groups and lone actors. It is characteristic that direct interaction with the victims is not avoided, with perpetrators using techniques such as carrying excessive and visible weaponry and wearing facial masks, to minimize face-to-face contact and assert confrontational tension/fear and emotional dominance. According to Collins (2008), the moment where the perpetrator executes the first act sets in motion a “forward panic.” The perpetrator enters what can be pictured as an emotional tunnel, where he or she can probably only be stopped by use of force (Collins 2008).

From the perpetrator's perspective, the attack represents their last, supreme moment. Two variants of suicide are frequently observed in proximal attacks (especially in school shootings) (e.g., Robertz 2004): suicide may have been an integral component of fantasies and planning from the outset, for example, to avoid arrest and prosecution (and thus a further loss of control) or it may be spontaneous, when the perpetrator emerges from the forward panic and realizes the implications of his or her actions.

Suicide attack is relatively rarely observed in relation to lone-actor targeted violence, and more commonly associated with organized extremist groups (Mackert 2007). Since the 1980s, suicide attacks have become a global phenomenon practiced by various terrorist groups (Mackert 2007).

The defining feature of this mode of execution is that the perpetrator kills him- or herself at the same moment they kill their victims. As Collins (2014) points out, this form of violence allows the perpetrators to avoid entering into interaction with their victims and consciously experiencing the consequences of their actions. According to Collins, there is also a tactical advantage in suicide bombers pretending to be absolutely normal and harmless until the moment the vest is detonated, which demands great self-discipline. They have to keep their concentration focused on normal everyday routines. Lankford (2013) distinguishes four different types of suicide attacker according to motive; for the lone actor, context suicidality and fatalism toward powerful enemies are particularly decisive.

The third form is distance attacks (e.g., bombings, acts of sabotage, and shootings with precision weapons). As in the case of suicide attacks, direct confrontation with the victims is avoided. Concentration on the technical aspects allows perpetrators to suppress fear and tension. Today lone actors can find instructions for building and using unconventional explosive and incendiary devices widely available on the internet, including from extremist groups.⁵ Some authors argue that the Internet, with its diverse multimodal possibilities, has increasingly acquired the role of a training camp or “distance university for terrorists” (Ziercke 2016). The large number of failed attacks, however, demonstrates that this form of action demands more advanced technical expertise and logistics, which can generally only be accessed by larger groups and networks.

Second assumption: school rampage and lone-actor terrorism are expressive-demonstrative acts of violence

What all the described variants share in common is that the outburst of violence is sudden, and as such enables the perpetrator to assert tactical and emotional dominance. The escalation of violence is completely unexpected for the victims. The chaos that frequently follows the first act of violence (e.g., as people try to escape) supplies the perpetrator with emotional confirmation of his or her situational superiority.

School shootings and lone-actor terrorism generally occur in public space. As for the aspect of effective execution of the attack, (2) the locations are selected for their symbolic significance (see also Newman et al. 2004). Schools, public squares, magazine offices, concert venues, and government buildings may all be regarded as symbolic sites representing powerful societal institutions: “The ritualized gathering has a symbolic meaning—in the Durkheimian sense, it is where the group celebrates itself through communion with its sacred objects.” (Collins 2014, p. 4). Thus, the execution of the attack always also involves a demonstration of the vulnerability and destructibility of what the perpetrator regards as a powerful group or institution (Leuschner 2013).

Another similarity between most terrorist attacks and most attacks considered as school shootings, is (3) generalized or symbolic selection of victims. In other words, the perpetrator targets persons with whom they have no direct personal relationship, but who represent a social group they regard as the “enemy.”

The fourth and most important similarity, already hinted in the choice of symbolic locations and generalized victims, is that both phenomena involve a (4) communicative meaning that transcends the attack itself. The circles addressed by the violence extend far beyond the immediate physical victims. The situations of violence involved in school shootings, and terrorist attacks can best be understood as triads of perpetrator, victims, and third parties (the audience, both immediately present and via the media) (Leuschner 2016). With respect to the communicative meaning of the acts, two aspects need to be distinguished:

First, the communicative meaning can be described as an expression of personality, where the perpetrator seeks to present their own personal and/or social identity, and to generate outside recognition.

Second, the acts of violence under consideration here are directed forms of communication. The acts of violence are bound up with a message intended by the perpetrators, which they want others to share: for example, where the perpetrator draws attention to injustice, seeks to spread fear and panic, or hopes to mobilize others to do the same. The success of the act thus depends—from the perpetrator's perspective—largely on the responses of others. And if society's response defines success or failure, the perpetrators must ensure that their message is understood (Muschert and Ragnedda 2011; Waldmann 1998). For this reason, perpetrators generally seek to shape the public interpretation of their actions through “manifestos,” letters, videos, and personal writings. In this context, it would appear justified to describe school shootings and acts of terrorism as demonstrative acts of violence.⁶ “Demonstrative violence seeks to spread terror, to earn respect, to dispel boredom. It has a genuine social meaning. […] Violence in this context is self-presentation and self-commendation” (Sofsky 2002, p. 34).

Third assumption: the act of violence supplies pointers to the path to violence

Examination of these fundamental similarities in situation and execution between school shootings and terrorist attacks supplies pointers to previous processes leading up to the attack:

First, the planned style of execution suggests similarities in preparation processes and planning and acquisition of competence at violence. These are not spontaneous situational acts; the perpetrators have to plan ahead, acquire weapons, prepare messages, and so on.

Second, both school shootings and terrorist attacks are characterized by symbolic and/or generalized choice of victims. That means, in contrast to the majority of homicides, that there is generally no immediate previous personal conflict between perpetrator and victims. This points to previous processes of social categorization of outgroups and psychological distancing from them.

Third, the staging and presentation that characterizes many school shootings and terrorist attacks (in particular clothing, symbols, shouted statements) points in turn to processes of identification with groups and/or ideologies.

Fourth, the intended communication (messages, statements of responsibility, writings) involved in school shootings and acts of terrorism indicates that the perpetrator feels a need to justify his/her actions to himself/herself and others.

Developmental Paths Toward Demonstrative Violence

Taking the attack as the starting point, a number of theses can be formulated concerning the developmental path of school shootings and acts of terrorism by lone actors.

In terms of the genesis of demonstrative violence, we begin by noting that both the developmental path models for school shootings and the radicalization models describing the pathway to terrorism divide the process into steps or phases. The literatures on school shootings and terrorist radicalization both name specific mechanisms that lead individuals from one stage to the next on the path to violence. A comparison of the models not only allows us to identify developmental sequences shared by both phenomena but also isolates important distinctions that suggest particular differences between the phenomena and/or a necessity to further differentiate paths and perpetrator types within one or other.

Thesis 1: personal grievances and crises as the starting point

For both school shootings and lone-actor terrorism the models identify a phase of personal grievances and crisis marking the start of a developmental process leading to an act of violence (Böckler and Seeger 2010; Larkin 2009; Moghaddam 2005; Newman et al. 2004; Pisoiu 2013; Wiktorowicz 2005). Investigations of school shootings show that most perpetrators experienced critical life events and/or chronic stressors that can be collectively designated as “significant loss of status within the school framework” (Wieczorek 2010). The manifestations include bullying, social exclusion, and peer rejection (Leary et al. 2003; Levin and Madfis 2009; Newman et al. 2004; Sommer et al. 2014; Vossekuil et al. 2004), unfair treatment by teachers (Bondü and Scheithauer 2014a), lack of recognition in school (Robertz 2004), and academic failure with resulting loss of career prospects.

Studies of lone-actor terrorists also generally find an initially subjective dissatisfaction with social and institutional structures that grows through various experiences of crisis. Radicalization processes may be preceded by experiences of discrimination, injustice, powerlessness, and alienation, as well as socioeconomic disadvantage and relative deprivation (Khosrokhavar 2005; Roy 2004).

Walther (2014) introduces the concept of dissonance to describe the effect of the states of tension this produces. What is involved here is a subjectively experienced contradiction between a person's inner wishes and external reality, which creates a desire to change their situation (Walther 2014). If inadequacy of personal and social resources prevents resolution of the tensions, manifest existential crisis may ensue. States of dissonance may come to a head in particular where they are joined by specific accentuated personality traits or even psychopathologies.

Thesis 2: school shooters and lone-actor terrorists generally exhibit functional processing of reality

A number of studies in forensic psychiatry treat mental health as an important explanatory factor. Langman (2009), for example, emphasizes that all school shooters exhibit psychopathological abnormalities, to which their actions can be attributed. This finding recurs in other explanatory models, where in particular personality disorders, such as social behavior disorders with depressive episodes, paranoid and in particular narcissistic disorders, are regarded as causes of violence (Bannenberg 2013; Bondü and Scheithauer 2015). However, these findings must be treated with caution on account of the difficulties associated with retrospective psychiatric assessment. For example, Giebel and colleagues (2014) demonstrate in a systematic literature review that the data for the connection between manifest psychopathologies (here: clinical, psychiatric diagnoses) and rampage killings is unclear and often contradictory.

To date, there are no reliable findings postulating a relationship between psychopathological abnormalities and activity in terrorist groups. Studies do show, however, that in comparison to members of terrorist groups, psychological disorders are identified up to 13 times more frequently in lone-actor terrorists (Corner and Gill 2015; Gruenewald et al. 2013). A large proportion of lone-actor terrorists attract attention for their social problems in advance of the act (Gill et al. 2014; Meloy and Yakeley 2014; Spaaij 2010). For example, they may experience significant difficulties establishing close and intimate relationships. But a small number of exceptions aside, lone-actor terrorists also demonstrate functional processing of reality and act in a rational and organized manner (Pantucci 2011).

While manifest psychopathologies tend to be the exception, specific accentuated personality traits are frequently noted. The research on school shootings notes, as a precondition for biographical crises, a particular disposition that makes adolescents especially vulnerable to the behavior of others, for example, the aforementioned social insecurity or narcissistic personality structures. Feelings of vulnerability, distress, and anger create a need for public justice and revenge. A small number of studies in the field of terrorism also point to accentuated personality traits suspected of fostering involvement in terrorism; alongside narcissistic and psychopathic tendencies, these include egocentrism and aggression (Gottschalk and Gottschalk 2004; Merari 2010; Nedopil 2014).

Thesis 3: cultural and ideological scripts expedite identification processes

The immediate crisis is followed by an exploratory phase searching for new life concepts and alternative frames of reference. Both terrorism and school shooting research attribute particular importance to the (ideological) paradigms, to which perpetrators and perpetrator groups refer before and during the attack, upon which they orientate their presentation, and which they reproduce through their own narratives and actions. These are not only points of reference for the perpetrators to legitimize their actions but can also become a breeding ground for identification processes and copycat acts (Zick and Böckler 2015).

The structure and relevance of paradigms and worldviews

An ideological paradigm is a set of convictions, values, principles, and goals passed on culturally within particular groups. Ideologies serve the fundamental human need to avoid internal conflict and dissonance by supplying a self-contained worldview that lends meaning to the life and actions of those who subscribe to them, reduces complexity, and supports adjustments (e.g., Borum 2015). The essential core of extremist ideologies is the production of a collective idea whose profile is sharpened in particular by demarcation processes and social categorization into good (in-group) and bad (out-group) (Benford and Snow 2000). Such a logic is inherent both to the ideological narratives of extremist groups and to the public statements of many lone-actor terrorists and school shooters. Böckler and Seeger (2010) identify in the public statements of school shooters a recurring argumentation structure that exhibits many parallels to militant extremist ideologies:

Perpetrators relate negative social experiences and associated feelings of distress, powerlessness, and anger, contrasting these revelations with a new self-description, in which they present themselves as the avenger.

Perpetrators seek to attribute blame for their psychosocial condition. Most of their public statements generalize and direct public blame toward society as a whole.

The later perpetrator calls on those with a similar set of experiences to join him/her in a violent “revolution.”

Both terrorist perpetrators and school shooters thus justify their act of violence primarily in terms of their own victimhood and seek to transform their violence from sin into virtue through public condemnation of the supposed aggressors. In the context of jihadist radicalization, this logic corresponds with the cult of martyrdom.

Cultural, traditional, and biographical compatibility of relevant ideological paradigms

Extremist groups generally achieve successful mobilizations where they manage to present relevant elements of the ideology in such a way that they dovetail with the lifeworlds, values, and cultural narratives of the targeted recruits (Snow et al. 1986).

As noted by Newman and colleagues (2004), school shooters seek status-elevating resolutions for their personal grievances. Eric H. and Dylan K. systematically linked their attack at Columbine High with aesthetic elements derived from youth culture. Their cineastic staging of the attack is probably one important reason why it became an attractive script for others to emulate (Larkin 2009). Eric H. and Dylan K., similar to later school shooters after them, referred explicitly to films such as Terminator, Matrix, Natural Born Killers, Basketball Diaries, and Rage—cultural products' media models where a lone individual wreaks vengeance on society in a trail of destruction (Cullen 2009; Kiilakoski and Oksanen 2011; Larkin 2009).

Other school shooters too have often drawn inspiration from films and other aspects of pop culture. Generally, these centers are on the motifs of the underdog and the struggle between good and evil (van Brunt and Lewis 2014). In this context, the cultural idolization of the male appears to offer the perpetrators an important point of reference for individual identity formation (Kimmel and Mahler 2003).

Extremist groups, which pursue lone-actor strategies in both the right-wing and jihadist spectrums, have long been aware that adolescents and young adults represent one of the most important target groups for their agitation and work to relate to youth culture in their recruitment and mobilization. This is clearly reflected in the appropriation of modern styles and the use of corresponding youth-oriented dissemination channels. For example, one propaganda video the so-called Islamic State borrows from the visual style of the popular video game Grand Theft Auto, in which the hero steals and kills while accomplishing various missions. Islamic State begins its recruitment video with the line: “Your games which are producing from you, we do the same actions in the battlefields [sic!]!!” (Giessler 2014).

While martialistic descriptions of fighters are especially attractive to young men in personal crisis, women are generally addressed as supporters, although that should not obscure the fact that a subset of females are drawn by the warlike presentation and see themselves as warriors for a common cause (Böckler 2016). School shooting research too has observed how female perpetrators reinterpret essentially masculine scripts in the sense of a “bad femininity” (Roth et al. 2015).

Alongside elements of youth culture, historical, traditional, and cultural aspects may accompany the process of matching ideology and individual. These would include propagandistic content designed to persuade the target group that, for example, swearing allegiance to the so-called Islamic State means rediscovering one's traditional and religious roots or—to cite an example from the white supremacy movement—that the survival of the “white race” can only be defended through militant struggle: “We must secure the existence of our people and a future for white children” (Southern Poverty Law Center 2017).

Alongside such narratives emphasizing group membership and social identity and the threat they face from an enemy, others build on biographical experiences (personal experience of bullying, discrimination, etc.). This is reflected, for example, in the excessive use of the motif “ghuraba” (the strangers) in Salafist jihadist propaganda. It specifically addresses adolescents who suffer from experiences of discrimination and a feeling of not belonging. Through the propaganda, they experience a “positive reversal of exclusion as self-affirmation in combination with a feeling of superiority” (Taam et al. 2016, p. 9).

Social embedding of relevant ideological paradigms

One of the most reliable predictors of involvement in right-wing or Islamist radical milieus is contact to individuals with extremist attitudes (Bakker 2006; Sageman 2004; Wiktorowicz 2005). Contact to milieus increases the probability of radicalization for those who start to identify with attitudes (ideologies) or people from the milieus. Given that both school shooters and lone-actor terrorists are characterized by social withdrawal, social ties are established primarily through virtual media contexts.

Gill (2015) describes how the Internet generally plays an important role in preattack behavior, for example to reinforce the perpetrator's own radical thoughts, ideas, and beliefs to legitimize violent action, to disseminate propaganda, or to inform others of the imminent act of violence.

Since the advent of Web 2.0, relationship-forming on the Internet obeys similar mechanisms to offline contexts and certainly enables viable emotional contacts (Cortesi and Gasser 2015). School shooters' public statements and frames of reference are also widely discussed, disseminated, and reproduced in virtual networks, to the point of creating veritable fan groups (Böckler and Seeger 2013; Oksanen et al. 2014). Böckler and Seeger, for example, demonstrate that some of the participants in these groups share a similar psychosocial outlook with the school shooters and feel an emotional and biographical affinity. As one adolescent put it in an interview:

“I can still remember how I felt when I read Eric's diary […]. I was astonished. It was as if Eric put into words all the rage and scorn I had been unable to express myself. It was astonishing to read his words and realize that was just how I felt. I was just unable to express it myself.” (YouTube user, 19 years old, Böckler and Seeger 2010, p. 183).

The emergence of actual perpetrators from such fan groups are often been observed (Böckler and Seeger 2013).

Thesis 4: redefinition of self-concept leads to escalation of radicalization

Another escalation on the path to violence is expedited by the later perpetrator's growing identification with an ideological worldview. The radicalizing individual is increasingly motivated to interpret and consolidate their self-concept in terms of the ideology and feels growing loyalty toward the belief system and the social group advocating it. This identification—as a rule engendered through propaganda and/or social relationships—increasingly shifts the focus from individual grievances to collectively experienced injustices and their culprits (moral outrage). This mechanism, which involves a shift in focus from the personal to the social (from “I” to “we”), has found its way into a wide range of radicalization models (Borum 2011; Moghaddam 2005; Silber and Bhatt 2007).

Similar dynamics are also found in the developmental pathways of school shooters. In certain cases, later perpetrators can be observed successively altering their perceptions and interpretations of self, world, and their own (social) experiences in the course of their interest in the topic of school rampage. The more the adolescents recognize their own sentiments in the shooters' biographies, the greater the attraction of committing a similar act of violence (Robertz 2004). As with group and solo terrorism, a phase of “moral outrage” can also be identified in the case of some school shooters, where anger over the perceived moral injustice of the world merges with identification with the collective and with the subjectively experienced personal crisis (Meloy et al. 2015). Such a process is frequently expressed in the preattack statements of school shooters. The following quote from a later perpetrator is archetypal:

“Like Cho, Eric Harris, Ricky Rodriguez and others, I'm going out to make a stand for the weak and the defenseless this is for all […] those people who've been abused and mistreated and taken advantage of by this evil sick religion Christian America this is YOUR Columbine” (Matthew, J. M., 2007, cited from Osher et al., 2007).

One central question in the context of the genesis of targeted acts of violence remains the role (if any) ultimately played by ideology in the development toward violence. Is violence in the radical context learned successively as a pattern of behavior or is ideology tapped only for purposes of ex-post rationalization of a preexisting leaning toward violence? The research shows that both dynamics are found in the development paths of both school shooters and terrorists (members of groups and lone actors alike) (Borum 2013). The complexity and diversity of relevant personality and environmental factors is reflected in the very wide range of classifications of perpetrators (Endrass et al. 2015; Meloy 2011; Post 2005).

Thesis 5: clandestine planning amplifies a development toward violence

The existing research on both school shootings and lone-wolf terrorism indicates that a self-redefinition out of a previous victim role can be associated with a self-empowerment for violent action and the start of a phase where the act is increasingly thought about and clandestinely planned. This phase is characterized by an ambivalence between secret private rituals and public intimation (leakage).

Between public and clandestine

Even if the perpetrators under discussion in this study are lone actors, the process of clandestine planning reveals similar features to those described also for “clandestine groups” (Mackert 2011) and “secret societies” (Simmel 1992). Lone actors possess a “deep backstage” (Collins 2014) where their fantasies experience confirmation and recognition, upon which a further cognitive escalation and self-commitment play out, and where emotional preparation for the act occurs.

The fact of secrecy produces decisive aspects affecting escalation: Because the interaction processes with the real or imaginary peer group are hidden and clandestine, they are subject to a disinhibition mechanism that causes steadily growing polarization toward groups and individuals perceived as hostile and confirmation of the perpetrator's own convictions. This disinhibition mechanism has been described both for face-to-face interactions in clandestine groups and in the context of “online disinhibition” (Suler 2004) for interactions on the internet.

The permanent danger of discovery of the preparation measures (attack fantasies, planning, acquisition of weapons, training) and consequent sanctioning leads to the emergence of protective mechanisms within clandestine social structures in the form of hierarchies and rituals (Mackert 2011): In clandestine groups hierarchies serve to exercise strong control and pressure to conform, to exclude actions that could lead to danger for the entire group (such as betrayal). Rituals, such as illegal acts committed collectively, function as additional protective mechanisms. Functional equivalents to these group processes are observed in connection with both school shootings and lone-actor terrorism: private rituals and self-controlling behavior.

Collins (2014) describes how school shooters often create a ritualized hidden arsenal around which their fantasies and activities revolve. Their knowledge of the illegality of the arsenal and their own associated potential to kill creates a clandestine excitement that ultimately supplies the emotional energy for carrying through the attack itself. This mechanism has also been identified in lone-actor terrorists (Meloy et al. 2015). In this way, resources for the new self-concept—in the form of potentially lethal weapons—are clandestinely acquired. During this phase, ownership and handling of real weapons can itself have an escalating and urgency-producing effect where the weapons are experienced as sensually stimulating. They also symbolize the possibility of turning fantasies of power and vengeance into reality.

Leakage as potentially observable changes in behavior

Alongside secret planning and associated private rituals, however, the new self-concept is also expressed outwardly and reflected in visibly altered behavior, for which the term leakage (also leaking) has become established (Bondü and Scheithauer 2014b; Meloy and O'Toole 2011; O'Toole 1999).

International studies on school shootings (e.g., Bondü and Scheithauer 2014b; Hoffmann et al. 2009; McGee and DeBernardo 1999; Verlinden et al. 2000; Vossekuil et al. 2004) have found that in 90–100% of cases, the perpetrator threatened or announced the attack, or intimated it through various types of behavior. Such leakage can also be identified in connection with lone-actor terrorists. As Meloy and colleagues (2015) relate, especially with lone-actor terrorists, the desire for self-projection often overpowers the tactical need for discretion, where the attack planning is not subject to the discipline of a group.

In his analysis of 119 perpetrators, Gill (2015) shows that 83% had drawn attention before the attack. In 64% of cases, family members or friends actually knew that the perpetrator was planning an attack. In 58%, there was evidence of research, planning, and preparation for an attack. In almost 60% of cases, the later perpetrator wrote relevant letters, statements, or shared knowledge of his plans by other channels (Gill 2015; Meloy et al. 2015).

The explanation for the phenomenon of leakage (announcements and hints) appears to be that in interaction with persons who notice the signs or may even be explicit addressees (potential victims or bystanders) fantasy and reality become intertwined and an “imaginary space” is created, in which the perpetrator's fantasies can be shared and tested (Robertz 2004). Our analyses show that later school shooters created poems, drawings, or showed weapons they already possessed to others. These communications and the displayed personal redefinition also generate enormous pressure to carry through the attack, because any deviation from the leaked plans and the new role would be experienced as weakness and potentially interpretable as confirmation of the earlier self-definition as victim.

One could say that through leakage the perpetrator creates a “self-obligation” to carry through the attack. Of course leakage must never go as far as to create a danger of the secret attack plans actually being discovered. For this reason, we also always observe self-controlling behaviors in lone actors, such as precautionary measures, diversionary maneuvers, and deception strategies that serve to keep others from discovering the deep backstage. As such, leakage describes the perpetrator's game of hinting at the secret plans to others, while at the same time warding off those who come too close to discovering the secret—which heightens the secret excitement.

Thesis 6: concrete triggers can escalate developments toward attack

Even if the deep backstage self-obligation and escalation mechanisms described above drive developments to the point of violent action, there is no automatism. Whether an attack is actually carried out will depend inter alia on concrete triggers. Many investigations have been able to reconstruct decisive trigger events in relationship to both school shootings and acts of terrorism (Böckler & Seeger 2010; Corner and Gill 2015; Leary et al. 2003; Meloy and Gill 2016; Scheithauer and Bondü 2011). That said that trigger events may appear in very different forms:

First, events that generate pressure to act both for school shooters and lone-actor terrorists, such as events that suggest a concrete danger of discovery of attack planning, for example, where a perpetrator becomes aware that the authorities have received warnings about their plans (e.g., Della Porta 2013).

Second, especially in the case of lone-actor terrorists, retraumatizing events may reactivate earlier negatively experienced emotional states or negatively connoted self-images (e.g., victimization). So, for example, a recent slight or subjectively experienced injustice can reactivate the earlier traumatic experience of loss of status and trigger the actual intention to carry through the attack.

Beyond this, third, we must consider events in the social setting that radicalized perpetrators perceive as legitimization of their ideological beliefs and attack planning. These can include events that are experienced as a massive attack on the ingroup and its ideology, such as acts of violence, vilification, and abuse from the outgroup. Such signal events exhibit strong potential for emotional and moral outrage and as such are certainly suited to mobilizing individuals and groups to commit violence.

Finally, perpetrators may experience loss events as triggers. One example would be the end of an important relationship that previously represented a social connection outside the clandestine radical arena.

All four trigger types help the radicalized person to view the act of violence as necessary, justified, inevitable, and meaningful. The decisive concrete trigger or combination of events in a particular case can generally only be determined retrospectively. Attempts to identify generally applicable triggers for acts of violence are therefore pointless. Instead, it must be assumed that in each individual case the interaction of individual decisions, positive and negative feedback processes (e.g., social reflection, feelings of empowerment), changed perception of opportunity costs, and biographical breaks become crystallization points for dominant action patterns and paths toward violence.

The final preparations

The phase of final preparations also belongs in the context of trigger events. It can include procuring weapons and training in their use (or acquiring bomb-making equipment, constructing, and testing), logistical planning, reconnaissance of target locations, and the preparation of messages, suicide notes, and videos. The extent to which immediate preparations occur before or after trigger events differs from case to case. As already described in the discussion of the planning phase (see Thesis 5), the planning and escalation process can be accelerated where weapons are acquired and handled. In such cases, the final preparations merely involve setting the place and date and calibrating concrete aspects of implementation.

One decisive aspect of all forms of preparation is that the perpetrator must acquire at least a modicum of expertise in using violence for the attack to succeed. These include the cognitive, technical, and physical ability to handle the chosen weapons, as well as the psychological and emotional capacity to use them as intended (emotional self-control, etc.). This applies in particular to persons without previous experience committing acts of violence, where it must be assumed that a violent confrontation will create states of fear and tension (Collins 2008).

Comparison of expressive-demonstrative acts of violence reveals very clearly how different the types of expertise are and how different types of attack demand different skills: a suicide bombing demands different skills than a remote-controlled bomb, a knife attack, a sniper killing, or an attack with handguns. What this means is that physical/technical and psychological/emotional abilities have to be adapted to the type of attack and/or that preexisting abilities determine the spectrum of possible forms of attack. The influencing factors in the final preparation context are opportunity structures for acquiring particular weapons, availability of instructions (e.g., for bomb-making), and possibilities for instruction and training (e.g., training camps, computer simulations). Extremist groups usually maintain such forms of infrastructure in locations that are secret or difficult to reach.

The situation is more difficult for small clandestine groups and lone actors without extensive contacts in terrorist or criminal networks. New opportunity structures for terrorist infrastructure and possibilities for acquiring competence at violence have emerged over the past 15 years, in particular via the Internet (e.g., weapons sales on the dark web, bomb-making instructions) and computer games (especially first-person shooters)—paving the way for so-called “low-cost terrorism” (Fischer and Pelzer 2016).

Summary and Conclusions

In terms of execution and developmental path, school shooters and lone-actor terrorists appear to have a great deal more in common than previously thought. In relationship to execution, this applies to the planned mode of assassination and the communicative significance attached to both phenomena. In connection with the developemntal path, we find that similar processes of progressive cognitive transformation (toward a polarized and violent interpretative framework) occur in a context of experienced grievances and crises, whereby both groups tend to exhibit functional processing of reality.

Processes of identification with biographically and culturally compatible worldviews and interpretative frameworks lead to a redefinition of self-concept, and in turn to cognitive escalation and changes in behavior. The path toward violent action is supported by social mechanisms arising out of the necessity to keep this cognitive and behavioral escalation process secret. Finally, similar trigger events are observed for both phenomena.

In these theses on the developmental process, it is important to note that we in no way assume an automatism of escalation. Instead, such a developmental model enables clarification of the individual preconditions and social mechanisms that have to interact as a precondition for the type of lone-actor violence under discussion here to occur at all. Our intention in this connection is to make a contribution to early recognition and prevention by clarifying the preconditions for planned lethal violence by lone actors. In particular, “leakage” in the sense of observable signs and changes in behavior that accompany the process of cognitive transformation and later behavioral escalation certainly possess the potential to improve early detection and prevention without in the process resorting to escalation-promoting mechanisms.

Even if the presented similarities of violent actions and theses on developmental paths already rest on empirical evidence, the described mechanisms and their interaction as yet possess only model character and need to be empirically verified in the course of further research. There is a particular need to encourage research addressing different phenomena of violence from a comparative perspective.

Footnotes

Author Disclosure Statement

No competing financial interests exist.

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