AGGRESSION IN TERRORISM
JORDAN MAILE, TALI K. WALTERS,
J. MARTIN RAMÍREZ, AND DANIEL ANTONIUS
Abstract: Behavioral scientists have attempted to describe and explain
terroristic aggression in various ways. Acts of terrorism have typically
been labeled as instrumentally aggressive in nature, however, we argue
that this descriptor is insufficient in capturing the complexity of terroristic
aggression. In light of this, we propose a new term called “programmatic
aggression” that may better serve to capture the multiple levels of
influence in generating terroristic aggression. We also review how
personality and psychopathological models and theories of aggression,
including the frustration-aggression hypothesis, social learning theory, and
the General Aggression Model, have been applied and fall short in the
explication of terroristic aggression. Finally, we suggest some future
directions of research that would likely benefit the study of terrorism and
aggression, including analysis of social psychological work on group
dynamics and their influence on individual and group behavior, as well as
forensic risk and threat assessment research that could inform future efforts
at predicting and hopefully, preventing acts of terroristic aggression.
Keywords: Terrorism, aggression, etiology.
“When man had reached the stage of having weapons, clothing, and social
organization, so overcoming the dangers of starving, freezing, and being
eaten by wild animals, and these dangers ceased to be the essential factors
influencing selection, an evil intra-specific selection must have set in. The
factor influencing selection was now the wars waged between hostile
—Lorenz, On Aggression, 1966, pg. 39
Aggression, whether expressed by the leaders or the members of a
terrorist group, is a central component of terrorism; characterized by the
defined rationale of a violent outcome with the intent to elicit fear and
terror based on social, political and/or religious reasons (e.g., see
WordNet, 2009; The Free Dictionary, 2009). This “outcome” has been
important since the term terrorism was first popularized during the “Reign
of Terror” in France in the 1790s (Hoffman, 1998)1. During this period of
the French Revolution, conflict between rival political parties resulted in
indiscriminate aggression and violence by the state against its civilian
population. Tens of thousands of people were killed over a period of
approximately ten months for the purpose of instilling fear in the public
and preventing a counter-revolution. Several thousands were executed in
public as part of educational propaganda (Kerr, 1927).
Since the “Reign of Terror,” numerous definitions of terrorism have
emerged that encompass aggression and violence (or the threat of such
behavior) as major components of terroristic acts (Laqeuer, 1999). For
example, the United Nations Security Council’s Resolution 1566 (2004)
describes terroristic behavior as:
“…criminal acts, including against civilians, committed with the intent to
cause death or serious bodily injury, or taking of hostages, with the
purpose to provoke a state of terror in the general public or in a group of
persons or particular persons…”
Similarly, the United States federal law (United States Code, § 2331,
2007) characterizes terrorism as:
“…involve[ing] violent acts or acts dangerous to human life that are a
violation of the criminal laws of the United States or of any State…
intended to intimidate or coerce a civilian population; to influence the
policy of a government by intimidation or coercion; or to affect the
conduct of a government by mass destruction, assassination, or
The Terrorism Act 2000 of the United Kingdom’s Parliament (2000)
describes terrorism as an action that:
“…involves serious violence against a person… serious damage to
property… endangers a person’s life, other than that of the person
committing the action… creates a serious risk to the health or safety of the
public or a section of the public.”
Aggression in Terrorism
Although definitions of aggression also vary, the primary component is
the intent to do harm. Terrorism is characterized by an additional element;
the intent to instill fear in the target – whether the aggression is covert, as
in planning a terror attack, or overt, when carrying out the terror attack,
the intent to cause fear and terror is typically present. Given that acts of
terrorism are often considered intentional and of a premeditated nature,
theoretical work has justifiably focused on why and how such individuals
can carry out such extreme acts of violence against innocent others.
However, it should be noted that defining terrorism has been a subject
of ongoing debate (Hoffman, 1998), confounded by changes in meaning of
the term throughout history and cultural and political differences in
conceptualization of the term. For example, the above descriptions represent
Western-centric definitions, which typically attribute the terroristic behavior
to illegitimate groups that are nation-less (Tal & Yinon, 2009). Islamic
definitions, in contrast, also consider acts of fear-inducing violence by
militaristic states as terrorism (Tal & Yinon, 2009).
In the present chapter we provide an overview of extant theory
examining the psychological roots of terrorism. First, a psychological
definition of aggression and its relevance to terrorism will be provided.
Next, aggressive typologies will be presented with a discussion of how
these existing categories may fail to capture the complexity of terroristic
behavior. In addition, we will present a new type of aggression, called
programmatic aggression, that we argue sidesteps the shortcomings of
these existing typologies. This will be followed by a discussion of the
contended role of personality and psychopathological factors in terroristic
behavior. Next, we will summarize psychological models of aggression,
including the frustration-aggression hypothesis, social-learning theory, and
the general aggression model (GAM) and explicate how these have been
applied to terrorism along with their relative shortcomings. Finally, we
will briefly suggest future directions for research, including areas of
research that may be particularly fruitful in their application to terroristic
aggression, such as social psychological principles of group behavior, and
forensic work on risk assessment.
1. Defining and Studying Aggression
and its Relevance to Terrorism
A number of definitions of aggression have been put forth. Some of
these definitions include covert aggression such as aggressive fantasies
and plans, while others denote self-directed aggression or aggressive
behavior towards inanimate objects. Many definitions are influenced by
the academic discipline of the author (i.e., psychology, sociology,
criminology, biology, etc) and the aggression-related mechanisms studied,
while other definitions use aggression interchangeably with other terms
such as violence, hostility, agitation, anger, etc. Despite the various
descriptions used to capture and characterize aggression, and whether the
aggressive behavior is physical, mental or verbal, committed by
individuals or groups, directed towards others, self, or inanimate objects,
associated with mental illness, antisocial personality characteristics, or
cultural, political, or religious views, most definitions include an aspect of
overt violent behavior with intent to cause damage, pain or harm (for a
thoughtful discussion on the topic see Jan Volavka’s seminal book,
Neurobiology of Violence, 2002, as well as Martin Ramirez: Human
Aggression: A Multifaceted Phenomenon, 2003). It should also be noted
that “harm” does not have to be limited to physical harm, but can also
include psychological and emotional harm, and therefore, would
encompass the intent to intimidate or instill fear in the target group. It is
this definition of intent to cause physical and/or psychological harm that
we use to inform our discussion of terroristic aggression throughout the
When studying violent and aggressive behavior, particularly in
humans, it is often examined from a perspective in which aggression is
considered as a unitary construct and a categorical approach is used; an
individual or individual act is either aggressive or not, or a person has an
“aggressive” personality type or not. Although simplistic, the use of this
type of framework in studying aggression has the advantage of being
parsimonious and facilitating research efforts, and accordingly, many
measures of aggression use this approach. For instance, some theorists
have noted the nature of terroristic violence is consistent with what is
called “instrumental” or “reactive” aggression, one form of violence in a
bimodal theory of aggression. We will now briefly describe this bimodal
theory of aggression, and discuss how it may be relevant in furthering our
understanding of terroristic violence.
1.1. Instrumental versus Reactive Aggression
The bimodal theory of aggression describes aggression as occurring in
one of two forms (Barratt, 1991; Stanford, Houston, Mathias,
Villemarette-Pittman, Helfritz, et al., 2003). The first form is called
“reactive” aggression (also referred to as impulsive, expressive, hostile,
unintentional, or affective aggression) and occurs in response to a
perceived threat or provocation. It is characterized by a reaction of fear or
Aggression in Terrorism
anger with autonomic arousal, a loss of behavioral control (Barratt, 1991),
and is normally immediate and defensive in nature (Meloy, 2006). The
second type is referred to as “instrumental” aggression (also called
premeditated, intentional, predatory, proactive, or cold-blooded aggression)
and is goal-oriented, planful, tends to be characterized by the lack of or
minimal emotional and autonomic arousal (Stanford, Houston,
Villemarette-Pittman, & Greve, 2003; Meloy, 2006), and is typically
offensive in nature (Meloy, 2006).
This bimodal theory of aggression is supported by a growing body of
empirical research (Meloy, 2006). Psychophysiologically, reactive
aggressors appear to evidence increases in heart rate in response to a
perceived provocation whereas instrumental aggressors do not (Gottman,
Jacobson, Rushe, Shortt, Babcock, et al., 1995). Instrumental aggression
has distinct neurobiological correlates that differ from that of reactive
aggression (Blair, 2001; 2003). Reactive aggression has been related to
hyperactivity in the amygdala (Siever, 2008) and amygdala-orbitofrontal
cortex dysfunction (Coccaro, McCloskey, Fitzgerald, & Phan, 2007).
Amygdala hypofunction, however, is more commonly related to
instrumental aggression (Blair, 2001). These neurobiological deficits
appear linked to impaired processing of distress-related emotion cues, in
that there is a disruption in the generation of appropriate responses to
emotional stimuli. In other words, the aggression-prone individuals may
lack proper inhibition mechanisms for aggressive and violent behavior.
Experts have speculated that reactive aggressors may lack executive
control over their emotions and behavior causing them to react violently in
the “heat of the moment,” whereas instrumental aggressors do not lack
executive control and, hence, engage in more “cold-blooded” and
calculated acts of violence (Raine, Meloy, Bihrle, Stoddard, LaCasse, et
al., 1998). In terms of neurochemistry, studies have shown that
noradrenergic and dopaminergic systems are associated with the facilitation
of reactive aggression (McEllistrem, 2004), while cholinergic systems are
implicated in the facilitation of instrumental aggression (Miczek, 1987). In
addition, neuropsychological studies have shown that reactive aggressors
appear to demonstrate poorer verbal ability and intelligence than their
instrumental counterparts (Barratt, Stanford, Kent, & Felthous, 1997;
Vitiello, Behar, Hunt, Stoff, & Ricciuti, 1990). Taken together, these
results provide strong empirical support for two forms of aggression with
different underlying psychophysiological, neurobiological, neurochemical,
and neuropsychological substrates (for a deeper analysis of this
dichotomous categorization of aggression see Ramirez & Andreu, 2003;
It has not escaped the attention of terrorism researchers that terroristic
behavior can be construed as a form of instrumental aggression; the
outcome (harm to others) is often secondary to the primary politically-
motivated goal of social change (Megargee, 1993). Similarly, the outcome
might be secondary to other religious, social, and/or ideological goals. In
fact, terroristic acts meet many of the defining criteria of instrumental
aggression according to Meloy’s scheme (2006). More specifically,
terroristic acts are generally planned and purposeful, are not enacted in
immediate response to a perceived instigating event (i.e., not time limited)
and accordingly, there is often no imminent perceived threat from the
enemy. However, there are theoretical problems when attempting to
directly apply this dichotomous typology of aggression to terroristic
behavior. Most importantly, reactive and instrumental forms of aggression
are typically applied to individuals or individual acts. Therefore, applying
the label of reactive or instrumental aggression to a specific terrorist or
terroristic act may attempt to force an individual-level theoretical construct
to a person/event that has individual, group, and societal-level
At the individual-level, the dichotomization of each terrorist’s behavior
as reactive or instrumental aggression may obscure the dynamic nature of
the motivations of the aggressive act(s). Each event may be composed of
both reactive and instrumental motivational elements (Meloy, 2006), and
the motivations of each terrorist may change over time. For example, an
individual’s initial reason for joining a terrorist organization (e.g., anger in
response to a perceived injustice) may change over time, particularly as
the person becomes more enmeshed in the organization. At this point,
group-level influences may take on an increasingly salient role and the
individual’s goals may shift more in line with the group’s goals.
At the group-level (i.e., the terrorist organization), terrorist acts are
generally categorized as instrumentally aggressive (Megargee, 1993).
However, as already discussed, reactively or instrumentally motivated
aggressive acts are typically limited to a discrete event or the acts of one
individual, whereas terrorist activities are often carried out over a
protracted period of time and by numerous individual members of the
terrorist organization, both in solitary and cooperative efforts.
Conceptualizing terrorist behavior as instrumental aggression does not
adequately address the group- and societal-level influences in the
commission of such behavior. Therefore, a more appropriate label may be
programmatic aggression, a group-level expression of instrumental
aggression. The label of programmatic aggression is intended to make no
assumptions about the motivations of the individual terrorists, whom may
Aggression in Terrorism
be motivated by reactive and/or instrumental reasons. Moreover,
programmatic aggression would not be encumbered by the time, event,
and person-limited nature of the individual-level construct of instrumental
aggression. Most importantly, it would allow for discussion and exploration
of group- and societal-level influences on aggressive behavior as enacted
by a collective of individuals. Nonetheless, although this characterization
may be useful in describing terroristic aggression, it does not address the
etiological factors of such behavior. In the next section, we will present
psychological theories that attempt to explicate the roots of terror-based
2. Etiological Theories of Terroristic Aggression
The etiological factors that underlie the development of terroristic
behavior have been a source of theoretical contention for over four
decades in the social sciences (Silke, 1998). Psychological theorists have
debated the centrality of the role of personality or psychopathological
factors in its development. While some experts have opined that terrorists
suffer from fundamental personality deficits or mental illness that make
them more likely to affiliate with terrorist organizations and engage in
terroristic activities, others argue that terrorists, in general, are
psychologically “normal.” In this section, we summarize theoretical
conceptualizations of the terrorist “personality,” the role psychopathology
may play in the development of terroristic behavior, as well as the
methodological and theoretical limitations in these avenues of investigation.
2.1. Personality Factors
Much of the psychological research over the past four decades has
been predicated on the assumption that terrorists are psychologically
different from non-terrorists, particularly in terms of their personality
make-ups (Silke, 1998). This conceptualization, chiefly derived from a
psychodynamic or psychoanalytic perspective, posits that certain
individuals possess or lack certain personality traits that make them more
susceptible to joining terrorist organizations and engaging in terroristic
behavior than those individuals who do not (Ruby, 2002). This personality
defect model asserts that this “type” of personality is largely the result of a
dysfunctional childhood that fosters an impoverished sense of self and
hostility toward authority (Ruby, 2002). This resentment to authority may
be an outgrowth of unconscious hostility toward abusive or controlling
parents, and is later reflected in the adult terrorist’s rigid mindset (Kent &
In line with this conceptualization, Post (1984) referred to this type of
terrorist as an “anarchic ideologue,” an individual who is primarily
motivated by an unconscious hostility toward authority figures (in this
case, the target of the terroristic act(s)) due to a dysfunctional relationship
with his or her parents, particularly the father. However, he also posited an
alternative pathway to terrorism, in which an individual, whom he termed
a “nationalist secessionist,” experiences a relatively stable upbringing and
healthy parental relationships, but instead seeks violent retribution for
perceived wrongs perpetuated against his or her parents (Post, 1984).
Strentz (1981) delimited three prototypical terrorist personality
profiles. The “Leader” is the intellectual force or “brains” of the terrorist
operation and experiences an underlying sense of inadequacy that s/he
projects onto society. Society, therefore, is viewed as inadequate and
hence a logical target for social change. The “Opportunist” is characterized
as the “muscle” of the group and often exhibits antisocial traits and has a
history of criminal conduct predating his or her affiliation with the terrorist
organization. Finally, the “Idealist” is described as a young and naïve
individual who is drawn to a terrorist organization in the hope of effecting
political and/or social change.
Based on developmental theory, LoCicero and Sinclair (2007) posit a
more social-developmental approach to terrorism. They argue that the
terrorist’s personality evolves over time, and is not influenced by one
domain but instead by various different factors including parents, peers,
environment, etc. An individual may join a group based on basic non-
violent religious or political views, or for other reasons, and it is in this
group that a person’s ideology is slowly shaped. However, if this group is,
or becomes, involved in a violent conflict, in which the enemy might be
viewed as evil, the individual’s group belongingness and her/his desire to
be loyal may take precedence. Further, this may result in re-shaping of the
individual’s principles and consequently lead to her/him becoming
emerged in the violent conflict as a terrorist/soldier fighting for the
With respect to suicide bombers, a more specific group of terrorists,
Meloy and colleagues (2001, 2004) have suggested that many can be
described as “violent true believers” or individuals who are “committed to
an ideology or belief system which advances homicide-suicide as a
legitimate means to further a particular goal.” These individuals are
typified by a constellation of traits including: a belief and understanding
that suicide is a terroristic weapon, envious impulse (i.e., desire to
Aggression in Terrorism
damage/destroy coveted qualities of the target), helpless dependence (on
the target as an object of envy), a sense of omnipotence (with the power to
kill), history of depression or despair (that will fluctuate prior to the
suicide mission and degree of social isolation), sense of entitlement
(reflected by disregard of human life and inflated self-importance),
possible psychopathy, capacity for emotional detachment, paranoia, a
sense of a foreshortened future and use of predatory violence to achieve
goals (Meloy, 2004; Meloy, Mohandie, Hempel, & Shiva, 2001).
Although other personality typologies have been offered in the
psychological literature, it is beyond the scope of this chapter to provide
an exhaustive account. Nonetheless, personality deficit models reflect the
primary role of pathological personality, resulting from an unstable
upbringing and hostility toward authority, in explaining why some
individuals go on to engage in terroristic activities. However, other
theorists argue that mental disorder, particularly personality disorders,
may play a prominent role in terroristic behavior (Borum, 2004).
Ostensibly, the difference between these two explanatory models is the
degree of severity of personality disturbance, with the psychopathology
model suggesting a more extreme personality disturbance.
2.2 Psychopathological Factors and Personality Disorders
Although depressive and hypomanic disorders have been implicated in
the motivation for terroristic behavior (Turco, 1987), these have received
less attention than other forms of psychopathology. According to Silke
(1998), attempts to explain terroristic behavior in terms of psychopathology
have generally focused on three personality disorders: antisocial
personality disorder (and psychopathy), narcissistic personality disorder,
and paranoid personality disorder.
Antisocial personality disorder (ASPD), a disorder characterized by
chronic disregard of social norms and laws, lack of remorse, impulsivity,
and other traits, would seem a suitable diagnosis for explaining terroristic
behavior. Indeed, some researchers have opined that a subset of terrorists
would meet criteria for a diagnosis of ASPD, while many others would
exhibit traits of ASPD without meeting full diagnostic criteria (Martens,
2004). Martens (2004) points out that many individuals with ASPD share
certain characteristics with terrorists, such as a sense of social alienation,
early maladjustment, impulsivity and hostility.
Psychopathy, although not an official diagnosis in the Diagnostic and
Statistical Manual of Mental Disorders (DSM-IV; American Psychiatric
Association, 1994), is a personality and behavioral syndrome that shares
many features with ASPD, with an additional emphasis on less observable
personality variables, such as emotional callousness and manipulative
tendencies, and has been implicated in terroristic behavior (Corrado, 1981;
Pearce, 1977). Corrado (1981) opined that psychopathy was one of the
most “prominent” mental disorders associated with terrorists. Similarly,
Pearce (1977) suggested that terrorists are “aggressive psychopaths” who
use a political cause as an avenue to vent their frustrations over perceived
wrongs and to engage in the domination and humiliation of others.
In a review of research on bombers and psychopaths, Meloy &
McEllistrem (1998) noted similarities between the two groups including:
an inflated sense of self-importance, emotional callousness, lack of
remorse and a proclivity to engage in criminal conduct. In addition, they
report that some bombers may evidence decreased autonomic reactivity, a
trait often found in habitual criminals and psychopaths. Finally, they found
that bombers tend to lack a future-orientation, evidence poor long-term
planning, and engage in predatory or “cold-blooded” acts of violence,
hallmarks of a psychopathic personality. However, they are careful to note
that most terrorists are not psychopaths, and that terrorist bombers also
evidence certain characteristics that differentiate them from prototypical
psychopaths. For instance, bombers tend to be socially isolated and
solitary and usually subscribe to a strong ideological belief system, traits
not typically associated with psychopaths. They suggest that the passive-
aggressive use of violence (i.e., bombing) and avoidant personality traits
of the terrorist bomber may reflect a phenotypic variant of the
psychopathic genotype (Meloy & McEllistrem, 1998). Other researchers
have echoed this caveat with regard to terrorists in general, in that ASPD
or psychopathy may be represented in only a subset of terrorists,
particularly in leaders (Martens, 2004). Even among these individuals,
they tend to demonstrate traits that would differentiate them from
prototypical psychopaths, such as: a strong sense of loyalty to group
members, use of violence that is limited to targets of terror and not
specific to individuals (e.g., governmental or bureaucratic agencies), and
ability to follow and execute long-term plans (in this case, campaigns of
violence) (Martens, 2004).
Narcissistic Personality Disorder has also been used to explain
involvement in terrorist behavior (Lasch, 1979; Pearlstein, 1991).
Proponents of this view point out that although antisocial and narcissistic
personality disorders demonstrate some overlap in features such as lack of
empathy and disregard for the rights of others, terrorists also evidence a
desire for admiration and attention, a hallmark of narcissism (Ruby, 2002).
Their chosen methods of violence are often spectacular and attention
Aggression in Terrorism
grabbing, suggesting a more narcissistic clinical presentation (Ruby,
2002). Other theorists argue that narcissistic traits, particularly in
combination with antisocial traits, may be more common among terrorist
leaders, and not necessarily among terrorists in general (Johnson &
Feldmann, 1992). These individuals may engage in what is called
narcissistic aggression, a form of aggression motivated by psychological
injuries to their ego (Ross, 1996).
Finally, Paranoid Personality Disorder, a clinical picture characterized
by marked suspiciousness, irrational mistrust of others, rigidity in beliefs,
and an unwillingness to compromise, has been associated with terrorists
(Silke, 1998). Given the rigid and extreme ideological belief systems,
often centered around themes of oppression and persecution that terrorists
often espouse, paranoid personality disorder would seem a logical fit
(Turco, 1987). Not surprisingly, experts tend to agree that paranoid
personality disorder may be more common among leaders than among
non-leaders of terrorist organizations (Johnson & Feldmann, 1992; Turco,
1987), ostensibly due to the greater material and social resources, such as
prestige, the leaders stand to lose.
Although much attention has been paid to the possible personality and
psychopathological factors that may facilitate the development of terroristic
behavior, some critics also argue that personality traits and mental illness
that predisposes an individual to become a terrorist is largely inaccurate.
Reid (2003), for example, argues that the attempt to psychologically
profile the typical terrorist is simply an attempt to “figure them out”, but
“wishing doesn’t make it so” (p. 285). Other critics of the personality/
psychopathology approach discount this body of research on methodological
and theoretical grounds, which we discuss further in the following section.
2.3. Methodological and Theoretical Problems of the
Personality Defect and Psychopathology Models of Terrorism
In terms of methodology, many critics point out that many personality
defect and psychopathology models of terrorism and terrorists largely rely
on anecdotal evidence or lack empirical support (i.e., suffer from small
sample sizes) (Crenshaw, 2000), or derive personality profiles from
secondary sources of information, such as interviews with family members
or archival records (Silke, 1998). Indeed, Meloy (2006) qualified the entire
body of research regarding the personalities and motivations of bombers
as “anecdotal, descriptive, and conjectural,” and resting on “expert
authority, not science” (p. 561). Conversely, studies that have employed
more stringent methodological standards have found that terrorists are
largely indistinguishable from non-terrorists, both in terms of personality
(Horgan, 2003; Taylor & Quayle, 1994) and mental health (Borum, 2004).
In one of the only studies of its kind in which incarcerated terrorist
murderers were compared to a control group of incarcerated non-terrorist
murderers, the terrorist group evidenced more psychological stability and
less psychopathology, and tended to come from more stable family
backgrounds than their non-terrorist counterparts (Lyons & Harbinson,
When researchers have examined terrorists directly, findings have
supported the view that terrorists are psychologically “normal” relative to
non-terrorists (Ferracuti & Bruno, 1983; Heskin, 1994; Rasch, 1979).
Moreover, when psychopathology is present in terrorists, they typically
employ peripheral functions in the terrorist organization (Silke, 1998).
Ruby (2002) also points out that in the rare case that a terrorist does meet
diagnostic criteria for a mental disorder, it may be the result of affiliating
and socializing with a terrorist organization and not a causal reason for
joining one. Reid (2003) speculates that most individuals who become
involved in terroristic acts “do not have more psychological flaws than
Theoretically, opponents of the personality defect and psychopathological
models of terrorism argue that attributing terrorist behavior to internal
characteristics, such as personality disorders and/or mental illness, is an
application of the “fundamental attribution error” (Eisen, 1979). In other
words, proponents of these models tend to ascribe terroristic behavior to
personological factors of the individual terrorists, while discounting the
role that contextual or structural variables may play in the commission of
such behavior (Atran, 2003; Silke, 1998). There is now general consensus
in the terrorism research community that empirical attention needs to
incorporate multiple levels of analysis, including individual, group, and
societal levels (Crenshaw, 2000). Crenshaw (1992, 2000) argues that when
these levels of analysis are incorporated, terroristic behavior appears
psychologically normative and rational given the sociopolitical climate in
which many of these terrorists live. This view is in support of the
aforementioned social-developmental model proposed by LoCicero and
Sinclair (2007), which emphasizes numerous factors of influence on a
In sum, modern etiological theories of terroristic behavior seem to
discount individual personality and/or psychopathological factors in
explaining terroristic behavior, and instead favor group- and societal-level
factors. However, psychology has the ability to contribute additional
Aggression in Terrorism
theoretical and empirical work that may have a direct bearing on the
genesis of terroristic behavior, particularly with respect to aggression.
Psychology has forwarded many theoretical models to account for
aggression. In terms of explaining terroristic behavior, three schools of
thought have received particular attention: the frustration-aggression
hypothesis, social learning theory, and the general aggression model (or
GAM). In the next few sections, we will provide an overview of each
theoretical position along with how it has or could be applied to explain
terroristic behavior and discuss each school’s relative weaknesses.
2.4. The Frustration-Aggression Hypothesis
The frustration-aggression hypothesis was forwarded in 1939 in an
effort to explain aggression in its totality (Dollard, Doob, Miller, Mowrer,
& Sears, 1939). The basic premise of this hypothesis opined that any and
all instances of aggression were the result of frustration, which was
conceptualized as any event/stimulus that prevents an individual from
attaining some goal and its accompanying reinforcing quality. These
authors stipulated that frustration was a necessary condition for
aggression, but contextual factors, such as threat of punishment, could
inhibit aggressive responding (Dollard et al., 1939). However, even when
an aggressive response is suppressed, the use of non-aggressive strategies
may fail to achieve the desired goal and therefore be extinguished, and an
aggressive behavior would become the dominant response (Miller, 1941).
Since its original conceptualization, this hypothesis has been applied to
Most notably, Gurr (1968, 1970) suggested that “relative deprivation,”
or a subjective sense of being deprived of certain needs or freedoms by a
domestic or international governing body, can result in feelings of
frustration. Moreover, if these feelings of frustration are left to percolate,
they can eventually culminate in acts of violence and terrorism (Margolin,
Berkowitz (1989) reframed the frustration-aggression hypothesis in
light of cognitive neoassociationist theory. Essentially, he argued that it is
not the frustration stimulus or event per se that causes aggression, but
rather the negative affect that is experienced when frustrated. Initially, a
frustration or aversive event will generate diffuse negative affect in an
individual with concomitant physiological and memory-related reactions
associated to fight or flight (Berkowitz, 1989, 1990). At this point,
cognition plays a minimal role, only serving to invest the affect with its
negative valence. The cognitive-neoassociationist piece of this model
proposes that concepts and ideas form nodes that are “networked” in
memory, such that related concepts (and their emotions) are connected;
stimulation of one network node will stimulate related nodes. Berkowitz
(1989, 1990) argues that negative affect is conceptually linked to
aggression-related “nodes” in the individual’s mnemonic networks.
Therefore, the experience of negative affect will stimulate aggression-
related ideas/concepts (for further discussion on important psychological
constructs related to aggression, see Ramirez & Andreu, 2006), making
them more readily accessible for the individual to use in guiding his or her
behavior, thereby increasing the likelihood that the individual will aggress.
In this way, it is suggested that negative affect in general, and not just
anger, will increase the probability that an individual will behave
Following this initial and more automatic experience of diffuse
negative affect, an individual can engage in effortful elaboration on the
meaning of the situation. In other words, an individual can evaluate the
situation in terms of whom or what is the source of the frustration, whether
the frustration was intentional and what response options are available and
Moreover, Berkowitz (1989, 1990) asserts that learning experiences
will likely influence the process of attributing meaning to the situation. It
is this stage of the process that may be of particular relevance to terroristic
behavior. Ostensibly, the socialization processes in a terrorist organization
will likely foster and encourage attributing hostility to the actions of their
enemies, even if ambiguous. Cognitively, the consistent social
reinforcement of this type of thinking provided by the terrorist group
would strengthen connections between negative affect, aggression-related
ideas and the enemy. Therefore, over time, the terrorists association of
negative feelings and ideas with the enemy would become more intense,
potentiating aggressive retaliation.
However, Berkowitz (1989) cautions that the cognitive-
neoassociationistic adaptation of the frustration-aggression hypothesis is
best suited in helping to explain reactive aggression. In addition, although
the model affords room for learning experiences in shaping aggressive
tendencies, it does not explicitly address societal or group-level influences
in explaining terroristic behavior. Finally, it does not provide an
explanation as to why terrorists are capable of such sensationalistically
cruel acts of violence against targets who are not directly responsible for
their frustration. In order to shed light on these issues, we now turn our
attention to social learning theory.
Aggression in Terrorism
2.5. Social Learning Theory
Social learning theory proposes that much of human behavior,
including aggression, is learned through socializing with and observing
others, and “modeling” or mimicking such behavior (Bandura, 1978).
Depending on their developmental history, individuals will be differentially
reinforced or punished for the use of aggressive behavior. It is these
differential histories of reinforcement and punishment that shape an
individual’s propensity toward aggression.
In terms of terrorism, Bandura (1990, 2004) asserts that socialization
within terrorist organizations facilitates the use of extremely violent
behavior through learning specific mechanisms of moral disengagement.
He states that humans typically internalize personal moral standards that
guide their behavior, and violation of these standards causes self-
condemnation. Accordingly, individuals are motivated to avoid self-
derogation by adhering to these moral standards. In terms of violence,
internalized social norms encourage restraint from violence, particularly
extreme forms that can lead to the death of others. However, terrorists are
socialized in specific ways that permit them to suspend or “disengage”
from these moral standards, even if their violence is directed at innocent
members (i.e., typically civilians) of the target group of their hostility.
One of the principle ways in which terrorists learn to morally
disengage from the implications of their violent actions is to reframe the
moral meaning of the violent behavior. In other words, by learning to
justify the use of violence as morally defensible, such as by invoking
patriotic or ideological rhetoric, the normally morally reprehensible action
is reframed as morally legitimate and even necessary. For example,
Islamic extremists have explained their terrorist actions as a defensive
response to encroaching attempts of Westerners to control the Muslim
world. Alternatively, terrorist groups may make appeals to utilitarian logic
such that their own acts of violence are deemed necessary in order to
prevent greater and more atrocious acts of violence from another
instigating group (i.e., Westerners in the latter example); in essence, it
becomes a simple calculus involving human life (Bandura, 1990, 2004).
Terrorists may also engage in what Bandura (1990, 2004) calls
“advantageous comparison,” which involves contrasting their own acts of
terrorism with acts committed by other groups that appear more
reprehensible. In effect, this contrasting process softens the severity and
moral weight of their own terrorist act. In a similar vein, terrorists may use
euphemistic language to minimize the perceived impact of terrorist
behavior in terms of both morality and human life. The use of such
language minimizes or eliminates connotations of harm and responsibility.
In addition, Bandura (1990, 2004) argues that terrorists employ
techniques to both displace and diffuse their personal sense of responsibility
in their terroristic actions. Terrorists may rationalize their acts as having
been mandated by some authority greater than themselves, such as a
leader, ideological principle, or deity, thereby shifting responsibility to the
authority figure. In addition, some terrorist organizations are hierarchically
structured, entailing division of labor. This division of labor serves to
parse out different functions and roles, therefore, any one individual is
only responsible for their small contribution to the total terrorist act. In this
way, responsibility for the final act is shared by, and thereby minimized
for each member of the terrorist organization who was involved in the
Bandura (1990, 2004) also notes that terrorist organizations and their
individual members are indoctrinated into an ideological system that
dehumanizes their enemies. He points out that as we invest others with
shared human qualities, we facilitate an empathic connection with them.
Conversely, casting an individual or group of individuals as subhuman or
as lacking in common human qualities, terrorists are able to divorce
themselves from normal empathic constraints on inflicting harm on these
individuals. Accordingly, this negates or depresses their own personal
moral sanctions against harming another human being. Finally, terrorists
often minimize or simply ignore the harmful impact their actions may
have on their targets of terror.
In sum, Bandura’s social learning model and mechanisms of moral
disengagement help in explaining why terrorists, who for the most part are
psychologically “normal”, are capable of such extreme violence against
innocent targets. However, it does not appear to provide as detailed an
analysis as Berkowitz’s reformulation of the frustration-aggression
hypothesis of the individual level processes or factors involved in the
decision to engage in terroristic behavior, such as emotion. More recently,
the General Aggression Model (Anderson & Bushman, 2002), has been
developed in an attempt to incorporate social learning theory, social
cognition and biological factors in aggression.
2.6. General Aggression Model (GAM)
The General Aggression Model (GAM) is a biosocial model of
aggression that includes social learning, social cognitive, and biological
mechanisms to explain aggression. This model conceptualizes aggression
Aggression in Terrorism
as occurring as a synergy of three influences: inputs, present internal state,
and outputs (Anderson & Bushman, 2002).
Inputs consists of both situational information and personological
factors. In terms of situational information, cues in the environment can
serve to facilitate or inhibit the potential for aggression (Anderson &
Carnagey, 2004). For instance, a frustrating event or situation in which
expectations for aggression are made salient (e.g., a sporting event or
verbal provocation) will create an environment conducive to aggression.
In addition to situational factors, the individual also brings their own
attitudes, beliefs and personality to the mix, the latter of which may be
partially biologically influenced (Anderson & Bushman, 2002; Anderson
& Carnagey, 2004).
It should be noted that this model conceptualizes personality as a
collection of stable knowledge structures that an individual holds and uses
to interpret the world around them (Anderson & Bushman, 2002).
Proponents of this model argue that an individual may inherit a biological
proclivity to learn and maintain aggression-related knowledge structures,
i.e., develop an aggressive personality type (Anderson & Carnagey, 2004).
Importantly, this model posits that personality, i.e., knowledge structures,
can be changed over time through social learning processes. In other
words, the social environment can influence an individual’s beliefs,
attitudes, and personality or how they perceive the world.
Inputs, in turn, serve to influence the present internal state of the
individual in response to a given situation. A person’s pre-existing
personality, beliefs, and attitudes will affect how they feel, think, and
physiologically react to a situation, which in turn will influence the
individual’s behavior, or outcome, in the situation.
In the outcome stage of the GAM, individuals appraise the situation
and arrive at a behavioral decision (Anderson & Bushman, 2002).
Individuals may engage in two types of appraisals. The first type is a more
“automatic” form of appraisal that involves little thought or weighing of
alternative response options that results in some type of impulsive
behavior, most likely aggression. Automatic appraisals typically occur
when an individual does not have time, or the emotional and/or cognitive
capacity to think a situation through; therefore, this type of appraisal is
most likely to lead to reactive aggression. The second type of appraisal is
referred to as “reappraisal” and involves an individual considering
alternative response options that may or may not include non-aggressive
ones. This does not imply that the individual is less likely to aggress,
rather, they are more likely to think about what they are doing before they
decide upon a course of action (Anderson & Bushman, 2002; Anderson &
In terms of terroristic behavior, this model appears to offer a more
comprehensive theoretical framework for understanding the genesis of
terroristic behavior. With respect to the situational information component
of inputs, terrorists are socialized in an environment that promotes
aggressive and violent acts against a specified target. In this way, they are
embedded in a context that is replete with overt and covert cues that
facilitate the use of violence, at least against a select target.
GAM also provides a framework for understanding, albeit speculatively,
as to why an individual joins a terrorist organization and how their
ideological beliefs become more extreme over time. By examining the
personological component of the input stage of the GAM, we can begin to
shed light on these two processes. As previously mentioned, GAM asserts
that certain individuals may show a biological predilection to constructing
aggression-related knowledge structures (i.e., forming an “aggressive
personality”) (Anderson & Carnagey, 2004). It may be the case that
individuals who become motivated to join a terrorist organization are
those individuals who are more likely (from the perspective of a biological
predisposition) to become angered and motivated to action by the
perceived persecution by a perceived enemy. Once the individual has
begun to affiliate with or joined a terrorist group, social learning processes
can then exert their effects in further modifying their knowledge
structures, beliefs, and attitudes. More specifically, the dogmatic
demonization of an enemy in a terrorist group serves to reinforce the
individual terrorist’s existing associations among aggression-related
concepts, negative affect and the enemy in memory networks. Over time,
what may have begun as a somewhat effortful cognitive exercise (i.e.,
contemplating and ruminating over the evil nature of the enemy) will
become less effortful as these associations are reinforced and strengthened
through socialization within the terrorist group, to the point of
automaticity. Moreover, it would appear feasible that it is during this
socialization process that individuals are psychologically and ideologically
trained in the forms of moral disengagement that Bandura (1990, 2004)
argues are necessary to commit terroristic acts. As becomes evident, the
socialization processes in a terrorist organization will afford situational
cues and modify personological factors that will encourage violence
against a selected enemy.
The GAM posits that input variables will influence the present internal
state of the individual. In terms of the terrorist, the input variables will
serve to facilitate negative feelings, thoughts, and physiological reactions
Aggression in Terrorism
(likely related to anger and/or fear) toward the enemy, which in turn will
affect the appraisal and decision making processes in the outcome stage.
The previous two stages will have a direct effect on how the terrorist
appraises, both automatically and in terms of reappraising, their previous,
current, and future interactions with their perceived enemy. However,
given that terroristic violence is not typically impulsive/reactive in nature,
appraisals and decisions in this stage of the GAM are more likely to be
influenced by reappraisal processes and not automatic ones. In other
words, terrorists are likely to reflect upon previous wrongs inflicted upon
them by their enemy, which will reinforce their image of the enemy as a
source of persecution, thereby making decisions to retaliate violently
easier and more likely.
The GAM, given its incorporation of multiple domains of psychological
theory on aggression, provides a more comprehensive analysis of
aggression. As a result, when applied to terroristic aggression, it appears to
offer a more complete explanatory model than either the frustration-
aggression hypothesis or social learning theory alone. Nonetheless, similar
to the frustration-aggression hypothesis and social learning theory, it fails
to account for how group dynamics and societal level influences generate
and affect terroristic behavior. Although it accounts for influences of
socialization on the pre-existing and developing mindset of the individual
terrorist, it does not examine how group-level behavior or sociocultural
and political conditions foster the growth of terrorist individuals and
organizations. However, this criticism is not unique to the GAM, but to all
of the theories previously discussed. Therefore (and this argument is
hardly new) it becomes incumbent upon researchers on the field to
incorporate multiple levels of analysis, including individual, group, and
societal levels when attempting to provide a fuller account of terroristic
3. New Methods for Research on Terrorism
In terms of describing terroristic aggression, assigning it a label
according to the reactive/instrumental dichotomization appears insufficient
to capture the nature of such behavior. Therefore, we have proposed a
third type of aggression called programmatic aggression that asserts
terroristic behavior is a unique type of instrumental aggression as
performed by a collective of individuals, characterized by a dynamic
interplay of individual, group and societal level influences. In explaining
the generation and escalation of terroristic behavior, it would appear the
GAM provides the most comprehensive (albeit untested) framework. But
as many other researchers have argued, existing theoretical explanations
for terrorism are too focused on one level of analysis (e.g., Ross, 1993,
1994); most psychological models, including the GAM, fail to fully
account for group-level or even acknowledge societal level influences.
Addressing the former concern, Pynchon & Borum (1999) provide an
excellent review and much needed first step in attempting to explain how
social psychological principles of group behavior can be applied to explain
Perhaps threat assessment of terrorism can benefit from decades of
sophisticated research in violence risk assessment in forensic psychology
and psychiatry. Forensic risk assessment does not explain aggression or its
etiology. Rather, it predicts future violence by looking at factors that are
associated with future risk, using an individual’s sociological,
psychological, and biological history and current life context. However,
this body of research has examined risk for violence in individuals and not
organizations; nonetheless, it may prove a beneficial starting point for
future research efforts in examining group-level risk assessment. For
example, some researchers have opined that individuals that engage in
targeted violence (i.e., plan to harm only one or multiple specific
individuals) may often follow a sequence of behaviors “on a path toward
violence” (Borum, Fein, Vossekuil, & Berglund, 1999). Identifying
analogous sequences of behavior that precede terrorist acts, both at the
organizational/group and individual level would provide critical data
toward informing prevention efforts. In an exciting move in this direction,
Pynchon and Borum (1999) provide a tentative guideline on how social
psychological principles of group behavior can be applied to risk
assessment of terrorist groups. Additional theoretical and empirical work
is sorely needed in this area in order predict and ultimately prevent future
acts of terroristic violence.
We have provided a summary of psychological theory in both
describing and explaining terroristic behavior. Attempts to describe
terroristic behavior in terms of a bimodal theory of aggression (i.e.,
reactive or instrumental in nature) appear insufficient given their neglect
of group and societal-level influences in explaining aggression. We
forward a third type of aggression, called programmatic aggression, in
order to address this shortcoming.
Aggression in Terrorism
In terms of etiological factors in terroristic aggression, it appears that
previous attempts, particularly in terms of a “terrorist personality” or
mental illness, have largely failed. Moreover, psychologically grounded
etiological theories of aggression may be limited in their utility in
explaining terroristic aggression due to their primary focus on the
individual-level of analysis. While these theories do attempt to account for
socialization processes (i.e., a group-level influence) in the development
of terrorism, they do not do so to a sufficient degree; more importantly,
they only indirectly or completely ignore the influence of sociocultural
and political factors in generating and maintaining terroristic behavior.
Finally, social psychology of group behavior and the literature on violence
risk assessment can offer useful starting points in extending our
knowledge of causes of terroristic aggression, and inform prevention
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1 Although the history of terrorism (the act of terroristic behavior by groups)
clearly dates back further than the French Revolution and the Reign of Terror (e.g.,
see Terrorism Research, 2009), we are in this chapter referring to what many
scholars consider the epoch when the term was initially commonly accepted and
popularized (Hoffman, 1998). However, it should also be noted that the term
“terror,” which stems from the Latin word meaning “to frighten,” was used as
early as 105BC by Romans to describe attacks by warriors of the Germanic Cimbri
tribe (terror cimbricus) (Gjerset, 1969).