Stimulation-induced behavioral inhibition: A new model for understanding physical violence

Physical violence is widely considered to result from action carried out with the intention of causing injury; that is, from aggression. However, the “hypothesis” of aggression is inapplicable in all but a few instances as well as inappropriate for many destructive rage-associated responses directed at inanimate objects. This paper outlines a new perspective on physical violence, reinterpreting many behaviors hitherto labeled aggressive as stimulation-seeking behaviors (SSBs) above an arbitrary level of intensity. It is further proposed that: 1) physical violence is a by-product of SSB, driven, in part by brain catecholaminergic (CA) systems, and the direct result of exchanges of energy that exceed the body's tolerance threshold; 2) allegedly discrete categories of motor-motivational behavior represent overlapping bands of intensity on a continuous spectrum of SSB; and 3) the sensory input derived from SSB is fed back into the central nervous system where it activates, brain serotonergic and/or cholinergic systems, which in turn inhibit CA systems, resulting in a general state of behavioral quiescence. In addition to accounting for a number of previously unexplained observations, the model suggests that physical violence could be prevented by providing groups at high risk with extensive opportunities for therapeutic sensory stimulation to substitute for that derived from excessive SSB. For people at especially high risk, portable devices could be developed that would allow the user to self-administer desired levels of sensory stimulation at moments of intense anger, thereby preventing potentially dangerous outbursts of SSB prior to the onset of the behavior.     

日常环境中的暴力暴露对攻击行为的长期影响:一个有调节的中介模型

以850名大学生为被试,探讨日常环境中的暴力暴露与攻击行为的关系,并在此基础上提出一个有调节的中介模型,考察攻击性信念的中介作用和人际信任的调节作用。结果发现:(1)日常环境中的暴力暴露对攻击行为有显著的正向预测作用;(2)攻击性信念在日常环境中的暴力暴露与攻击行为的关系中起部分中介作用;(3)攻击性信念的中介作用会受到人际信任的调节。对于低人际信任个体,攻击性信念起部分中介作用;对于高人际信任个体,攻击性信念的中介效应不显著,日常环境中的暴力暴露对攻击行为只有直接作用。     

New insights into the regulation of synaptic plasticity from an unexpected place: Hippocampal area CA2

The search for molecules that restrict synaptic plasticity in the brain has focused primarily on sensory systems during early postnatal development, as critical periods for inducing plasticity in sensory regions are easily defined. The recent discovery that Schaffer collateral inputs to hippocampal area CA2 do not readily support canonical activity-dependent long-term potentiation (LTP) serves as a reminder that the capacity for synaptic modification is also regulated anatomically across different brain regions. Hippocampal CA2 shares features with other similarly "LTP-resistant" brain areas in that many of the genes linked to synaptic function and the associated proteins known to restrict synaptic plasticity are expressed there. Add to this a rich complement of receptors and signaling molecules permissive for induction of atypical forms of synaptic potentiation, and area CA2 becomes an ideal model system for studying specific modulators of brain plasticity. Additionally, recent evidence suggests that hippocampal CA2 is instrumental for certain forms of learning, memory, and social behavior, but the links between CA2-enriched molecules and putative CA2-dependent behaviors are only just beginning to be made. In this review, we offer a detailed look at what is currently known about the synaptic plasticity in this important, yet largely overlooked component of the hippocampus and consider how the study of CA2 may provide clues to understanding the molecular signals critical to the modulation of synaptic function in different brain regions and across different stages of development.     

Early Health Risk Factors for Violence: Conceptualization, Review of the Evidence, and Implications

Violence and aggression are public health problems that can benefit from ongoing research into risk reduction and prevention. Current developmental theories of violence and aggression emphasize biological and psychosocial factors, particularly during adolescence. However, there has been less focus on understanding the interactive, multiplicative effects of these processes. Furthermore, little attention has been given to the pre-, peri-, and postnatal periods, where prevention and intervention may yield effective results. Early health risk factors that influence negative behavioral outcomes include prenatal and postnatal nutrition, tobacco use during pregnancy, maternal depression, birth complications, traumatic brain injury, lead exposure, and child abuse. There is an ample literature to suggest that these early health risk factors may increase the likelihood of childhood externalizing behaviors, aggression, juvenile delinquency, adult criminal behavior, and/or violence. This paper proposes an early health risk factors framework for violence prediction, built on existing developmental theories of criminal behavior and supported by empirical findings. This framework addresses gaps in the adolescent psychopathology literature and presents a novel conceptualization of behavioral disturbance that emphasizes the pre-, peri-, and post-natal periods, when a child's development is critical and the opportunity for behavioral and environmental modification is high. Implications for such a framework on violence prevention programs are discussed.     

Media violence, physical aggression, and relational aggression in school age children: a short-term longitudinal study

Many studies have shown that media violence has an effect on children's subsequent aggression. This study expands upon previous research in three directions: (1) by examining several subtypes of aggression (verbal, relational, and physical), (2) by measuring media violence exposure (MVE) across three types of media, and (3) by measuring MVE and aggressive/prosocial behaviors at two points in time during the school year. In this study, 430 3rd-5th grade children, their peers, and their teachers were surveyed. Children's consumption of media violence early in the school year predicted higher verbally aggressive behavior, higher relationally aggressive behavior, higher physically aggressive behavior, and less prosocial behavior later in the school year. Additionally, these effects were mediated by hostile attribution bias. The findings are interpreted within the theoretical framework of the General Aggression Model.     

Reactive and proactive aggression: predictions to physical violence in different contexts and moderating effects of parental monitoring and caregiving behavior

This study aimed at (a) comparing the links of proactive and reactive aggression at 13 years of age to delinquency-related violence and dating violence at ages 16 and 17, and (b) examining the moderating effects of parental supervision, and mother's and father's warmth and caregiving behaviors on these links. Based on a sample of 525 Caucasian boys, the results showed that proactive aggression uniquely predicted delinquency-related violence, whereas reactive aggression uniquely predicted later dating violence. The relation between proactive aggression and delinquency-related violence, however, was moderated by parental supervision. The relation between reactive aggression and dating violence was moderated by mother's warmth and caregiving behavior. The implications of the findings for the theoretical and practical distinction between proactive and reactive aggression are discussed.     

The role of affective and cognitive empathy in physical, verbal, and indirect aggression of a Singaporean sample of boys

Bullying behavior is a serious form of school violence, affecting many children. This study investigated the contributions of 2 specific components of empathy (affective and cognitive empathy) on the 3 forms of aggressive behaviors in a sample of 241 Grade 4 and Grade 5 boys from Singapore. The 2 components of empathy differed in their relation with the 3 types of aggression. After accounting for cognitive empathy, affective empathy was associated with physical aggression. Neither affective empathy nor cognitive empathy was associated with verbal aggression. With control for affective empathy, cognitive empathy was associated with indirect aggression. Results suggest that empathy training based on specific deficits may be helpful in intervention and prevention of specific aggressive behaviors.     

Developmental trajectories of childhood disruptive behaviors and adolescent delinquency: a six-site,cross-national study

This study used data from 6 sites and 3 countries to examine the developmental course of physical aggression in childhood and to analyze its linkage to violent and nonviolent offending outcomes in adolescence. The results indicate that among boys there is continuity in problem behavior from childhood to adolescence and that such continuity is especially acute when early problem behavior takes the form of physical aggression. Chronic physical aggression during the elementary school years specifically increases the risk for continued physical violence as well as other nonviolent forms of delinquency during adolescence. However, this conclusion is reserved primarily for boys, because the results indicate no clear linkage between childhood physical aggression and adolescent offending among female samples despite notable similarities across male and female samples in the developmental course of physical aggression in childhood.     

The effects of viewing physical and relational aggression in the media: Evidence for a cross-over effect

Research has shown that viewing violence in the media can have a profound impact on aggressive thoughts and behaviors. However, the impact of viewing relational aggression in the media has rarely been examined. This paper presents the results of an experimental study that examines the impact of viewing relational and physical aggression in the media on subsequent aggression. In this study, adult females were shown video clips containing no-aggression, relational aggression, or physical aggression. Their aggressive behavior was measured through the use of a competitive reaction time task (physical aggression) and evaluations of a confederate of the experiment (relational aggression). As a whole, participants viewing either relational or physical aggression behaved similarly. Specifically, participants who viewed either type of aggression were subsequently more physically and relationally aggressive than those who viewed the non-aggressive clip. The results show evidence for a generalization effect of viewing media aggression, in that viewing one form of aggression can influence the manifestation of other forms. This is the first study to show that viewing relational aggression in the media can increase subsequent physical aggression. Implications for parents, media producers, and policy makers are discussed.     

Treatment of aggression in a brain injured adolescent

A traumatically brain injured (TBI) adolescent exhibited physical aggression requiring physical intervention. Aggressive behavior was eliminated in 2 weeks when a point system with response cost and contingent home visits were used. The point system alone maintained aggression at zero episodes for 4 weeks. In addition to eliminating aggression, the point system increased attendance to therapies and classes, waking up on time, and prosocial behaviors.     

A neurodevelopmental perspective on male violence

Research is increasingly documenting a neurobiological basis to violence. This review takes a neurodevelopmental perspective on the very small group of males who grow up to become persistent violent offenders. After outlining six criteria for what constitutes a neurodevelopmental disorder, the extent to which chronic violence meets these definitional criteria is examined, covering the fields of genetics, structural and functional brain imaging, and neuropsychology. Early health risk factors for violence are then outlined, including birth complications, minor physical anomalies, prenatal smoking and alcohol exposure, poor nutrition, lead exposure, and traumatic brain injury. Persistent adult violence is argued to originate in aberrant temperamental behavior in early childhood, to have a stable developmental trajectory, and to be associated with impaired education, social, and occupational functioning. Taken together, it is argued that chronic adult violence meets criterion for being conceptualized as having neurodevelopmental origins and that an important, but not sole, source of neural maldevelopment lies in prenatal and early postnatal risk factors. This review concludes with a recognition of the sociopolitical context within which a neurodevelopmental perspective on chronic violence sits, together with directions for future research, including whether a neurodevelopmental hypothesis is best applied to reactive as opposed to proactive aggression.     

Increased use of safety-seeking behaviors in chronic back pain patients with high health anxiety

Many patients with chronic pain also exhibit elevated levels of health anxiety. This study examined the effect of health anxiety on the use of safety-seeking behaviors (SSBs) in pain-provoking situations. Participants were 20 chronic back pain patients with high health anxiety (Group H), 20 with low health anxiety (Group L) and 20 pain-free controls (Group C). Two physical tasks were video recorded, and compared both for overt pain behavior (identified by blind observers following a standardized procedure) and for the occurrence of SSB (identified by showing the participants video playback and asking them to specify motivation for all actions/behaviors displayed during the tasks). While there were no differences in the display of overt pain behaviors, Group H deployed a greater number of SSBs than Groups L and C. This finding held true for both tasks and remained significant when concurrent pain and mood ratings were statistically controlled for. SSB was correlated with catastrophizing thoughts but not pain intensity; pain intensity was correlated with overt pain behavior but not catastrophizing. Taken together, these findings suggest that SSB is distinct from overt pain behavior and may be a defining characteristic of chronic pain patients reporting high levels of health anxiety.     

Gender Differences in Predicting Antisocial Behaviors: Developmental Consequences of Physical and Relational Aggression

This study investigated gender differences in the relationship of early physical and relational aggression to later peer rejection and overt and covert antisocial behaviors. Significant gender differences were found indicating physically aggressive boys were more likely than girls to experience later peer rejection. Early physical aggression was related to later overt antisocial behavior for boys and girls, and more strongly for girls than for boys. Early relational aggression was not associated with later forms of antisocial behavior. In the context of early physical aggression, for boys and girls peer rejection generally served to increment risk for later overt and covert antisocial behavior in an additive fashion. The data suggest some gender specificity in the social risk processes associated with the development of early overt and covert antisocial behaviors.     

Youth Exposed to Violence: Stability, Co-occurrence, and Context

With considerable literature establishing how separate types of violence disrupt the lives of children, there is emerging interest in examining violence across multiple interpersonal domains. This article examines four commonly occurring and frequently researched domains of violence exposure: marital physical aggression, mother-to-youth aggression, father-to-youth aggression, and community violence. A community-based sample of 103 parents and youth provided three waves of data at annual intervals beginning when the youth were aged 9–10. We explored stability of exposure, co-occurrence across different types of violence exposure, and associations with co-occurring risk factors. Approximately 30–45% of youth reported intermittent exposure over the 3 years. In addition to overlap among types of violence exposure within the family, we found overlap between parent-to-youth aggression and community violence, an association that was exacerbated in families where fathers reported high levels of global distress symptoms. Mother-to-youth, father-to-youth, and community violence related to youth behavior problems beyond the contextual risk factors of low income, stressful life events, and parents’ global distress symptoms. These results highlight the importance of examining violence longitudinally, across multiple types, and with attention to contextual factors.     

Infant Parasympathetic and Sympathetic Activity during Baseline,Stress and Recovery: Interactions with Prenatal Adversity Predict Physical Aggression in Toddlerhood

Exposure to prenatal adversity is associated with aggression later in life. Individual differences in autonomic nervous system (ANS) functioning, specifically nonreciprocal activation of the parasympathetic (PNS) and sympathetic (SNS) nervous systems, increase susceptibility to aggression, especially in the context of adversity. Previous work examining interactions between early adversity and ANS functioning in infancy is scarce and has not examined interaction between PNS and SNS. This study examined whether the PNS and SNS moderate the relation between cumulative prenatal risk and early physical aggression in 124 children (57% male). Cumulative risk (e.g., maternal psychiatric disorder, substance (ab)use, and social adversity) was assessed during pregnancy. Parasympathetic respiratory sinus arrhythmia (RSA) and sympathetic pre-ejection period (PEP) at baseline, in response to and during recovery from emotional challenge were measured at 6 months. Physical aggression and non-physical aggression/oppositional behavior were measured at 30 months. The results showed that cumulative prenatal risk predicted elevated physical aggression and non-physical aggression/oppositional behavior in toddlerhood; however, the effects on physical aggression were moderated by PNS and SNS functioning. Specifically, the effects of cumulative risk on physical aggression were particularly evident in children characterized by low baseline PNS activity and/or by nonreciprocal activity of the PNS and SNS, characterized by decreased activity (i.e., coinhibition) or increased activity (i.e., coactivation) of both systems at baseline and/or in response to emotional challenge. These findings extend our understanding of the interaction between perinatal risk and infant ANS functioning on developmental outcome.     

The role of warning behaviors in threat assessment: an exploration and suggested typology

The concept of warning behaviors offers an additional perspective in threat assessment. Warning behaviors are acts which constitute evidence of increasing or accelerating risk. They are acute, dynamic, and particularly toxic changes in patterns of behavior which may aid in structuring a professional's judgment that an individual of concern now poses a threat - whether the actual target has been identified or not. They require an operational response. A typology of eight warning behaviors for assessing the threat of intended violence is proposed: pathway, fixation, identification, novel aggression, energy burst, leakage, directly communicated threat, and last resort warning behaviors. Previous research on risk factors associated with such warning behaviors is reviewed, and examples of each warning behavior from various intended violence cases are presented, including public figure assassination, adolescent and adult mass murder, corporate celebrity stalking, and both domestic and foreign acts of terrorism. Practical applications and future research into warning behaviors are suggested.     

Chronic violent video game exposure and desensitization to violence: Behavioral and event-related brain potential data

Numerous studies have shown that exposure to media violence increases aggression, though the mechanisms of this effect have remained elusive. One theory posits that repeated exposure to media violence desensitizes viewers to real world violence, increasing aggression by blunting aversive reactions to violence and removing normal inhibitions against aggression. Theoretically, violence desensitization should be reflected in the amplitude of the P300 component of the event-related brain potential (ERP), which has been associated with activation of the aversive motivational system. In the current study, violent images elicited reduced P300 amplitudes among violent, as compared to nonviolent video game players. Additionally, this reduced brain response predicted increased aggressive behavior in a later task. Moreover, these effects held after controlling for individual differences in trait aggressiveness. These data are the first to link media violence exposure and aggressive behavior to brain processes hypothetically associated with desensitization.     

Psychosocial correlates of dating violence victimization among Latino youth

To examine the association between physical dating violence victimization and risk and protective factors, an anonymous, cross-sectional, self-reported survey was administered to Latino youth (n=446) residing in suburban Washington, DC. Multivariate logistic regression models were constructed, and adjusted OR and 95% CI were examined. Approximately 9% of Latino adolescents reported physical dating violence victimization. Overall, youth who reported carrying a gun, involvement in physical fights and suicidal thoughts were at greater odds of reporting dating violence. Among females, fighting was the sole risk behavior associated with dating violence. Girls who reported a stronger sense of self were less likely to report dating violence. Among males, gun carrying, but not physical fighting, and having considered suicide were associated with dating violence. Spending time each week with a mentor was also positively associated with male dating violence victimization. Dating violence appeared to cluster with other risk behavior engagement. Important gender differences in associated risk and protective behaviors were identified and should be incorporated into primary and secondary prevention activities.     

The accuracy of risk assessment instruments in the prediction of impulsive versus predatory aggression

Actuarial violence risk assessments, many of which include the construct of psychopathy, have been shown to be superior to clinical judgment in the prediction of long-term risk of community violence and recidivism. While these instruments initially appeared to provide similarly accurate judgments of risk of institutional aggression, recent research has indicated that such assessments may be less robust in this setting. One explanation may lie in the types of aggression most frequently observed in each setting. Impulsive (or reactive/affective) is the type of physical aggression most commonly exhibited in psychiatric facilities. This research examines the relationship between risk assessments and aggression in an inpatient forensic setting, with such aggression categorized as impulsive, predatory or psychotic aggression. Consistent with previous research, impulsive aggression was the most frequent type observed (58%). Anger (as measured by the Novaco Anger Scale) and clinical issues (as measured by the HCR-20) were most associated with impulsive aggression, with AUC values of .73 and .71 respectively. In contrast, anger and psychopathy (as measured by the PCL-R) were more associated with predatory aggression, with AUC values of .95 and .84 respectively. Psychotic symptoms were highly associated with psychotically motivated aggression (AUC = .90). These results suggest that traditional violence risk assessments may have limited utility in predicting aggression in an institutional setting and that psychiatric symptoms and heightened affect are more relevant. Copyright © 2008 John Wiley & Sons, Ltd.     

Natural born killers: The genetic origins of extreme violence

The current article examines the influence of genetics and evolution on acts of extreme and criminal violence among human primates. Moderate aggression can function to increase an organism's reproductive success; extreme violence can place the organism at unnecessary risk. Genetic polymorphisms that have been linked to extreme acts of violence are reviewed as is research elucidating how genetic risk and environmental stress may interact to increase risk of extreme violence. Extreme violence is viewed as high-end variance in an evolutionarily adaptive process in which the propensity for aggression and violent behavior, in moderate doses, has been adaptive for individual humans.