Hormones and aggression in childhood and adolescence

This review is a survey on recent psychobiosocial studies on association between hormones and aggression/violence in children and adolescents, with a special focus on puberty, given the rapid changes in both hormones and behavior occurring during that developmental period. Since it cannot be assumed that all readers have much background knowledge, it inevitably begins with some comments about the concept and multifaceted nature of aggression, as well as with a brief reminding about hormone candidates to be linked to aggression during human development. Then, we finish off with the status of its knowledge in today's science, tackling in a systematic way with the main data published, hormone by hormone. The origin of the gender-based differences in aggression must lie in neuroendocrinological events occurring during prenatal life or early in postnatal life. A complex and indirect effect of testosterone on aggression is proposed. A low HPA axis activity seems associated with chronic aggressive and antisocial behaviors. It is also suggested that early adrenal androgens contribute to the onset and maintenance of persistent violent and antisocial behavior, and that it begins early in life and persists into adulthood, at least in young boys. There are also some studies suggesting an association between aggression and some pituitary hormones in children, even if present data are still far from being consistent. The hormone-aggression link during development thus is not consistently reported. There can be an indirect relation in three ways: hormones can be involved in the development of aggression as a cause, as a consequence, or even as a mediator. Psychosocial factors may influence the causation and progression of violence in children through hormonal action.     

The frontal lobe and aggression

Frontal lesions often lead to psychosocial problems. It is not surprising that frontal lobe dysfunctions have been proposed to underlie antisocial behaviour in individuals without apparent lesions. However, physical aggression and violence have never been systematically related to acquired lesions. Whereas, traditional neuropsychological testing identifies problems in cognitive and emotional information processing, recent brain-imaging studies have revealed both the frontal structural and functional underpinnings of antisocial behaviour. Careful characterization of antisocial behaviour subtypes seems to indicate that cognitive-neuropsychological function is systematically poor in physical aggression and hyperactivity. Recent refinements point to biological and genetic moderators of that association.     

Predictors of aggression in Southeast Asian female prisoners

Although aggression is universal, few studies examine violence from an Asian perspective, and even fewer consider female offenders from Southeast Asia. The current study examined whether correlates of aggression in western male offenders are similarly effective for predicting aggression in female inmates (n = 114) from a local prison in Singapore. Aggression was measured using the Buss–Perry Aggression Questionnaire (comprising dimensions of physical and verbal aggression, anger and hostility) which we sought to predict from measures of impulsivity, general personality traits (neuroticism, agreeableness), psychopathy, and empathy. Impulsivity and agreeableness were significant predictors of self-reported physical and verbal aggression and anger, whereas neuroticism contributed to anger. Neuroticism and psychopathy were significant predictors of hostility. Empathy did not significantly predict any of the four aggression dimensions. Personality, impulsivity and psychopathy appear fair predictors of aggression for female offenders from Southeast Asia, just as they are for the western male offenders.     

Violence restrained: Effects of self-regulation and its depletion on aggression

Aggressive impulses arise from many factors, but they are usually held in check by social norms for self-control. Thus, the proximal cause of aggression is often failure of self-restraint. In five studies, depleted capacity for self-regulation (caused by prior, even irrelevant acts of self-regulation) increased aggressive responding, especially after an insulting provocation. When participants were insulted and their self-regulatory strength was depleted (i.e., after completing previous tasks that required self-regulation), participants were more likely to aggress. When the urge to aggress was relatively weaker (i.e., when participants were not insulted), self-regulatory depletion did not increase aggressive behavior. This effect was moderated by trait self-control: Participants low in trait self-control were particularly likely to express intentions of behaving aggressively in response to provocation, whereas participants high in trait self-control did not express intentions of responding aggressively. Laboratory, autobiographical memory, and hypothetical responses confirmed the pattern.     

The effect of the amount of blood in a violent video game on aggression, hostility, and arousal

The current study utilized the General Aggression Model, with an emphasis on aggression-related priming, to explore the different effects on hostility, physiological arousal, and state aggression in those who played a violent video game (Mortal Kombat: Deadly Alliance) with differing levels of blood (maximum, medium, low, and off). Simple effects analyses showed that those in the maximum blood and medium blood conditions had a significant increase in hostility and physiological arousal, while those in the low blood and no blood conditions did not have such an increase in arousal and hostility. Further analyses indicated that those in the maximum and medium blood conditions used the character’s weapon significantly more often than those in the low and blood absent conditions. Implications and future research are discussed.     

This is your brain on violent video games: Neural desensitization to violence predicts increased aggression following violent video game exposure

Previous research has shown that media violence exposure can cause desensitization to violence, which in theory can increase aggression. However, no study to date has demonstrated this association. In the present experiment, participants played a violent or nonviolent video game, viewed violent and nonviolent photos while their brain activity was measured, and then gave an ostensible opponent unpleasant noise blasts. Participants low in previous exposure to video game violence who played a violent (relative to a nonviolent) game showed a reduction in the P3 component of the event-related brain potential (ERP) to violent images (indicating physiological desensitization), and this brain response mediated the effect of video game content on subsequent aggressive behavior. These data provide the first experimental evidence linking violence desensitization with increased aggression, and show that a neural marker of this process can at least partially account for the causal link between violent game exposure and aggression.     

An empirical examination of sex differences in scoring preschool children's aggression

Sex differences in adults’ observations and ratings of children’s aggression was studied in a sample of preschool children (N = 89, mean age = 44.00 months, SD = 8.48). When examining the direct observations made by trained observers, male observers, relative to female observers, more frequently recorded aggressive bouts, especially of boys. On rating scales assessing aggression, trained male raters also gave higher aggressive ratings than female raters. Lastly, we compared the ratings of trained female raters and female teachers on the same scale and found no differences. Results are discussed in terms male raters’ and observers’ prior experiences in activating their experiential schemata where males’ greater experience in aggression, relative to that of females, leads them to perceive greater levels of aggression.     

Facial affect recognition deficits: A potential contributor to aggression in psychotic illness

The current literature suggests a relationship between psychosis and the likelihood of engaging in aggressive behavior, though the factors involved are unclear. In this paper we use a social information processing framework to consider mediators of aggressive behavior in psychosis, especially facial affect recognition (FAR) deficits. The theoretical underpinnings of aggressive behavior are explored using the General Aggression Model (GAM) and FAR deficits are posited as a possible contributor to increased aggression in psychosis. Current research investigating the relationship between FAR, psychosis, and aggression is critically examined, and the role of potential confounding variables including positive symptoms, psychopathic personality traits, childhood trauma, and substance use briefly explored. In conclusion, we argue that socioemotional processing deficits, such as impaired FAR, are a fruitful area for research aimed at understanding, and hence reducing the risk of violence in psychosis.     

Risk and dynamics of violence in Asperger's syndrome: A systematic review of the literature

The main purpose of this article is to delineate findings from a review of the literature on the empirical basis for the existence of a relationship between Asperger's syndrome (AS) and violence risk. A second aim is to examine whether certain characteristics of the disorder may have a higher violence-triggering potential. Results of this review show that there are very few empirical studies that confirm a stable link between AS and violence. Only 11 studies involving 22 patients and 29 violent incidents met the criteria for inclusion in the review after the search of the literature. However, a qualitative analysis of the studies yielded some indications of possible patterns of dynamics of violence that may prove to be typical of persons with AS. A tentative comparison of AS and psychopathy indicated that there may be qualitative differences in the characteristics of violent behavior between the disorders. Suggestions for further research are presented.     

Anger,aggression, risky behavior,and crash-related outcomes in three groups of drivers

High anger drivers who acknowledged problems with driving anger and were interested in treatment were compared to high and low anger drivers who did not acknowledge problems with driving anger or want treatment. Although high anger drivers who acknowledged problems reported greater anger on two measures than high anger drivers who did not acknowledge problems, both high anger groups tended not to differ from one another and were more frequently and intensely angered when driving, reported more aggressive and less adaptive/constructive forms of expressing anger while driving, engaged in more aggressive and risky behavior on the road, and experienced more of some accident-related outcomes than low anger drivers. High anger groups did not differ from each other, but reported more trait anxiety and anger and more outward negative and less controlled general anger expression than the low anger group. The two groups of high anger drivers, however, require different types of interventions given their state of readiness for driving anger reduction. Results were also interpreted as supportive of the state-trait model of anger and construct validity of the Driving Anger Scale.     

Defensive self-esteem and aggression in childhood

Research examining the association between self-esteem (SE) and aggressive behavior in childhood has produced mixed findings. Some of the confusion may stem from the fact that researchers have relied on explicit measures of SE, thus conflating two distinct types of positive self-regard: secure SE (characterized by high levels of explicit and implicit SE), and defensive SE (characterized by high levels of explicit but low levels of implicit SE). The current study tested the hypothesis that children with high levels of defensive, but not secure, SE would engage in higher levels of aggressive behavior. Ninety-three children completed measures of both explicit and implicit SE. Teachers assessed children’s level of physical and relational aggression in the school setting. As predicted, there was a positive association between explicit SE and aggression when levels of implicit SE were low, but not when levels of implicit SE were high.     

Emotion regulation and aggression

This review considers the impact of deliberate emotion regulation on aggression, by integrating findings from recent emotion regulation research with a contemporary model of aggressive behavior, the General Aggression Model. First, it considers how individuals who under-regulate anger and other emotions may be more likely to behave aggressively in an attempt to repair, terminate, or avoid uncomfortable emotional states. Second, it explores how over-regulation of emotion may lead to aggressive behavior by increasing negative affect, reducing inhibitions against aggression, compromising decision making processes, diminishing social networks, increasing physiological arousal and hindering the resolution of difficult situations. Finally, it reviews three skills thought to underlie deliberate emotion regulation: emotional awareness, emotional acceptance and proficiency in a variety of emotion regulation strategies. Treatment encompassing all of these skills may improve an individual's ability to regulate difficult emotion states more adaptively and thereby lessen aggressive behavior.     

How attribution influences aggression: Answers to an old question by using an implicit measure of anger

The present study investigated how aggressive reactions to frustration are influenced by attributional processes. In particular, we examined how the information that another person did not intend a frustration affects anger and aggression. Previous research was inconclusive if attribution to unintentionality decreases anger and aggressive impulses or if it increases the control of aggressive impulses resulting in a selective decrease of aggressive reactions that are controllable. To test these assumptions, two thirds of participants were frustrated by negative evaluations that were paired with aversive sounds from an ostensible team partner. The remaining participants received positive evaluations that were paired with pleasant sounds. Then, half of the frustrated participants obtained a message suggesting that their partner had confused the response scale and had actually meant to deliver an opposite evaluation. This apologizing information was effective in decreasing subsequent aggressive behavior but not in reducing anger as assessed by an implicit measure. This finding is in line with the notion that attribution to unintentionality leads to control of aggressive impulses. We conclude that such attributions influence aggressive behavior mainly via reflective pathways, while impulsive processes remain largely unaffected.     

Experiences of peer aggression and parental attachment are correlated in adolescents

Whether levels of parental attachment differentiate how individuals are peer victimised was studied in 13, 14 and 15 year olds (N = 204), who completed a modified version of the Direct and Indirect Aggression Scales (DIAS) and the parent sections of the Inventory of Parent and Peer Attachment (IPPA). Results showed a moderate negative correlation between Total Victimisation scores and Total Attachment scores (r = −.254, p = .001, CI₉₅ = [−.38, −.12]); the magnitude of correlations was similar for subscale scores and for data on both mother and father considered separately; data did not differ by gender of the respondent. Attachment to mother significantly exceeded attachment to father. The factor structure of the self-report DIAS was explored and a hierarchical solution suggested that it measures general experience of victimisation along with two lower order factors defined by experiences of either direct or indirect aggression.     

Body weight, not facial width-to-height ratio, predicts aggression in pro hockey players

Studies indicate that facial characteristics may predict behavior, but it is unclear if this will hold within highly selective populations. One relevant characteristic is the face’s width-to-height ratio (FWHR), a sexually dimorphic trait that has been shown to predict aggression. That FWHR may predict aggression within highly selective populations was suggested by Carré and McCormick’s (2008) finding that professional hockey players with greater FWHRs accrued more penalties. We attempted to replicate this result using all NHL players. We also explored fighting penalties as another aggression measure and height and weight as additional aggression predictors. We found that body weight predicted substantial variance in aggression but FWHR did not. Thus, in highly selective populations, inferences based on faces may be inaccurate.     

Dostoevsky’s enigmas: An analysis of violent men

For the calculating male adult criminal, violent acts would appear largely counterproductive. Scholarly disagreements about these behaviors are substantial, although recent ethnographic reports emphasize the subjective sense of the experience. These reports have an existential aspect, focusing on the meaning of violent, anarchic acts to the identities of perpetrators. The earliest and best known existentialist writer on criminality is Fyodor Dostoevsky whose violent characters Smerdiakov, Svidrigailov, and Stavrogin, are enigmas to their fictional counterparts, much as violent American contemporaries are to authorities and the general public. Dostoevsky’s three enigmatic characters are reckless publicity seekers; like aliens in their own land, they habitually deceive, intimidate, and exploit while still considering themselves to be decent individuals. These depictions are congruent with Yochelson and Samenow’s much more recent forensic observations and reinforce an antisocial prototype. Bogg (1994) offers a behavioral communality for this class of violent men: patterns of self-aggrandizing gaming developed in childhood. The game player derives extraordinary pleasure from victories, although this orientation effectively counters socialization. From Dostoevsky’s views an existential nihilistic construct can be derived. This construct depicts the persona of an inveterate violent game player and is consistent with Durkheimian theory and with ethnographic and forensic/clinical observations. The prevention of a gaming orientation is feasible but appears to require parental skills and community resources.     

Moral judgments of the powerless and powerful in violent intergroup conflicts

The present research examined observers' moral judgments of groups in conflict. Study 1 found support for the prediction that actions are interpreted as more moral in the context of low power. People judged the violent actions of a fictitious group as more moral and justifiable when done by a smaller, less powerful country compared to a larger one. However, a second study found that violence may undermine the moral advantage accorded underdog groups. People reading about Israeli construction of settlements in Palestinian territories judged the Israeli actions to be more moral when Palestinians resisted violently compared to when they used non-violent resistance tactics. Together, these studies demonstrate how moral judgments of the actions of groups in conflict are influenced by contextual factors independent of the actions themselves.     

Evaluation of a Spanish version of the Buss and Perry aggression questionnaire: Some personal and situational factors related to the aggression scores of young subjects

The psychometric properties of a Spanish translation of the Buss and Perry aggression questionnaire adapted for pre-adolescents and adolescents have been studied. A maximum-likelihood confirmatory factor analysis corroborates Buss and Perry’s four-factor structure. The internal consistency of each factor and of the total score has proved to be satisfactory. The four factors are more closely interrelated in pre-adolescents than in adolescents.A second aim of this work has been to further our understanding of the possible relationship between aggression scores and certain outside-school activities of the subjects studied. Two thousand two hundred and eight students filled in the questionnaire together with a self-report concerning their habits. The results show that the aggression scores rise concomitantly with time spent watching television and playing video games and decrease the greater the time devoted to extra-curricular reading or moderate amounts of homework. Statistically significant differences relating to age and gender were also found.