Testosterone, cortisol, and serotonin as key regulators of social aggression: A review and theoretical perspective

In human and non-human animals the steroid hormones cortisol and testosterone are involved in social aggression and recent studies suggest that these steroids might jointly regulate this behavior. It has been hypothesized that the imbalance between cortisol and testosterone levels is predictive for aggressive psychopathology, with high testosterone to cortisol ratio predisposing to a socially aggressive behavioral style. In this review, we focus on the effects of cortisol and testosterone on human social aggression, as well as on how they might modulate the aggression circuitry of the human brain. Recently, serotonin is hypothesized to differentiate between impulsive and instrumental aggression, and we will briefly review evidence on this hypothesis. The aim of this article is to provide a theoretical framework for the role of steroids and serotonin in impulsive social aggression in humans.     

Startle modulation during violent films: Association with callous–unemotional traits and aggressive behavior

The current study examined the unique and interactive associations of callous–unemotional (CU) traits, impulsive and premeditated aggression with startle modulation to violent films. Eighty-five participants (Mage = 20.52) at differential risk of CU traits, selected from a sample of 1105 young adults, participated in the physiological experiment. Startle eye-blink responses to acoustic probes were recorded during violent, comedy and neutral films. Self-report ratings of valence and arousal were also collected. Findings from regression analysis documented that CU traits were associated with diminished startle potentiation to violent films, whereas impulsive aggression was associated with increases in startle potentiation. Further, the negative association between CU traits with startle potentiation, valence, and arousal ratings to violent films was moderated by impulsive aggression. At the group level, individuals high on impulsive aggression without CU traits were the ones showing the highest levels of startle potentiation to violent films, and scored on the opposite extreme compared to individuals high on both CU traits and impulsive aggression.     

Similarities and differences in impulsive/premeditated and reactive/proactive bimodal classifications of aggression

Despite broad consensus regarding the value of the impulsive/premeditated and reactive/proactive aggression classifications, confusion as a result of imprecise language and the exact nature of subtypes have threatened its utility for clinical and research purposes. In order to increase the usefulness of these subtypes in research, prevention, and treatment, the current review examines whether differences in these two subtype classifications are theoretical, semantic or empirical. Correlates of impulsive, premeditated, reactive, or proactive aggression measures were examined for consistency. Based on the different conceptual roots, we expected that each subtype pair would evidence only partial correspondence such that the classification systems may actually be capturing different constructs. The findings of a targeted and selective review suggest there is more correspondence between reactive and impulsive aggression than there is between proactive and premeditated aggression. An agenda for future research is outlined.     

Empathic deficits and alexithymia in trauma-related impulsive aggression

Our long term interest is to develop a developmental model of impulsive aggression based on a confluence of social, psychological and biological features. This approach incorporates neurobiological research, which has identified language processing deficits as a unique characteristic of impulsive aggressors and extends it to include emotional deficits. As an initial test of this hypothesis, we examined whether empathy and alexithymia were associated with impulsive aggression. Regressions were performed to explore the associations among impaired empathy, alexithymia, impulsive aggression, verbal and physical general aggression. Among impulsive aggressive veterans (n = 38) recruited from a VA trauma clinic, alexithymia predicted impulsive aggression and empathic deficits predicted verbal aggression. Neither emotional awareness deficit predicted general physical aggression in this middle-aged sample. Results suggested that empathic deficits were associated with general verbal aggression, but alexithymia was uniquely associated with impulsive aggression. Consideration of alexithymia in impulsive aggression has implications for its etiology, prevention and treatment. Published in 2008 by John Wiley & Sons, Ltd.     

Parent–child interactions and relational aggression in peer relationships

The major aim of this review is to propose new ways of thinking about the role of parents in the development and course of children’s relationally aggressive behavior. An important theoretical framework from which to start thinking about linkages between parenting and relational aggression is provided by attachment theory. Attachment theory proposes that early family experiences are an important basis for the development of later peer relationships. Recent studies are only beginning to suggest possible linkages between children’s parental attachment and relational aggression. One possible reason for the scant research is that theoreticians studying these constructs have not yet developed a conceptual framework combining the two, but rather have focused on different characteristics of different interpersonal contexts. Based on the premise that both relational aggression and attachment are relational constructs and given the already established correlations between insecure attachment and physical aggression, this paper will attempt to devise a heuristic model that may serve as an aid to discover links between parent–child interactions, attachment, and relational aggression. Finally, implications for future studies of relational aggression are discussed.     

An Integrative Model of Work Attitudes,Motivation, and Performance

A comprehensive theoretical model of work attitudes, motivation, and performance is presented that integrates key constructs prevalent in more limited theories. The constructs were selected on the basis of their importance as shown by past research and because of their seeming complementarity rather than redundance with one another. The framework connects the constructs causally on the basis of both logic and empirical evidence. It is expressed in the form of a path diagram amenable to empirical test, in the hope that it will have heuristic value. It is expected that such an integration will provide a better basis for understanding and improving work attitudes, motivation, and performance than do the more limited approaches.     

A goal model of catharsis

Although research in social psychology has repeatedly refuted the idea that aggression reduces subsequent aggression (e.g., Bushman, 2002), we suggest a more fine-grained analysis of catharsis. We will present and discuss a social-cognitive goal model of cathartic effects in aggression that predicts under which conditions aggression increases or reduces subsequent aggression. The model assumes that the accessibility of aggression-related constructs is a function of goal fulfilment: Prior to goal fulfilment constructs related to the goal are highly accessible in order to facilitate goal fulfilment. However, after goal fulfilment this heightened accessibility loses its functionality and aggressive constructs are consequently inhibited. In the present article we will review empirical work testing this model. Moreover, we will extend this model to the effects of violent computer games. Finally we will discuss theoretical challenges and applied relevance of our model for intervention strategies aimed at reducing aggression.     

Relations between mechanisms of CNS arousal and mechanisms of stress

In the centennial year of the birth of Hans Selye, this review compares his classical concepts of stress with a modern approach to mechanisms of CNS arousal. Relations between the two concepts are described. Neuroanatomical, neurophysiological, and functional genomic mechanisms underlying CNS arousal are briefly reviewed. Controls over stress responses and arousal are compared to particular concepts of control system engineering. Understanding these two systems is of crucial importance because their dysregulation is associated with large numbers of disease states.     

Psychopathy and Axis I psychiatric disorders among criminal offenders: relationships to impulsive and proactive aggression

Both psychopathology and aggression are heterogeneous constructs. Determining which forms of psychopathology relate to risk for different classes of aggressive behavior has implications for risk recognition and management. This study examined the relationships of impulsive aggression (IA) and proactive aggression (PA) to psychopathy and symptoms of several Diagnostic and Statistical Manual Axis I disorders in a sample of criminal offenders. Results replicated prior findings from community samples of a broad relationship between psychopathology and IA. PA was related only to psychopathy. An interaction was found whereby IA was associated with impulsive–antisocial traits of psychopathy only for individuals with moderate to high levels of generalized anxiety. Results indicate that assessing and treating several Axis I disorders in offenders may decrease risk for IA. Moreover, current findings raise the possibility that generalized anxiety is a key, modifiable component of the relationship between IA and impulsive–antisocial traits. Aggr. Behav. 36:45–53, 2010. © 2009 Wiley‐Liss, Inc.     

Impulsive versus premeditated aggression: implications for mens rea decisions

Science can provide more information about the nature of aggressive acts, and therefore the mens rea of criminal offenses, than is commonly assumed. For example, progress has been made in classifying aggression as impulsive or premeditated within the context of the role of conscious experience in controlling behavior. This review of the status of the scientific ability to distinguish conscious from unconscious acts and more specifically impulsive from premeditated aggressive acts is organized around four themes: (i) How is aggression defined and measured in general? (ii) How does the distinction between impulsive and premeditated aggression relate to the legal concept of mens rea? (iii) How do various scientific disciplines contribute to the mind/body discourse? (iv) What risk factors are associated with impulsive and premeditated aggression respectively? The authors conclude that the most promising approach to researching the nature of behavioral intention and motivation is to apply a discipline neutral model that integrates the data from multiple disciplines, collectively designated the cognitive neurosciences.     

Personality and self-regulation: trait and information-processing perspectives

This article introduces the special issue of Journal of Personality on personality and self-regulation. The goal of the issue is to illustrate and inspire research that integrates personality and process-oriented accounts of self-regulation. The article begins by discussing the trait perspective on self-regulation--distinguishing between temperament and personality accounts--and the information-processing perspective. Three approaches to integrating these perspectives are then presented. These range from methodological approaches, in which constructs representing the two perspectives are examined in integrated statistical models, to conceptual approaches, in which the two perspectives are unified in a holistic theoretical model of self-regulation. The article concludes with an overview of the special issue contributions, which are organized in four sections: broad, integrative models of personality and self-regulation; models that examine the developmental origins of self-regulation and self-regulatory styles; focused programs of research that concern specific aspects or applications of self-regulation; and strategies for increasing the efficiency and effectiveness of self-regulation.     

Men's likelihood of sexual aggression: the influence of alcohol,sexual arousal,and violent pornography

Previous research findings have indicated that both alcohol intoxication and violent pornography exposure may contribute to increased sexual aggression by men. This study used an experimental paradigm to examine the effects of a moderate alcohol dose, alcohol‐related beliefs, and victim response on men's self‐reported likelihood of committing sexual aggression. A community sample of male social drinkers (N=84) participated in an experiment in which they read an eroticized rape depiction after completing an alcohol administration protocol. The stimulus story varied whether the victim, who initially expressed unwillingness to engage in sexual activity, expressed pleasure or distress in response to the man physically forcing her to perform several explicit sex acts. A path analytic model illustrated that participants' self‐reported likelihood of behaving like the sexual aggressor in the story was directly related to their own sexual arousal. Heightened sexual arousal was reported by participants who had consumed alcohol, those who read the victim‐pleasure story, and those who believed that drinking women are sexually vulnerable. Results suggest that sexual arousal to violent pornography, as influenced by acute alcohol intoxication and other factors, may be an important component of men's perceptions of their own sexual aggression likelihood. Aggr. Behav. 32:581–589, 2006. © 2006 Wiley‐Liss, Inc.     

Stepping up the pressure: arousal can be associated with a reduction in male aggression

The attentional myopia model of behavioral control [Mann and Ward, 2007] was tested in an experiment investigating the relationship between physiological arousal and aggression. Drawing on previous work linking arousal and narrowed attentional focus, the model predicts that arousal will lead to behavior that is relatively disinhibited in situations in which promoting pressures to aggress are highly salient. In situations in which inhibitory pressures are more salient, the model predicts behavior that is relatively restrained. In the experiment, 81 male undergraduates delivered noise-blasts against a provoking confederate while experiencing either high or low levels of physiological arousal and, at the same time, being exposed to cues that served either to promote or inhibit aggression. In addition to supporting the predictions of the model, this experiment provided some of the first evidence for enhanced control of aggression under conditions of heightened physiological arousal. Implications for interventions designed to reduce aggression are discussed.     

Forms and Functions of Aggression in Adolescents: Validation of the Portuguese Version of the Peer Conflict Scale

Aggression in adolescence may assume different forms and functions, and is often associated with maladjustment. To adequately assess aggression in adolescence, instruments need to evaluate both its forms and its functions, as is the case with the Peer Conflict Scale. This research presents and evaluates the Portuguese version of this instrument, and evaluates levels of aggression in an adolescent community sample (n?=?785; 63.6 % female, mean age of 15.97 years old). The four factor structure originally proposed for the instrument (i.e. proactive overt, reactive overt, proactive relational and reactive relational aggression) represented a satisfactory solution for the data, and for both girls and boys. Results also have shown adequate reliability. Regarding levels of aggression, boys reported being overall more aggressive than girls. When aggression is impulsive/ reactive, both boys and girls practice its overt form. It is only when the aggression is pondered upon (proactive) that boys and girls chose to use different forms of aggression. Accurately evaluating different forms and functions of aggression has implications for designing, implementing and evaluating adequate and tailored interventions.     

The therapeutic alliance–A conceptual analysis

The role and function of the therapeutic alliance in psychotherapy has increasingly been the focus of clinicians' and researchers' interests over the last decade. Alliance concepts have, however, been criticized for lack of conceptual clarity. The paper presents a generic model as a heuristic means for clarifying the conceptual meaning of the therapeutic alliance. The model distinguishes between the personal relationship aspect, and the collaborative, task-related aspect of the alliance, with therapist, patient, and common contributions to each of these aspects. The model is compared to other alliance conceptualizations, and its implications for alliance theory and research are discussed. A content analysis of four widely used alliance scales in relation to the model shows the scales to represent conceptually different, yet overlapping constructs. It is argued that the componential nature of the therapeutic alliance will render difficult any interpretation of findings regarding the relationship between alliance and outcome in traditional process-outcome research. More complex research strategies guided by theory are called for, if the therapeutic alliance should remain a vital field of research.     

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.     

Characterization of aggressive behavior and phenytoin response

Recent work has suggested that the success of pharmacological treatment for chronic aggressive behavior may depend, in part, on the subtype of aggressive behavior displayed (e.g. reactive, impulsive aggression vs. predatory, premeditated aggression). The present study examined the usefulness of characterizing aggressive behavior during a 16‐week double‐blind crossover study of phenytoin (PHT) treatment in 41 aggressive adult males. The Impulsive/Premeditated Aggression Scales (IPAS) were used to characterize aggressive behavior as predominantly impulsive or predominantly premeditated in nature. Analyses indicated that participants who did not respond to PHT treatment endorsed significantly more premeditated characteristics on the IPAS than those who responded to PHT treatment. Non‐responders also exhibited fewer aggressive outbursts during placebo treatment, suggesting a greater level of behavior control. Participants who did not complete the study were younger, endorsed significantly more premeditated aggression characteristics and reported more lifetime antisocial behaviors than those who completed the study. Taken together, these data emphasize several factors that may influence the success of pharmacological treatment in aggressive individuals, namely the importance of characterizing the predominant type of problem aggressive behavior. Aggr. Behav. 00:1–6, 2005. © 2005 Wiley‐Liss, Inc.     

Homeostasis,discrepancy, dissonance

The argument is presented that motivation is equated to energy mobilization, and that the mechanism involved in all such instances of arousal is a discrepancy-detecting and -reducing mechanism. Motives are specific categories of discrepancy but they operate through a common arousal system. This system, further, may be coopted into (integrated into) processes involving social comparison, relative deprivation, discrepancies with respect to ego-involved persons and objects, and industrial, social, and political motives. While biological homeostasis provides the basic CNS system, other forms of discrepancy-triggered energy arousal must be recognized as important. Hedonism and theories of curiosity, as well as other similar factors, can be subsumed under discrepancy theory.A portion of this paper was prepared with the support of NIMH Fellowship 1-F03-MH-54564-01.