Being aggressive and by extension, dominant, is an important mechanism for determining access to resources such as mates or territories. While predictors of contest outcome and dominance are increasingly studied, we have a poor understanding of how they vary across populations. Here, I use the widely distributed Australian agamid lizard, the Jacky dragon (Amphibolurus muricatus), to quantify variation in features predicting contest outcome among males of different populations. I measured physical attributes, maximal physiological performance capacity (sprint speed, endurance, bite force) and visual displays during staged encounters. I found that morphology, performance capacity and the type and frequency of visual displays used during agonistic interactions varied significantly across populations. Contest winners from the Cann River State Forest population favored tail-flicks and push-up/body-rocks, while those from Royal National Park were more likely to chase and individuals from Yarratt State Forest performed more bite-lunges than other populations. The losers of contests also differed in their displays. Individuals from the Cann River population were dominant over the others based on behavioral attributes (i.e., aggressive visual displays, chases and bite-lunges). I suggest that population differences in signal form and function could have implications for range dynamics as populations come into contact in an era of rapid environmental change.

Aggressive behaviors have been related to approach/avoidance tendencies. In our current study, we investigated whether approach/avoidance tendencies for angry versus fearful emotional expressions were differentially predictive of children's reactive and proactive aggression. A total of 116 children (58 girls, Mage = 10.90, standard deviation SDage = 0.98) completed an approach/avoidance task (AAT) and a stimulus-response compatibility task (SRCT), both measuring the extent to which they tended to approach or avoid angry and fearful facial expressions relative to neutral facial expressions. Children also completed a self-report scale of reactive and proactive aggression. Although none of the approach/avoidance tendency scores correlated significantly with either of the aggression scores, stronger approach tendencies for angry faces and stronger avoidance tendencies for fearful faces in the AAT predicted more reactive aggression. Similar yet nonsignificant results were found for proactive aggression, but no effects were replicated in the SRCT. Our results thus invite the conclusion that reactive aggression is characterized by a tendency to approach angry faces and a tendency to avoid fearful faces. However, the poor discrimination between both types of aggression as well as the lack of convergence between the results of our two measures of approach/avoidance tendencies indicates that further research is needed to establish the role of approach/avoidance tendencies for emotional faces as markers for childhood aggression.

Aggression refers to a wide range of behaviors with lasting individual and societal consequences. Recurrent, unplanned aggressive behavior is the core diagnostic criterion for intermittent explosive disorder (IED). In this study, we compared two behavioral measures of aggression in the laboratory: the Taylor Aggression Paradigm (TAP) and the Point-Subtraction Aggression Paradigm (PSAP). This sample (n = 528) included community participants who met DSM-5 criteria for IED (n = 156), met DSM-5 criteria for a nonaggressive psychiatric disorder (n = 205), or did not meet DSM-5 criteria for any psychiatric disorder (n = 167). All participants completed the TAP, a single-session PSAP, and relevant self-report measures. MANOVA analyses demonstrated differences between IED participants and nonaggressive participants; however, these group differences were no longer significant for the PSAP after including demographic variables. Correlation analyses found that the TAP and PSAP were positively related to one another and the composite variables associated with aggressive behavior (i.e., history of aggression, impulsivity, and propensity to experience anger) and; dependent correlations revealed that past aggression and trait anger were more strongly related to the TAP. Differences in TAP and PSAP outcomes may be partially attributed to operationalizations of aggression and methods of aggression and provocation. Further, as aggressive and nonaggressive participants differed on the PSAP somewhat mirroring the TAP, our results add to growing evidence of the validity of a single-session PSAP; further research is needed to fully establish single-session PSAP as a laboratory aggression task compared to the multi-session PSAP.

This study examined the mediating role of anger rumination in the relationship between anger and reactive aggression and the potential of adaptive anger rumination in reducing reactive aggression. Study 1, a two-wave longitudinal survey of 177 Chinese adolescents, showed that anger rumination mediated the relationship between anger and reactive aggression. Study 2, an experimental study with 160 university students, showed that the self-distanced group had lower aggression than the self-immersed group, and anger rumination mediated the impact of anger on reactive aggression in only the self-immersed group. These findings clarify the role of anger rumination concerning the relationship between anger and reactive-aggression and highlight the importance of self-distanced anger rumination in preventing reactive aggression among adolescents and young adults.

Green spaces, integral to natural environments, have been extensively studied for their positive impact on mental health, yet their influence on social behavior, particularly aggression, is less explored. While prior research has predominantly emphasized the effects of actively engaging with nature, the significant role of passive nature exposure-a more common daily occurrence-has often been overlooked. We conducted two studies to explore the influence of passive green space exposure on aggression and the mediating effect of the sense of control. Study 1 (N = 240) utilized a cross-sectional survey to assess the relationship between passive green space exposure, sense of control, and aggression. Study 2 (N = 260) employed a single-factor between-subjects experimental design to further explore these relationships in a controlled environment. The results from both studies indicated that passive green space exposure is negatively related to aggression, and that this relationship is partially mediated by an increased sense of control. Specifically, passive green space exposure was found to negatively predict aggression by bolstering individuals' sense of control. These findings underscore the potential of enhancing the sense of control through environmental factors like green spaces as an effective strategy to reduce aggression. This study enriches our understanding of the broader impacts of green spaces, extending beyond mental health to include social behaviors. We discussed both the theoretical and practical implications of our findings, highlighting how urban planning and environmental design can incorporate green spaces to foster community well-being and mitigate aggressive behaviors.

Chronic exposure to trauma and violence can promote aggressive behavior. Oxytocin and variants in the oxytocin receptor (OXTR) gene may play a role in the etiology of proactive, that is, goal‐oriented instrumental aggression, or reactive aggression, which typically occurs in response to emotionally triggering situations. The current study builds on previous findings that experienced and witnessed trauma in childhood predicts higher levels of appetitive aggression, a form of proactive aggression characterized by the enjoyment of participating in violent behavior. The current study explores the role of OXTR rs2254298 and rs53576 variants in appetitive and reactive aggression. Adult males living in Cape Town, South Africa, and at risk for violent behavior completed the Appetitive Aggression Scale (AAS) and Buss–Perry Aggression Questionnaire (BPAQ). OXTR rs2254298 and rs53576 were successfully genotyped via restriction fragment length polymorphism (RFLP) analysis in 238 and 239 participants, respectively. Regression analysis showed that rs2254298 G/G and A/G genotypes and the rs53576 A/G genotype were significantly associated with lower AAS scores (p < .001) compared to the A/A genotype. Additionally, genotype interaction analyses conducted in 232 participants, found that the combination of rs2254298 A/G and rs53576 G/G genotypes produced opposite effects on appetitive and reactive aggression. Specifically, this combination was associated with a 0.29‐point increase in AAS scores (p = .032) and a 0.13‐point decrease in BPAQ scores (p = .037) when compared to A‐allele homozygosity for both variants. These results suggest that genetic variation in a signaling system involved in influencing environmental and social salience may contribute to appetitive aggression.

The coevolution of bullying and friendship networks and the moderating effects of classroom bullying popularity norms were examined in a sample of 965 students (52.1% boys) in 22 fourth- and fifth-grade classes. Longitudinal social network analysis showed that children were more likely to bully their friends' victims (bully influence effect) and to be bullied by their friends' bullies (victim influence effect); two children bullying the same child were likely to be friends (bully selection effect), and two victims bullied by the same child were likely to be friends (victim selection effect). Bullying popularity norms served as moderators, and the bully selection effect was significant weaker in the context of low bullying popularity norms. This study adds understanding of bullying as a group process and provides implications for preventing school bullying.

1. AGGRESSIVE BEHAVIOR will consider manuscripts in the English language concerning the underlying causes or consequences of aggressive, antisocial, and violent behavior.Both behavioral and neuro-physiological studies concerning the underpinnings of human and animal aggression will be considered, and articles that integrate the two approaches are particularly encouraged.The journal focuses on empirical studies, but broad theoretical reviews are also encouraged.

The purpose of this study was to test whether the psychological inertia process believed to give rise to crime continuity is limited to aggressive delinquency or evolves from both aggressive and nonaggressive delinquency. Self-report data provided by 845 early adolescent youth (406 boys, 439 girls) were analyzed in an effort to test the hypothesis that aggressive rather than nonaggressive delinquency precipitates a rise in delinquency through the intervening influence of cognitive impulsivity but not moral neutralization. The hypothesis stated that of the four models evaluated in this study (aggressive delinquency → moral neutralization → offense variety; aggressive delinquency → cognitive impulsivity → offense variety; nonaggressive delinquency → moral neutralization → offense variety; nonaggressive delinquency → cognitive impulsivity → offense variety), only the aggressive delinquency → cognitive impulsivity → offense variety model would achieve significance. Consistent with this hypothesis, only the aggressive delinquency → cognitive impulsivity → offense variety pathway was, in fact, significant. The current findings suggest that the psychological inertia process may be driven by a pattern of aggressive delinquency followed by cognitive impulsivity and that neither nonaggressive delinquency nor moral neutralization contribute to the process. Theoretical and practical implications of these results are discussed.

This paper re-examined the factor structure of a recently developed parent report of aggression, the Provoked and Unprovoked Aggression Questionnaire, and evaluated measurement invariance and latent mean differences across gender, age, and time. Participants were 333 mothers of toddlers (younger age group: n = 167, 53.9% boys, Mage Time 1 = 18.30 months, SD = 0.45; older age group: n = 166, 48.8% boys, Mage Time 1 = 24.29 months, SD = 0.38) who filled out provoked (eightitems) and unprovoked (fiveitems) aggression scales twice over a 3-month period. We found evidence for the configural, metric, and scalar measurement invariance-a requirement needed to make a meaningful comparison between aggression means across gender, age groups, and time. When comparing means for boys and girls, gender differences emerged earlier for unprovoked than provoked aggression. Also, the frequency of provoked aggression increased among younger, but not older, toddlers. By developing a brief parental report of aggression in toddlerhood, we hope to fill a void of early aggression measures that tap the contextual variability in aggressive behaviors, and thereby stimulate more research to further our understanding of different types of aggression and their correlates in toddlerhood.