Predatory aggression in the mink (Mustela vison): Roles of serotonin and food satiation

5-Hydroxytrypotophan at a dose of 50 mg/kg intraperitoneally (i.p.) sharply increased neural serotonin (5-HT) levels in mink and considerably inhibited that animal's predatory attack on rats. Intraperitoneal injection of 5-HT (10 and 20 mg/kg) did not influence such rat-killing. Neural levels of 5-HT or 5-hydroxyindoleacetic acid (5-HIAA) and subsequent aggression by the predator did not change to any great degree after ingestion of a single meal. Abundance of natural mink food for 3 days was associated with an increased level of 5-HIAA in the lateral hypothalamus and the amygdala as well as with an increased latency to attack and to kill rats. 5-HT seems to represent an endogenous factor that inhibits predatory attack by the mink; this effect appears to function through increased metabolism of 5-HT in some brain regions, which is evident after abundant intake of tryptophan with the natural diet.     

Is indirect aggression typical of females? gender differences in aggressiveness in 11- to 12-year-old children

Gender differences regarding aggressive behaviour were investigated in 167 school children, 11 to 12 years of age, through peer-rating techniques supported by self-ratings and interviews. The social structure of the peer groups also was studied. The principal finding was that girls made greater use of indirect means of aggression, whereas the boys tended to employ direct means. Gender differences in verbal aggression were less pronounced. The social structure of peer groups was found to be tighter among girls, making it easier for them to exploit relationships and harm their victims by indirect manipulative aggression. Because indirect aggression has rarely been satisfactorily studied with tests of aggression, this finding may help to explain 1) the generally lower correlation found between peer-rated and self-rated aggression in girls than among boys (indirect means not being so readily recognized by the subject as a kind of aggression) and 2) the low stability of aggressiveness in girls often found in developmental studies.     

Facet-level analysis of the relations between personality and laboratory aggression

Multiple reviews and meta-analyses have identified the low pole of the Five-Factor Model (FFM) Agreeableness (also called Antagonism) as the primary domain-level personality correlates of aggression across self-report and behavioral methodologies. In the current study, we expand on this literature by investigating the relations between FFM facets and aggressive behavior as measured by laboratory competitive reaction time tasks (CRTTs). Across three samples (total N = 639), we conducted weighted mean analyses, multiple regression analyses, and dominance analyses to determine which FFM facets were the strongest predictors of aggression within and across domains. These analyses suggested that facets of Agreeableness were among the strongest consistent predictors of CRTT aggression, including Sympathy (r = −.21) and Cooperation (r = −.14), but facets from other FFM domains also yielded meaningful relations (e.g., Anger from Neuroticism; r = .17). We conclude by discussing these results in the context of controversies surrounding laboratory aggression paradigms and emphasizing the importance of considering small effect sizes in the prediction of societally harmful behavior like aggression.     

Internalizing problems and their impact on the relation between callous-unemotional traits,narcissism, and aggression

Narcissism and callous-unemotional (CU) traits have demonstrated relations with youth aggression across studies. However, different forms of narcissism and internalizing problems may exacerbate the relation between CU traits and aggression. To that end, the current study examined the degree to which interactions among internalizing problems, CU traits, and dimensions of narcissism related to aggression in a sample of 219 adolescents (83.1% males), ages 16–19, enrolled in a military-style residential program. Consistent with previous research, psychopathy-linked narcissism significantly moderated the relation between CU traits and aggression. Addtionally, self-reported aggression was highest among adolescents who endorsed high levels of CU traits, psychopathy-linked narcissism, and internalizing problems. The same pattern of results was not evident for other forms of narcissism. These results suggest that internalizing problems further increase the probability of aggression among adolescents with psychopathic tendencies (i.e., CU traits, psychopathy-linked narcissism). Further implications are discussed.     

Cyberbullying,cyber aggression,and cyber victimization in relation to adolescents’ dating and sexual behavior: An evolutionary perspective

This study examined adolescents’ cyberbullying, cyber aggression, and cyber victimization from an evolutionary perspective, extending previous research showing that traditional forms of bullying, aggression, and victimization are associated with reproductively relevant outcomes. Consistent with hypotheses based on theory and research linking bullying and aggression to intrasexual competition for mates, results indicated that cyber victimization was positively associated with a number of dating and sexual partners. Findings for cyber aggression were more complex, depending on the degree of cyber victimization experienced by the perpetrator, and the balance of power between the perpetrator and victim. Specifically, nonbullying cyber aggression by perpetrators with equal or less power than the victim had stronger positive relations with the number of dating or sexual partners when perpetrators experienced a high level of cyber victimhood. In contrast, cyberbullying by perpetrators with more power than the victim was negatively associated with the number of dating partners when the perpetrators’ exposure to cyber victimization was low. Although cyber aggression and cyber victimization are new forms of aggression that involve the use of modern electronic devices, the results of this study demonstrate the usefulness of viewing this behavior from an evolutionary perspective and show that adolescents are likely to use cyber aggression against rivals in the context of intrasexual competition for mates.     

A combination of combat experience,early abduction,and severe traumatization fuels appetitive aggression and violence among abductees of rebel war in Northern Uganda

Individuals who perpetrate violence may likely perceive violence as appealing and infliction of violence to derive pleasure is termed as appetitive aggression. Individuals who were abducted as children into an armed group often experience a higher number of traumatic event types, that is traumatic load and are usually socialized in a violence-endorsing environment. This study aims to investigate the interaction between age at initial abduction with that of traumatic load, and their influence on appetitive aggression along with perpetration of violent acts by former members of an armed rebel group of both sexes. Semi-structured interviews were conducted among a target group of formerly abducted rebel-war survivors (including participants with and without combat experience) from Northern Uganda. Participants included 596 women and 570 men with N = 1,166 (M_age = 32.58, SD_age = 9.76, range: 18–80 years). We conducted robust linear regression models to investigate the influence of age at initial abduction, traumatic load, combat experience, and biological sex on appetitive aggression as well as their perpetrated violent acts. Our study shows, appetitive aggression and the number of perpetrated violent acts were specifically increased in individuals who were abducted young, experienced several traumatic events in their lifetime, and with previous combat experience. For perpetrated violence men showed increased levels whereas for appetitive aggression the association was independent of biological sex. Therefore, early abducted individuals with a higher traumatic load, who have combat experience, need to be given special intervention to prevent any further violence.     

Relations between forms and functions of aggression and moral judgments of aggressive transgressions

The present study sought to examine the influence of aggressive behavior, psychopathy, and gender on moral judgments of aggressive transgressions. A two-dimensional conceptualization of aggression was used, such that proactive relational aggression, reactive relational aggression, proactive physical aggression, and reactive physical aggression were treated as distinct subtypes of aggression and also as distinct subtypes of moral judgments of aggression. Participants were 421 emerging adults (215 women). Self-report measures of aggression, psychopathy, and moral judgments were collected. Peer-reports of aggression and psychopathy were obtained from a randomly assigned subsample of 73 participants (46 women) for validity purposes. Unique associations were found between subtypes of aggression and corresponding moral judgments of the same subtypes.     

Making Americans Feel Great Again? Personal Significance Predicts Political Intentions of Losers and Winners of the 2016 U.S. Election

Reactions of losers and winners of political elections have important consequences for the political system during times of power transition. In four studies conducted immediately before and after the 2016 U.S. presidential elections, we investigated how personal significance induced by success or failure of one's candidate is related to hostile versus benevolent intentions toward political adversaries. We found that the less significant supporters of Hillary Clinton and supporters of Donald Trump felt after an imagined (Study 1A) or actual (Study 2) electoral failure the more they were willing to engage in peaceful actions against the elected president and the less they were willing to accept the results of the elections. However, while significance gain due to an imagined or actual electoral success was related to more benevolent intentions among Clinton supporters (Study 1B), it was related to more hostile intentions among Trump supporters (Studies 1B, 2, and 3).     

留守初中生同伴侵害与攻击性的关系:链式多重中介模型

为探究留守初中生同伴侵害与攻击性的关系机制,通过构建链式多重中介模型,考察歧视知觉、孤独感和心理韧性在二者关系中的多重中介效应。采用问卷调查法对519名留守初中生进行调查,结果显示：（1）留守初中生同伴侵害的发生率为96.3%,具有普遍性;（2）留守初中生同伴侵害、歧视知觉、孤独感、心理韧性与攻击性之间均呈显著相关;（3）留守初中生的歧视知觉、孤独感和心理韧性在其同伴侵害与攻击性的关系中具有链式多重中介作用;（4）同伴侵害与攻击性关系模型具有一定稳定性,同时在是否留守及单亲与双亲外出留守初中生群体中存在显著差异。研究结果揭示了同伴侵害与攻击性的关系机制,可为探索留守初中生不良同伴关系的教育策略提供参考。     

Just banter? Friendship,teasing and experimental aggression in adolescent peer networks

Aggressive behaviour serves many useful social functions, yet can also have damaging consequences. In line with evidence showing adolescent development in social cognitive abilities, we hypothesized that the use of aggression would become more sophisticated with age. We investigated adolescent aggression towards peers using an experimental, hypothetical aggression paradigm, the hot sauce paradigm, in a school‐based social network setting. Participants (N = 162 aged 11–17, 98 male) indicated which strength of imaginary hot sauce they would allocate to each of their classmates. A Social Network Questionnaire quantified participants’ perceived dyadic social tie strength with each classmate, and the incidence of mutual or unilateral dyadic real‐world aggression (e.g. teasing). Participants allocated weaker hot sauce to peers with whom they reported strong, positive social ties and an absence of self‐reported unilateral real‐world aggression. With increasing cross‐sectional age, there was a decrease in the impact of social tie strength and an increase in the extent to which hot sauce allocation was predicted by self‐reported mutual real‐world aggression. This pattern of findings is consistent with young (vs. late) adolescent use of experimental, hypothetical Hot Sauce aggression to reflect real‐world animosity, while late adolescents’ behaviour is more subtle. These findings extend our understanding of the dyadic social context of adolescent aggressive behaviour using a novel experimental aggression paradigm.