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Although it is known that social dominance orientation directly affects hate speech perpetration, few studies have explored the mechanisms by which this effect takes place during adolescence. Based on the socio‐cognitive theory of moral agency, we aimed to fill this gap in the literature by exploring the direct and indirect effects of social dominance orientation on hate speech perpetration in offline and online settings. The sample included seventh, eigth, and ninth graders (N = 3225) (51.2% girls, 37.2% with an immigrant background) from 36 Swiss and German schools who completed a survey about hate speech, social dominance orientation, empathy, and moral disengagement. A multilevel mediation path model revealed that social dominance orientation had a direct effect on offline and online hate speech perpetration. Moreover, social dominance also had indirect effects via low levels of empathy and high levels of moral disengagement. No gender differences were observed. Our findings are discussed regarding the potential contribution to preventing hate speech during adolescence. [ABSTRACT FROM AUTHOR]

Dominance hierarchies are generally established based on the levels of aggressiveness that animals present. Frequently, animals fight to establish a dominance hierarchy and obtain a disputed resource. The Mexican mojarra Cichlasoma istlanum is a native species of the Balsas river basin and coexists there with four nonnative cichlids: tilapia Oreochromis sp., convict cichlid Amatitlania nigrofasciata, spotcheek cichlid Thorichthys maculipinnis, and green terror Andinoacara rivulatus. These five cichlid species compete for spaces for reproduction, feeding, and shelter and frequently engage in aggressive interactions to obtain these resources. We quantified dominance indices to evaluate the hierarchical structure of dominance among these five cichlids and the duration of aggressive behaviors of the Mexican mojarra during experimental contests between the native species and each of the four nonnative species. The Mexican mojarra was consistently dominant over the other four cichlid species, performing a larger number of aggressive behaviors and investing more time in attacking than the nonnative cichlids, which resulted in a higher hierarchical position. Our results show that the native fish, Mexican mojarra, established dominance over all four nonnative cichlid fish of the Balsas basin. Thus, the establishment of nonnative cichlid species in the Balsas basin is likely associated with factors other than behavioral dominance. [ABSTRACT FROM AUTHOR]

Research has consistently demonstrated that faces manipulated to appear more masculine are perceived as more dominant. These studies, however, have used forced‐choice paradigms, in which a pair of masculinized and feminized faces was presented side by side. These studies are susceptible to demand characteristics, because participants may be able to draw the conclusion that faces which appear more masculine should be rated as more dominant. To prevent this, we tested if dominance could be perceived when masculinized or feminized faces were presented individually for only 100 ms. We predicted higher dominance ratings to masculinized faces and better memory of them in a surprise recognition memory test. In the experiment, 96 men rated the physical dominance of 40 facial photographs (masculinized = 20, feminized = 20), which were randomly drawn from a larger set of faces. This was followed by a surprise recognition memory test. Half of the participants were assigned to a condition in which the contours of the facial photographs were set to an oval to control for sexual dimorphism in face shape. Overall, men assigned higher dominance ratings to masculinized faces, suggesting that they can appraise differences in facial sexual dimorphism following very brief exposure. This effect occurred regardless of whether the outline of the face was set to an oval, suggesting that masculinized internal facial features were sufficient to affect dominance ratings. However, participants' recognition memory did not differ for masculinized and feminized faces, which could be due to a floor effect. [ABSTRACT FROM AUTHOR]

Two trials were carried out to determine: (a) if there is a positive relation between the frequency of aggressive interactions among female pampas deer and their position within the hierarchy (HI), (b) if short-term removal of the male triggers an increase in the frequency of aggression, and (c) if the magnitude of this increase is related to the individual rank position of the female. Each of 19 breeding groups comprised one adult male and from four to six adult females. The HI was determined for each female and all aggressive interactions were recorded. These were recorded while the male was present (i.e., all of Trial 1 and the "with male" period in Trial 2) and after removal of the male (i.e., the "without male" period in Trial 2). The individual percentage change in the frequency of aggressive interactions after male removal was calculated. In Trial 1 the HI, the frequency of different types of aggressive interaction and the total of aggressive interactions were positively related (all: p < .001; General Linear Mixed Model [GLMM]). In Trial 2, the frequency of total aggressive interactions increased after male removal (F(1, 27) = 3.5; p < .001; GLMM). The individual percentage changes in aggressive interaction between periods were positively related to HI (F(6, 24) = 2.56; p = .05; GLMM). For female pampas deer maintained in breeding groups, we conclude that the frequency of aggressive interactions increases within the hierarchy. Aggression also increases after the short-term removal of the male, mainly among females of higher social status. [ABSTRACT FROM AUTHOR]

Online video games are social spaces for players from around the world. They use this space to form communities, relationships, and identities. However, gaming communities are not always welcoming, and some are even perceived as being "toxic." A prevalent issue is online sexual harassment, which is keeping many women from participating in the gaming community. Research on the factors contributing to the problem is limited, though. The present study replicates and expands previous research, using a sample of 856 online gamers. The study supports earlier findings that found hostile sexism and social dominance orientation as predictors of sexual harassment perpetration in online video games. In addition, we expanded the previous research with additional predictors: machiavellianism, psychopathy, and gamer identification predicted higher sexual harassment perpetration. Our results have implications for the gaming community's role in curtailing sexual harassment and making itself a more inclusive community. [ABSTRACT FROM AUTHOR]

Psychological research suggests that violent extremism (e.g., terrorism) stems partly from existential motives, such as individuals' need to achieve significance in life after experiencing failure, ostracism, or humiliation (Significance Quest Theory; SQT). Parallel investigations from sociology and criminology established similar findings by linking anomia-a syndrome including feelings of meaninglessness, powerlessness, isolation, self-estrangement, and normlessness-with violent behavior. In line with SQT, this contribution tested if anomia could mediate Loss of Significance effects on violent extremism. Accordingly, three studies conducted in France highlight indirect effects of exposure to discrimination on legitimation of political violence (Study 1, cross-sectional, minority population sample, N = 110), violent behavioral intentions (Study 2, experimental, undergraduate sample, N = 249), and support for ISIS fighters (Study 3, experimental, undergraduate sample, N = 221) through anomia. A subsequent study shows this indirect effect to be robust when controlled for Social Dominance Orientation and Political Extremism (Study 4, cross-sectional, undergraduate sample, N = 279). A final investigation re-analyzing data collected in Turkey highlights a reverse effect when the independent variable tapped into social inclusion (rather than exclusion; Study 5, cross-sectional, undergraduate sample, N = 321). This indirect effect was also robust to Political Extremism and Intolerance as control variables. These results support the usefulness of considering anomia as a proximal predictor of violent extremism in a SQT perspective. [ABSTRACT FROM AUTHOR]

Negative consequences of video games have been a concern since their inception. However, one under-researched area is the potential negative effects of sexualized video game content on players. This study analyzed the consequences of sexualized video game content on online sexual harassment against male and female targets. We controlled for a number of variables that might be related to online sexual harassment (i.e., trait aggressiveness, ambivalent sexism, online disinhibition). Participants (N = 211) played a video game with either sexualized or non-sexualized female characters. After gameplay, they had the opportunity to sexually harass a male or a female partner by sending them sexist jokes. Based on the General Aggression Model integrated with the Confluence Model of Sexual Aggression (Anderson & Anderson, ), we predicted that playing the game with sexualized female characters would increase sexual harassment against female targets. Results were consistent with these predictions. Sexual harassment levels toward a female partner were higher for participants who played the game with sexualized female characters than for participants who played the same game with non-sexualized female characters. These findings indicate that sexualization of female characters in a video game can be a sufficient condition to provoke online sexual harassment toward women. [ABSTRACT FROM AUTHOR]

Research from a variety of disciplines suggests a positive relationship between Western cultural sexualization and women's likelihood of suffering harm. In the current experiment, 157 young men were romantically rejected by a sexualized or non-sexualized woman then given the opportunity to blast the woman with loud bursts of white noise. We tested whether the activation of sexual goals in men would mediate the relationship between sexualization and aggressive behavior after romantic rejection. We also tested whether behaving aggressively toward a woman after romantic rejection would increase men's feelings of sexual dominance. Results showed that interacting with a sexualized woman increased men's sex goals. Heightened sex goal activation, in turn, predicted increased aggression after romantic rejection. This result remained significant despite controlling for the effects of trait aggressiveness and negative affect. The findings suggest that heightened sex goal activation may lead men to perpetrate aggression against sexualized women who reject them. [ABSTRACT FROM AUTHOR]

Based on a social dominance approach, aggression is conceptualized as a strategy used to gain position, power, and influence within the peer network. However, aggression may only be beneficial when targeted against particular peers; both victims' social standing and the number of victims targeted may impact aggressors' social standing. The current study examined associations between aggressors' targeting tendencies (victims' social standing and number of victims) and aggressors' own social standing, both concurrently and over time. Analyses were conducted using three analytic samples of seventh and eighth grade aggressors (Ns ranged from 161 to 383, 49% girls; 50% Latina/o). Participants nominated their friends; nominations were used to calculate social network prestige. Peer nominations were used to identify aggressors and their victim(s). For each aggressor, number of victims and victims' social network prestige were assessed. Aggressors with more victims and with highly prestigious victims had higher social network prestige themselves, and they increased more in prestige over time than aggressors with fewer victims and less prestigious victims (though there were some differences across analytic samples). Findings have implications for the need to extend the social dominance approach to better address the links between aggressors and victims. Aggr. Behav. 43:364-374, 2017. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Malamuth's (1998) confluence model holds that the combination of hostile masculinity, impersonal sexuality, and the constellation of high dominance and low nurturance plays a crucial role in explaining men's sexual aggression against women. Most studies on the confluence model concentrate on hostile masculinity and impersonal sexuality rather than dominance and nurturance. Using a person-centered approach, we investigated whether sexual aggressive men could be better identified in a sample of 692 men when not only hostile masculinity and impersonal sexuality but also dominance and nurturance were used as indicators in a latent profile analysis. Regardless of whether dominance and nurturance were considered or not, latent profile analyses revealed a high-risk group, which showed higher sexual aggression than other groups. In both cases, the sensitivity (i.e., the proportion of sexually aggressive men correctly assigned to the high-risk group) was low (33% and 31%, respectively) but increased substantially for the identification of severe sexual aggression. The positive prediction value, however, increased from 68% to 78% when dominance and nurturance were considered as predictor variables in addition to hostile masculinity and impersonal sexuality, indicating that more men assigned to the high-risk group were indeed sexually aggressive. These results demonstrate the power of the confluence model for identifying sexually aggressive men from a person-centered perspective. They also point to the necessity of expanding this perspective by considering further (e.g., situational) risk factors, which have previously been identified as predicting sexually aggressive behavior in men. Aggr. Behav. 43:251-262, 2017. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The dual-hormone hypothesis suggests that testosterone is positively associated with status-seeking tendencies such as aggression and dominance, particularly in individuals with low levels of cortisol. Although recent research supports the dual-hormone hypothesis, its boundary conditions under which the dual-hormone interaction is likely to emerge are not clearly understood. In the present study (N = 153), the dual-hormone hypothesis was empirically tested in the context of an economic game that included a decision whether to dominate another individual. We also examined whether the dual-hormone interaction is more likely to be found in individuals who are chronically prone to dominance tendencies. Results revealed a significant testosterone × cortisol interaction in line with the dual-hormone hypothesis. Additionally, the testosterone × cortisol interaction was only significant in individuals with a high level of chronic dominance. Overall, the present work suggests that chronic personality tendencies should be taken into account in order to explore (the boundary conditions) of hormone-behavior associations. Aggr. Behav. 43:85-92, 2017. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Online video games afford co-play and social interaction, often anonymous, among players from around the world. As predicted by the social identity model of deindividuation effects, undesirable behavior is not uncommon in online gaming environments, and online harassment has become a pervasive issue in the gaming community. In this study, we sought to determine what personality traits and game-related variables predicted two types of online aggression in video games: general harassment (e.g., skill-based taunting, insulting others' intelligence) and sexual harassment (e.g., sexist comments, rape threats). Men who play online video games (N = 425) participated in an anonymous online survey. Social dominance orientation and hostile sexism predicted higher levels of both sexual harassment and general harassment in online games. Game involvement and hours of weekly gameplay were additional predictors of general harassment. We discuss implications of online social aggression and online sexual harassment for online gaming. We also apply our findings to the broader understanding of online harassment, cyberaggression, cyberbullying, and other forms of online hostility in computer-mediated communication contexts. Aggr. Behav. 42:513-521, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

This study expands on prior research suggesting that children who either over- or under-estimate their social competence relative to others' reports are more likely to be aggressive. Linear and curvilinear associations between biased social self-perceptions and forms (physical vs. relational) and functions (proactive vs. reactive) of aggression were tested along with three moderators (peer rejection, social dominance goals, and child sex). Children in the fifth through eight grade (N = 167) completed self-reports of perceived social competence and social dominance goals. Teachers completed ratings of children's social competence, peer rejection, and reactive and proactive physical and relational aggression. Bias in self-perceived social competence was quantified as the residual difference between child and teacher ratings of the child's social competence. There was a significant interaction between quadratic bias and peer rejection predicting reactive physical aggression; rejected children with a positive bias or a negative bias were highest in reactive physical aggression. The interaction between linear bias, social dominance goals, and the sex of the child was also significant when predicting proactive physical aggression. Among girls who highly valued social dominance, a positive bias predicted greater proactive physical aggression. Results are discussed in terms of implications for aggression theory and intervention. Aggr. Behav. 42:498-509, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The relevance of interpersonal hostile-dominance (HD) to post-discharge aggression in mental health patients is unclear. This study assessed whether (1) HD is stable over time; (2) the relationship between HD and positive, negative, disorganized, and excited symptoms is consistent over time; and (3) HD is related to aggression post-discharge. Two hundred psychiatric inpatients were recruited on admission to hospital; 41 were available for follow-up at 6 months post-discharge, including 29 men and 12 women, with an age range of 19-63 (M = 39.63 years, SD = 12.69 years). Psychiatric symptomatology and interpersonal style were assessed at recruitment and follow-up; aggression in the community post-discharge was measured at follow-up. Results showed that (1) HD was stable over time despite an overall reduction in psychiatric symptoms, (2) HD was positively correlated with symptom severity at both time points, and (3) higher HD, excited symptoms, and positive symptoms measured in the community, and more severe positive symptoms measured in hospital, were associated with aggressive behavior post-discharge. These results suggest that HD is a risk factor for more severe psychopathology. Furthermore, HD, positive symptoms, and excited symptoms measured in the community act as risk factors for aggressive behavior post-discharge. As such, treatment planning and risk assessment should consider HD. Aggr. Behav. 42:324-332, 2016. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

It has been shown that a smaller ratio between the length of the second and fourth digit (2 D:4 D) is an indicator of the exposure to prenatal testosterone ( T). This study measured the 2 D:4 D of men and assessed dominance as a personality trait to investigate indirectly if the exposure to prenatal T is related to a dominant personality later in life. Results showed that men had a more aggressive dominant personality when having a more masculine (lower) 2 D:4 D, while there was no relationship between sociable dominance and 2 D:4 D. Findings from this study indicate that it is important to distinguish different forms of dominance since other studies failed to find relationships between dominance and 2 D:4 D. Aggr. Behav. 38:208-212, 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Applying resource control theory and social exchange theory, we examined the social network conditions under which elementary age children were likely to engage in relational aggression. Data on classroom peer networks and peer-nominated behaviors were collected on 671 second- through fourth-grade children in 34 urban, low-income classrooms. Nested regression models with robust cluster standard errors demonstrated that the association between children's number of relationships and their levels of relational aggression was moderated by the number of relationships that their affiliates had. Children with more peer relationships (i.e., higher network centrality) exhibited higher levels of relational aggression, but only when these relationships were with peers who had fewer connections themselves (i.e., poorly connected peers). This finding remained significant even when controlling for common predictors of relational aggression including gender, overt aggression, prosocial behavior, victimization, social preference, and perceived popularity. Results are discussed in terms of their implications for advancing the literature on childhood relational aggression and their practical applications for identifying children at risk for these behaviors. [ABSTRACT FROM AUTHOR]

This study examined adolescent narcissism, temperament (frustration and affiliation), and social goals in association with peer-reported physical and relational aggression ( N = 384; 12-14 years). Narcissism was positively associated with dominance goals and negatively with closeness goals for peer interaction. Moreover, narcissism was positively associated with physical aggression via dominance goals for boys, and with relational aggression via dominance goals for both genders. Temperamental frustration and affiliation were both positively associated with relational aggression, but also interacted in their associations with this variable; affiliation was positively associated with relational aggression only at high levels of frustration. Supporting and extending existing research, the present findings suggest that adolescent personality and social goals are meaningfully associated with physical and relational aggression in the peer context. [ABSTRACT FROM AUTHOR]

This longitudinal, naturalistic study addressed behavioral and social cognitive processes implicated in preschool children's social dominance. In the first objective, we examined the degree to which peer aggression, affiliation, and postaggression reconciliation predicted social dominance across a school year. Consistent with predictions, all three predicted dominance early in the year while only affiliation predicted dominance later in the year, suggesting that aggression, affiliation, and reconciliation were used to establish social dominance where affiliation was used to maintain it. In the second, exploratory, objective we tested the relative importance of social dominance and reconciliation (the Machiavellian and Vygotskian intelligence hypotheses, respectively) in predicting theory of mind/false belief. Results indicated that social dominance accounted for significant variance, beyond that related to reconciliation and affiliation, in predicting theory of mind/false belief status. Results are discussed in terms of specific behavioral and social cognitive processes employed in establishing and maintaining social dominance. Aggr. Behav. Aggr. Behav. 37:248-257, 2011. © 2011 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Hormones seem to play important roles in the regulation of human aggression. Multiple studies have confirmed that testosterone (T) levels exhibit complex relationships with aggression, dominance, and/or risk-taking behavior. Some evidence suggests that cortisol (CORT) interacts with T and may also be associated with aspects of mood and aggression. However, almost no research to date has investigated the possibility that these neuroendocrine factors are associated with variations in political attitudes or with political aggression. During the second intifada, we tested the hypothesis that morning salivary T and/or salivary CORT levels might be associated with self-rated aggression or with support for religio-political aggression (RPA) among 14-year-old Palestinian boys living in Gaza. We obtained and averaged weekly 09:00 hr salivary measures of T and CORT for more than 1 month. Averaged morning T levels did not correlate with self-rated aggression, but were positively associated with agreement with the statement 'religious ends justify any means,' ( r = .355, P = .014) and marginally associated with a composite measure of support for RPA ( r = .247, P = .094). Average CORT levels were inversely correlated with self-rated aggression ( r = −.328, P = .037) and with anger ( r = −.373, P = .016), but CORT levels were not associated with support for RPA or with the statement 'religious ends justify any means.' Acknowledging that a modest sample size and methodological issues necessarily limit confidence in our conclusions, these results may represent the first findings regarding neurobiological correlates of support for political aggression. Aggr. Behav. 37:121-132, 2011. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The literature suggests that status goals are one of the driving motivations behind bullying behavior, yet this conjecture has rarely if ever been examined empirically. This study assessed status goals in three ways, using dyadic network analysis to analyze the relations and goals among 10–11 and 14–15 year olds in 22 school classes (N boys=225; N girls=277). As a validation bullies were contrasted with victims. Bullies had direct status goals (measured with the Interpersonal Goal Inventory for Children) and showed dominance as measured with proactive aggression. Moreover, as predicted from a goal perspective, bullying behavior was related to prestige in terms of perceived popularity. In contrast, victims lacked status goals, were only reactively aggressive, and low on prestige. That being popular is not the same as being liked could be shown by the fact that bullies were just as rejected as victims by their classmates. Eighth-grade bullies had more direct status goals than fourth-grade bullies, possibly indicating that striving for the popularity component of status increases in early adolescence. Aggr. Behav. 35:57–67, 2009. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

In this experiment, learned helplessness was studied from an ethological perspective by examining individual differences in social dominance and its influence on the effects of helplessness. Ninety animals were used, 30 randomly selected and 60 selected because of their clear dominance or submission. Each condition (dominant, submissive, and random) was distributed in three subgroups corresponding to the triadic design. The test consisted of an escape/avoidance task. The results showed that the animals in the uncontrollable condition performed worse than those in the controllable and no treatment conditions. Social submission and dominance reduced vulnerability of the subjects against learned helplessness. Submission had a facilitating effect on subsequent learning, independently of whether pretreatment was controllability or uncontrollability. Learned mastery was observed in the submissive condition, because submission benefited the subjects in the controllable condition in comparison with the untreated subjects, and dominance impaired the subjects in the controllable condition. Aggr. Behav. 34:273–281, 2008. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

This paper examines the relation of the four subscales (physical, verbal, anger and hostility) of the Buss–Perry Aggression Questionnaire (BPAQ) to act-based aggression questionnaires (involving same-sex or partners as opponents, and direct or indirect aggression) and evolutionarily based predictors of aggression, using an online student sample. All aggression measures were moderately correlated with one another. The BPAQ physical and verbal scales were most closely related to act-based measures of direct aggression to a same-sex other and the hostility scale to indirect aggression to a same-sex other. The evolutionary variables were less closely related to the BPAQ than were the act-based measures. Dominance and sexual jealousy were predictors of BPAQ physical, verbal and anger, and impulsiveness was a significant predictor of anger. Aggr. Behav. 32:1–10, 2006. © 2006 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Principles of conspecific defense have been analyzed for rodents, in which specific target sites for biting by attackers on defenders serve as an important determinant of the actions involved in both attacker and defender behavior. In an effort to determine the generality of these principles, attack and defensive behaviors and target sites for biting attack were evaluated in a nonrodent species, the tree shrew (Tupaia belangeri ). Brief daily and repeated conspecific dyadic encounters between adult, socially experienced males (dominants, attackers), and adult, socially naive males (subordinates, defenders) that had been transferred into the territory of the dominants, produced a polarization of attack and defense. The dominant males showed chase, chase attack, jump attack, and biting behaviors, while the subordinates displayed flight and freezing. The vast majority of bites, as well as wounds and bruises, were on the subordinates’ backs. These patterns are very similar to those previously found in rats and mice and suggest that the organization of fighting, with targets of biting (or other painful) attack serving as an important determinant of both attacker (dominant) and defender (subordinate) behavior, may show considerable generality across nonrodent as well as rodent species. Although relatively few wounds were found after 28 days of repeated and daily encounters, the subordinate tree shrews show a variety of behavioral, neuroendocrine, and central nervous changes, indicating that they are stressed by these encounters per se. Aggr. Behav. 27:139–148, 2001. © 2001 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

In a series or three studies, we investigated the influence of a selective serotonin re- uptake inhibitor (fluoxetine) on the rough-and-tumble play of juvenile rats. In Experiment 1, both members of eight pairs of solitary-housed juvenile rats received either vehicle, 2.5, 5, or 10 mg/kg fluoxetine in a counterbalanced within-subject design 20 rain before being allowed to play for 5 rain periods on four successive test days. The 5 and 10 mg/kg pretreatments significantly reduced incidence of pins during play without affecting dorsal contacts. In Experiment 2, one member of each of 19 established play pairs received 5mg/kg fluoxetine 20 min before play, while the other member received vehicle. Dominant rats showed no reduction in pins as a result of fluoxetine treatment, but subordinate rats who received fluoxetine exhibited significant reductions in pins. Subsequent dyadic analyses indicated that in pairs where the subordinate animal received fluoxetine, dominant animals maintained their pinning advantage over the l0 days of testing, but in pairs where the dominant animals received fluoxetine, this pinning asymmetry diminished. In Experiment 3, we replicated the above procedure with inexperienced play pairs, to control for the effects of prior social learning, Fluoxetine treatment (5 mg/kg) significantly reduced both pins and dorsal contacts in all treated rats. The results indicate that fluoxetine can reduce the playful pins of juvenile rats, but that prior social learning mediates the strength of these effects. [ABSTRACT FROM AUTHOR]

Study I compared the extent to which 8- and 11.year.old girls and boys (N = 86) participated in specific types of rough-and-tumble play. It used an observational methodology. The data were used to test two prominent hypotheses about the evolutionary function of this general category of play behaviour that have been applied to children, especially boys, of this age. One is that rough-and-tumble play provides practice for the development of real fighting skills and the other that it serves as a safe way to establish/display social dominance. Both hypotheses predict that boys will engage in more rough-and-tumble play than girls, especially those types that are used in fighting/dominance contests. Boys were found to engage in significantly more chase initiation activities, more bouts of brief rough-and-tumble play, more bouts of restraining and more bouts of boxing/hilting than girls. These data provide some support for the two hypotheses, although significant sex differences were not found for all types of rough-and-tumble play ob- served. No significant age differences were obtained, suggesting that the two hypotheses may be applicable throughout the 8-to 1l-year-old period and not just at the end of it a previous research had suggested, Study 2 presented observational data concerning the motor patterns used in aggressive fighting, in all but one case, there were no significant differences in the extent to which 8/9- and 10/11-year-old girls and boys employed wrestling, hitting and restraining, supporting the view that the practice fighting hypothesis is relevant throughout the 8-ll-year-old period. It was argued that age and sex differences provide a useful means of scrutinising functional hypotheses, and that splitting behavioural categories that contain disparate action patterns facilitates more refined tests of those hypotheses. [ABSTRACT FROM AUTHOR]

The play fighting behaviour of male rats (Rattus norvegicus castrated at weaning was compared to that of intact controls during the juvenile and post-pubertal phases of development. Following puberty, both the castrated and intact animals exhibited an age- related change in their play fighting; the frequency of initiating play fighting decreased and juvenile patterns of playful defense were replaced by more adult-like patterns. As these changes occurred even in the absence of the pubertal surge of gonadal hormones, they were more likely to result from the organizational effects of gonadal hormones in the perinatal period than the activational effects of these hormones at puberty. Although the castrated animals exhibited the age-related changes in behaviour, they did not exhibit the asymmetries in play associated with dominance relationships. As demonstrated in previous studies, in pairs of intact rats, the animal that attacks the most and uses more juvenile defends during play fighting and weighs the least is typically the subordinate. In the castrates, asymmetries in weight and playful defense are not related to play frequency, indicating the absence of a dominance relationship. Although the characteristic changes in male play fighting at puberty are independent of the activational effects of gonadal hormones, dominance reIationships and their associated changes in play fight- tug are dependent on these hormones. Therefore, in the perinatal period gonadal hormones most likely organize the age-related changes in play behaviour, whereas post-pubertally gonadal hormones activate dominance relationships and thus, indirectly modify play fighting by affecting dominance-associated assymetries in behaviour. [ABSTRACT FROM AUTHOR]

In decapods, no analysis has ever been conducted or the force exerted by chelae, and the role that strength plays in the establishment of hierarchies. For this purpose, a device was designed to measure the force produced by the major chela in the freshwater crab Potamon fluviatile, where dominance hierarchy and agonistic behavioral patterns have previously been analyzed. Experiments showed that only in the females is strength the main factor influencing the outcome of contests. In males chela size more than chela strength is used to settle conflicts, together with other nonphysiognomic characteristics, molding the aggressive state of one individual, such as its history, including isolation from conspecifics, and possibly hormone concentration and metabolic levels. [ABSTRACT FROM AUTHOR]

Factors influencing the tendency to be aggressive were investigated in male house mice using a series of paired encounters. Body size, body length, body temperature, age, and anogenital distance were measure on all males. Paired encounters were conducted using a standard mouse cage as an arena. Across 64 males involved in 224 encounters, the tendency to be dominant and win encounters was significantly correlated only with anogenital distance (r=0.383). These findings suggest that there are significant behavioral effects that have been elucidated in female house mice and other rodents. [ABSTRACT FROM AUTHOR]

The effects of competing asymmetries (intruder size advantage vs. prior residence) on dominance relationships were investigated in a laboratory setting. Sexually mature (Form I) male red swamp crayfish, 25%-27% larger than the average member of several mixed- sex communities of 20-25 sexually mature conspecifics individually intruded upon these communities on successive days. Each community was invaded once a day, with each of these large intruders invading every community once during the experiment. Five days after the last large intruder invasion, novel intruder group males, approximately the same size as the average community member, individually invaded the same communities, all communities being invaded once during a single day of testing. These novel intruders were used to differentiate the effects of intruder size from those effects of being put into a novel environment. During each intrusion, the frequencies of dominance, submission, aggressive standoffs, and nonaggressive interactions between the intruder and members of the community were recorded. The large intruders on each day immediately and virtually completely dominated all encountered community members and the large intruders were significantly more dominant than the novel, smaller-sized intruders. The size advantage of the large intruders overwhelmed prior residence in influencing dominance outcomes, even in these well established communities. [ABSTRACT FROM AUTHOR]

A 3 day long cohabitation in pairs of previously isolated adult male Betta splendens was studied. The first two mornings started with intense fighting, the frequency of which decreased during the day. The bursts of aggression noticed in the mornings were associated with a significant carbohydrate metabolism activation, while daytime activity resulted in a reduction of muscle proteins in the evenings. These changes were more pronounced in submissives than in dominants. The third day marked a shift in the behavior of the pairs: burst of attack activity were not noticed, while the threatening display frequency increased. During this day a similar reduction in lipids was observed in dominants and submissives. While during the first 2 days the dominant position offered some metabolic advantage, this advantage disappeared during the third day when both members of the dyad seemed to do equally less well than their isolated counterparts. Combined with previous findings obtained in this series of experiments, the present results support the assumption that in this species the presence of one opponent is less well tolerated than the presence of four conspecifics. [ABSTRACT FROM AUTHOR]

There is currently much interest in the potential impact of psychological factors on immune responses. An attempt was made to assess the effects of dominant/subordinate polarity in male mice on the cytotoxic activities of their natural-killer (NK) cells. On the basis of repeated agonistic encounters, categories of subordinate and dominant animals were selected. These animals were compared with manipulated controls (introduced to a novel test cage without an opponent on each occasion) and undisturbed controls (who remained in isolation without manipulation). In terms of NK activity, immunosuppression was observed in both dominant and subordinate categories when compared to undisturbed controls. There were, however, no differences between the fighting exposed subjects and the manipulated controls, suggesting that stress accounts for any changes. [ABSTRACT FROM AUTHOR]

The article presents information about literature on aggressive behavior which is based on Source Publications provided by Automatic Subject Citation Alert from the Institute for Scientific Information. Some of the articles mentioned are: Crowds, Riots, and the Police-An Observational Study of Collective Violence by O.M.J. Adang; Violence Hits Home- Comprehensive Treatment Approaches to Domestic Violence by G.D. Aguilar; The Treatment of Aggression Problems in Cats by H.R. Askew.

Social dominance was analyzed in a group of Lemur macaco over a one-year period. Agonistic dominance was assessed by computing a dominance index for each individual in baseline conditions and in a competitive drinking situation, where success was measured as the amount of time in possession of the resource (a bottle of fruit juice). Dominance indexes during drinking competition were significantly correlated with baseline dominance indexes but were not correlated with individual drinking success. Adult females were agonistically dominant over all other individuals, but were frequently challenged by juveniles of both sexes for access to the drinking bottle. In males, there was a significant negative correlation between age and dominance indexes during competition tests, and between age and drinking success. Result are analysed in the light of recent theories concerning the emergence of female social dominance. [ABSTRACT FROM AUTHOR]

Adult male rats living together form dominance relationships, with one dominant and the remainder adopting subordinate roles. In previous studies, it was shown that in adult male pairs the subordinate rat initiates more playful contacts and retains a more juvenile response to the playful contacts by the dominant. In this experiment triads were used to examine the play between subordinate males. The subordinates directed fewer playful contacts to each other than to the dominant rat, and there was a symmetrical play relationship between the subordinates. After the dominant was removed from the colony, one subordinate became the dominant. Playful interactions amongst these pairs increased, with the subordinate initiating more playful contacts titan the dominant. Furthermore, from a similarly low frequency of juvenile-type response to playful contact to each other when in triads, the subordinate in the dyads increased its frequency of Juvenile type response to the dominant partner. This supports the hypothesis that (be playful behavior of subordinate male rats towards the dominant is an adaptive response, serving a "friendship maintenance" function. Finally, when in triads, one sub- ordinate was more playful with the dominant than the other subordinate. It was the least playful subordinate that was the most likely to become the dominant. This suggestive that within a colony, not all subordinates are the same. [ABSTRACT FROM AUTHOR]

In the highly social rat, male juvenile and adult subordinates initiate more playful contacts with dominant pairmates than vice versa. This study examined the effect of dominance on playful contracts in the relatively asocial golden hamster. Pairs of male hamsters were reared together from weaning, and their play was filmed in the juvenile (28–36 days) and the young adult (60–70 days) stages of development. By the adult stage, it became clear that one pairmate was dominant over the other. The dominant pairmate launched all aggressive attacks (i.e., bites to the lower flanks and rump), and the subordinate pairmate performed all the submissive gesturing (e.g., tail up submissive posture). Playful contact, which in this species involves gentle nibbling of the posterior cheeks, was more frequently launched by the dominant than by the subordinate. This was not only true at the adult stage, but also at the juvenile stage, before dominance-subordination relationships were sharply polarized. Therefore, it would appear that in the relatively asocial hamster, the subordinates tend to avoid playful contact with dominants. This is markedly different to rats, where the subordinates actively seek out and engage dominants in play. This contrast further supports our hypothesis that subordinate male rats use play as a means of maintaining familiarity with dominants. [ABSTRACT FROM AUTHOR]

The resident-intruder paradigm was used to examine the effects of social dominance and individual recognition on odor preferences and urine-marking in male rats. Resident males were significantly more aggressive than intruders and spent more time investigating the odors of familiar intruders. Resident males urine-marked most over the odors of females and familiar intruders while intruders marked least over the odor of the familiar resident. Intruders did not avoid investigating nor marking over the odors of familiar resident males or other conspecifics. These results suggest thin Individual odors of male rats may be more salient than a general odor of dominance, and that the dominant males increase their investigation and marking over the odors of familiar sub-ordinates but not unfamiliar subordinates. The importance of olfactory learning during aggressive interactions is discussed. [ABSTRACT FROM AUTHOR]

From weaning until sexual maturity, the rates at which young male rats hold each other supine during play fighting appear to become progressively asymmetrical. These changes have been previously thought to reflect an initial lack of dominance and a later development of dominance subordinance relationships. In this paper it is shown that pairs of male rats exhibit asymmetries in playful attack and playful defense throughout development. The changes, resulting in greater asymmetry of pinning rates, are shown to result from age-dependent changes in defensive tactics; the relationship, therefore, remains constant while the form of the behavior changes. Furthermore, it is not the animals showing the highest rates of playful attack who become dominant in older ages. [ABSTRACT FROM AUTHOR]

Changes in testosterone (T) and cortisol (C) were evaluated in males competing in a non-athletic laboratory reaction time task. Subjects were randomly assigned to "win" or "Lose" by adjusting feedback regarding their task performance. Further, subjects were randomly assigned to either a Close Contest condition (where one person barely "defeats" his opponent), or a Decisive condition (In which (be victory was clear). Throughout competition, samples of saliva were taken and assayed later for T and C. Post-competition mood and attributions were also measured. Winners had higher over- all T levels than losers, with no significant difference between Close Contest or Decisive Victory conditions. In contrast, C levels did not differ between winners and losers nor did Condition (Close or Decisive) have any effect. Mood was depressed in Decisive loser compared to all other groups. The results indicate that the perception or winning or losing, regardless of actual performance or merit on the task, differentially Influenced I (but not C) kwh, and that such hormonal changes are not simply general arousal effects but are related to mood and status change. [ABSTRACT FROM AUTHOR]

There is disagreement concerning the role or importance of social leaping, compared with peeks and threats, in the dominance relations of fowl. As an approach to this issue, the current paper reports two experiments that used aggression-inducing isolation-rearing conditions of either 8 days or 8 weeks. In 5-min tests in pairs after isolation it was found that leaping was the key aggressive response in conflicts between 14-to 15-week-old roasters. Leaps were more frequent overall and occurred earlier than did pecks. Although both dominant and subordinate birds leaped at one another to some degree, only the dominant birds had both ‘leap rights’ and ‘peck rights.’ The data indicated that leaping is a behavior that has an important, central role in the social organization of male domestic chickens. These laboratory results were comparable in certain archival data from classic field research. [ABSTRACT FROM AUTHOR]

Small all-male groups of rabbits were studied for periods of 15-20 days in a seminatural setting, giving the animals the possibility of initiating and pacing their social interactions. Behavioral observations included: intermale activity recorded daily and the reactions to the occasional introduction of an intruder female. Hormones were measured in blood samples taken at the beginning and at the end of the experimental period. A combination of behavioral and endocrine parameters, rather than single measures, was used to assign each individual its social rank within each group. Tables of concordance between behavioral and endocrine parameters were compiled to evaluate the dominance and the subordination hierarchy. Different behavioral categories and elements characterized dominance and subordination, indicating the two as distinct rather than simply reciprocal traits. Their endocrine basis is also different, final levels of testosterone and estradiol being associated with dominance, and corticosterone, ACTH, and androstenedione with subordination. The same hormones in the initial samples were unrelated to the subsequent social status, indicating that hormones are not prerequisites of status. The relevance of specific behavioral and endocrine parameters is discussed. [ABSTRACT FROM AUTHOR]

"A Guide to the Literature on Aggressive Behavior," is based on Source Publications provided by Automatic Subject Citation Alert from the Institute for Scientific Information. The key words used in weekly computer searches of nearly 5,800 science, technical, and social science journals from around the world are: attack, fight, dominant, aggression, violence, agonistic, hostility and anger. Articles are drawn from Science Citation Index, Social Sciences Citation Index and Current Contents. Journals surveyed include areas like: agricultural, biological, and environmental science, engineering, technology and applied sciences, medical and life sciences, and physical and chemical sciences.

Social dominance rank in red grouse has a large inherited component. The relative contributions of mothers and fathers to the dominance ranks of their sons and daughters were studied by breeding a dominant and a subordinate strain and crossing them. Both parents contributed equally to the dominance ranks of both sons and daughters. Cocks from the dominant strain were more aggressive and had bigger combs than cocks from the subordinate strain. Dominant cocks and hens, however, did not weigh more than subordinates. [ABSTRACT FROM AUTHOR]

The experiments were performed on adult male cats selected initially as good mouse-killers. Cats were tested in pairs and each pair was introduced separately to the experimental compartment. The attitude toward the partner before and during the predatory competition test as well as superiority in catching and killing the mice, considered as an index of dominance, were registered. In the course of experiment five types of relations between the predatory dominance and aggressive behavior were observed. The concept of dominance as an outcome of several factors was discussed. It was concluded that predatory dominance is not based exclusively on aggressive mechanisms, as it may be formed and sustained without overt aggression. [ABSTRACT FROM AUTHOR]

Small groups of female Siamese fighting fish were observed in an attempt to determine whether a dominance order exists in these fish. Each fish, in each group, was allocated a rank for each activity on each day of observation. The rankings for the number of bites of food from a restricted source, the number of displays, the order of attacks, and the number of attacks each showed a significant concordance from day to day. A significant concordance was also found between the rankings of the different parameters. These data show that a stable dominance order is formed when females are in small groups. The top-ranked fish engages in mere mutual displays and single-fish displays with the second-ranked fish than with the bottom-ranked fish. Displays showed differences in duration dependent upon whether or not they resulted in an attack. These data are discussed in terms of the conflict hypothesis and are in agreement with Simpson [1968] concerning the use of that hypothesis. [ABSTRACT FROM AUTHOR]

Six male mice placed In a large, moderately complex enclosure formed a stable dominance hierarchy in which two mice defended adjacent floor areas and the remaining four mice were subordinate and did not form territories. Intruder mice with winning or losing experience in prior paired encounters, or those with no fighting experience, were introduced individually into the colony for 30 minute periods. These Intruders were attacked by the dominant members of the colony, and the fighting outcomes were strongly dependent upon the fighting experience of the Intruder. Intruders with losing or no fighting experience engaged in little mutual fighting with residents, were easily defeated, and terminated attacks by engaging in subordinate behaviors. Intruders with winning experience fought vigorously with residents, attacked and, in many cases, defeated residents. These results suggest that relatively little winning experience gained in earlier paired encounters may be sufficient to overcome the various fighting advantages enjoyed by a dominant territorial holding member of a colony. [ABSTRACT FROM AUTHOR]

The present study employed β-Phenylethylamine - an automatic, novel method of measuring outcomes of competitive interactions in rats that is both under experimenter control and not confounded by decreased incentive for the winning animal as consumption becomes prolonged. Twenty-four female rats, derived from the colony maintained in the Department of Psychology, University of Liverpool, were housed under constant conditions. Competitive interactions were monitored using two modified chambers. Competitive sessions showed clear evidence of preferential access to food in all dyads. Although treatment at 20 mg/kg was without effect, the higher dose of 30 mg/kg produced a marked change with previously losing animals spending longer in the food hopper during signaled presentations with an apparent reversal of status.

This article analyses if the concept of dominance is useful in understanding rodent behavior. As defined by van Kreveld, "Dominance is a priority of access to an approach situation or of leaving an avoidance situation that one individual has over another." This definition has the advantage that dominance can be measured by depriving a group of a resource and then observing which animal has priority of access when the resource is replaced. It should not be assumed that the term dominance will necessarily be the best label for the many ways in which winners and losers differ. The term dominance already has very wide connotations, which has led to the misleading use of competitive tasks.

The diallel cross genetic design was employed to determine the pattern of inheritance of male--male agonistic behavior in laboratory mice. The results indicated strong strain differences in agonistic behaviors and strain ranks that replicated previous findings. The genetic analysis showed the presence of additive and nondirectional dominance effects on the behaviors measured. This pattern has been characterized as indicating the action of stabilizing selection and indicates that the trait has not been under directional selection. [ABSTRACT FROM AUTHOR]

Sibling red grouse resembled each other and their parents in social dominance rank and in an aggressiveness score. This was shown by comparisons of variance within and among clutches, correlations between parents and offspring, and experiments involving selection. Both dominance and aggressiveness scores were inherited. There was weak evidence that a laying hen's nutrition and crowding might also influence the dominance of her offspring. These results indicate mechanisms that may underlie fluctuations in the numbers of wild red grouse. [ABSTRACT FROM AUTHOR]

The social relations of three adult males in a captive chimpanzee group were evaluated for 12 months. The observations encompassed a period of transition in the dominance hierarchy providing an opportunity to assess behavioral patterns involved in the initiation of status changes. This study shows that dominance in the chimpanzee is expressed primarily through ritualized and non-contact behavior rather than by overt aggression. In particular, display behavior is important for indicating dominance rank, in communicating aggressive intent, and as a prelude to status struggles. The functional relationships between status, displays and other socio-sexual behavior patterns are presented. [ABSTRACT FROM AUTHOR]