Aggression,friendship, and reconciliation in Russian primary schoolchildren

Aggression and reconciliation were studied in a group of 6‐ to 7‐year‐old Russian schoolchildren using the matched control approach and the two methods used in primate ethology—the postconflict period–matched control period and the time rule methods. Aggression was found to be positively correlated with friendly behavior at the dyadic level. It is demonstrated that children, like nonhuman primates, tend to reconcile within 1 min after the conflict. Victims tend to redirect aggression at other individuals. No effect of gender on reconciliation was found. The reconciliation tendency is less expressed in friends than in children who are not friends. A new reconciliation measure is introduced, and an operational definition of friendship is suggested. Aggr. Behav. 25:125–139, 1999. © 1999 Wiley‐Liss, Inc.     

Social and personal determinants of workplace aggression: Evidence for the impact of perceived injustice and the Type A Behavior Pattern

Four hundred fifty‐two employed persons rated the frequency with which they had been the victims of a wide range of aggressive actions at work. In addition, they also rated the frequency with which they themselves had aggressed against others in their workplaces. Three hypotheses were investigated: (1) covert forms of aggression, in which aggressors seek to conceal their identity from target persons, are significantly more frequent in workplaces than overt forms of aggression; (2) the greater the perceived injustice reported by employees, the greater their tendency to engage in workplace aggression; and (3) the higher individuals' scores on a measure of the Type A Behavior Pattern, the greater their reported frequency of engaging in various forms of workplace aggression. Results offered support for all three hypotheses. In addition, several demographic variables (participants' age and gender; the physical location of their workplaces) were also found to play a role in the occurrence of workplace aggression. Together, these findings were interpreted as underscoring the importance of establishing close conceptual links between research on workplace aggression and basic research on human aggression. Aggr. Behav. 25:281–296, 1999. © 1999 Wiley‐Liss, Inc.     

Effects of NMDA receptor channel blockade on aggression in isolated male mice

N‐Methyl‐D ‐aspartate (NMDA) receptor antagonists are perspective candidates for medication development for a number of diseases/states that are associated with increased aggressiveness (e.g., opioid withdrawal). The prototypic NMDA receptor antagonist phencyclidine (PCP) itself is a widely abused substance and is known to elevate levels of aggression in drug users. The present study was aimed at testing several drugs that share with PCP the ability to block NMDA receptor–associated channel. The resident‐intruder procedure was used to assess drug effects on aggressive behavior in isolated male mice. Resident aggressive mice were administered NMDA channel blockers (PCP; 0.3–10 mg/kg), dizocilpine (MK‐801; 0.01–0.3 mg/kg), memantine (1–30 mg/kg), and MRZ 2/579 (0.1–5.6 mg/kg). The competitive NMDA receptor antagonist D CPPene (0.1–5.6 mg/kg) was also tested as a compound representing an alternative approach to reduce activity of NMDA receptor complex. PCP, dizocilpine, and memantine inhibited expression of aggressive behaviors only at doses that produced ataxia. The novel channel blocker MRZ 2/579 also produced ataxia at the highest dose level but failed to affect aggressiveness. Reduction in aggression with a corresponding increase in sociability was observed after administration of D ‐CPPene. Overall, the present results suggest that NMDA receptor channel blockers do not exert selective effects on aggressive behavior. Aggr. Behav. 25:381–396, 1999. © 1999 Wiley‐Liss, Inc.     

Fighting,nonagonistic social behavior,and exploration in isolation‐reared rats

Sixty hooded Long‐Evans rats were assigned to one of three conditions: isolation‐rearing (from 14–30 days of age), brief isolation (from 28–30 days of age), and normal (no isolation). From day 14 to day 21, the isolation‐reared animals were maintained in an incubator set at 35°C to prevent hypothermia and were separated from each other by Plexiglas. They learned to nourish themselves by lapping milk that continuously flowed down one side of the enclosure. Thereafter, they were housed in standard hanging wire cages. Unlike previous studies of isolation at this age, there were no significant weight differences between the isolation‐reared group and the two control groups. At 30 days of age, the three groups were compared on fighting (serious and play), nonagonistic social behaviors (following and crawling under), and exploratory behavior (open‐field ambulation). The isolation‐reared group was significantly different from the normal group on all measures (isolates were higher on all measures except exploration). The isolation‐reared animals showed significantly more serious fighting (aggression) than the brief isolation animals, whereas these two groups did not differ on other behaviors. This methodology allows for the study of isolation‐rearing without the nutritional confounds found in previous research and shows an effect on aggression that is not accounted for by recent isolation. Aggr. Behav. 25:211–223, 1999. © 1999 Wiley‐Liss, Inc.     

Differential effect of handling on adult aggression in male mice bidirectionally selected for attack latency

Individual variation in intermale aggression is to a significant degree based upon genetic variation, but environmental factors can also exert their influence on the level of aggression. Moreover, genotype–environment interactions are a well‐known phenomenon. In the present experiment, I tested whether cage size or handling during development had an influence on adult attack latency scores. To be able to study a genotype–environment interaction, mice from two bidirectionally on attack latency selected lines were used. The size of the cage in which the mice grew up had no long‐term effect on aggression, neither in the high‐ nor in the low‐aggressive line. Handling, however, significantly increased the adult aggression of males from the low‐aggressive line. Despite the differential effect of handling on genetically high‐ and low‐aggressive mice, handling was not able to undo the marked differences in attack latencies between mice from both lines. Aggr. Behav. 25:365–368, 1999. © 1999 Wiley‐Liss, Inc.     

Interfemale aggression in adult bank voles (Clethrionomys glareolus)

Agonistic interaction may play a large role in shaping the social structure and spatial distribution of rodents such as Clethrionomys glareolus. Aggressive and non-aggressive behaviors of adult bank vole females were investigated with a home cage test during 10 min sessions. The number of attacks was significantly higher in virgin females kept with intact adult males than in singly reared females or those exposed to male urine. Bulbectomy of the tested females completely inhibited the male stimulating effect. This indicates that males influence the behavior of females by activating their olfactory systems. Aggressive behavior in pregnant or lactating females, which is linked to maternal behavior, was also tested. Female bank voles between 11 and 17 days of pregnancy or lactating at 3–4 days or 9–10 days attacked their partners significantly more frequently than virgins did. Females that had direct contact with males, even if they were not fertilized, appeared to be more successful in same-sex competition. Aggr. Behav. 24:53–61, 1998. © 1998 Wiley-Liss, Inc.     

Gonadal hormones and intrasexual aggressive behavior in female bank voles (Clethrionomys glareolus)

The effects of gonadal hormones on aggressive behavior in the female bank vole was investigated in 10 min home cage tests. Ovariectomized (ovx) or intact females injected with oil, with progesterone (P), with a mixture of progesterone and estrogen (P+E), or with testosterone (T) alone were confronted in a resident-intruder test with unfamiliar, nonoperated females as intruders. Intact females showed aggressive behavior more frequently than ovx females. Ovx females injected with P, with P+E, or with T made significantly more attacks, and these attacks lasted longer than those observed for oil-treated voles. The results indicate that P, the typical female hormone, is responsible for aggressive behavior in female bank voles; however, only T increased the duration of interfemale aggression. Aggr. Behav. 24:63–70, 1998. © 1998 Wiley-Liss, Inc.     

Extremes of self-esteem and narcissism and the experience and expression of anger and aggression

This study examined the level of self-esteem and narcissism as personality variables involved in the disposition to experience and express anger. Three hundred thirty-eight subjects were sampled across two higher education centres and one student teaching programme in the United Kingdom. It was reasoned that individuals with both high self-esteem and narcissism would report especially high tendencies to experience and express anger and aggression and that those with high self-esteem and low narcissism would report the lowest. These predictions were influenced by theories that emphasise the role of threats to high self-esteem in the production of aggression and violence. Results indicate that groups defined by their extreme scores on self-esteem and narcissism scales produced levels of anger expression in the predicted direction. The importance of considering extreme levels of self-esteem and narcissism (in conjunction with other factors) in an analysis of anger is discussed with reference to currently influential theories in the field. Aggr. Behav. 24:421–438, 1998. © 1998 Wiley-Liss, Inc.     

Early antecedents of spouse abuse

Males taken into police custody for reported spouse abuse (n = 19) and a matched control group (n = 19) were asked to describe the drinking habits of their parents and the extent of intra-family violence witnessed by them as children. The retrospective data were compared to the participant's own present alcohol use and aggressiveness (CTS). Excessive paternal drinking and intra-family violence were recalled significantly more often by the spouse abusers than by the controls. A latent structure model suggested that the accumulated violence history was less well predicted by either paternal violence or present aggressiveness than by the direct and indirect effects related to drinking. Context-specific social learning could explain why the parental drunken violence behavior pattern witnessed by the child was repeated by the adult spouse abuser. Aggr. Behav. 23:239–243, 1997. © 1997 Wiley-Liss, Inc.