Salivary testosterone and self-report aggressive and pro-social personality characteristics in men and women

Measures of salivary testosterone and the personality dimensions of aggression and pro-social behavior were obtained in 306 (155 male and 151 female) university students. Each participant provided two samples of saliva and completed ten self-report personality scales from multiple inventories. A factor analysis of the personality scales produced two factors, an aggression factor and a pro-social behavior factor. Men averaged five times the amount of salivary testosterone as women (99 pg/ml vs. 18.5 pg/ml) and rated themselves as more aggressive and less nurturant. Within each sex, testosterone was positively correlated with aggression and negatively correlated with pro-social personality. Structural equation modelling analyses suggested that a direct effect model best described the relationship between salivary testosterone and the latent personality dimensions of aggression and pro-social behavior. © 1996 Wiley-Liss, Inc.     

The perception of preschool social dominance

Children's and teachers' perception of social dominance was examined using a behavioral criterion for determining accuracy of verbal judgments. Video records of agonistic interactions were obtained during approximately 60 hours of free-play at two preschool centers. Analyses of social conflict episodes ending in submission revealed linear dominance structures for both groups. Dominance perception was assessed in two ways. Both teachers and children were asked to rank-order a subgroup of children according to dominance. They were also asked to select the more dominant children in a number of predetermined pairs. Results indicated that teachers could accurately judge dyadic dominance relations, and that accuracy among children varied as a function of their status within the group hierarchy. Findings have implications for social dominance assessment methodology, and for the issue of consensual versus ecological validity in developmental studies of social perception.     

The Relation of Perceived Neighborhood Danger to Childhood Aggression: A Test of Mediating Mechanisms

In the current study, two mediational mechanisms, parenting practices and children's beliefs about aggression, were hypothesized to account for the relationship between perceived neighborhood danger and childhood aggression. Using structural equation modeling, data were analyzed from an inner-city school-based sample of 732 predominantly African American 5th graders. Results suggested that perceived neighborhood danger was associated with strong positive beliefs about aggression, which in turn was associated with high levels of aggression. The hypothesized mediating role of parenting practices (restrictive discipline, parental monitoring, and parental involvement) on the relation between perceived neighborhood danger and child aggression was not supported. However, the current findings suggest that children's positive beliefs about aggression mediated the relationship between restrictive discipline and aggression. Directions for future research are discussed.     

Dominance assertion in male chimpanzees (Pan troglodytes)

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.     

Aggression and peer victimization as predictors of self‐reported behavioral and emotional adjustment

The relative contributions of aggression and victimization to the prediction of self‐reported emotional and behavioral difficulties over and above self‐reported prior problems were investigated in a 1‐year longitudinal study. Fourth‐, fifth‐, and sixth‐graders (N = 471) completed peer nominations of aggression and victimization as well as self‐report measures of social, behavioral, and emotional problems at baseline and at 1‐year follow‐up. Peer aggression added to the prediction of externalizing problems, specifically, self‐report of aggression and delinquency. In contrast, victimization by peers contributed to self‐reported unpopularity but not depression. Victimization among girls was also predictive of subsequent self‐reported delinquency. Theoretical and practical implications of the findings, as well as future directions for research, are discussed. Aggr. Behav. 26:345–358, 2000. © 2000 Wiley‐Liss, Inc.     

Video game violence: A review of the empirical literature

The popularity of video games, especially violent video games, has reached phenomenal proportions. The theoretical line of reasoning that hypothesizes a causal relationship between violent video-game play and aggression draws on the very large literature on media violence effects. Additionally, there are theoretical reasons to believe that video game effects should be stronger than movie or television violence effects. This paper outlines what is known about the relationship between violent video-game playing and aggression. The available literature on virtual reality effects on aggression is discussed as well. The preponderance of the evidence from the existing literature suggests that exposure to video-game violence increases aggressive behavior and other aggression-related phenomena. However, the paucity of empirical data, coupled with a variety of methodological problems and inconsistencies in these data, clearly demonstrate the need for additional research.     

Cooperative social coordination and aggression: Sex and strain differences in the effects of housing on gonadectomized rats with hormone replacement

Laboratory rats were used to investigate sex and strain differences in the effects of aggression on a cooperative behavior in which pairs learn to coordinate shuttling in a rectangular chamber. The level of aggression was manipulated by comparing males and females of the aggressive S3 strain and a less aggressive Sprague-Dawley-derived strain and by housing same-sex partners either together or individually (eight groups, n = 7 pairs per group). Hormone levels were stabilized by gonadectomy and daily injections of the appropriate sex hormone. The only serious coordination deficits were in individually housed males, associated with violent fighting and an extreme dominance/subordinance relationship that was not observed in females. All other groups readily learned and performed the coordination, with evidence that low and moderate levels of aggression could facilitate coordination by evoking species-typical behaviors that increased proximity, synchrony, and differentiation within pairs. The discussion focused on models of affiliative behavior in the study of aggression and the compatibility between moderate levels of aggression and cooperation.     

Variation in aggressive behavior and anatomo-physiological correlates generated by crowding without physical contact in the house mouse

Behavioral, physiological (i.e., endocrine), and anatomical consequences of crowding in mice were studied in a situation where animals were in auditory, visual, olfactory, and tactile contact but restrained from full physical interactions, to prevent overt aggression. Males that cohabited with females undisturbed by neighboring conspecifics showed greater propensity to attack same-sex intruders and had higher plasma testosterone levels than did their “crowded” counterparts, that is, males cohabiting with females and housed adjacent to other male/female pairs. In this respect, the latter animals resembled submissive males. However, a significant increase in weight of androgen-dependent target organs (i.e., seminal vesicles and preputial glands) was found in crowded males. These data indicate that despite the observed inhibition of social aggression these males are not physiologically comparable (homologous) to male mice that experienced defeat and the stress of submission during fighting. The intriguing possibility that different conversion pathway of testosterone are accelerated, as a result of social communication, in males living in these two environments and the behavioral implications of these possibilities are discussed. Finally, the parental behavior of crowded animals, although not freely interacting with each other, was disrupted, causing a marked decrease in reproductive success. In this situation a high incidence of infanticide of their offspring by both parents was observed, whereas this behavior was virtually absent in non-crowded male/female pairs.     

Women's Sexual Aggression Against Men: Prevalence and Predictors

In this study, we investigated the prevalence of women's sexual aggression against men and examined predictors of sexual aggression in a sample of 248 women. Respondents reported their use of aggressive strategies (physical force, exploitation of a man's incapacitated state, and verbal pressure) to make a man engage in sexual touch, sexual intercourse, or oral sex against his will. Childhood abuse, gender role orientation, ambiguous communication of sexual intentions, level of sexual activity, and peer pressure were included as predictors of sexual aggression. Almost 1 in 10 respondents (9.3%) reported having used aggressive strategies to coerce a man into sexual activities. Exploitation of the man's incapacitated state was used most frequently (5.6%), followed by verbal pressure (3.2%) and physical force (2%). An additional 5.4% reported attempted acts of sexual aggression. Sexual abuse in childhood, ambiguous communication of sexual intentions, high levels of sexual activity, and peer pressure toward sexual activity were linked to an increased likelihood of sexual aggression. The findings are discussed in relation to the literature on men's sexual aggression.