Instrumental and expressive representations of aggression: One scale or two?

The Expagg questionnaire was developed to measure a subject's view of their own aggression as a relatively instrumental or relatively expressive act. Two issues have been raised pertaining to the dimensional structure of the questionnaire: the use of principal components analysis on dichotomous responses and the possibility that instrumental and expressive representations might be independent dimensions rather than opposite ends of a single continuum. In study 1, dichotomous Expagg data from 405 subjects were subjected to microfact, principal components, and factor analysis. Each produced a first general factor, and the correlations between the item loadings were in excess of r = .99. In study 2, a 40‐item Likert scale version of Expagg was given to 295 subjects. Principal components analysis, paired item correlations, and subscale correlations suggested partial independence of instrumental and expressive items. Two new 8‐item scales measuring instrumental and expressive representations were constructed that maximise their independence. Potential uses of these revised scales are discussed. Aggr. Behav. 25:435–444, 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.     

Aggression and testosterone: Testing a bio-social model

Based upon reports of a positive correlation between circulating testosterone levels and aggression, we draw upon evolutionary psychology to place the action of testosterone in a broader perspective. We propose that testosterone affects competitive status-seeking and that under certain circumstances (including youth) this is expressed as aggression. Involvement in aggression in turn is associated with adherence to an instrumental social representation of aggression which justifies aggression as a means of imposing control over others and increasing self-esteem. Measures of salivary testosterone, masculinity, preferred social representation of aggression, and multiple aggression scales were collected from an undergraduate sample of 119 men. An Aggression factor was derived from principle components analysis of the aggression measures. The strongest correlates of Aggression were holding an instrumental social representation of aggression and youth. Testosterone showed no significant relationship to the single or aggregate measures of aggression or to any of the other psychometric measures. We suggest ways in which previous work may have over-estimated the strength of the association between circulating testosterone and aggression and discuss the possible relationships between age, social representation, and aggression. Aggr. Behav. 23:239–238, 1997. © 1997 Wiley-Liss, Inc.     

Effects of provocation on emotions and aggression in males

The effects of provocation of emotions and human physical aggression were examined using a competitive reaction time paradigm. Fifty-four males participated in the competitive task with a fictitious opponent. Participants were assigned to two conditions, low-constant provocation and increasing provocation. Aggression was defined as the intensity of electric shocks participants selected for the opponent to receive. Negative emotions (threat, harm) and positive emotions (benefit, challenge) were assessed at four times during the experimental task. The results revealed that both aggressive responding and harm emotions differed as a function of opponent's level of provocation. There was little compelling evidence that emotions served as an important intervening variable in the relationship between provocation and aggression. Aggr. Behav. 23:1–10, 1997. © 1997 Wiley-Liss, Inc.     

Expectations and prescriptions for responding to peer aggression: The adolescent offenders' perspective

The purpose of the current research was to investigate adolescent offenders' perspectives about responses to interpersonal aggressive encounters. Specifically, participants' perspectives were assessed regarding the role of a bystander when either a friend or an acquaintance of the bystander was the victim of an aggressive act. Two aggressive acts were presented. First, the bystander witnessed an acquaintance stealing from the victim. Second, the bystander witnessed an acquaintance hitting the victim. Participants were asked to indicate (a) if the bystander would do anything (bystander expected behavior), (b) what the bystander would do (expected behavioral action), (c) if the action would be the right thing to do (evaluation of bystander expected behavioral action), and (d) what the bystander should do in response to the violation (prescribed bystander behavioral action). Results indicate that the adolescent offenders' perspectives varied as a function of offender status, type of aggressive act, as well as relationship of the victim to the bystander. Aggr. Behav. 23:149–160, 1997. © 1997 Wiley-Liss, Inc.     

Attack and defense in conspecific fighting in tree shrews (Tupaia belangeri)

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.