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.     

ON THE BENEFITS OF PHILOSOPHY AS A WAY OF LIFE IN A GENERAL INTRODUCTORY COURSE

Philosophy as a way of life (PWOL) places investigations of value, meaning, and the good life at the center of philosophical investigation, especially of one’s own life. This essay argues that PWOL is compatible with general introductory philosophy courses, further arguing that PWOL-based general introductions have several philosophical and pedagogical benefits. These include the ease with which high-impact practices, situated skill development, and students’ ability to “think like a disciplinarian” may be incorporated into such courses, relative to more traditional introductory courses, as well as the demonstration of philosophy’s value to students by explicitly tying philosophical investigation to students’ own lives.     

Developing and validating a new multi-dimensional scale for anti-social behavior in a higher education setting

The purpose of this research is to construct and validate a multi-dimensional scale of Anti-social Behavior (hereafter ASB) in a Western higher education context (i.e., USA). To achieve this, four studies, each with a different sample, were performed. Study 1 (n = 150) followed an exploratory design to generate a pool of potential items measuring ASB. Study 2 (n = 254) explored the dimensionality of the items produced in Study 1 using exploratory factor analysis (EFA) and reliability measures. Study 3 (n = 654) confirmed the factorial structure from Study 2 and assessed the measurement model invariance using structural equation modeling (SEM). Finally, Study 4 (n = 287) assessed the predictive validity of the ASB measure through testing a hypothetical path model linking ASB to narcissism and Machiavellianism via an SEM procedure. In total, our research findings conclude that the ASB measurement model is a two-factor multi-dimensional structure comprising: Interpersonal Antagonistic Behavior (six items) as well as Indirect Distractive Behavior (four items). The research and practical implications for universities are thereafter discussed.     

Aggressive behavior in the free-ranging rhesus monkeys of kathmandu,nepal

We present a composite sample of the aggressive behavior of free-ranging rhesus monkeys (Macaca mulatta), recorded at two temples in Kathmandu, Nepal. We analyze the total number and the rate per monkey of threats, chases, attacks, fights, and aggressive acts directed at other species (principally humans), in order to elucidate social dynamics of the troop as a whole. Our 1,506 hours of observation were divided among the four seasons; between a.m. and p.m.; and among a temple yard, two parklands, and a forested garden. We found seasonal patterns to be the most important correlates of aggressive behavior. Habitat was a modulating influence, and time of day was the least important factor. Rates of aggression were generally higher per male monkey than per female. In terms of total aggression recorded, however, females instigated significantly more than males, both in encounters between monkeys and in aggression against other species. This finding is consistent with the females' greater numbers in the troop and with their lifelong membership in the troop. Analysis of behavior by social groups, rather than by individual rates, points up the iomportance of adult females and their social stability in troop behavior.     

Effects of medial preoptic hypothalamus anterior lesions on three kinds of behavior in the rat: Intermale aggressive,male-sexual,and mouse-killing behavior

Large lesions in the medial preoptic area-anterior hypothalamus (MPOA-AH) of adult male S3 rats reduce both intermale aggressive behavior and male sexual behavior considerably, but mouse-killing behavior is not impaired. Daily treatment with high doses of testosterone propionate for 21 days does not restore these behavioral effects. Smaller lesions in the same area affect male sexual and intermale aggressive behavior differently; in the frontal part of the MPOA-AH they affect aggressive behavior, while in a more caudal part they affect sexual behavior. Indications were found that lesions in specific parts of the stria terminalis and the medial forebrain bundle inhibit aggressive and sexual behavior.     

Intersexual aggression and male sexual activity in captive rhesus macaques

Rape has been posited to be an outgrowth of male reproductive strategies. Forced copulations may have evolved as a consequence of the low parental investment made by males in producing and raising offspring. We designed a laboratory experiment which paired rhesus macaque males with females in order to assess the influence of intersexual aggression on male sexual activity. Younger and older adult males had comparable levels of sexual behavior, but younger males were more aggressive towards females than were older males. In addition, females threatened younger males more than older males. Male attacks on females did not result in sexual intercourse. On the contrary, a negative correlation existed between male aggression towards females and male success at achieving intromissions. Female aggression towards males appeared to be an effective tactic which reduced the chances of sexual intercourse. We conclude that intersexual aggression acts either as a mechanism of dominance assertion or as a means to increase spatial distance between individuals. These data do not support the idea that rape in humans has an evolutionary foundation derived from male reproductive strategies.     

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 learned 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 housing same-sex partners either together or individually (8 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.     

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.     

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.