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.     

Sex differences in the perceived causal structure of date rape: A preliminary report

The present study examines the perceived causes of date rape by the use of network analysis. The 142 subjects in the study were presented with grids containing 9 causes listed by row and column. They were asked to indicate if they belived there was a causal link between each of the 72 causal pairings. The resulting network placed emphasis on male and female drunkenness, norms of dating, and society's attitude to date rape as distal causes of date rape. Misunderstanding of behavior by men, male attitude that date rape is unimportant, and need by males for dominance were seen as proximal causes. Further networks for each sex were constructed: these showed clear division of opinion on the causes of date rape. © 1995 Wiley-Liss, Inc.     

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.     

Effects of neonatal treatment with 1-(2,5-dimethoxy-4-lodophenyl)-2 aminopropane HCI (DOI) and ritanserin on agonistic behavior in adult male and female rats

The role played by the neonatal 5-hydroxytryptamine (5HT) system in the organization and sexual differentiation of adult agonistic behavior was investigated in rats. Focus was on the 5HT2 receptor subtype, which has been demonstrated to be involved in agonism control in the adult. 5HT2 activity was experimentally manipulated by administration of a specific agonist [1-(2, 5-dimethoxy-4-iodophenyl)-2-aminopropane HCl (DOI)] or antagonist (ritanserin) during the second week of life, when serotonin is known to concur to anatomical and behavioral sexual differentiation. Interactions between early 5HT2 activity, genetic sex, and neonatal circulating testosterone (T) were studied by administering the ligands to males, females, and androgenized females. At adulthood, the animals were tested for both aspects of agonism, i. e., aggression and defense, in a 20-min confrontation with an unfamiliar conspecific of the same sex, age, body weight, and social experience. Neonatal administration of the 5HT2 antagonist ritanserin increased aggression independently of sex; it also increased defense, but this effect was confined to males. The agonist DOI had no effect on aggression, but enhanced defense in males and androgenized females, with an effect which depended therefore more on neonatal T than genetic sex. Females appeared in general less sensitive to neonatal 5HT2 manipulation than both androgenized females and males; this suggests that neonatal T is crucial for experimental modifications of neonatal 5HT2 activity to have any consistent effect on adult agonistic behavior. On the other hand, effects observed in males and androgenized females were dependent on the behavior considered and the drug administered. This was especially evident for defense, enhanced by ritanserin in males only, and in both males and androgenized females by DOI. Neonatal 5HT2 activity seems therefore to play a role in the modulation of adult agonistic behaviors, which depends on the behavior considered and is under multiple control of genetic sex and hormonal neonatal substrate. © 1994 Wiley-Liss, Inc.     

Sex differences in maternal behaviors of immature rats: The role of emotionality

Immature rats are able to give maternal care to pups and may increase their inclusive fitness by helping newborn siblings. Immature males are generally reported to be more maternal than females. In this research we studied sex differences and the extent to which they may be due to a different emotional response to novelty. We studied maternal response in two groups of immature rats of both sexes: in the naive group, juveniles aged from 18 to 30 days were given one test and showed clear-cut sex differences. The experience group was submitted to repeated tests from 18 to 30 days of age, thus eliminating the effects of novelty: as a result, all differences between sexes disappeared. A second experiment was designed in 24-day-old females to differentiate the effects of repeated handling and exposure to the test situation from that of repeated exposure to pups; moreover, the effects of an anxiety-reducing drug (diazepam) were studied. Exposure to pups is particularly efficient in facilitating maternal response. Diazepam injection was also effective, but its control showed that the injection per se was responsible for the effect. In conclusion, our results stress the importance of response to novelty and suggest that sex differences in maternal behavior of immature rats may be modulated by different emotional responses by males and females. In fact, emotionality competes with, and may exert an inhibitory effect on, the expression of a vast array of behaviors. © 1994 Wiley-Liss, Inc.     

Testing two variances for superiority/non-inferiority and equivalence: Using the exhaustion algorithm for sample size allocation with cost

The equality of two group variances is frequently tested in experiments. However, criticisms of null hypothesis statistical testing on means have recently arisen and there is interest in other types of statistical tests of hypotheses, such as superiority/non-inferiority and equivalence. Although these tests have become more common in psychology and social sciences, the corresponding sample size estimation for these tests is rarely discussed, especially when the sampling unit costs are unequal or group sizes are unequal for two groups. Thus, for finding optimal sample size, the present study derived an initial allocation by approximating the percentiles of an F distribution with the percentiles of the standard normal distribution and used the exhaustion algorithm to select the best combination of group sizes, thereby ensuring the resulting power reaches the designated level and is maximal with a minimal total cost. In this manner, optimization of sample size planning is achieved. The proposed sample size determination has a wide range of applications and is efficient in terms of Type I errors and statistical power in simulations. Finally, an illustrative example from a report by the Health Survey for England, 1995–1997, is presented using hypertension data. For ease of application, four R Shiny apps are provided and benchmarks for setting equivalence margins are suggested.     

得失情境下他人参照点及心理距离对自我-他人利益权衡的影响

以福利权衡率(WTR)为利他程度的指标, 通过3个实验逐步深入地考察了得失情境下他人参照点及心理距离对自我-他人利益权衡的影响。实验1的结果表明, 得失情境并未改变被试的WTR。实验2引入他人底线、现状和目标三个参照点变量, 发现被试获益情境下的WTR高于损失情境, 且WTR从高到低依次为他人临近底线、目标和现状; 他人临近底线时, 被试在获益情境下的WTR高于损失情境, 而他人临近现状和目标时, 个体在得失情境下的WTR无显著差异。实验3进一步引入心理距离变量, 发现心理距离较近他人的WTR高于较远他人, 且与得失情境和参照点发生了复杂的交互效应, 得失情境的主效应消失了, 但总体上并未改变实验2发现的参照点效应。这些结果对于更深入地理解得失不对称效应、三参照点理论及社会折扣和自我-他人决策差异研究的相关发现具有一定的启示意义。     

Cyberbullying,cyber aggression,and cyber victimization in relation to adolescents’ dating and sexual behavior: An evolutionary perspective

This study examined adolescents’ cyberbullying, cyber aggression, and cyber victimization from an evolutionary perspective, extending previous research showing that traditional forms of bullying, aggression, and victimization are associated with reproductively relevant outcomes. Consistent with hypotheses based on theory and research linking bullying and aggression to intrasexual competition for mates, results indicated that cyber victimization was positively associated with a number of dating and sexual partners. Findings for cyber aggression were more complex, depending on the degree of cyber victimization experienced by the perpetrator, and the balance of power between the perpetrator and victim. Specifically, nonbullying cyber aggression by perpetrators with equal or less power than the victim had stronger positive relations with the number of dating or sexual partners when perpetrators experienced a high level of cyber victimhood. In contrast, cyberbullying by perpetrators with more power than the victim was negatively associated with the number of dating partners when the perpetrators’ exposure to cyber victimization was low. Although cyber aggression and cyber victimization are new forms of aggression that involve the use of modern electronic devices, the results of this study demonstrate the usefulness of viewing this behavior from an evolutionary perspective and show that adolescents are likely to use cyber aggression against rivals in the context of intrasexual competition for mates.     

Facilitating Adolescent Well‐Being: A Review of the Challenges and Opportunities and the Beneficial Roles of Parents,Schools, Neighborhoods,and Policymakers

Adolescents face exceptional challenges and opportunities that may have a lifelong impact on their consumption and personal and societal well‐being. Parents, community members (schools and neighborhoods), and policymakers play major roles in shaping adolescents and influencing their engagement in consumption behaviors that are either developmentally problematic (e.g., drug use and unhealthy eating) or developmentally constructive (e.g., academic pursuits and extracurricular activities). In this article, we discuss two main topics: (a) the challenges and opportunities that characterize adolescence, based primarily on research in epidemiology and neuroscience, and (b) the ways that parents, community members, and policymakers can facilitate positive adolescent development, based on research from many disciplines including marketing, psychology, sociology, communications, public health, and education. Our goal is to summarize the latest scientific findings that can be used by various stakeholders to help adolescents navigate this turbulent period and become well‐adjusted, thriving adults.