Frequency Of Aggression Research Articles

It’s “Mean,” But What Does It Mean to Adolescents? Relational Aggression Described by Victims, Aggressors, and Their Peers

Early adolescent girls and boys ( N = 33) with known histories of relational aggression and/or victimization gave detailed accounts of the nature, frequency, intensity, course, and impact of relational aggression among their peers. They also described reasons for, and forms of, aggression after being prompted by a series of hypothetical vignettes. Despite identifying many forms of aggression that were similar for girls and boys, some sex differences were found; girls were described as experiencing more victimization within close friendships than boys, with a focus on maintaining exclusivity. Boys described exclusion from larger groups with themes of masculinity, athletic skill, and/or perceived sexual identity. Girls’ and boys’ perceptions about the motivations for these different forms of relational aggression were quite similar. These included power, popularity, and wanting to fit in as well as the aggressors’ emotional states and the victims’ characteristics.

Gender Differences in the Costs that Subordinate Group Members Impose on Dominant Males in a Cooperative Breeder

AbstractIn group‐living species, a dominant male’s ability to monopolize reproduction, and the cost of doing so, are expected to vary with a group’s gender composition. We used spawning observations of a group‐living cichlid,Neolamprologus pulcher, to test this expectation. We constructed groups that contained a dominant breeding pair and either two male subordinates, one male and one female subordinate or two female subordinates. Parasitic spawning by male subordinates was more common in groups with two male subordinates than in groups with one male and one female subordinate. Female subordinates were never observed laying eggs in dominant females’ clutches, but three female subordinates laid independent clutches. During spawning, frequencies of dominant male aggression towards male and female subordinates were similar. Dominant males were less aggressive during non‐reproductive periods. The declines were greater for female subordinates, such that, during non‐reproductive periods, dominant males were more aggressive towards male subordinates. Aggression towards each subordinate was also affected by the second subordinate’s gender; the direction of that effect differed for large and small subordinates. Male subordinates approached breeding shelters less often than female subordinates, and both male and female subordinates approached shelters more frequently when the second subordinate was male. Collectively, these patterns suggest: (1) that male subordinates impose higher costs on dominant males than female subordinates do and (2) that the presence of a second male subordinate imposes additional costs beyond those of the first male subordinate. We discuss the implications of these effects for dominant and subordinate group members.

The impact of structured risk assessments followed by management recommendations on aggression in patients with personality disorder

This study tested the proposition that structured risk assessments followed immediately by the risk assessment results and recommendations for management can reduce the frequency of aggression in high-risk personality-disordered patients. The study included three phases during which aggressive behaviour was recorded: (a) baseline, (b) daily risk assessment using the Dynamic Appraisal of Situational Aggression (DASA) and HCR-20 Clinical Scale, and (c) daily DASA risk assessment followed by risk assessment results and risk management recommendations. Following the third phase a staff survey was conducted to measure the clinical utility of the DASA and the risk management recommendations. Results revealed no significant difference in the frequency of aggression between the three phases. The staff survey revealed varied reactions to the DASA and to the utility of the risk assessment results and management recommendations. Possible reasons for the limited impact of the DASA and opportunities for future research are discussed.

Impact of REM sleep on distortions of self-concept, mood and memory in depressed/anxious participants

Introduction We tested the hypothesis that REM sleep contributes to core features of cognitive dysfunction of anxious depression including negative self-appraisals, biased memory processing and unpleasant dream content. Methods After a habituation night in a sleep lab, a convenience sample of 35 healthy college students and 20 depressed/anxious students were awakened 10 min into a REM sleep episode and then 10 min into a NREM sleep episode. Awakenings were counterbalanced to control circadian effects. After each awakening participants reported a dream and then completed memory recall, mood and self-appraisal tasks. Results Self-appraisals of depressed/anxious participants were significantly less positive and significantly more negative after awakenings from REM sleep vs NREM sleep. Appraisal of the REM sleep dream self was negative for depressed/anxious subjects only. Recall of negative memories was significantly more frequent after REM vs NREM sleep awakenings for both depress/anxious and healthy participants. REM sleep dreams were associated with greater frequencies of negative emotion, greater aggression and victimization rates than dreams in NREM sleep for depressed/anxious participants. Limitations Depressed/anxious participants were classified as such on the basis of mood scales rather than clinical interview. All participants were drawn from a volunteer college student population and thus our results may not be applicable to some elderly clinical populations. Conclusions REM appears to facilitate cognitive distortions of anxious depression.

Social Relationships in Free-Ranging Male Macaca arctoides.

Macaque social relationships differ greatly between species. Based on captive studies that focus mainly on females, researchers have classified stumptail macaque (Macaca arctoides) social relationships as tolerant, as indicated by a high rate of affiliation, frequent aggression, and symmetrical conflicts. To accumulate more data on male social relationships, which are relatively understudied, and to generate comparative data, we investigated male social relationships in a provisioned group of 68 free-ranging, naturally dispersing stumptail macaques in southern Thailand. We collected continuous focal animal and ad libitum data on 7 adult and 2 subadult males, recording social behavior during 283 contact hours between December 2006 and March 2007. Stumptail macaques of this population were less tolerant than predicted based on previous studies on captive groups: Rates of spatial proximity, affiliation, and aggression were low, most males directed affiliative behavior toward higher-ranking males, and conflicts were generally of low intensity and relatively asymmetrical. Thus, male stumptail macaques of the focal group appear to differ in their social style from a previous study of a captive group that mainly comprised of females. In some traits, they are even more intolerant than rhesus macaques, an intensively studied intolerant macaque species. We also compare our data on stumptail macaque males to those on other male macaques, but available data are too sparse to draw final conclusions.

Ontogeny of space use and diet of two temperate damselfish species, Parma microlepis and Parma unifasciata

Studies of reef fish herbivory have mainly focused on the impacts and behaviour of adults of tropical species. In this study, the ontogenetic shifts in home range, aggression, feeding rate, diet and gut morphology in juveniles and adults of two temperate territorial damselfishes, Parma microlepis and Parma unifasciata, were determined. Both P. microlepis and P. unifasciata juveniles under 80 mm TL exhibited no aggressive chases towards conspecifics or other species, while above 80 mm TL aggressive chase frequency increased in conjunction with an increase in home range, defended as a territory. Ontogenetic diet shifts, characterised by an increase in herbivory (P. unifasciata: juveniles: 64% plant material, adults: 95% plant material; P. microlepis: juveniles: 43% plant material, adults: 67% plant material) were observed for both species. The ratio of digestive tract length to body length, which often accompanies a switch to herbivory, increased significantly with ontogeny for both species. Compared to tropical confamilial grazers, these temperate damselfish species feeding rates were lower, and they had larger territories which were not as strongly defended (fewer aggressive chases).

Behavioral Interactions Between Non-Cohabiting Bess Beetles, Odontotaenius disjunctus (Illiger) (Coleoptera: Passalidae)

The bess beetle, Odontotaenius disjunctus (Illiger), is a large subsocial beetle that inhabits decaying logs in which adults build tunnel systems and raise their larvae. Adults are territorial and both males and females protect tunnels from intruders. Though the behavior of many passalid beetle species, including O. disjunctus, has been studied, adult behavior toward conspecifics has not been thoroughly documented and many interactive behaviors have yet to be defined. We describe behaviors exhibited during laboratory interactions between non-cohabitating O. disjunctus adults. Twenty-four O. disjunctus were each tested in two experimental trials, once as a resident and once as an intruder, and in one control trial. We observed 18 behavior patterns and monitored them during trials. There were significant differences between control and experimental trials in some aggression behaviors, and in the total frequency of aggression, but no significant differences in submission, investigation, and neutral behaviors. Our data expand the behavioral repertoire for this species. Adults may use the described mild aggression behaviors in a territorial context, but we found no significant difference in total frequency of mild aggression between residents and intruders.

Self-Harm and Aggression in Dangerous and Severely Personality Disordered Patients of a High-Security Hospital

This study examined the frequency, prevalence and co-occurrence of aggression and self-harm in patients admitted for assessment and treatment to a high-security dangerous severe personality disorder (DSPD) hospital. Results showed that most patients admitted to this unit were aggressive and many patients self-harmed during the period of study. Few patients were neither aggressive nor self-harming. Patients who self-harmed and behaved aggressively were typically aggressive before their first episode of self-harm, and the likelihood of self-harm seemed to increase during the later stages of their hospital stay. Possible explanations for these findings are offered.

Associations Between Verbal Reasoning, Normative Beliefs About Aggression, and Different Forms of Aggression

The purpose of the present study was to examine the impact of sex, verbal reasoning, and normative beliefs on direct and indirect forms of aggression. Three scales from the Peer Estimated Conflict Behavior Questionnaire, Verbal Reasoning tests, and an extended version of Normative Beliefs About Aggression Scale were administered to 663 Estonian students (289 boys and 374 girls; 150 fifth, 264 seventh, and 249 ninth graders; ages 11–16). Self‐ and same‐sex peer ratings were used to assess the frequency of aggression. Associations between study variables were examined using structural equation modeling. Results showed that boys had higher levels of physical and verbal aggression in all the grades and higher levels of indirect aggression in Grade 7. Verbal reasoning predicted negatively all the forms of aggression, except for indirect aggression in Grade 7. Normative beliefs had a positive effect on all three forms of aggression in Grade 7 and Grade 9.

A Statistical Modelling Approach to the Occurrence and Timing of Reconciliation in Wild Japanese Macaques

AbstractIn various social species, animals have been observed to share friendly relationships with some group members and to resolve conflicts through reconciliation, the exchange of affiliative behaviour soon after a conflict that functions to restore the relationship between the former opponents. The valuable relationship hypothesis predicts that reconciliation should be observed more often after conflicts between friends. Friendly relationships can be described by three dimensions (i.e. value, security and compatibility); however, research into the relative importance of these dimensions for the occurrence of reconciliation is sparse. Moreover, reconciliation may depend on factors other than the social relationship between opponents including, for example, their social status or the context of the conflict. Our study aimed at analysing which factors are important determinants of reconciliation and at testing the valuable relationship hypothesis, by analysing the relative effects of relationship value, security and compatibility on the occurrence and timing of reconciliation. We collected data on two troops of wild Japanese macaques living on Yakushima Island, Japan, and selected the best predicting variables of reconciliation using linear mixed models. Our results show that reconciliation occurs more frequently, and earlier, after conflicts between opponents who exchange a higher percentage of grooming. Two additional variables related to relationship security and value were selected in the best models: frequency of aggression and of approaches resulting in tolerated co‐feeding. Among the variables not related to relationship quality, distance between opponents at the end of the conflict, kinship, sex of the opponents and context of conflict (i.e. during feeding or social time) were included in our models. Our findings support the valuable relationship hypothesis and, in particular, highlight that the fitness‐related benefits of social relationships (i.e. the relationship value) are important determinants of the evolution of friendly relationships and reconciliation.

Sexual Narcissism and the Perpetration of Sexual Aggression

Despite indirect evidence linking narcissism to sexual aggression, studies directly examining this relationship have yielded inconsistent results. Likely contributing to such inconsistencies, prior research has used global measures of narcissism not sensitive to whether the components of narcissism are activated in sexual versus non-sexual domains. The current research avoided such problems by using a measure of sexual narcissism to predict sexual aggression. In a sample of 299 men and women, Study 1 validated the Sexual Narcissism Scale, a new sexuality research instrument with four subscales-Sexual Exploitation, Sexual Entitlement, Low Sexual Empathy, and Sexual Skill. Then, in a sample of 378 men, Study 2 demonstrated that sexual narcissism was associated with reports of the frequency of sexual aggression, three specific types of sexual aggression (unwanted sexual contact, sexual coercion, and attempted/completed rape), and the likelihood of future sexual aggression. Notably, global narcissism was unrelated to all indices of sexual aggression when sexual narcissism was controlled. That sexual narcissism outperformed global assessments of narcissism to account for variance in sexual aggression suggests that future research may benefit by examining whether sexual narcissism and other sexual-situation-specific measurements of personality can similarly provide a more valid test of the association between personality and other sexual behaviors and outcomes (e.g., contraceptive use, infidelity, sexual satisfaction).

Food limitation increases aggression in juvenile meerkats

Both the rate and severity of sibling aggression are predicted to be higher when food availability is low. Although there is now good evidence that food availability influences sibling aggression in facultatively siblicidal species, where aggression commonly results in the death of a competitor, little is known about the proximate causes of aggression in nonsiblicidal species, where aggression rarely results in serious injury. Here, we investigated patterns of aggression between juvenile meerkats (Suricata suricatta), a species where littermate aggression is common, but never lethal. We show that the frequency of aggression between littermates increased when rainfall and helper number, both predictors of the amount of food available to pups, were low. Short-term feeding experiments demonstrated that reducing pup hunger by provisioning them before a foraging session significantly reduced their frequency of aggression in comparison to unfed controls. There was no evidence that offspring sex or weight influenced either the rate at which pups were aggressive, or which littermates they were aggressive to. These results suggest that food availability is an important factor affecting the severity of aggressive competition between offspring, even in the absence of lethal aggressive attacks.

Clinical Behavior of Papillary Thyroid Carcinoma Smaller than 1.5 cm

Background and Objectives With the increasing use of high resolution sonography and fine needle aspiration biopsy, the proportion of newly diagnosed thyroid papillary carcinomas have increased. However, it is not entirely clear whether microcarcinomas detectable by the above technology the should be considered a threshold for risk evaluation. The purpose of this study is to evaluate the clinical behavior of papillary carcinomas smaller than 1.5 cm. Subjects and Method A retrospective chart review was conducted for 181 patients who underwent surgery for thyroid cancer and was proven to have papillary carcinoma smaller than 1.5 cm in size from 1997 to 2006. The patients were divided into 3 groups according to cancer size. The patient’s gender, age, surgical method, pathology, initial neck node and neck recurrence was analyzed by chi-square test, analysis of variance (ANOVA) test and multinomial logistic regression analysis. Results Progressively increasing frequency of signs of tumor aggressiveness (multifocal, bilateral, extracapsular spread) was observed with increasing size. The rate of lymph node metastasis increased also, but it did not reach a significant value. Despite the increasing rate of aggressiveness and lymph node metastasis, there was no significant difference in recurrence between these groups. Conclusion Although the long term outcome does not seem to directly depend on tumor size in these small thyroid cancers, a progressing frequency of aggressiveness with increasing cancer size at presentation is evident.

Interactions between visitors and Formosan macaques (Macaca cyclopis) at Shou‐Shan Nature Park, Taiwan

Ecotourism involving feeding wildlife has raised public attention and is a controversial issue, especially concerning nonhuman primates. Between July 2002 and April 2005, the behavior of monkeys and tourists was collected through scan samplings, focal samplings and behavior samplings at the Shou-Shan Nature Park located in Taiwan's second largest city--Kaohsiung. In addition, the number of tourists and monkeys was counted in different hours and places within the park. Four hundred visitors were interviewed using a questionnaire to gather data on sex, age, purpose and frequency of visit to the park. The number of tourists was significantly higher during weekends than in weekdays in all locations. Humans dominated in the initiation of interspecies interactions--the overall ratio of human-initiated and monkey-initiated interactions was 2.44:1. Human-monkey conflicts accounted for only 16.4% of the total interactions (n=2,166), and adult human males and adult male macaques participated in higher rates than other age/sex groups in these conflicts. Visitors showed more affiliative behavior (15.9%) than agonistic behavior (8%) toward the macaques. In response to visitors' threat or attack, the Formosan macaques mostly showed submissive behavior with bared teeth, squealed or ran away to avoid confrontation (69.1%)--only few responded with counteraggression (18.7%). This study for the first time provided evidence that food provisioning increased both the frequency and duration of aggression among Formosan macaques (P<0.001). During food provisioning, the average frequency and the duration of agonistic events of macaques were more than 4 times higher compared with those without food provisioning. The average frequency of food provision by tourists was 0.73 times/hr--more than twice the incident that monkeys grabbed the food from tourists (0.34 times/hr). If people refrain from feeding monkeys and destroying the city park's natural vegetation, monkeys can be used to educate public about nature conservation in an urban setting.

Sex differences in aggressive incidents towards staff in secure services

Limited research is available regarding the impact of staff sex and the staff sex ratio on inpatient aggression. However, some research has suggested that opposite staff sex can help to prevent incidents of aggression by patients towards staff. This suggestion was explored in a medium secure unit in the North-West of England on two female wards and two male wards. This study examined the effects of staff sex and the staff sex mix on the ward on the frequency of aggression, both physical and verbal. It was found that patients were more likely to be aggressive to staff members of the same sex; however, this initially appeared to be a reflection of the sex staff ratio at the time of the attack. After controlling for the sex staff ratio, we found that patient sex still predicted victim sex. This was found for both verbal and physical aggression. These results may have direct implications for the way staffing in secure services is structured.

Relationships between aggression management training, perceived selfefficacy and rural general hospital nurses’ experiences of patient aggression

Relationships between nurses’ experiences of patient aggression in the previous three months, participation in aggression management training in the previous five years and perceived self-efficacy in dealing with patient aggression are reported. Over 76 per cent of general hospital nurses employed by a rural Area Health Service in New South Wales, Australia experienced patient aggression within a three-month period. Registered Nurses and Midwifes were most affected, with over 83 per cent experiencing recent patient aggression. Most of this aggression was in the form of verbal abuse. Almost 40 per cent of nurses had not participated in aggression management training or updates in the previous five years. Approximately 70 per cent of survey respondents reported their perceived self-efficacy in dealing with patient aggression in the low to mediumhigh range. No significant association was detected between participation in aggression management training in the previous five years and the frequency of patient aggression experienced in the previous three months. Significant though very weak associations were detected between participation in aggression management training, the proportion of patient aggression experienced as verbal abuse and perceived self-efficacy in dealing with patient aggression.The findings of this and other studies highlight the need for more rigorous approaches to evaluating the effectiveness of aggression management training and undertaking patient aggression management research more broadly.

Effects of participation in a martial arts–based antibullying program in elementary schools

AbstractThis study evaluated the Gentle Warrior Program, a traditional martial arts–based intervention to reduce aggression in children, as it was implemented in three elementary schools. The sample consisted of 254 children in grades 3, 4, and 5 who participated in the Gentle Warrior Program as part of a larger school violence intervention. Results indicated that boys who participated in more Gentle Warrior sessions reported a lower frequency of aggression and greater frequency of helpful bystanding (i.e., helpful behavior toward victims of bullying) over time, relative to boys with less frequent participation. The effect of participation on aggression was partially mediated by empathy. The effect of participation on helpful bystanding was fully mediated by changes in student empathy. No significant results were found for girls. Results of the study provide preliminary support for the use of martial arts–based interventions to address bullying in schools for boys, by teaching empathy, self‐control, and peaceful strategies to resolve conflicts. © 2008 Wiley Periodicals, Inc.

Downlink co-channel interference cancellation in multihop relay networks

In this paper, we study the use of iterative multi-user detectors for co-channel interference suppression in wireless cellular systems. We investigate the benefits of using iterative interference cancellation in the mobile receiver in the downlink scenario of traditional single-hop wireless cellular networks as well as two-hop relay networks. To illustrate these benefits, as an example we consider a receiver with a single receive antenna that is capable of detecting and cancelling a single in-band interferer that uses the same coding and modulation scheme as the desired signal. Simulation results show significant improvements with iterative interference cancellation in terms of the average system throughput and outage probability. Because the interference canceller is so effective, more aggressive frequency reuse schemes can be now considered, such as using smaller cluster sizes, using 3-sectored cells where all sectors share the same frequency band, and using non-orthogonal channels for relaying.

Mating Tactics in Male Grey‐Cheeked Mangabeys (Lophocebus albigena)

AbstractReproductive tactics of males can change with individual quality, relatedness and social structure. Here we describe the behaviours of male grey‐cheeked mangabeys towards other males, and females and their offspring (Lophocebus albigena) in relation to male status (high‐ranking/low‐ranking/transient) and group composition in Kibale National Park, Uganda. High‐ranking males had the highest mating success, frequency of loud calls, mate guarding and aggression towards females and males. Only transient males were often observed to be aggressive towards juveniles, while some high‐ranking males provided infant care. Mating tactics of high‐ranking males varied greatly among the five studied groups, probably as a function of the intensity of male–male competition. These results are discussed with regard to the role of male–male competition and behaviours that could affect female mate choice as tactics to obtain reproductive success.

The effect of substrate availability on behavioural and physiological indicators of welfare in the African cichlid (Oreochromis mossambicus)

AbstractMale African cichlids (Oreochromis mossambicus) establish territories on the substrate upon which spawning pits are dug, thus attracting females. The substrate, therefore, plays a very significant role in its lifecycle. The effects of substrate access on behaviour and physiology in captivity were assessed. Mixed-sex, all-male and all-female groups were observed for five days, with and without substrate. Social patterns, behaviour directed towards the substrate, locomotor activity and spatial behaviour were recorded, and haematocrit, plasma cortisol and glucose levels were measured. Substrate inclusion saw a significant increase in behavioural diversity, sexual behaviour of dominant males in mixed groups, pit digging and territoriality whereas a lack of substrate was characterised by increased chafing and inactivity. Vacuum-pit digging was also observed. Frequency of aggression did not differ significantly and female behaviour was not affected by the presence of substrate. For both sexes, no differences in cortisol and glucose levels were found between the two treatments, but haematocrit increased with substrate. The key role played by substrate in territorial males is consistent with the behavioural and physiological data reported. In the absence of substrate, decreased territorial behaviour is contrasted with similar levels of aggression, cortisol and glucose; all of which are suggestive of a stress-related context. Moreover, the exhibition of vacuum activities is a signal that behavioural needs are not being met and may be some form of coping mechanism. These findings, taken in conjunction with the variations in behavioural diversity and inactivity, suggest that the welfare of male cichlids may be adversely affected by the absence of substrate.