Aggression studies in laboratory animals have largely focused on natural species-specific forms of aggression that poorly reflect pathological types of aggression in humans. The primary goal of this dissertation was to identify and characterize a subtype of aggression in support for a congenital animal model of reactive/impulsive-aggression in humans. Experiments using novel second-by-second analyses to investigate for individual differences in aggression and impulsive choice showed detailed quantitative and qualitative differences, and identified a convergence of behaviors to one distinct impulsive-aggressive profile in high-attack frequency (HAF) hamsters. As aggression and impulsivity widely implicate the serotonin (5HT) system, and previous studies have similarly characterized the neural control of aggression in hamsters, it was hypothesized that impulsive-aggression in HAF individuals was associated to common neurobiology. While 5HT does play a role, immunocytochemical experiments and pharmacological manipulations showed a distinct neurobiological profile of decreased 5HT availability, increased densities of 5HT1A and 5HT3 receptor subtypes, and drastically differential and opposite phenotypic-dependent reactivity to 5HT3 receptor blockade. Moreover, the current studies also showed that while 5HT3 receptor activity has broad effects, attenuating all behavioral aspects of the impulsive-aggressive phenotype (i.e. aggression, repetitiveness, fragmentation, and impulsive choice), 5HT1A receptor activity seems to have more limited effects. Additional retrospective studies investigated developmental and etiological differences between the phenotypes. HAF adults were associated with low agonistic activity in early puberty and an early emergence of impulsivity-related characteristics. These data indicate a differential developmental trajectory of behavior and accelerated maturation, consisting of a lack of play fighting during early puberty. The HAF phenotype was additionally associated with paternal, but not maternal influence, suggesting male genetic contribution. Together, these data support a congenital animal model that better reflects reactive forms of aggression in humans through the behavioral, neurobiological, and developmental characterization of HAF hamsters described herein. These data have pre-clinical and clinical significance and can be applied to diagnostic and preventative measures, as they illustrate the importance of distinguishing predictions about extreme fringe populations from that of normal populations, point towards more specific pharmacological therapeutic applications, identify early predictive behaviors of impulsive-aggression, and suggest heritability. / text

Due to the seriousness and prevalence of eating disorders, exploring the etiology of these disorders and identifying specific at-risk populations is crucial. One promising risk factor that has been linked to the development of eating disorders is competitiveness (Burckle, Ryckman, Gold, Thornton, & Audesse, 1999; Striegel-Moore, Silberstein, Grunberg, & Rodin, 1990). Additionally, specific populations of women have been shown to experience higher rates of eating disorders. Women in sororities are one such group identified with higher rates of disordered eating than their non-sorority counterparts (Basow, Foran, Bookwala, 2007; Crandall,1988; Schulken, Pinciaro, Sawyer, Jensen, & Hoban, 1997). Therefore this study will seek to understand more about how competitiveness may differentially impact this population of women and contribute to higher rates of eating disorder symptomatology. This project has several objectives. First, the prevalence of eating disorders, competition among women, and relational aggression among women in sororities will be addressed. In order to assess whether women in sororities differ from women who are not in sororities on measures of eating disorders symptomatology, a one-way analysis of variance (ANOVA) will be conducted. The constructs of competitiveness and relational aggression will be compared amongwomen in sororities and their non-sorority counterparts. A one-way multivariate analysis of variance (MANOVA) will be conducted to determine whether there are mean differences between women in sororities and those not on four constructs of competitiveness (hypercompetitiveness, personal development competitiveness, female competition for status competitiveness, and female competition for mates competitiveness). Finally, an ANOVA will be conducted to determine if there are mean differences between women in sororities and women not in sororities on a measure of relational aggression. The second focus of this project is to examine if different forms of competitiveness are better at predicting eating disorders. The constructs of competitiveness that have been individually demonstrated to predict eating disorder behavior will be included. Multiple regression will be used to examine how well knowing a participant’s type of competitive attitude will help explain eating disorder symptomatology. Lastly, because the literature has not yet explored how relational aggression relates to the development of eating disorders, the final purpose of this study will be to understand this relationship. In attempting to understand this relationship, a mediation model will be performed. Participants for this study will include 270 undergraduate women from the Educational Psychology subject pool. / text

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In the wake of 21 year old Don Sanderson’s death (January 1st, 2009), the direct result of head injuries sustained during an on-ice hockey fight, the social and political appetite for eliminating violence in amateur hockey appears to be at an all time high. Unfortunately, due to a variety of methodological and conceptual limitations previous research is currently unable to provide a unified and valid explanation for sport-specific aggression (Kirker, Tenenbaum, & Mattson, 2000). One of the primary impediments facing our understanding of sport-specific aggression is the descriptive and fragmented nature of the current body of literature. Over the years a number of independent lines of research have been undertaken, through which several psychological and social factors have been identified as potential determinants. However, in many cases these constructs have yet to be tested against athletes’ actual aggressive behaviour in sport and thus their predictive contribution to our understanding is still unknown. Consequently, the purpose of the current investigation was to assess the predictive influence of several commonly cited psychosocial constructs on amateur hockey players actual within-competition use of aggressive behaviour over a competitive season. A trait aggressive personality disposition emerged as the strongest and most stable predictor of athletes’ aggressive behaviour, accounting for 10 – 40% of the statistical variance depending upon the age and competitive level of the athletes under investigation. Differences in the overt expression of the this trait aggressive disposition between age cohorts (bantam / midget) and competitive levels (house league / rep) suggests that environmental and contextual factors also play a significant role in facilitating or repressing athletes’ aggressive behaviour. As such, the results of the current study support an interactive explanation for hockey-related aggression, whereby situational (e.g., team norms, perceived reinforcement) and personal factors (e.g., trait aggressive disposition, ego orientation) interact to either increase or decrease an athlete’s likelihood for committing aggressive penalty infractions over a competitive season. The current results are plotted and discussed within the parameters of Anderson and Bushman’s (2002) General Aggression Model (GAM), which is a frequently cited interactionist framework used in the broader study of human aggression.

This article offers a perspective on adolescents' experiences of aggression in a secondary school, with a focus on the manifestation, contributing factors, consequences, and learners' opinions on aggression. An inductive qualitative research approach was chosen, where learners wrote about their experiences and participated in focused semi-structured interviews. Central themes were derived by means of thematic content analysis. The results revealed that a substantial number of learners experienced negative feelings about aggression at school and that aggression was related to individual characteristics, the adolescent's developmental stage, socialisation, status, competition, home environment, prior experiences, learnt behaviour and the effect of the media and music. Aggression was present among all genders. ages and cultures in school. It seemed to have a higher prevalence among boys, but was also significantly present among girls. Physical and emotional bullying had a high prevalence. which showed that bullying is problematic at schools. Passive aggression was mostly present in the form of oppositional behaviour towards authorities at school and educators are often verbally abused and ignored by learners, but their classrooms are also damaged. Individual characteristics, interpersonal relationships, multicultural interaction and a lack of sufficient social skills contributed towards many acts of aggression. Aggression was prominent in the reciprocal relationships between adolescents and their social environment. Being part of a group and forming a social identity are very important. Confiding in groups may expose learners to peer pressure, which may lead to activities and behaviour that are aggressive in nature. There were reports of discrimination and it seemed that learners get along better with others who share an equal status. This may possibly explain why aggression seemed less between white English-speaking and black English-learners, while it was more common between white Afrikaans and white/black English-speaking learners. Increased social contact between members of different social groups could reduce prejudice if these persons have an equal status. Exposure to aggression had emotional consequences, and some learners were prone to feelings of anger, fear, depression, being controlled and a loss of self-content. Behavioural responses included retaliation, pacifism, vandalism and suicide. Exposure to aggression (directly and indirectly) provoked several responses. These responses may be emotional or behavioural in nature. Emotions such as fear and anger and feeling overwhelmed, depressed and helpless may be elicited in response to aggression. Some learners may retaliate towards an aggressive incident through physical or verbal behaviour; others may withdraw and avoid social interactions. Learners may direct their aggression towards others (people and objects) or themselves. In the case of the latter, it may lead to depression, self-harm or even suicide. No single factor propels an adolescent to act aggressively. Instead, the causes of such behaviour are complex and multifaceted. Most participants in this research experienced aggression at school as unhealthy. Aggression may have emotional and behavioural consequences such as disruption, discomfort and disturbance of normal functioning. Although aggression seemed relatively under control at this particular school, there are signs of an increase in aggression and in the severity of some of the incidents, and of the possibility of desensitisation towards aggression, with the agonising possibility that aggression is serving as a form of entertainment for some learners. The need for learner involvement, school guidance programmes and life-skill training was prominent, accompanied by the need for school counsellors to assist in the management of aggression. Teachers must have better knowledge of the adolescent developmental phase so that they could understand and identify behavioural problems among learners. / Thesis (M.Sc. (Clinical Psychology))--North-West University, Potchefstroom Campus, 2007

Syrian hamsters are a useful model for offensive aggression because males and females spontaneously engage in agonistic bouts. In hamsters, there is a large sex difference on aggression in the serotonin (5-HT) pathways. Male aggression is inhibited and female aggression increases with injections of a 5-HT agonist into the anterior hypothalamus (AH), but little is known if similar effects are seen in adult hamsters with repeated systemic administration of the selective serotonin reuptake inhibitor (SSRI), fluoxetine (FLX), which is one of the few approved pharmacological treatments for mood disorders in children and adolescents. The goal of this study is to determine if repeated intraperitoneal injections of FLX over 30 days in adolescent male and female hamsters has an effect on offensive aggression similar to site specific alterations of the 5-HT system in the AH. Our data suggest that systemic administration of FLX as adolescents over 30 days does not affect offensive aggression in males or females as adults.

Elever med sociala och emotionella svårigheter beskrivs ibland som problematiska och svårhanterliga. Lärarens bemötande och inlevelseförmåga av eleven är av stor betydelse. Syftet med studien var att undersöka lärares empati i mötet med elever med utagerande beteende. Centralt har varit hur empatin yttras samt om lärares empati skiljer sig åt mellan elever med och utan diagnos. Utifrån att deltagarna fick läsa två olika fallbeskrivningar utfördes en skriftlig intervju med totalt 13 personer, varav nio kvinnor och fyra män. I fallbeskrivningarna redogjordes för två scenarier med elever i utsatta situationer. Kvalitativ innehållsanalys användes som forskningsmetod och därav baserades studien på tolkning av texter. Med en hermeneutisk ansats i studien fanns en strävan om att inta en så objektiv ställning som möjligt till texterna. Analysen resulterade i ett antal bemötanden som är vanliga hos lärare: (1) läraren visar varsamhet och hänsyn till eleven, (2) läraren känner ansvar, (3) läraren vill förstå eleven, (4) läraren skuldbelägger inte eleven, (5) läraren vill hjälpa eleven. Resultat pekar på stor empatisk förmåga hos lärarna inom dessa områden. Det var även vanligare att lärarna bemötte eleven med diagnos mer empatiskt än eleven utan diagnos. Resultaten kan vara till hjälp för lärare att öka sin medvetenhet kring empati.

From early on, social adjustment among peers is crucial to healthy development. Social status, a reflection of adjustment among peers, can be considered in terms of acceptance or likeability, and rejection, or dislikability, as well as popularity or reputational prestige in the peer group. Research finds meaningful links between peer status and social behaviors like aggression, but has not examined the role of dimensions of peer status in association with perceptions of the self. I conducted a set of studies examining associations among peer status (likeability, dislikability, and popularity) and self-perceptions (self-esteem and self-concept clarity), and social goals as moderators of these associations. In Study 1, I examined cross-sectional associations between peer-reported status and aggression and self-perceptions and social goals in adolescents. In Studies 2, 3, and 4, I experimentally examined the effects of peer status on the self, as well as social goals as moderators of these effects, in young adults using two newly developed manipulations of peer status. Contrary to my hypotheses, the results suggested that self-esteem and self-concept clarity were not directly associated with peer status, and that these associations largely did not differ based on social goals. However, further exploratory analyses revealed meaningful links among the study variables in youth and adults. Results have theoretical and practical implications for understanding peer status, the self, and aggression. Limitations and future directions are discussed.

Using longitudinal peer and self-report data (n = 1490; 10th to 12th grade), changes in relational and overt aggression were each regressed onto social acceptance, close friendships, and their interaction. Links between social acceptance, close friendships and overt or relational aggression were dependent upon whether adolescents or their peers assessed their friendships and aggression. For both genders, peers were more likely to see adolescents with many friends and close friendships as being more overtly and relationally aggressive. In contrast, self-reports of close friendship and social acceptance were either unrelated or negatively related to peer-reported overt and relational aggression. When predicting peer-reported overt aggression, self-reported close friendships and self-reported social acceptance interacted such that males who believed they had close friendships and were socially accepted were more likely to be rated by peers as overtly aggressive. No connections between friendship and aggression were found when adolescents rated their own overt aggression and friendship / Graduate

Experiential avoidance (EA) is a process in which a person attempts to avoid, dismiss, or change experiences such as emotions, behaviors, and thoughts. EA is associated with a number of psychological disorders and is generally harmful to psychological well-being. Various studies have explored the role of EA as a mediator, while others have studied EA as a moderator. The current study aimed to further understand and broaden the knowledge of the role of EA in regard to trauma, substance abuse, aggression, and impulsivity by examining relationships between these variables with EA as a mediator and as a moderator. Experientially avoidant behaviors (i.e., substance abuse, aggression, and impulsivity) were related to higher levels of EA. EA was found to partially mediate the relationship between the number of traumatic experiences and posttraumatic stress disorder (PTSD) symptoms, as well as the relationship between substance abuse and PTSD. EA was also found to moderate the relationship between PTSD symptoms and aggression. Findings from the present study as well as its limitations and future directions for research are discussed.