It is common for pigs to engage in physical aggression when mixed into new social groups, in order to establish dominance relationships. Phenotyping aggression is time consuming, however skin lesions resulting from physical aggression are quick to record, are genetically correlated with aggressive behavioural traits, and have low to moderate heritability (0.19 to 0.43). Reducing aggression via selection on skin lesion traits would provide a socially acceptable, long-term solution to the problem. Barriers to implementing selection against skin lesions lie in the lack of understanding regarding the underlying genetic basis of aggression, and its relationship with other behaviour and production traits. This thesis has focused on dissecting the phenotypic and genetic relationship between skin lesions recorded 24 hours after mixing (SL24h), and either 3 or 5 weeks later (SL3wk/SL5wk, respectively), with aggression performed at mixing, and several production traits. Chapter 2 provided evidence of a potential trade-off between involvement in aggression upon first mixing, and receipt of aggressive attacks several weeks after mixing. In particular, animals that avoid aggression at mixing had the highest fresh skin lesion numbers at 3 weeks. This suggests that reciprocal fighting at mixing may be beneficial for long-term group social stability. It also suggests that it may be possible to phenotype the least aggressive individuals in a group using SL3wk. In Chapter 3, I quantified the magnitude of reduction in complex aggressive behavioural traits when using SL24h or SL3wk as selection criteria, to identify the optimum skin lesion trait for selection purposes. The results of Chapter 3 provided evidence that selection against anterior SL24h would result in the greatest genetic and phenotypic reduction in aggressive behaviour recorded at mixing. Although there is evidence that selection for increased SL3wk would reduce aggression at mixing, current understanding of aggressive behaviour under stable group conditions is insufficient to recommend using this trait for selection purposes. Chapter 4, presented genetic associations between skin lesion traits as a measure of short- and long-term aggression, and commonly used commercial performance measures: growth, feed intake, feed efficiency, and carcass traits. The results suggested that, genetically, animals that receive many lesions show improved performance compared to those with few lesions, except for anterior SL24h, which have been shown to be genetically positively correlated with the initiation of nonreciprocal attacks. The aim of Chapter 5, was to determine whether skin lesion traits are phenotypically or genetically associated with behavioural measures of fearfulness. As found in Chapter 4, there was some evidence of an association between SL5wk and the traits, however this was not the case for anterior SL24h. For the 6th and final Chapter, we used skin lesion data from 1,840 pigs to perform genome wide association studies (GWAS), which detected a single SNP significantly associated with SL5wk on a genome wide level, as well as several SNPs associated with both SL24h and SL5wk on a chromosome wide level.

Magister Artium - MA / This thesis examined the use of aggression by youth in Pollsmoor Prison during incarceration. Though the incarceration of children and youth is a problem internationally, it is particularly problematic in South Africa where these prison facilities are overcrowded and result in disturbing social practices. They are often at risk for assault, rape and other violent interactions, often within a structured and hierarchical prison gang system. The gang culture within prisons is a crucial factor contributing to its high levels of violence, and its examination is vital to the understanding of power and aggression as a form of survival in prison. / South Africa

Magister Legum - LLM

Although researchers have often focused on the victims of aggression, the detrimental effects of engaging in aggression and/or displaying symptoms of externalizing disorders have been clearly identified in children and adolescents. Longstanding consequences of externalizing problems include internalizing difficulties such as depression. There is an increasing interest in identifying the direction of effect and understand whether externalizing problems precede internalizing problems, vice-versa, or whether they share a bi-directional relation. However, the study of the temporal sequence between aggression, externalizing disorders, and internalizing disorders in children and adolescents has yielded inconsistent findings. The sequential relation between externalizing and internalizing difficulties in children and adolescents was examined in this dissertation consisting of three studies. In Study 1, the moderating role of worry in the relation between aggression and depression was examined. The sample consisted of girls nominated as either relationally or physically aggressive by their peers. Results indicated that worry exacerbated the risk of reporting elevated depressive symptoms concurrently and one year later for physically aggressive girls. In Study 2, three competing hypotheses on the longitudinal relation between aggression and depression were compared. Findings from this study supported the hypothesis that symptoms of depression are preceded by aggressive behaviour. Additionally, it was found that engaging in physical aggression predicted depressive symptoms for girls but not for boys. The results of the first two studies suggest that for girls, engaging in non-normative forms of aggression is associated with greater mental health problems. In Study 3, the temporal relation between symptoms of externalizing disorders, namely oppositional defiant disorder and conduct disorder, and symptoms of depression was examined. Results provided support that the progressive relation between symptoms of externalizing and internalizing disorders was bi-directional. In summary, although it seems that engaging in externalizing behaviour, such as aggression, predicts symptoms of depression, findings from the third study suggest that the sequential relation between symptoms of externalizing problems, which may or may not include aggressive behaviour, and symptoms of depression seem to share a reciprocal relation.

This paper describes the development of the Beliefs About Overt and Relational Aggression Scale. The Beliefs About Overt and Relational Aggression Scale was designed to assess preschoolers' normative beliefs about these two types of aggression. Findings about the scale's internal reliability and test-retest reliability are presented. Findings about similarities and differences between beliefs about relational and overt aggression and gender are also discussed. Discussions about correlates of aggression, measuring aggression, and measuring beliefs are included.

The study reported here attempts to demonstrate the utility of group play therapy as a method of reducing aggression in preadolescent aged boys. Previous research has attempted to demonstrate the value of play therapy as a method of dealing with a variety of emotional and behavioral problems.

Magister Artium (Child and Family Studies) - MA(CFS) / To some extent all families experience family conflict; however, the concern is when it has an effect on preadolescents (age 10-12), behaviorally and psychologically. Preadolescence is a period marked by pubertal, emotional and behavioural changes. Family conflict may intensify preadolescents' experience of managing difficult situations. Self-determination theorists suggest that in order to have good mental health, basic psychological needs (autonomy, competence and relatedness) need to be met. Literature suggests that family conflict shapes behaviour and thus plays a pivotal role in externalizing behaviour (aggressive and antisocial behaviours). This study aimed to determine the effects of family conflict on preadolescents' basic psychological needs and externalizing behaviour. A quantitative approach and a crosssectional research design were employed in this study. A probability random sample was selected from two low socio-economic communities in Hout Bay, Cape Town. The sample consisted of N =128 preadolescents in grades 4, 5 and 6. The data for the study was obtained using self-report questionnaires that included - demographics, Family Environment Scale (FES), Basic Psychological Needs Scale (BPNS), Youth Self Report (YSR) and Buss Perry Aggression Questionnaire (BPAQ). Participants could choose whether they preferred responding in English or Afrikaans. The data was analysed using the Statistical Package for Social Sciences (SPSS) V23. The results were provided using descriptive and inferential statistics. The findings of the study indicated that there is a significant positive relationship between family conflict and preadolescents psychological needs, antisocial behaviour and aggression (with the exception of verbal aggression). The results, yielded by regression analysis, indicated that physical aggression (β = 0.31, p = 0.01) and need frustration, significantly predicted antisocial behaviour (β = 0.28, p = 0.00); need frustration (β = 0.28, p = 0.00) and antisocial behaviour significantly predicted physical aggression (β = 0.30, p = 0.00); antisocial behaviour (β = 0.24, p = 0.01) significantly predicted verbal aggression; need frustration (β = 0.35, p = 0.00) significantly predicted anger and need frustration (β = 0.26, p = 0.01) significantly predicting hostility. The assumptions of this study were confirmed - family conflict frustrates the basic psychological needs of preadolescents, and family conflict is related to the externalizing behaviour of preadolescents. The researcher ensured that confidentiality, anonymity and respect were adhered to throughout the study.

No description available.

Low levels of physiological arousal in response to stress (e.g., low skin conductance level reactivity; SCLR) have long been conceptualized as a marker of fearlessness and a risk factor for physical aggression (e.g., hitting). Less is known, however, about how individual differences in children’s SCLR and early caregiving experiences interact to produce aggressive behavior. Preliminary evidence suggests that children with low SCLR may be at an increased risk of aggression in the context of highly negative or low positive parenting. Additionally, although most early parenting socialization research has focused on physical aggression, mounting evidence implicates parenting style in the development of relational aggression (i.e., inflicting harm by damaging one’s relationships). In a community sample of 236 pre-adolescent children, we examined children’s SCLR, assessed during a standard laboratory interview, as a moderator of the link between parents’ self-reported positive (i.e., authoritative) and negative (i.e., permissive, authoritarian, psychologically controlling) parenting styles and children’s relational aggression, reported by teachers. Results indicated that increased levels of negative parenting predicted increased relational aggression; however, only permissive parenting marginally interacted with SCLR (p = .076), such that higher levels of permissive parenting predicted increased relational aggression for children with low, but not high, SCLR. No significant main effects or interactions were found with positive parenting. Overall, the results from the present study suggest that decreasing rates of negative parenting may be key to decreasing children’s relational aggression, and that behavioral monitoring and limit-setting with follow-through may be especially important facets of parenting for children with low physiological reactivity.

Behavioral difficulties in the early school years pose a risk to psychosocial functioning. The failure model suggests that peer rejection explains longitudinal associations between aggression and internalizing symptoms. The model postulates that aggression leads to increases in peer rejection, which, in turn, contributes to internalizing symptoms. This study tests pathways posited by the failure model, examining direct and indirect longitudinal effects. Direct effects models examined associations between reactive aggression and internalizing problems, reactive aggression and peer rejection, and peer rejection and internalizing symptoms. A mediation model examined the indirect effect of reactive aggression to internalizing symptoms, via peer rejection. Because distinct components of the failure model are presumed to share genetic influences, removing potential genetic contributions is important when examining the environmental influences over developmental pathways posited by the model. To this end, longitudinal tests were conducted with traditional (non-genetically controlled) and MZ twin difference (genetically controlled) designs. The latter disentangled nonshared environment effects from those for genetic factors from environmental factors. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection