TY - GEN A1 - Eccard, Jana A1 - Fey, Karen A1 - Caspers, Barbara A. A1 - Ylönen, Hannu T1 - Breeding state and season affect interspecific interaction types BT - indirect resource competition and direct interference T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - Indirect resource competition and interference are widely occurring mechanisms of interspecific interactions. We have studied the seasonal expression of these two interaction types within a two-species, boreal small mammal system. Seasons differ by resource availability, individual breeding state and intraspecific social system. Live-trapping methods were used to monitor space use and reproduction in 14 experimental populations of bank voles Myodes glareolus in large outdoor enclosures with and without a dominant competitor, the field vole Microtus agrestis. We further compared vole behaviour using staged dyadic encounters in neutral arenas in both seasons. Survival of the non-breeding overwintering bank voles was not affected by competition. In the spring, the numbers of male bank voles, but not of females, were reduced significantly in the competition populations. Bank vole home ranges expanded with vole density in the presence of competitors, indicating food limitation. A comparison of behaviour between seasons based on an analysis of similarity revealed an avoidance of costly aggression against opponents, independent of species. Interactions were more aggressive during the summer than during the winter, and heterospecific encounters were more aggressive than conspecific encounters. Based on these results, we suggest that interaction types and their respective mechanisms are not either–or categories and may change over the seasons. During the winter, energy constraints and thermoregulatory needs decrease direct aggression, but food constraints increase indirect resource competition. Direct interference appears in the summer, probably triggered by each individual’s reproductive and hormonal state and the defence of offspring against conspecific and heterospecific intruders. Both interaction forms overlap in the spring, possibly contributing to spring declines in the numbers of subordinate species. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 729 KW - rodents KW - aggression KW - seasonality KW - space use KW - winter biology Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-429398 SN - 1866-8372 IS - 729 SP - 623 EP - 633 ER - TY - JOUR A1 - Möller, Ingrid A1 - Krahé, Barbara A1 - Busching, Robert T1 - Consumption of media violence and aggressive behavior a longitudinal study of German adolescents with and without migration background JF - Zeitschrift für Entwicklungspsychologie und pädagogische Psychologie N2 - The consumption of media violence and aggressive behavior were assessed three times in a sample of N=1,052 German adolescents with and without migration background over a period of two years with 12-month intervals. The adolescents in the two groups, who were in grades 7 and 8 at T1, were matched by gender, age, type of school, and academic achievement. Students in the migrant group reported higher consumption of violent media. At T3, they showed more physical but less relational aggression than their peers of German background. Cross-lagged panel analyses showed parallel associations between media violence use and aggression in both groups: Media violence consumption at T1 and T2 predicted physical aggression at T2 and T3 independent of ethnic background. The reverse path from physical aggression to media violence consumption was nonsignificant. No link was found between media violence use and relational aggression over time. KW - media violence KW - aggression KW - migration KW - adolescence KW - longitudinal study Y1 - 2013 U6 - https://doi.org/10.1026/0049-8637/a000086 SN - 0049-8637 VL - 45 IS - 3 SP - 121 EP - 130 PB - Hogrefe CY - Göttingen ER - TY - INPR A1 - Krahé, Barbara T1 - Restoring the spirit of fair play in the debate about violent video games a comment on Elson and Ferguson (2013) T2 - EUROPEAN PSYCHOLOGIST N2 - This commentary argues that, rather than providing an "exhaustive review," Elson and Ferguson (2013) discuss a selective sample of empirical studies on violent video game use which corroborate their claim that there is no systematic evidence for a link between violent video game play and aggression. In evaluating the evidence, the authors portray a biased picture of the current state of knowledge about media violence effects. They fail to distinguish between aggression and violence and between everyday and clinical forms of aggression. Furthermore, they misrepresent key constructs, such as mediation, moderation, and external validity, to discredit methodologies used to assess aggression and media violence use. The paper moves the debate backward rather than forward, falling behind existing meta-analytic studies that consider a much wider and more balanced range of studies. KW - media violence KW - aggression KW - mediation KW - socialization effects Y1 - 2014 U6 - https://doi.org/10.1027/1016-9040/a000165 SN - 1016-9040 SN - 1878-531X VL - 19 IS - 1 SP - 56 EP - 59 PB - Hogrefe CY - Kirkland ER - TY - JOUR A1 - Busching, Robert A1 - Krahé, Barbara T1 - The Girls Set the Tone: Gendered Classroom Norms and the Development of Aggression in Adolescence JF - Personality and social psychology bulletin N2 - In a four-wave longitudinal study with N = 1,321 adolescents in Germany, we examined the impact of class-level normative beliefs about aggression on aggressive norms and behavior at the individual level over the course of 3 years. At each data wave, participants indicated their normative acceptance of aggressive behavior and provided self-reports of physical and relational aggression. Multilevel analyses revealed significant cross-level interactions between class-level and individual-level normative beliefs at T1 on individual differences in physical aggression at T2, and the indirect interactive effects were significant up to T4. Normative approval of aggression at the class level, especially girls' normative beliefs, defined the boundary conditions for the expression of individual differences in aggressive norms and their impact on physically and relationally aggressive behavior for both girls and boys. The findings demonstrate the moderating effect of social norms on the pathways from individual normative beliefs to aggressive behavior in adolescence. KW - aggression KW - normative beliefs KW - adolescence KW - class-level effects KW - multilevel modelling Y1 - 2015 U6 - https://doi.org/10.1177/0146167215573212 SN - 0146-1672 SN - 1552-7433 VL - 41 IS - 5 SP - 659 EP - 676 PB - Sage Publ. CY - Thousand Oaks ER - TY - JOUR A1 - Rohlf, Helena L. A1 - Krahé, Barbara T1 - Assessing anger regulation in middle childhood: development and validation of a behavioral observation measure JF - Frontiers in psychology N2 - An observational measure of anger regulation in middle childhood was developed that facilitated the in situ assessment of five maladaptive regulation strategies in response to an anger-eliciting task. 599 children aged 6-10 years (M = 8.12, SD = 0.92) participated in the study. Construct validity of the measure was examined through correlations with parent- and self-reports of anger regulation and anger reactivity. Criterion validity was established through links with teacher-rated aggression and social rejection measured by parent-, teacher-, and self-reports. The observational measure correlated significantly with parent- and self-reports of anger reactivity, whereas it was unrelated to parent- and self-reports of anger regulation. It also made a unique contribution to predicting aggression and social rejection. KW - anger regulation KW - middle childhood KW - behavioral observation KW - aggression KW - social rejection Y1 - 2015 U6 - https://doi.org/10.3389/fpsyg.2015.00453 SN - 1664-1078 VL - 6 PB - Frontiers Research Foundation CY - Lausanne ER - TY - GEN A1 - Rohlf, Helena L. A1 - Krahé, Barbara T1 - Assessing anger regulation in middle childhood BT - development and validation of a behavioral observation measure T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - An observational measure of anger regulation in middle childhood was developed that facilitated the in situ assessment of five maladaptive regulation strategies in response to an anger-eliciting task. 599 children aged 6-10 years (M = 8.12, SD = 0.92) participated in the study. Construct validity of the measure was examined through correlations with parent- and self-reports of anger regulation and anger reactivity. Criterion validity was established through links with teacher-rated aggression and social rejection measured by parent-, teacher-, and self-reports. The observational measure correlated significantly with parent- and self-reports of anger reactivity, whereas it was unrelated to parent- and self-reports of anger regulation. It also made a unique contribution to predicting aggression and social rejection. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 407 KW - anger regulation KW - middle childhood KW - behavioral observation KW - aggression KW - social rejection Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-406241 IS - 407 ER - TY - GEN A1 - Busching, Robert A1 - Krahé, Barbara T1 - The girls set the tone BT - gendered classroom norms and the development of aggression in adolescence T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - In a four-wave longitudinal study with N = 1,321 adolescents in Germany, we examined the impact of class-level normative beliefs about aggression on aggressive norms and behavior at the individual level over the course of 3 years. At each data wave, participants indicated their normative acceptance of aggressive behavior and provided self-reports of physical and relational aggression. Multilevel analyses revealed significant cross-level interactions between class-level and individual-level normative beliefs at T1 on individual differences in physical aggression at T2, and the indirect interactive effects were significant up to T4. Normative approval of aggression at the class level, especially girls’ normative beliefs, defined the boundary conditions for the expression of individual differences in aggressive norms and their impact on physically and relationally aggressive behavior for both girls and boys. The findings demonstrate the moderating effect of social norms on the pathways from individual normative beliefs to aggressive behavior in adolescence. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 401 KW - aggression KW - normative beliefs KW - adolescence KW - class-level effects KW - multilevel modelling Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-404831 IS - 401 ER - TY - JOUR A1 - Krahé, Barbara A1 - Busching, Robert T1 - Breaking the Vicious Cycle of Media Violence Use and Aggression: A Test of Intervention Effects Over 30 Months JF - Psychology of violence N2 - Objective: This study examined the sustained efficacy of a media violence intervention in reducing media violence use, normative acceptance of aggression, and aggressive behavior in adolescents. It used an experimental design to evaluate the effects of the intervention over a period of 30 months. Method: N = 627 German 7th and 8th graders were assigned to a 5-week school-based intervention to reduce media violence use or to a no-intervention control group. Media violence use, normative acceptance of aggression, and aggressive behavior were measured 3 months before the intervention (T1), 7 months post intervention (T2), and at 2 follow-ups 18 (T3) and 30 (T4) months after the intervention. This article focuses on the findings from the 2 follow-ups. Results: Controlling for baseline levels and various demographic covariates, media violence use at T2, T3, and T4 and self-reported physical aggression at T3 were significantly lower in the intervention group, and the indirect path from the intervention to T3 aggression via T2 media violence use was significant. Lower T2 media violence use predicted lower T3 normative acceptance of aggression among participants with lower initial aggression. No effects on nonviolent media use and relational aggression were observed. Conclusion: The findings show that a short class-based intervention can produce lasting changes in media violence use that are linked to a decrease in aggression. KW - aggression KW - experimental evaluation KW - intervention KW - longitudinal study KW - media violence Y1 - 2015 U6 - https://doi.org/10.1037/a0036627 SN - 2152-0828 SN - 2152-081X VL - 5 IS - 2 SP - 217 EP - 226 PB - American Psychological Association CY - Washington ER - TY - GEN A1 - Makowicz, Amber M. A1 - Tiedemann, Ralph A1 - Steele, Rachel N. A1 - Schlupp, Ingo T1 - Kin recognition in a clonal fish, Poecilia formosa T2 - PLoS ONE N2 - Relatedness strongly influences social behaviors in a wide variety of species. For most species, the highest typical degree of relatedness is between full siblings with 50% shared genes. However, this is poorly understood in species with unusually high relatedness between individuals: clonal organisms. Although there has been some investigation into clonal invertebrates and yeast, nothing is known about kin selection in clonal vertebrates. We show that a clonal fish, the Amazon molly (Poecilia formosa), can distinguish between different clonal lineages, associating with genetically identical, sister clones, and use multiple sensory modalities. Also, they scale their aggressive behaviors according to the relatedness to other females: they are more aggressive to non-related clones. Our results demonstrate that even in species with very small genetic differences between individuals, kin recognition can be adaptive. Their discriminatory abilities and regulation of costly behaviors provides a powerful example of natural selection in species with limited genetic diversity. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 431 KW - toxic hydrogen-sulfide KW - sexual selection KW - hybrid origin KW - discrimination KW - behavior KW - competition KW - aggression KW - cues KW - consequences KW - avoidance Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-411329 ER - TY - JOUR A1 - Holz, Nathalie A1 - Boecker-Schlier, Regina A1 - Buchmann, Arlette F. A1 - Blomeyer, Dorothea A1 - Baumeister, Sarah A1 - Hohmann, Sarah A1 - Jennen-Steinmetz, Christine A1 - Wolf, Isabella A1 - Rietschel, Marcella A1 - Witt, Stephanie H. A1 - Plichta, Michael M. A1 - Meyer-Lindenberg, Andreas A1 - Schmidt, Martin H. A1 - Esser, Günter A1 - Banaschewski, Tobias A1 - Brandeis, Daniel A1 - Laucht, Manfred T1 - Evidence for a Sex-Dependent MAOAx Childhood Stress Interaction in the Neural Circuitry of Aggression JF - Cerebral cortex N2 - Converging evidence emphasizes the role of an interaction between monoamine oxidase A (MAOA) genotype, environmental adversity, and sex in the pathophysiology of aggression. The present study aimed to clarify the impact of this interaction on neural activity in aggression-related brain systems. Functional magnetic resonance imaging was performed in 125 healthy adults from a high-risk community sample followed since birth. DNA was genotyped for the MAOA-VNTR (variable number of tandem repeats). Exposure to childhood life stress (CLS) between the ages of 4 and 11 years was assessed using a standardized parent interview, aggression by the Youth/Young Adult Self-Report between the ages of 15 and 25 years, and the VIRA-R (Vragenlijst Instrumentele En Reactieve Agressie) at the age of 15 years. Significant interactions were obtained between MAOA genotype, CLS, and sex relating to amygdala, hippocampus, and anterior cingulate cortex (ACC) response, respectively. Activity in the amygdala and hippocampus during emotional face-matching increased with the level of CLS in male MAOA-L, while decreasing in male MAOA-H, with the reverse pattern present in females. Findings in the opposite direction in the ACC during a flanker NoGo task suggested that increased emotional activity coincided with decreased inhibitory control. Moreover, increasing amygdala activity was associated with higher Y(A)SR aggression in male MAOA-L and female MAOA-H carriers. Likewise, a significant association between amygdala activity and reactive aggression was detected in female MAOA-H carriers. The results point to a moderating role of sex in the MAOAx CLS interaction for intermediate phenotypes of emotional and inhibitory processing, suggesting a possible mechanism in conferring susceptibility to violence-related disorders. KW - aggression KW - amygdala KW - fMRI KW - life stress KW - MAOA Y1 - 2016 U6 - https://doi.org/10.1093/cercor/bhu249 SN - 1047-3211 SN - 1460-2199 VL - 26 SP - 904 EP - 914 PB - Oxford Univ. Press CY - Cary ER -