@article{ZimmermannSener2014, author = {Zimmermann, Andreas and Sener, Meltem}, title = {Chemical Weapons and the International Criminal Court}, series = {American Journal of International Law}, volume = {108}, journal = {American Journal of International Law}, number = {3}, publisher = {ASIL}, address = {Washington}, issn = {0002-9300}, doi = {10.5305/amerjintelaw.108.3.0436}, pages = {436 -- 448}, year = {2014}, language = {en} } @article{TetznerKlieglKraheetal.2017, author = {Tetzner, Julia and Kliegl, Reinhold and Krah{\´e}, Barbara and Busching, Robert and Esser, G{\"u}nter}, title = {Developmental problems in adolescence}, series = {Journal of Applied Developmental Psychology}, volume = {53}, journal = {Journal of Applied Developmental Psychology}, publisher = {Elsevier}, address = {New York}, issn = {0193-3973}, doi = {10.1016/j.appdev.2017.08.003}, pages = {40 -- 53}, year = {2017}, abstract = {This longitudinal study investigated patterns of developmental problems across depression, aggression, and academic achievement during adolescence, using two measurement points two years apart (N = 1665; age T1: M = 13.14; female = 49.6\%). Latent Profile Analyses and Latent Transition Analyses yielded four main findings: A three-type solution provided the best fit to the data: an asymptomatic type (i.e., low problem scores in all three domains), a depressed type (i.e., high scores in depression), an aggressive type (i.e., high scores in aggression). Profile types were invariant over the two data waves but differed between girls and boys, revealing gender specific patterns of comorbidity. Stabilities over time were high for the asymptomatic type and for types that represented problems in one domain, but moderate for comorbid types. Differences in demographic variables (i.e., age, socio-economic status) and individual characteristics (i.e., self-esteem, dysfunctional cognitions, cognitive capabilities) predicted profile type memberships and longitudinal transitions between types.}, language = {en} } @phdthesis{Rohlf2016, author = {Rohlf, Helena L.}, title = {The development of aggression in middle childhood}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-95457}, school = {Universit{\"a}t Potsdam}, pages = {242}, year = {2016}, abstract = {Background: The engagement in aggressive behavior in middle childhood is linked to the development of severe problems in later life. Thus, identifying factors and processes that con-tribute to the continuity and increase of aggression in middle childhood is essential in order to facilitate the development of intervention programs. The present PhD thesis aimed at expand-ing the understanding of the development of aggression in middle childhood by examining risk factors in the intrapersonal and interpersonal domains as well as the interplay between these factors: Maladaptive anger regulation was examined as an intrapersonal risk factor; processes that occur in the peer context (social rejection and peer socialization) were included as interpersonal risk factors. In addition, in order to facilitate the in situ assessment of anger regulation strategies, an observational measure of anger regulation was developed and validated. Method: The research aims were addressed within the scope of four articles. Data from two measurement time points about ten months apart were available for the analyses. Participants were elementary school children aged from 6 to 10 years at T1 and 7 to 11 years at T2. The first article was based on cross-sectional analyses including only the first time point; in the remaining three articles longitudinal associations across the two time points were analyzed. The first two articles were concerned with the development and cross-sectional as well as longitudinal validation of observational measure of anger regulation in middle childhood in a sample of 599 children. Using the same sample, the third article investigated the longitudinal link between maladaptive anger regulation and aggression considering social rejection as a mediating variable. The frequency as well as different functions of aggression (reactive and proactive) were included as outcomes measures. The fourth article examined the influence of class-level aggression on the development of different forms of aggression (relational and physical) over time under consideration of differences in initial individual aggression in a sample of 1,284 children. In addition, it was analyzed if the path from aggression to social rejection varies as a function of class-level aggression. Results: The first two articles revealed that the observational measure of anger regulation developed for the purpose of this research was cross-sectionally related to anger reactivity, aggression and social rejection as well as longitudinally related to self-reported anger regula-tion. In the third article it was found that T1 maladaptive anger regulation showed no direct link to T2 aggression, but an indirect link through T1 social rejection. This indirect link was found for the frequency of aggression as well as for reactive and proactive aggression. The fourth article revealed that with regard to relational aggression, a high level of classroom ag-gression predicted an increase of individual aggression only among children with initially low levels of aggression. For physical aggression, it was found that the overall level of aggression in the class affected all children equally. In addition, physical aggression increased the likelihood of social rejection irrespective of the class-level of aggression whereas relational aggression caused social rejection only in classes with a generally low level of relational aggression. The analyses of gender-specific effects showed that children were mainly influenced by their same-gender peers and that the effect on the opposite gender was higher if children engaged in gender-atypical forms of aggressive behavior. Conclusion: The results provided evidence for the construct and criterion validity of the observational measure of maladaptive anger regulation that was developed within the scope of this research. Furthermore, the findings indicated that maladaptive anger regulation constitutes an important risk factor of aggression through the influence of social rejection. Finally, the results demonstrated that the level of aggression among classmates is relevant for the development of individual aggression over time and that the children´s evaluation of relationally aggressive behavior varies as a function of the normativity of relational aggression in the class. The study findings have implications for the measurement of anger regulation in middle childhood as well as for the prevention of aggression and social rejection.}, language = {en} } @article{Krahe2014, author = {Krah{\´e}, Barbara}, title = {Media violence use as a risk factor for aggressive behaviour in adolescence}, series = {European review of social psychology}, volume = {25}, journal = {European review of social psychology}, number = {1}, publisher = {Routledge, Taylor \& Francis Group}, address = {Abingdon}, issn = {1046-3283}, doi = {10.1080/10463283.2014.923177}, pages = {71 -- 106}, year = {2014}, language = {en} } @article{Krahe2017, author = {Krahe, Barbara}, title = {Gendered self-concept and the aggressive expression of driving anger}, series = {Sex roles}, volume = {79}, journal = {Sex roles}, number = {1-2}, publisher = {Springer}, address = {New York}, issn = {0360-0025}, doi = {10.1007/s11199-017-0853-9}, pages = {98 -- 108}, year = {2017}, abstract = {The aggressive expression of driving anger is a risk factor for aggressive and dangerous driving behavior and is associated with a greater risk of accident involvement. The present study related positive and negative facets of a masculine and feminine self-concept to aggressive and adaptive forms of anger expression while driving. A sample of 417 drivers (194 women, 46.5\%) in Germany completed the Positive-Negative Sex Role Inventory (PN-SRI) as a measure of positive and negative masculinity and femininity and the Driving Anger Expression Inventory (DAX) as a measure of driving anger expression. Aggressive forms of expressing driving anger were unrelated to gender but differed significantly in relation to gendered self-concept. Negative but not positive masculinity was found to predict higher aggressive and lower adaptive anger expression. No main effects of positive or negative femininity were found. However, the link between negative masculinity and aggressive anger expression was buffered by positive femininity: Negative masculinity was unrelated to aggressive anger expression when accompanied by positive femininity. Adaptive anger expression showed negative links with negative masculinity and positive links with positive masculinity. The findings held for both men and women and support the theoretical distinction between positive and negative facets of the gendered self-concept. The implications for the conceptualization of both gendered self-concept and anger expression on the road are discussed.}, language = {en} } @phdthesis{Kirsch2017, author = {Kirsch, Fabian}, title = {Intrapersonal risk factors of aggressive behavior in childhood}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-407369}, school = {Universit{\"a}t Potsdam}, pages = {X, 182}, year = {2017}, abstract = {BACKGROUND: Aggressive behavior at an early age is linked to a broad range of psychosocial problems in later life. That is why risk factors of the occurrence and the development of aggression have been examined for a long time in psychological science. The present doctoral dissertation aims to expand this research by investigating risk factors in three intrapersonal domains using the prominent social-information processing approach by Crick and Dodge (1994) as a framework model. Anger regulation was examined as an affective, theory of mind as a cognitive, and physical attractiveness as an appearance-related developmental factor of aggression in middle childhood. An additional goal of this work was to develop and validate a behavioral observation assessment of anger regulation as past research lacked in ecologically valid measures of anger regulation that are applicable for longitudinal studies. METHODS: Three empirical studies address the aforementioned intrapersonal risk factors. In each study, data from the PIER-project were used, a three-wave-longitudinal study covering three years with a total sample size of 1,657 children in the age between 6 and 11 years (at the first measurement point). The central constructs were assessed via teacher-reports (aggression), behavioral observation (anger regulation), computer tests (theory of mind), and independent ratings (physical attractiveness). The predictive value of each proposed risk factor for the development of aggressive behavior was examined via structural equation modeling. RESULTS AND CONCLUSION: The newly developed behavioral observation measure was found to be a reliable and valid tool to assess anger regulation in middle childhood, but limited in capturing a full range of relevant regulation strategies. That might be the reason, why maladaptive anger regulation was not found to function as a risk factor of subsequent aggressive behavior. However, children's deficits in theory of mind and a low level in physical attractiveness significantly predicted later aggression. Problematic peer relationships were identified as underlying the link between low attractiveness and aggression. Thus, fostering children's skills in theory of mind and their ability to call existing beliefs about the nature of more versus less attractive individuals into question may be important starting points for the prevention of aggressive behavior in middle childhood.}, language = {en} } @phdthesis{Jung2016, author = {Jung, Janis Moritz}, title = {The role of dysfunctional peer relationships and academic failure in the development and progression of aggression}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-394477}, school = {Universit{\"a}t Potsdam}, pages = {163}, year = {2016}, abstract = {Background: Aggression is a severe behavioral problem that interferes with many developmental challenges individuals face in middle childhood and adolescence. Particularly in the peer and in the academic domain, aggression inhibits the individual from making important learning experiences that are predictive for a healthy transition into adulthood. Furthermore, the resulting developmental deficits have the propensity to feedback and to promote aggression at later developmental stages. The aim of the present PhD thesis was to investigate pathways and processes involved in the etiology of aggression by examining the interrelation between multiple developmental problems in the peer and in the academic domain. More specifically, the relevance of affiliation with deviant peers as a driving mechanism for the development of aggression, factors promoting the affiliation with deviant peers (social rejection; academic failure), and mechanisms by which affiliation with deviant peers leads to aggression (external locus of control) were investigated. Method: The research questions were addressed by three studies. Three data waves were available for the first study, the second and third study were based on two data waves. The first study specified pathways to antisocial behavior by investigating the temporal interrelation between social rejection, academic failure, and affiliation with deviant peers in a sample of 1,657 male and female children and adolescents aged between 6 and 15 years. The second study examined the role of external control beliefs as a potential mediator in the link between affiliation with deviant peers and aggression in a sample of 1,466 children and adolescents in the age of 9 to 19 years, employing a half-longitudinal design. The third study aimed to expand the findings of Study 1 and Study 2 by examining the differential predictivity of combinations of developmental risks for different functions of aggression, using a sample of 1,479 participants in the age between 9 and 19 years. First, profiles of social rejection, academic failure, and affiliation with deviant peers were identified, using latent profile analysis. Second, prospective pathways between risk-profiles and reactive and proactive aggression were investigated, using latent path analysis. Results: The first study revealed that antisocial behavior at T1 was associated with social rejection and academic failure at T2. Both mechanisms promoted affiliation with deviant peers at the same data wave, which predicted deviancy at T3. Furthermore, both an indirect pathway via social rejection and affiliation with deviant peers and an indirect pathway via academic failure and affiliation with deviant peers significantly mediated the link between antisocial behavior at the first and the third data wave. Additionally, the proposed pathways generalized across genders and different age groups. The second study yielded that external control beliefs significantly mediated the link between affiliation with deviant peers and aggression, with affiliation with deviant peers at T1 predicting external control beliefs at T2 and external control beliefs at T1 predicting aggressive behavior at T2. Again, the analyses provided no evidence for gender and age specific variations in the proposed pathways. In the third study, three distinct risk groups were identified, made up of a large non-risk group, with low scores on all risk measures, a group characterized by high scores on social rejection (SR group), and a group with the highest scores on measures of affiliation with deviant peers and academic failure (APAF group). Importantly, risk group membership was differentially associated with reactive and proactive aggression. Only membership in the SR group at T1 was associated with the development of reactive aggression at T2 and only membership in the APAF group at T1 predicted proactive aggression at T2. Additionally, proactive aggression at T1 predicted membership in the APAF group at T2, indicating a reciprocal relationship between both constructs. Conclusion: The results demonstrated that aggression causes severe behavioral deficits in social and academic domains which promote future aggression by increasing individuals' tendency to affiliate with deviant peers. The stimulation of external control beliefs provides an explanation for deviant peers' effect on the progression and intensification of aggression. Finally, multiple developmental risks were shown to co-occur within individuals and to be differentially predictive of reactive and proactive aggression. The findings of this doctoral dissertation have possible implications for the conceptualization of prevention and intervention programs aimed to reduce aggression in middle childhood and adolescence.}, language = {en} } @article{HolzZohselLauchtetal.2016, author = {Holz, Nathalie E. and Zohsel, Katrin and Laucht, Manfred and Banaschewski, Tobias and Hohmann, Sarah and Brandeis, Daniel}, title = {Gene x environment interactions in conduct disorder}, series = {Neuroscience \& biobehavioral reviews : official journal of the International Behavioral Neuroscience Society}, volume = {91}, journal = {Neuroscience \& biobehavioral reviews : official journal of the International Behavioral Neuroscience Society}, publisher = {Elsevier}, address = {Oxford}, issn = {0149-7634}, doi = {10.1016/j.neubiorev.2016.08.017}, pages = {239 -- 258}, year = {2016}, abstract = {Conduct disorder (CD) causes high financial and social costs, not only in affected families but across society, with only moderately effective treatments so far. There is consensus that CD is likely caused by the convergence of many different factors, including genetic and adverse environmental factors. There is ample evidence of gene-environment interactions in the etiology of CD on a behavioral level regarding genetically sensitive designs and candidate gene-driven approaches, most prominently and consistently represented by MAOA. However, conclusive indications of causal GxE patterns are largely lacking. Inconsistent findings, lack of replication and methodological limitations remain a major challenge. Likewise, research addressing the identification of affected brain pathways which reflect plausible biological mechanisms underlying GxE is still very sparse. Future research will have to take multilevel approaches into account, which combine genetic, environmental, epigenetic, personality, neural and hormone perspectives. A better understanding of relevant GxE patterns in the etiology of CD might enable researchers to design customized treatment options (e.g. biofeedback interventions) for specific subgroups of patients.}, language = {en} } @article{HohmannZohselBuchmannetal.2016, author = {Hohmann, Sarah and Zohsel, Katrin and Buchmann, Arlette F. and Blomeyer, Dorothea and Holz, Nathalie and Boecker-Schlier, Regina and Jennen-Steinmetz, Christine and Rietschel, Marcella and Witt, Stephanie H. and Schmidt, Martin H. and Esser, G{\"u}nter and Meyer-Lindenberg, Andreas and Banaschewski, Tobias and Brandeis, Daniel and Hohm, Erika and Laucht, Manfred}, title = {Interacting effect of MAOA genotype and maternal prenatal smoking on aggressive behavior in young adulthood}, series = {Journal of neural transmission}, volume = {123}, journal = {Journal of neural transmission}, publisher = {Springer}, address = {Wien}, issn = {0300-9564}, doi = {10.1007/s00702-016-1582-x}, pages = {885 -- 894}, year = {2016}, abstract = {Findings on the etiology of aggressive behavior have provided evidence for an effect both of genetic factors, such as variation in the monoamine oxidase A (MAOA) gene, and adverse environmental factors. Recent studies have supported the existence of gene × environment interactions, with early experiences playing a key role. In the present study, the effects of prenatal nicotine exposure, MAOA genotype and their interaction on aggressive behavior during young adulthood were examined. In a sample of 272 young adults (129 males, 143 females) from an epidemiological cohort study, smoking during pregnancy was measured with a standardized parent interview at the offspring's age of 3 months. Aggressive behavior was assessed between the ages of 19 and 25 years using the Young Adult Self-Report. DNA was genotyped for the MAOA 5\&\#8242; untranslated region variable number of tandem repeats polymorphism (VNTR). Results revealed a significant interaction between MAOA and smoking during pregnancy, indicating higher levels of aggressive behavior in young adults carrying the MAOA low-expressing genotype who had experienced prenatal nicotine exposure (n = 8, p = .025). In contrast, in carriers of the MAOA high-expressing genotype, maternal smoking during pregnancy had no effect on aggressive behavior during young adulthood (n = 20, p = .145). This study extends earlier findings demonstrating an interaction between MAOA genotype and prenatal nicotine exposure on aggressive behavior into young adulthood. The results point to the long-term adverse effects of smoking during pregnancy on the offspring's mental health, possibly underlining the importance of smoking cessation during pregnancy. According to the nature of the study (particularly sample size and power), analyses are exploratory and results need to be interpreted cautiously.}, language = {en} } @phdthesis{Gschwendt2002, author = {Gschwendt, Miriam A.}, title = {Early manifestations of aggression in infants of high risk mother-infant dyads}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0000528}, school = {Universit{\"a}t Potsdam}, year = {2002}, abstract = {Ziel dieser Untersuchung war es fr{\"u}he Risikofaktoren von aggressivem Verhalten bei Kleinkindern in einer Stichprobe von Teenager-M{\"u}ttern und ihren Babys aus sozial schwachen Verh{\"a}ltnissen (high risk sample) zu identifizieren. In den zur{\"u}ckliegenden zwei Jahrzehnten haben Wissenschaftler immer wieder auf die Bedeutung von Strategien hingewiesen, die es erm{\"o}glichen, Kinder und Babys mit einem Risiko f{\"u}r aggresives Verhalten zu identifiezieren. Eine fr{\"u}he Identifizierung ist besonders wichtig, weil schon Babys und Kinder eine signifikante Psychopathologie besitzen k{\"o}nnen und u. U. von einer Behandlung profitieren. Außerdem postulieren einige Entwicklungstheorien, dass der Ursprung einer sp{\"a}teren Psychopathologie schon in Verhaltensmustern in den ersten Lebensjahren erkannt werden kann. Dies scheint insbesondere f{\"u}r aggressives Verhalten zu gelten. Deshalb besteht grosses Interesse daran, relevante Faktoren in der fr{\"u}hen Kindheit zu identifizieren, die es erlauben aggressives Verhalten im weiteren Verlauf der Kindheit vorauszusagen. Methodik 60 Teenager-M{\"u}tter im Alter zwischen 14 und 20 Jahre und ihre Kleinkinder im Alter zwischen 12 und 17 Monaten aus sozial schwachen Verh{\"a}ltnissen wurden untersucht (high risk sample). Die Teenager-M{\"u}tter f{\"u}llten Frageb{\"o}gen {\"u}ber ihre Kleinkinder (The Infant-Toddler Social and Emotional Assessment [ITSEA], Carter \& Briggs-Gowan, 1993) und {\"u}ber sich selber aus (The Parenting Stress Index [PSI], Abidin, 1990, The Symptom CheckList-90-Revised [SCL-90-R], Derogatis, 1986, The Demographic Q{\"u}stionnaire, Zelenko et al., in press). Die Kleinkinder nahmen weiters an zwei objektiven Laboruntersuchungen teil (The Strange Situation Procedure, [SS], Ainsworth, 1978, The Bayley Scales of Infant Development Assessment, [BSID-II], Bayley, 1993). Die Studie untersuchte folgende Beziehungen: (1) Psychosoziale Funktionen der Mutter mit berichteter (berichet von Mutter anhand des ITSEA) und beobachteter Aggression und negativer Emotionalit{\"a}t bei Kleinkindern (beobachtet w{\"a}hrend des BSID-II und SS), (2) berichtete Aggression und negative Emotionalit{\"a}t mit beobachteter Aggression und negative Emotionalit{\"a}t bei Kleinkindern, (3) negative Emotionalit{\"a}t mit Aggression bei Kleinkindern, (4) Emotionsregulation mit Aggression und negativer Emotionalit{\"a}t bei Kleinkindern, und (5) eine m{\"o}gliche Interaktion zwischen Emotionsregulation und negativer Emotionalit{\"a}t in Beziehung zu Aggression bei Kleinkindern. Zus{\"a}tzlich wurde die Frage untersucht, ob Geschlecht einen Einfluss hat auf die oben genannten f{\"u}nf Beziehungen. Ergebnisse M{\"u}tter mit h{\"o}heren Depressionenswerten und Stresswerten berichteten signifikant mehr negative Emotionalit{\"a}t und tendenziell mehr Aggressionen bei ihren Kleinkindern als M{\"u}tter mit niedrigeren Depressionswerten und Stresswerten. Keine signifikanten Beziehungen konnten festgestellt werden zwischen Depressionswerten und Stresswerten der Mutter und objektiv beobachteten Aggressionen und negativer Emotionalit{\"a}t bei Kleinkindern. Die Beziehung zwischen beobachteter und berichteter negativer Emotionalit{\"a}t bei Kleinkindern war schwach signifikant. Keine signifikante Beziehung konnte jedoch zwischen beobachteter und berichteter Aggression bei Kleinkindern gezeigt werden. Sowohl berichtete als auch beobachtete negative Emotionalit{\"a}t korrelierte signifikant mit berichteter und beobachteter Aggression bei Kleinkindern. Eine signifikante Beziehung zwischen Emotionsregulation und negativer Emotionalit{\"a}t und Aggression bei Kleinkindern konnte aufgezeigt werden. Kleinkinder mit schwacher Emotionsregulation zeigten signifikant mehr negative Emotionalit{\"a}t und Aggressionen als Kleinkinder mit starker Emotionsregulation. Kleinkinder mit hohen negativen Emotionswerten und schwacher Emotionsregulation zeigten signifikant mehr Aggressionen als Kleinkinder mit hohen negativen Emotionswerten und starker Emotionsregulation und Kleinkindern mit niedrigen negativen Emotionswerten und schwacher oder starker Emotionsregulation. Das Geschlecht des Kleinkindes hatte einen signifikanten Einfluss auf folgende Beziehungen: M{\"u}tter mit h{\"o}heren Depressionswerten und Stresswerten berichteten signifikant mehr Aggressionen und negative Emotionalit{\"a}t bei ihren T{\"o}chtern, jedoch nicht signifikant mehr Aggressionen und negative Emotionalit{\"a}t bei ihren S{\"o}hnen als M{\"u}tter mit niedrigeren Depressionswerten und Stresswerten. Das Geschlecht des Kleinkindes hatte keinen signifikanten Einfluss auf die Beziehung zwischen Depressionswerten und Stresswerten der Mutter und beobachteter Aggression und negativer Emotionalit{\"a}t bei Kleinkindern. Ein interessantes Ergebnis ergab sich hinsichtlich Geschlecht und Emotionsregulationsverhaltensweisen. Buben mit h{\"o}heren Aggressionswerten schauten signifikant weniger zu ihrer Mutter und signifikant weniger in die Umgebung als Buben mit niedrigeren Aggressionswerten. M{\"a}dchen mit h{\"o}heren Aggressionswerten schauten signifikant mehr zu ihrer Mutter, signifikant mehr in die Umgebung und signifikant mehr auf Spielzeuge als M{\"a}dchen mit niedrigen Aggressionswerten. Schlussfolgerung Die Ergebnisse der Untersuchung haben Implikationen f{\"u}r die Einsch{\"a}tzung und die Behandlung von Aggressionen bei Kleinkindern. Erstens, die Ergebnisse weisen darauf hin, dass es unter Umst{\"a}nden wichtig sein k{\"o}nnte verschiedene Messverfahren (Mutter Report und objektive Messverfahren) zu verwenden, um Kleinkinder zu diagnostizieren, die ein erh{\"o}htes Risiko aufweisen im Laufe ihres Lebens Aggressionen zu entwickeln. Zweitens, Ergebnisse identifizierten m{\"u}tterliche negative Attributionen als einen m{\"o}glichen Risikofaktor f{\"u}r sp{\"a}teres Aggressionsverhalten bei Kindern. Zuk{\"u}nftige Studien sollten die Beziehung zwischen Aggressionsverhalten im Kleinkindalter und Aggressionen im sp{\"a}teren Leben untersuchen. Ein weiteres interessantes Ergebnis ergab sich hinsichtlich Emotionsregulation. Kleinkinder mit hoher negativer Emotionalit{\"a}t und schwacher Emotionsregualtion zeigten die meisten Aggressionen. F{\"u}r die Behandlung und die zuk{\"u}nftige Erforschung von Kleinkindaggressionen sollten die drei Konstrukte (Emotionsregualtion, negative Emotionalit{\"a}t und Aggression) miteinander kombiniert werden und nicht alleine untersucht werden.}, subject = {Junge Mutter / Kind / Aggressivit{\"a}t / Risikoverhalten}, language = {en} } @article{EccardFeyCaspersetal.2011, author = {Eccard, Jana and Fey, Karen and Caspers, Barbara A. and Yl{\"o}nen, Hannu}, title = {Breeding state and season affect interspecific interaction types indirect resource competition and direct interference}, series = {Oecologia}, volume = {167}, journal = {Oecologia}, number = {3}, publisher = {Springer}, address = {New York}, issn = {0029-8549}, doi = {10.1007/s00442-011-2008-y}, pages = {623 -- 633}, year = {2011}, abstract = {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.}, language = {en} } @article{BuchmannZohselBlomeyeretal.2014, author = {Buchmann, Arlette F. and Zohsel, Katrin and Blomeyer, Dorothea and Hohm, Erika and Hohmann, Sarah and Jennen-Steinmetz, Christine and Treutlein, Jens and Becker, Katja and Banaschewski, Tobias and Schmidt, Martin H. and Esser, G{\"u}nter and Brandeis, Daniel and Poustka, Luise and Zimmermann, Ulrich S. and Laucht, Manfred}, title = {Interaction between prenatal stress and dopamine D4 receptor genotype in predicting aggression and cortisol levels in young adults}, series = {Psychopharmacology}, volume = {231}, journal = {Psychopharmacology}, number = {16}, publisher = {Springer}, address = {New York}, issn = {0033-3158}, doi = {10.1007/s00213-014-3484-7}, pages = {3089 -- 3097}, year = {2014}, abstract = {Considerable evidence suggests that genetic factors combine with environmental influences to impact on the development of aggressive behavior. A genetic variant that has repeatedly been reported to render individuals more sensitive to the presence of adverse experiences, including stress exposure during fetal life, is the seven-repeat allele of the dopamine D4 receptor (DRD4) gene. The present investigation concentrated on the interplay of prenatal maternal stress and DRD4 genotype in predicting self-reported aggression in young adults. As disruption of the hypothalamic-pituitary-adrenal system has been discussed as a pathophysiological pathway to aggression, cortisol stress reactivity was additionally examined. As part of an epidemiological cohort study, prenatal maternal stress was assessed by maternal interview 3 months after childbirth. Between the ages of 19 and 23 years, 298 offspring (140 males, 158 females) completed the Young Adult Self-Report to measure aggressive behavior and were genotyped for the DRD4 gene. At 19 years, 219 participants additionally underwent the Trier Social Stress Test to determine cortisol reactivity. Extending earlier findings with respect to childhood antisocial behavior, the results revealed that, under conditions of higher prenatal maternal stress, carriers of the DRD4 seven-repeat allele displayed more aggression in adulthood (p = 0.032). Moreover, the same conditions which seemed to promote aggression were found to predict attenuated cortisol secretion (p = 0.028). This is the first study to indicate a long-term impact of prenatal stress exposure on the cortisol stress response depending on DRD4 genotype.}, language = {en} }