High maternal aggression in dwarf hamsters (Phodopus campbelli and P. sungorus)

The defense of offspring, termed maternal aggression, is a highly conserved behavior in mammals, including rodents. This study examined relative levels of maternal aggression in two closely related dwarf hamster species, Phodopus campbelli and P. sungorus, that normally inhabit high latitude, boreal environments. When tested with first litters and with the breeder male remaining with the female (for P. campbelli the male is necessary for successful rearing of offspring), both species exhibited high levels of maternal aggression with average duration of aggressive behavior>80 sec for a 10 min test. For P. sungorus, males are not required to rear offspring. P. sungorus females with either one or multiple litters (singly housed after impregnation) exhibited significantly higher levels of aggression (>300 sec) relative to females co‐housed with the sires. In terms of species differences in attack style, P. campbelli exhibited a boxing or clawing strategy for ～50% of total attack time, but for P. sungorus, this form of attack occurred<5% of the time. For P. sungorus, attacks to the vulnerable belly and flank constituted>90% of all attacks, but these regions were attacked ～50% of the time for P. campbelli. A survey of levels of maternal aggression of rodents in other genera suggests that maternal aggression in Phodopus is at the high end of the spectrum. Results of this study suggest that the presence of the breeder male may actually suppress aggression in P. sungorus. This fact, as well as its high level of aggression and its distant relationship to mice and rats, suggest P. sungorus as a possible model for future studies on the neurobiological basis of maternal aggression. The relationship between the high rates of maternal aggression and life history strategy in Phodopus is discussed. Aggr. Behav. 00:000–000, 2005. © 2005 Wiley‐Liss, Inc.     

Anxiety sensitivity and retaliatory aggressive behavior in research volunteers

An important focus of recent aggression research has been to identify personality variables that influence the expression of aggression. One such variable may be anxiety sensitivity (AS). Individuals high in AS fear unpleasant anxiety-related physiological sensations and perhaps physiological arousal in general. Accordingly, people high in AS are motivated to avoid situations that produce these sensations. With respect to aggressive encounters, an intense attack by an opponent involves significant physiological arousal. High anxiety-sensitive individuals may therefore attempt to decrease the intensity of the interaction by responding in a non-aggressive or conciliatory manner. To test this possibility, 112 community volunteers completed a measure of AS and a well-validated laboratory task designed to assess aggressive behavior. As predicted, an inverse relation between AS and extreme aggressive responding was found. Specifically, as AS increases, retaliatory aggression is less likely after intense attack by an opponent.     

The Comorbidity of Conduct Problems and Depression in Childhood and Adolescence

An extensive body of research documents the high prevalence of comorbidity among child and adolescent disorders in general and between conduct problems and depression in particular. These problems co-occur at significantly higher rates than would be expected by chance and their comorbidity may have significant implications for nosology, treatment, and prognosis. Four main hypotheses have been put forth to account for these high rates of comorbidity. First, comorbidity may be a result of shortcomings associated with referral or informant biases. Second, comorbidity may be an artifact of overlapping definitional criteria. Third, one disorder may cause the other disorder by influencing the developmental trajectory and placing an individual at increased risk for further difficulties. Finally, comorbidity between two disorders may be explained by shared underlying causal or risk factors. The purpose of this review is to explore these possibilities, concentrating primarily on the common risk factors of parent psychopathology, emotion regulation, and cognitive biases that may underlie the co-occurrence of these two disorders. Based on our review, we propose a model for the development of comorbidity between these two disorders.     

A Longitudinal Study of Relational Aggression, Physical Aggression, and Children's Social–Psychological Adjustment

Although great strides have recently been made in our understanding of relational aggression and its consequences, one significant limitation has been the lack of prospective studies. The present research addressed this issue by identifying and assessing groups of relationally aggressive, physically aggressive, relationally plus physically aggressive (co-morbid), and nonaggressive children during their third grade year in elementary school and then reassessing them a year later, during fourth-grade (N = 224, 113 girls). Two aspects of social–psychological adjustment were assessed during both assessment periods including internalizing difficulties (i.e., withdrawal, depression/anxiety, and somatic complaints) and externalizing problems (i.e., aggressive behavior, delinquency). It was revealed that the strongest predictor of future social–psychological adjustment problems and increases in these problems from third to fourth was the combination of relational and physical aggression. Relational aggression also contributed unique information, relative to physical aggression, in the prediction of future maladjustment. Implications of these findings for future research and prevention efforts, particularly for aggressive girls, are discussed.

Individualism,collectivism, and Chinese adolescents' aggression: intracultural variations

This study examined the relations between cultural values (i.e., individualism and collectivism) and aggression among 460 (234 girls) Chinese adolescents. Conflict level and social status insecurity were examined as potential explaining mechanisms for these relations. The results showed that adolescents' endorsement of collectivism was negatively related to their use of overt and relational aggression as reported by teachers and peers, whereas positive associations were found between the endorsement of individualism and adolescent aggression. Adolescents' conflict level and social status insecurity accounted for a significant part of these associations. Findings of this study demonstrate the importance of examining intracultural variations of cultural values in relation to adolescent aggression as well as the process variables in explaining the relations. Aggr. Behav. 36:187–194, 2010. © 2010 Wiley‐Liss, Inc.     

Relations of proactive and reactive dimensions of aggression to overt and covert narcissism in nonclinical adolescents

In recent years, there has been increasing acknowledgment of the multidimensionality of narcissism and that different types of narcissism may relate differently to other domains of functioning. Similarly, aggression—a frequently discussed correlate of narcissism—is a heterogeneous construct. In this study, the relations of proactive and reactive aggression with overt and covert manifestations of narcissism were examined in a sample of 674 Italian high school students (mean age=15.5 years, SD=2.1 years). Overt narcissism was positively related to both proactive and reactive subtypes of aggression, whereas covert narcissism related only to reactive aggression. Vanity, Authority, Exhibitionism, and Exploitativeness were the components of overt narcissism related to Proactive Aggression (all remained unique correlates when controlling for Reactive Aggression), whereas Reactive Aggression was associated with the Exhibitionism, Superiority, and Entitlement subscales (only the latter was uniquely related when controlling for Proactive Aggression). Aggr. Behav. 36:21–27, 2010. © 2009 Wiley‐Liss, Inc.     

Chronic passive exposure to aggression escalates aggressiveness of rat observers

Previous studies have documented that exposure to aggression increases aggressiveness of human witnesses. However, the question of whether passive exposure to aggression can exclusively cause a risk of aggressive inclination for observers through a learning process, rather than mimicry effect, has not been readily addressed in the clinical literature. This study aimed to investigate this question by using a simple animal model to test the behavioral effect of chronic passive exposure to aggression. Our results indicate that observer rats that had been passively exposed to aggression for 10 min per day for 23 consecutive days exhibited more aggressive behavior than controls or those groups undergoing a single exposure to passive aggression. Furthermore, aggression levels in the group of 23‐day chronic exposure to aggression lasted 16 days after the recovery from exposure to aggression. These data suggest that the development of aggression in this model occurred through a learning process because only chronic exposure to aggression resulted in this behavioral outcome in the long run. Aggr. Behav. 36:54–66, 2010. © 2009 Wiley‐Liss, Inc.     

Simulating Natural History: Walking with Dinosaurs as Hyper-Real Edutainment

Abstract

Real-world experiments that test new technologies can affect policy and practice by introducing new objects of intervention through tinkering; the ad hoc work of realigning relations in the face of frictions, surprises, and disturbances that occur when introducing a technology. In a pilot study on aggression detection, tinkering moved aggression in and out of the human body. In the end, the pilot defined aggression as a set of acoustic-physical variables representing the aroused human body, alongside other signals of aggression. How aggression as an object intervention was shaped by tinkering is relevant because it involved inclusions and exclusions by the authorities who identified aggression, the methods they applied, and mandate for intervention. A focus on relations that are tinkered within a real-world experiment permits critical engagement with this format. Although the real-world experimental format is credited with producing knowledge about a technology's ‘actual’ performance, actors and events at the pilot study location were made only selectively relevant. Analyses of real-world experiments should therefore explain how experiments selectively make the world relevant, giving only particular objects of intervention a truth status.     

The Relation Between Early Adolescents’ Trust Beliefs in Peers and Reactions to Peer Provocation: Attributions of Intention and Retaliation

The authors examined the relation between early adolescents’ trust beliefs in peers and both their attributions for, and retaliatory aggression to, peer provocation. One hundred and eight-five early adolescents (102 male) from the United Kingdom (M age = 12 years, 2 months, SD = 3 months) completed the Children's Generalized Trust Beliefs in peer subscale (K. J. Rotenberg, C. Fox, et al., 2005) and reported the intentions of, and their retaliatory aggression to, hypothetical peer provocation. A curvilinear relation was found between trust beliefs in peers and retaliatory aggression but not for attributions of intention. Early adolescents with low and those with very high trust beliefs in peers reported greater retaliatory aggression than did early adolescents with the middle range of trust beliefs. The findings supported the conclusion that early adolescents who are high trusting, as well as those are very low trusting, are at risk for psychosocial maladjustment. Support was not obtained for a hostility attribution bias interpretation of those patterns.