Known risk factors for violence predict 12-month-old infants' aggressiveness with peers

This study tested the hypothesis that 12-month-old infants' use of force against peers is associated with known risk factors for violence. We conducted a prospective longitudinal study, which included laboratory observations of firstborn British infants (N = 271) during simulated birthday parties. No gender differences in aggressiveness were observed. The infants' observed aggressiveness was significantly correlated with mothers' mood disorder during pregnancy and with mothers' history of conduct problems. Infants' observed aggressiveness was correlated with parents' ratings of infants' anger and aggression, which were also predicted by mothers' mood disorder and history of conduct problems. Our findings indicate that infants at risk for serious aggression can already be identified when the motor ability to use physical force first enters the human repertoire.

Aggressiveness as a component of fighting ability in pigs using a game-theoretical framework

Understanding animal contests has benefited greatly from employing the concept of fighting ability, termed resource-holding potential (RHP), with body size/weight typically used as a proxy. However, victory does not always go to the larger/heavier contestant and the existing RHP approach thereby fails to accurately predict contest outcome. Aggressiveness, typically studied as a personality trait, might explain part of this discrepancy. We investigated whether aggressiveness forms a component of RHP, examining effects on contest outcome, duration and phases, plus physiological measures of costs (lactate and glucose). Furthermore, using the correct theoretical framework, we provide the first study to investigate whether individuals gather and use information on aggressiveness as part of an assessment strategy. Pigs, Sus scrofa, were assessed for aggressiveness in resident-intruder tests whereby attack latency reflects aggressiveness. Contests were then staged between size-matched animals diverging in aggressiveness. Individuals with a short attack latency in the resident-intruder test almost always initiated the first bite and fight in the subsequent contest. However, aggressiveness had no direct effect on contest outcome, whereas bite initiation did lead to winning in contests without an escalated fight. This indirect effect suggests that aggressiveness is not a component of RHP, but rather reflects a signal of intent. Winner and loser aggressiveness did not affect contest duration or its separate phases, suggesting aggressiveness is not part of an assessment strategy. A greater asymmetry in aggressiveness prolonged contest duration and the duration of displaying, which is in a direction contrary to assessment models based on morphological traits. Blood lactate and glucose increased with contest duration and peaked during escalated fights, highlighting the utility of physiological measures as proxies for fight cost. Integrating personality traits into the study of contest behaviour, as illustrated here, will enhance our understanding of the subtleties of agonistic interactions.

Integrating personality research and animal contest theory:Aggressiveness in the green swordtail xiphophorus helleri

Aggression occurs when individuals compete over limiting resources. While theoretical studies have long placed a strong emphasis on context-specificity of aggression, there is increasing recognition that consistent behavioural differences exist among individuals, and that aggressiveness may be an important component of individual personality. Though empirical studies tend to focus on one aspect or the other, we suggest there is merit in modelling both within- and among-individual variation in agonistic behaviour simultaneously. Here, we demonstrate how this can be achieved using multivariate linear mixed effect models. Using data from repeated mirror trials and dyadic interactions of male green swordtails, Xiphophorus helleri, we show repeatable components of (co)variation in a suite of agonistic behaviour that is broadly consistent with a major axis of variation in aggressiveness. We also show that observed focal behaviour is dependent on opponent effects, which can themselves be repeatable but were more generally found to be context specific. In particular, our models show that within-individual variation in agonistic behaviour is explained, at least in part, by the relative size of a live opponent as predicted by contest theory. Finally, we suggest several additional applications of the multivariate models demonstrated here. These include testing the recently queried functional equivalence of alternative experimental approaches, (e.g., mirror trials, dyadic interaction tests) for assaying individual aggressiveness. © 2011 Wilson et al.

Complex contests and the influence of aggressiveness in pigs

Animal contests vary greatly in behavioural tactics used and intensity reached, with some encounters resolved without physical contact while others escalate to damaging fighting. However, the reasons for such variation remains to be fully explained. Aggressiveness, in terms of a personality trait, offers a potentially important source of variation that has typically been overlooked. Therefore, we studied how aggressiveness as a personality trait influenced escalation between contestants matched for resource holding potential (RHP), using detailed observations of the contest behaviour, contest dynamics, and escalation levels. We predicted that winner and loser behaviour would differ depending on personality. This was tested by examining 52 dyadic contests between pigs (Sus scrofa). Aggressiveness was assayed in resident-intruder tests prior to the contest. Contests were then staged between pigs matched for RHP in terms of body weight but differing in their aggressiveness. In 27% of the contests a winner emerged without escalated physical fighting, demonstrating that a fight is not a prerequisite between RHP-matched contestants. However, the duration of contests with or without fighting was the same. In contests without a fight, opponents spent more time on mutual investigation and non-contact displays such as parallel walking, which suggests that ritualized display may facilitate assessment and decision making. Winners low in aggressiveness invested more time in opponent investigation and display and showed substantially less aggression towards the loser after its retreat compared to aggressive winners. Aggressiveness influenced contest dynamics but did not predict the level of escalation. Prominent behavioural differences were found for the interaction between personality and outcome and we therefore recommend including this interaction in models where personality is considered. Analyses based on contest duration only would miss many of the subtleties which are shown here and we therefore encourage more detailed analyses of animal contests, irrespective of the level of contest escalation.

Responses to interactive playback predict future pairing success in nightingales

Birdsong is a sexually selected trait that serves in territory defence and mate choice. Individual song traits can be affected by the body condition of the male and thus may reflect his quality. Such relations between male quality and general singing performance raise the question whether differences in male quality also affect response strategies used in dyadic interactions. To address this question, we studied the relation between pairing success of male common nightingales, Luscinia megarhynchos, and their responses to rivals posing different levels of threat. Using interactive playback, we exposed males prior to mating to either aggressively or moderately singing rivals (by song overlapping and song alternating, respectively). Males that remained unpaired throughout the season (bachelors) interrupted their singing significantly more often after being overlapped than after alternating playback, whereas subsequently mated males kept the number of singing interruptions more constant across playback treatment. This suggests that subsequently paired males are less discriminative than are bachelors when challenged by rivals varying in aggressiveness. Regardless of playback treatment, males that later became paired responded significantly more strongly than did bachelor males. Thus, an increase in singing after a vocal interaction prior to mating predicted future mating success. (c) 2006 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Probing aggressive motivation in a cichlid fish

The duration of startles provides an inverse measure of motivation to resume the previous activity. Here, we use a novel method in which one convict cichlid fish (Amatitlania nigrofasciata) of a competing pair was startled independently of the opponent. Fish were given various opponents and the mean startle duration determined. This mean was negatively correlated with the mean use of highly escalated 'frontal activities' such as biting and frontal display, but not the less escalated lateral displays or tail beating. Thus the startle duration was a reliable surrogate measure of the most escalated components of aggressive interactions. That is, it provided a motivational probe for aggressiveness of individual fish. Fight motivation is often determined in terms of fight duration or physiological costs for losers, who reveal the costs they are prepared to pay. We discuss various potential advantages of the motivational probe over previous measures, particularly with respect to winners and losers and different times during the interactions.

"To be accepted as normal": Public understanding and misconceptions concerning survivors of brain injury.

PRIMARY OBJECTIVE: To determine the views held by the general public in Northern Ireland towards survivors of brain injury. RESEARCH DESIGN: Qualitative semi-structured interviews. METHODS AND PROCEDURES: Interviews were conducted with 16 members of the general public. Ten questions addressed issues such as the role of survivors of brain injury in society, the challenges they face and the characteristics ascribed to them. MAIN OUTCOMES AND RESULTS: When asked to describe someone with a brain injury participants typically used negative labels and identified the most common problems as relating to physical, cognitive, emotional and social functioning. There was a general failure to recognize that brain injury was a 'hidden' disability, with most participants expecting some outward manifestation. Relatively few previous studies have employed a qualitative approach to explore how the public perceives survivors of brain injury. CONCLUSION: Members of the public have an increasing awareness of the challenges faced by survivors of brain injury. However, in spite of this, perceptions of aggressiveness, dependency and unhappiness were still evident, suggesting potential problems in reintegrating survivors of brain injury with their communities.

Influence of social status on the welfare of sows in static and dynamic groups

Forty-eight Large White x Landrace multiparous sows were mixed into twelve groups of four animals after their piglets were weaned. These groups were defined as static, with no animals being added to or removed from the groups after their formation. Aggressive and submissive behaviours were recorded continuously for 9 h after the sows were mixed, and the sows were assigned high or low social status on the basis of their relative aggressiveness and success in aggressive interactions. After five weeks, each static group was mixed into a dynamic group of 40+/-2 sows for an 11-week period. Three static groups (ie 12 animals) at a time were added to the dynamic group at three-week intervals; the same number of animals was removed at these time-points in order to maintain the group number at 40+/-2. Injury levels increased significantly with the transition from static groups to the dynamic group (P

Identifying early signs of aggression: psychometric properties of the cardiff infant contentiousness scale

Our aim was to develop an age-appropriate measure of early manifestations of aggression. We constructed a questionnaire about normative developmental milestones into which a set of items measuring infants’ use of physical force against people and expressed anger were included. These items comprise the Cardiff Infant Contentiousness Scale (CICS). Evidence for the reliability and validity of the CICS is provided from analyses of a sample of N5310 British infants, assessed at a mean age of 6 months as part of a larger longitudinal study of the development of aggression. The informants’ CICS ratings demonstrated reasonable levels of internal consistency and interrater agreement. Informants’ ratings were validated by observations of infants’ distress in response to restraint in a car seat. Longitudinal analyses revealed that contentiousness was stable over time and that contentiousness at 6 months predicted infants’ later use of force with peers. When used in the company of other methods, the simple four-item CICS scale could serve as a useful screen for early manifestations of aggressiveness in human infants.

Gene Expression Meta-Analysis Identifies VDAC1 as a Predictor of Poor Outcome in Early Stage Non-Small Cell Lung Cancer

Background: The bioenergetic status of non-small cell lung cancer correlates with tumour aggressiveness. The voltage dependent anion channel type 1 (VDAC1) is a component of the mitochondrial permeability transition pore, regulates mitochondrial ATP/ADP exchange suggesting that its over-expression could be associated with energy dependent processes including increased proliferation and invasiveness. To test this hypothesis, we conducted an in vivo gene-expression meta-analysis of surgically resected non-small cell lung cancer (NSCLC) using 602 individual expression profiles, to examine the impact of VDAC1 on survival.

Prognostic and therapeutic relevance of c-FLIP in acute myeloid leukaemia

Chemoresistance is a major contributor to the aggressiveness of AML and is often due to insufficient apoptosis. The CFLAR gene is expressed as long and short splice forms encoding the anti-apoptotic proteins c-FLIP(L) and c-FLIP(S) (CFLAR(L) and CFLAR(S) , respectively) that play important roles in drug resistance. In univariate analyses of CFLAR mRNA expression in adult AML patients, those individuals with higher than median mRNA expression of the long splice form CFLAR(L) (but not the short splice form) had significantly lower 3 year overall survival (P = 0·04) compared to those with low expression. In cell line studies, simultaneous down-regulation of c-FLIP(L) and c-FLIP(S) proteins using siRNA induced apoptosis in U937 and NB-4 AML cells, but not K562 or OCI-AML3 cells. However, dual c-FLIP(L/S) downregulation sensitized all four cell lines to apoptosis induced by recombinant tumour necrosis factor-related apoptosis-inducing ligand (rTRAIL). Moreover, specific downregulation of c-FLIP(L) was found to recapitulate the phenotypic effects of dual c-FLIP(L/S) downregulation. The histone deacetylase (HDAC)1/2/3/6 inhibitor Vorinostat was found to potently down-regulate c-FLIP(L) expression by transcriptional and post-transcriptional mechanisms and to sensitize AML cells to rTRAIL. Further analyses using more selective HDAC inhibitors revealed that HDAC6 inhibition was not required for c-FLIP(L) down-regulation. These results suggest that c-FLIP(L) may have clinical relevance both as a prognostic biomarker and potential therapeutic target for HDAC inhibitors in AML although this requires further study.

Theoretical investigation of the use of a moving vehicle to identify bridge dynamic parameters

Pavements and bridges are subject to a continuous degradation due to traffic aggressiveness, ageing and environmental factors. A rational transport policy requires the monitoring of this transport infrastructure in order to provide adequate maintenance and guarantee the required levels of transport service and safety. This paper investigates the use of an instrumented vehicle fitted with accelerometers on its axles to monitor the dynamics of bridges. A simplified quarter carbridge interaction model is used in theoretical simulations and the natural frequency of the bridge is extracted from the spectra of the vehicle accelerations. The accuracy is better at lower speeds and for smooth road profiles. The structural damping of the bridge was also monitored for smooth and rough road profiles. The magnitude of peaks in the power spectral density of the vehicle accelerations decreased with increasing bridge damping and this decrease was easier to detect the smoother the road profile.

Precursors to aggression are evident by 6 months of age

We tested the hypothesis that developmental precursors to aggression are apparent in infancy. Up to three informants rated 301 firstborn infants for early signs of anger, hitting and biting; 279 (93%) were assessed again as toddlers. Informants' ratings were validated by direct observation at both ages. The precursor behaviours were significantly associated with known risk factors for high levels of aggressiveness. Individual differences were stable from early infancy to the third year and predicted broader conduct problems. These findings suggest that some individuals set forth on the trajectory to high levels of aggression by 6 months of age. The findings have implications for developmental studies of aggression, clinical prevention and intervention strategies, and theoretical considerations regarding the detection of precursors in different domains of development.