Chronic Stressors and Adolescents’ Externalizing Problems: Genetic Moderation by Dopamine Receptor D4. The TRAILS Study

The existing literature does not provide consistent evidence that carriers of the Dopamine D4 Receptor 7-repeat allele are more sensitive to adverse environmental influences, resulting in enhanced externalizing problems, compared to noncarriers. One explanation is that the adverse influences examined in prior studies were not severe, chronic, or distressing enough to reveal individual differences in sensitivity reflected by DRD4–7R. This study examined whether the 7-repeat allele moderated the association between chronic stressors capturing multiple stressful aspects of individuals’ lives and externalizing problems in adolescence. We expected that chronic stressor levels would be associated with externalizing levels only in 7-repeat carriers. Using Linear Mixed Models, we analyzed data from 1621 Dutch adolescents (52.2% boys), obtained in three measurement waves (mean age approximately 11, 13.5, and 16 years) from the TRacking Adolescents’ Individual Lives Survey (TRAILS) population-based birth cohort and the parallel clinic-referred cohort. Across informants, we found that higher levels of chronic stressors were related to higher externalizing levels in 7-repeat carriers but not in noncarriers, as hypothesized. Although previous studies on the 7-repeat allele as a moderator of environmental influences on adolescents’ externalizing problems have not convincingly demonstrated individual differences in sensitivity to adverse environmental influences, our findings suggest that adolescent carriers of the Dopamine D4 Receptor 7-repeat allele are more sensitive to chronic, multi-context stressors than noncarriers.     

ADHD Symptoms in Middle Adolescence Predict Exposure to Person-Related Life Stressors in Late Adolescence in <Emphasis Type="Italic">5-HTTLPR</Emphasis> S-allele Homozygotes

Literature suggests that life stressors predict attention-deficit/hyperactivity disorder (ADHD) symptoms and that this relationship is moderated by the serotonin transporter polymorphism (5-HTTLPR). It is less clear whether, on reverse, ADHD symptoms may influence the risk of exposure to life stressors. Furthermore, the role of life stressors may vary across development depending on the type of life stressor. We used threewave longitudinal data of 1,306 adolescents from the general population and clinicreferred cohort of the TRacking Adolescents’ Individual Lives Survey. The 5-HTTLPR genotype (SS, LS, LL), parent-reported ADHD symptoms at three time points (T1: Mage?=?11.2; T2: Mage?=?13.5; T3: Mage?=?16.2 years), and the number of personrelated (‘dependent’) and environment-related (‘independent’) life stressors occurring between measurements (T1-T2, T2-T3) were assessed. Using path analyses, we examined bidirectional relations between exposure to these life stressors and ADHD symptoms between the separate waves moderated by 5-HTTLPR status. Exposure to life stressors did not predict ADHD symptoms. Rather, we found that in 5-HTTLPR Sallele homozygotes, ADHD symptoms in middle adolescence (T2) predicted exposure to the number of person-related life stressors later in adolescence (T2-T3, p?=?0.001). There was no relation with environment-related life stressors. Our study suggests that S-allele homozygotes with higher levels of ADHD symptoms in middle adolescence are more vulnerable to becoming exposed to person-related (‘dependent’) life stressors in late adolescence. Findings emphasize the need to be aware of social-emotional adversities that may occur in genetically vulnerable adolescents with ADHD symptoms in the transition into adulthood.     

Trust recovery following voluntary or forced financial compensations in the trust game: The role of trait forgiveness

One of the major challenges that actors in economic exchange relations face today concerns dealing with defection and overcoming the erosion of trust and cooperation that may result from a transgression. As transgressions in these relations usually entail a monetary loss for the victim, a common restorative approach involves providing a financial compensation to the victim. This research examines whether compensations that were provided voluntarily (rather than forced) would promote more trust among victims. In contrast to standard economic theory, we predict that individual differences exist that determine the degree to which victims are susceptible towards information about how the financial compensation is delivered in their decision to trust and cooperate again. Experimental data from a trust game confirmed our hypotheses by showing that whereas receiving a voluntary compensation from the transgressor communicates more repentance to victims than when this compensation was imposed, particularly people with a low tendency to forgive discount this repentance in their decision to trust again.     

Team history and choking under pressure in major soccer penalty shootouts

This study examined the links between historical team results and individual players' subsequent performances in a high-pressure real-world sport situation. Videos were obtained from all soccer penalty shootouts held in two major international tournaments (World Cup and European Championships) between 1976 and 2006 (n=260 players/309 kicks), and we controlled for team ability and country. The results showed that players on teams with preceding losses performed worse and generally took their shots more quickly than players on teams with preceding wins. These differences were also found with players who took no personal part in the preceding games. In conclusion, the results support the existence of historical dependency effects for performance on important and dramatic high-pressure tasks and they are in part consistent with a view of choking under pressure as a function of threatened egotism and self-regulation failure.     

Dopamine transporter gene moderates response to behavioral parent training in children with ADHD: a pilot study

There is great variability in the degree to which children with attention deficit/hyperactivity disorder (ADHD) improve through behavioral treatments. This study investigates the influence of the dopamine transporter gene (SCL6A3/DAT1) on outcome of behavioral parent training (BPT). Study subjects were a subsample (n = 50, for whom DAT1 genotypes were available) of a randomized controlled BPT effectiveness study (N = 94) comparing BPT plus ongoing routine clinical care (RCC) versus RCC alone in referred children (4-12 years old) with ADHD. Treatment outcome was based on parent-reported ADHD symptoms and behavioral problems. Presence of 2 versus no or 1 DAT1 10-repeat allele served as moderator variable. Time × Treatment × Genotype effect was analyzed with repeated-measures analysis of variance, controlling for baseline medication status. Results indicate that DAT1 moderated treatment response (p = .009). In children with no or 1 DAT1 10-repeat allele, superior treatment effects of BPT + RCC compared with RCC alone were present (p = .005), which was not the case in children with 2 DAT1 10-repeat alleles (p = .57). Our findings suggest that genetic differences in DAT1 in children with ADHD influence their susceptibility to a behavioral intervention directed at shaping their environment through their parents. The role of the dopamine system in motivation and learning and in the aberrant sensitivity to reinforcement in children with ADHD may explain this moderating effect, given that the management of contingencies is typically addressed in BPT.     

Time course of information processing during scene perception: The relationship between saccade amplitude and fixation duration

The present study focuses on two aspects of the time course of visual information processing during the perception of natural scenes. The first aspect is the change of fixation duration and saccade amplitude during the first couple of seconds of the inspection period, as has been described by Buswell (), among others. This common effect suggests that the saccade amplitude and fixation duration are in some way controlled by the same mechanism. A simple exponential model containing two parameters can describe the phenomena quite satisfactorily. The parameters of the model show that saccade amplitude and fixation duration may be controlled by a common mechanism. The second aspect under scrutiny is the apparent lack of correlation between saccade amplitude and fixation duration (Viviani, ). The present study shows that a strong but nonlinear relationship between saccade amplitude and fixation duration does exist in picture viewing. A model, based on notions laid out by Findlay and Walker's () model of saccade generation and on the idea of two modes of visual processing (Trevarthen, ), was developed to explain this relationship. The model both fits the data quite accurately and can explain a number of related phenomena.     

The Criminal Liability of Child Soldiers: In Search of a Standard

Despite the recent focus on the problem of the recruitment and use of child soldiers, there is still no clarity on the criminal liability of child soldiers who participate in conflict. In this article, we analyze the criminal liability of child soldiers against the historical background child soldiers. This aritle reports on its prevalence, and discusses the international legal framework liability. We pose the question whether the dual status of child soldiers as victims and perpetrators negatively impacts their criminal liability and whether it may in fact hamper the attainment of justice.