Prosociality from Early Adolescence to Young Adulthood: A Longitudinal Study of Individuals with a History of Language Impairment

Background: Longitudinal research into the development of prosociality contributes vitally to understanding of individual differences in psychosocial outcomes. Most of the research to date has been concerned with prosocial behaviour in typically developing young people; much less has been directed to the course of development in individuals with developmental disorders. Aims: This study reports a longitudinal investigation of prosocial behaviour in young people with language impairment (LI), and compares trajectories of development to typically developing age-matched peers (AMPs). Methods and Procedures: Participants were followed from age 11 years to young adulthood (age 24 years). Outcomes and Results: Participants with LI perceived themselves as prosocial; their ratings – though lower than those for the AMPs - were well within the normal range and they remained consistently so from 11 to 24 years. Two different developmental trajectories were identified for the LI group, which were stable and differed only in level of prosociality. Approximately one third of participants with LI followed a moderate prosociality trajectory whilst the majority (71%) followed a prosocial trajectory. We found evidence of protective effects of prosociality for social outcomes in young adulthood. Conclusions and Implications: The findings indicate that prosociality is an area of relative strength in LI

The Effects of Acute Tryptophan Depletion on Reactive Aggression in Adults with Attention-Deficit/Hyperactivity Disorder (ADHD) and Healthy Controls

Background: The neurotransmitter serotonin (5-HT) has been linked to the underlying neurobiology of aggressive behavior, particularly with evidence from studies in animals and humans. However, the underlying neurobiology of aggression remains unclear in the context of attention-deficit/hyperactivity disorder (ADHD), a disorder known to be associated with aggression and impulsivity. We investigated the effects of acute tryptophan depletion (ATD), and the resulting diminished central nervous serotonergic neurotransmission, on reactive aggression in healthy controls and adults with ADHD. Methodology/Principal Findings: Twenty male patients with ADHD and twenty healthy male controls were subjected to ATD with an amino acid (AA) beverage that lacked tryptophan (TRP, the physiological precursor of 5-HT) and a TRPbalanced AA beverage (BAL) in a double-blind, within-subject crossover-study over two study days. We assessed reactive aggression 3.25 hours after ATD/BAL intake using a point-subtraction aggression game (PSAG) in which participants played for points against a fictitious opponent. Point subtraction was taken as a measure for reactive aggression. Lowered rates of reactive aggression were found in the ADHD group under ATD after low provocation (LP), with controls showing the opposite effect. In patients with ADHD, trait-impulsivity was negatively correlated with the ATD effect on reactive aggression after LP. Statistical power was limited due to large standard deviations observed in the data on point subtraction, which may limit the use of this particular paradigm in adults with ADHD

Serotonergic Contribution to Boys' Behavioral Regulation

Animal and human adult studies reveal a contribution of serotonin to behavior regulation. Whether these findings apply to children is unclear. The present study investigated serotonergic functioning in boys with a history of behavior regulation difficulties through a double-blind, acute tryptophan supplementation procedure.Participants were 23 boys (age 10 years) with a history of elevated physical aggression, recruited from a community sample. Eleven were given a chocolate milkshake supplemented with 500 mg tryptophan, and 12 received a chocolate milkshake without tryptophan. Boys engaged in a competitive reaction time game against a fictitious opponent, which assessed response to provocation, impulsivity, perspective taking, and sharing. Impulsivity was further assessed through a Go/No-Go paradigm. A computerized emotion recognition task and a staged instrumental help incident were also administered.Boys, regardless of group, responded similarly to high provocation by the fictitious opponent. However, boys in the tryptophan group adjusted their level of responding optimally as a function of the level of provocation, whereas boys in the control group significantly decreased their level of responding towards the end of the competition. Boys in the tryptophan group tended to show greater perspective taking, tended to better distinguish facial expressions of fear and happiness, and tended to provide greater instrumental help to the experimenter.The present study provides initial evidence for the feasibility of acute tryptophan supplementation in children and some effect of tryptophan supplementation on children's behaviors. Further studies are warranted to explore the potential impact of increased serotonergic functioning on boys' dominant and affiliative behaviors

Patterns and correlates of prosocial behaviour development

The present thesis aimed to identify trends and individual differences in prosocial behaviour frequencies throughout childhood and adolescence, in addition to examining longitudinal patterns of association between prosocial behaviours and externalizing and internalizing problems. Neurochemical bases of prosocial behaviours, specifically serotonergic functioning, were also investigated. Three studies are presented.Study 1 longitudinally described prosocial behaviour development from childhood to adolescence, using multiple informants within Canadian and Italian samples. Participants were boys from low SES areas of Montreal, Canada, as well as boys and girls in Genzano, Italy. Developmental trajectories were estimated based on yearly ratings by mothers and teachers (Montreal, ages 10 to 15) and children and teachers (Genzano, ages 10 to 14). Results revealed that the majority of children, across cultures and informants, followed trajectories characterized by stable or declining levels of prosocial behaviours over time. Low to moderate agreement was observed between informants.Prosocial behaviour development must however be viewed within the broader context of children's behavioural and affective functioning. Study 2 therefore focused on longitudinal associations between prosocial behaviour development and the development of externalizing and internalizing problems. Potential predictors of joint development were also investigated. Using a large, representative sample of Canadian children, prosocial behaviour, physical aggression, anxiety, and depression developmental trajectories spanning ages 2 to 11 were modeled based ratings by the person most knowledgeable about the child. A negative association tended to operate between prosocial behaviour levels and levels of physical aggression and depression, while a more complex relationship emerged with anxiety. Child, mother, and family characteristics significantly contributed to the prediction of joint development, with evidence of maternal depression and low family income increasing the likelihood of displaying high levels of prosocial behaviours with high levels of externalizing and internalizing difficulties.Study 3 focused on the neurochemical underpinnings of prosocial behaviours, specifically investigating the impact of acute tryptophan supplementation, and by extension increased serotonergic functioning, on children's laboratory aggressive and prosocial behaviours. Boys with a history of relatively high levels of physical aggression were randomly assigned to a tryptophan supplementation or control condition following a double-blind procedure. Results revealed that boys in the tryptophan condition were more likely to sustain competition with a fictitious opponent during a computerized reaction time game. Boys in the tryptophan condition also showed greater perspective taking, as well as greater instrumental help.Taken together, results of the present thesis provide evidence of both stability and change in prosocial behaviour frequencies during childhood and adolescence. Results also highlight the complex relationship of prosocial behaviours with adjustment, as well as potential contributions of the serotonergic system to the regulation of prosocial responding in children. The present thesis sets the stage for future studies investigating the interplay of psychosocial and biological forces in determining individual differences in prosocial behaviour and related aspects of functioning.L'objectif de la présente thèse était d'identifier les patrons et les différences individuelles dans le développement des comportements prosociaux au cours de l'enfance et de l'adolescence, ainsi que d'examiner les associations longitudinales entre les comportements prosociaux et les problèmes extériorisés et intériorisés. Les bases neurochimiques des comportements prosociaux, spécifiquement le fonctionnement sérotonergique, ont également été examinées. Trois études sont présentées.La première étude décrit de façon longitudinale les comportements prosociaux au cours de l'enfance et l'adolescence, à l'aide de multiples informateurs et d'échantillons canadiens et italiens. Les participants étaient des garçons provenant de quartiers défavorisés de Montréal, Canada, et des garçons et des filles de la ville de Genzano, Italie. Des trajectoires développementales ont été estimées basé sur des évaluations annuelles faites par les mères et les enseignantes (Montréal, 10 à 15 ans) et par les enfants et les enseignantes (Genzano, 10 à 14 ans). Les résultats ont démontré que la majorité des enfants, au sein des deux cultures et pour tous les informateurs, suivait des trajectoires de comportements prosociaux aux niveaux stables ou déclinants au cours du temps. Un niveau faible à modéré d'accord était présent entres les différents informateurs.Le développement des comportements prosociaux doit toutefois être observé dans le contexte général du fonctionnement comportemental et affectif des enfants. La deuxième étude a donc examiné les associations longitudinales entre le développement des comportements prosociaux et des problèmes extériorisés et intériorisés. Les predicteurs potentiels du développement conjoint ont également été étudiés. Les trajectoires développementales (2 à 11 ans) de comportements prosociaux, agressivité physique, anxiété, et dépression ont été estimées à l'aide d'évaluations chez un large échantillon représentatif d'enfants canadiens. Une association négative tendait à être présente entre les niveaux de comportements prosociaux et les niveaux d'agressivité physique et dépression, tandis que des associations plus complexes étaient observées pour l'anxiété. Les caractéristiques de l'enfant, de la mère, et de la famille contribuaient significativement à la prédiction du développement conjoint, la dépression maternelle et un faible revenu famillial augmentant la probabilité de démontrer conjointement un haut niveau de comportements prosociaux et de hauts niveaux de problèmes extériorisés et intériorisés.La troisième étude a examiné les bases neurochimiques des comportements prosoicaux, évaluant spécifiquement l'effet de la supplémentation ponctuelle de tryptophan, ainsi donc de l'augmentation de la sérotonine, sur les comportements agressifs et prosoicaux des enfants en laboratoire. Des garçons présentant un historique relativement élevé d'agressivité physique ont été assignés au hasard à la supplémentation de tryptophan ou à la condition controle, suivant un devis double aveugle. Les résultats ont démontré que les garçons du groupe tryptophan étaient plus enclins à soutenir la compétition avec un adversaire fictic lors d'un jeu compétitif de temps de réaction sur l'ordinateur. Les garçons du groupe tryptophan ont également démontré une plus grande prise de perspective ainsi que plus de comportements d'aide.Globalement, les résultats démontrent la présence de stabilité et changements dans la fréquence des comportements prosociaux durant l'enfance et l'adolescence. Les résultats soulignent également la relation complexe entre les comportements sociaux et l'adaptation, ainsi que la contribution du système sérotonergique à la régulation de la prosocialité. La présente thèse invite les études futures portant sur l'interaction de facteurs psychosociaux et biologiques pouvant déterminer les différences individuellles en prosocialité et autres aspects du fonctionnement associés

Prosocial development from childhood to adolescence: a multi-informant perspective with Canadian and Italian longitudinal studies

To longitudinally describe prosocial behaviour development from childhood to adolescence, using multiple informants within Canadian and Italian samples. Participants in Study 1 were 1037 boys from low socioeconomic status (SES) areas in Montreal, Canada, for whom yearly teacher and mother reports were obtained between the ages of 10 and 15. Participants in Study 2 were 472 children (209 girls) from Genzano, Italy, for whom yearly self and teacher reports were obtained between the ages of 10 and 14. Developmental trajectories were estimated from ratings by each informant to identify subgroups of children following distinct courses of prosocial development. In Study 1, three trajectory groups (low/declining 53%, high/declining 16%, high/steep declining 31%) were identified from teacher ratings, while five trajectories (low/stable 7%, low/declining 19%, moderate/stable 41%, high/declining 24%, high/stable 9%) were identified from mother ratings. Small but significant associations were observed between mother and teacher ratings. In Study 2, three trajectory groups (low/stable 9%, moderate/stable 50%, high/stable 42%) were identified from self-ratings, while four trajectory groups (low/stable 8%, moderate/declining 48%, high/declining 37%, increasing 7%) were identified from teacher ratings. Small but significant associations were observed between self- and teacher ratings. The present studies investigated levels of prosocial behaviours from childhood to adolescence, using a multi-informant, cross-cultural perspective. All but one of the developmental trajectories identified were characterised by stable or declining levels of prosocial behaviours. Further research longitudinally investigating prosociality across developmental periods is needed to clarify prosocial behaviour development over time

Physical aggression trajectories from 17 to 84 months.

<p>Physical aggression trajectories from 17 to 84 months.</p

Points taken away (A) and decision time (B) at each phase of the competitive reaction time game.

<p>Values represent change (z score) in points taken away and decision time at each phase of the game, relative to the no provocation baseline.</p