This study examined the associations between intrinsic motivation and achievement in mathematics in a sample of 1,478 Canadian school-age children followed from Grades 1 to 4 (ages 7-10). Children self-reported their intrinsic motivation toward mathematics, whereas achievement was measured through direct assessment of mathematics abilities.…

This study used the monozygotic (MZ) twin difference method to examine whether differences in friends' aggression increased the differences in MZ twins' aggression and depressive symptoms from kindergarten to Grade 1 and whether perceived victimization by the friend played a mediating role in this context. Participants were 223 MZ twin pairs.…

Previous research has provided mixed results regarding the effect of anxiety on academic achievement. Building on this body of research, the present longitudinal study pursued two goals. The first goal was to describe trajectories of anxiety during elementary-school years. The second goal was to determine the predictive value of these trajectories…

Background: Disregard for rules, an important dimension of oppositional defiant and conduct disorders, is frequent during early childhood, but the development of its chronic form has not been studied during this key socialization period. This study aimed to describe the developmental trajectories of disregard for rules during early childhood and…

Using a genetic design of 840 60-month-old twins, this study investigated the genetic and environmental contributions to (a) individual differences in four components of cognitive school readiness, (b) the general ability underlying these four components, and (c) the predictive association between school readiness and school achievement. Results…

This study investigated associations between maternal prenatal smoking and physical aggression (PA), hyperactivity-impulsivity (HI) and co-occurring PA and HI between ages 17 and 42 months in a population sample of children born in Quebec (Canada) in 1997/1998 (N=1745). Trajectory model estimation showed three distinct developmental patterns for…

Using a prospective design spanning 17 years, the authors studied in a sample of 231 boys and girls the predictive links of verbal abuse by the teacher during childhood to high-school graduation and behavioral and emotional problems in young adulthood, as well as the putative mediating role of individuals' generalized and domain-specific…

The study identified independent individual, family, and neighborhood correlates of children's physical aggression and prosocial behavior. Participants were 2,745-11-year olds nested in 1,982 families, which were themselves nested in 96 Canadian neighborhoods. Hierarchical linear modeling showed that the total variation explained by the…

Contributing to the family violence and conflict literature, we examine prospective and concurrent risk factors associated with verbal and physical aggression toward mothers by 15/16 year-old adolescent sons and daughters. Data from the Quebec Longitudinal Study of Kindergarten Children is used to examine the influence of socioeconomic factors,…