Machiavellianism is an antisocial interpersonal style involving the use of manipulative, deceptive, and coercive behaviors in the pursuit of self-interest. Although widely studied as a "dark" personality trait in adults, relatively little is known about the developmental correlates of Machiavellian tendencies earlier in life. The present…

Children who show elevated levels of indirect aggression (IA) from childhood to adolescence are at increased risks of experiencing detrimental outcomes. Some studies suggest that psychopathic traits could act as a predisposing vulnerability in the development of IA, but the contributions of all three dimensions of psychopathic traits in explaining…

The present study investigated whether distinct developmental patterns of externalizing behaviors (EBs: hyperactivity-impulsivity, noncompliance, physical aggression) based on parent reports were repeatedly and differentially associated with separate dimensions of internalizing problems such as general anxiety, separation anxiety, and depressive…

In the present research, we provide empirical evidence for the process of symbolic integration of number associations, focusing on the development of simple addition (e.g., 5 + 3 = 8), subtraction (e.g., 5 - 3 = 2), and multiplication (e.g., 5 × 3 = 15). Canadian children were assessed twice, in Grade 2 and Grade 3 (N = 244; 55% girls). All…

The present study investigated prenatal and early postnatal risk factors associated with developmental patterns of disruptive behaviors (DBs; e.g., hyperactivity-impulsivity, noncompliance, physical aggression) from ages 1.5 to 5 years in a population birth cohort (N = 2,057; 50.7% boys). Six high-trajectory classes obtained by latent growth…

Past meta-analyses show that both child-mother and child-father attachment insecurity are independently and jointly associated with more externalizing behaviors in children. Little is known, however, on the ways that different types of insecure attachment independently and jointly predict the development of externalizing behaviors over time.…

When young children recruit others to help a person in need, media reports often treat it as a remarkable event. Yet it is unclear how commonly children perform this type of pro-social behavior and what forms of social understanding, cognitive abilities, and motivational factors promote or discourage it. In this study, 48 three- to four-year-old…

Indirect aggression has been associated with antisocial personality traits like Machiavellianism, but there is a lack of evidence on their longitudinal development across adolescence. Therefore, the joint developmental trajectories of adolescent indirect aggression and Machiavellianism across 3 years of high school (Grades 10 to 12) were…

This study examined the longitudinal contribution of four different childcare arrangements attended during the preschool years to social behaviors and academic achievement up to age 15 years. Children participating in a Canadian longitudinal survey with available information on childcare attendance between ages 3 and 5 years (N = 6,852) were…

The Dual Failure Model suggests that peer victimization (social failure) and academic difficulties (academic failure) mediate the association between externalizing and later internalizing problems. The present study sought to better understand why children with externalizing problems develop later internalizing problems by testing the Dual Failure…

This investigation examines the spread of problem behaviors (substance use and delinquency) between twin siblings. A sample of 628 twins (151 male twin pairs and 163 female twin pairs) drawn from the Quebec Newborn Twin Study completed inventories describing delinquency and substance use at ages 13, 14, and 15. A 3-wave longitudinal actor-partner…

In this study the associations between mothers' and fathers' differential parenting and children's oppositional and emotional problems were examined. A curvilinear relationship between differential parenting and children's outcomes was hypothesized, as well as the combined effect of mothers' and fathers' parenting. Data came from a community…

In light of emerging evidence suggesting that the affective quality of parent-child relationships may relate to individual differences in young children's executive functioning (EF) skills, the aim of this study was to investigate the prospective associations between attachment security in toddlerhood and children's EF skills in kindergarten.…

University/college can be a challenging time as students face developmental tasks such as building new social networks and achieving academically. Social anxiety may be disadvantageous in this setting given that social situations often include drinking and individuals with social anxiety tend to self-medicate through alcohol use. However, findings…

Three complementary models of how peer relationship problems (exclusion and victimization) and aggressive behaviors relate to prospective levels of internalizing problems are examined. The additive risks model proposes that peer problems and aggression cumulatively increase risks for internalizing problems. The reciprocal risks model hypothesizes…