The directionality and longitudinal course between perfectionism and academic achievement throughout adolescence remains unclear as most studies rely on cross-sectional or short-term data and many examine these associations in university students who do not represent the full spectrum of learners. Moreover, most studies are hampered by their…

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 parental perceptions of the character traits of children with autism from early childhood to age 11. Parents (n = 153) provided descriptions of the "best things" about their children on the Child Behavior Checklist (CBCL) at ages 3-4, 7-8, and 10-11 years. Descriptions were coded using the framework of the Values in…

Research concerning temperament in children and adults with autism spectrum disorder (ASD) has suggested a consistent profile of low positive affect, high negative affect, and low regulation (Visser et al., 2016). One area receiving less attention is individual differences among children diagnosed with ASD. The primary objective of this study was…

Temperament is a construct that is relatively stable over time but varies between individuals. Research suggests that children with autism spectrum disorder have a 'reactive' temperament profile when compared to peers with or without disabilities. However, our understanding of how temperament varies within children with autism and how it relates…

Numerous studies consider competition and jealousy within an evolutionary framework, yet less is known about the relation between aggression vis-à-vis hypercompetitiveness (i.e., competing to win) and jealousy. We investigated the longitudinal relations between hypercompetitiveness, jealousy, and aggression and the moderating role of gender in a…

There is growing interest in perfectionism among children and adolescents as well as growing interest in the measures designed to assess perfectionism in young people. The current article describes the development and psychometric characteristics of the Child-Adolescent Perfectionism Scale (CAPS), a measure that assesses self-oriented…