In 2013, Drs Allen and Adele Gottfried shared the Fullerton longitudinal data with us. The data provided a unique opportunity to investigate the intellectual development and the longitudinal relation between intelligence and academic achievement. Previous studies have seldom addressed the latent nature of intelligence and academic achievement.…

Autism spectrum disorder (ASD) and Attention-deficit/hyperactivity disorder (ADHD) are often comorbid. The purpose of this study is to explore the relationships between ASD and ADHD symptoms by applying causal modeling. We used a large phenotypic data set of 417 children with ASD and/or ADHD, 562 affected and unaffected siblings, and 414 controls,…

This study examines reciprocal effects between self-concept and achievement by considering a long time span covering grades 5 through 9. Extending previous research on the reciprocal effects model (REM), this study tests (1) the assumption of developmental equilibrium as time-invariant cross-lagged paths from self-concept to achievement and from…

Young children removed from institutions and placed into foster care or adoptive homes have been shown to experience significant gains in IQ relative to children who remain in institutions. Less is known about the long-term impact of severe early deprivation on development in late childhood. Data are presented from a follow-up of children at 12…

The theory of triarchic intelligence posits that, in addition to the widely acknowledged analytical reasoning abilities, creative and practical abilities should be included in the assessments of intellectual capacities and identification of gifted students. To find support for such an approach, the present study examined the psychometric…