This study examined the mediating role of emotional availability in the relation between parent positive personality and toddler problem behavior. The sample comprised 654 twins at 12 and 32 months. Primary caregivers (>95% mothers) completed six measures indexing parent positive personality assessed at 12 months, and emotional availability and…

Alterations in social cognition are hypothesized to underlie social communication challenges in autism spectrum disorder. However, the etiologic underpinnings driving this association, as well as the impact of other psychiatric conditions on the association, remain unclear. Using a co-twin control design, we examined n = 308 twins (mean age =…

Obesity is an important global health problem. Although obesity is not directly related to access to health care or constrained by resource deprivation, overweight status is predominantly found in poor, less-educated populations. This paper seeks to identify the causal role of schooling in affecting obesity among children and adolescents, using…

Little is known about the etiology of developmental change and continuity in educational achievement. Here, we study achievement from primary school to the end of compulsory education for 6000 twin pairs in the UK-representative Twins Early Development Study sample. Results showed that educational achievement is highly heritable across school…

There has been an increase in research regarding experiences within virtual education. However, little attention has been given to the middle level context. Through a theoretical lens grounded in stage-environment fit theory, this phenomenological case study describes the lived experiences of two middle level virtual learners as they engage in an…

According to the hybrid model (van Bergen, van der Leij, & de Jong, 2014), the significant association among executive functioning (EF), reading, and math may be partially explained by parent-reported EF's role as a common risk and/or protective factor in reading and math (dis)abilities. The current study used a sample of 434 twin pairs…

This essay is focused on the research into the genetic etiology of creativity and related processes. In an attempt to identify the most salient points of this research, the article provides a brief overview of quantitative-genetic (family and twin) and molecular-genetic (candidate-gene and whole-genome) studies of creativity. To conclude, the…

Symptoms of anxiety and depression are commonly comorbid and partially share a genetic etiology. Mean levels of anxiety and depression increase over the transition to adolescence, particularly in girls, suggesting a possible role of pubertal development in the activation of underlying genetic risks. The current study examined how genetic and…

Given the importance of writing for academic achievement, this study aimed to understand how early oral language contributes to later writing skills. The first objective was to determine if preschool language skills were associated with high school writing, and if so, whether they contributed directly or indirectly through school age language. The…

Purpose: Oxytocin and arginine vasopressin are associated with different aspects of the stress response. As stress is regarded as a risk factor for vocal symptoms, we wanted to explore the association between the oxytocin receptor gene ("OXTR") and arginine vasopressin 1A receptor gene ("AVPR1A") single-nucleotide polymorphisms…

We investigated the double-deficit hypothesis (DDH) in samples of U.S. (N = 489), Australian (N = 264), and Scandinavian (N = 293) children followed from preschool to grade 2. Children were assigned to double deficit, single deficit and no deficit subtypes in preschool, kindergarten, and grade 1 and compared on reading and spelling in grades 1 and…

Childhood gender nonconformity (femininity in males, masculinity in females) predicts a nonstraight (gay, lesbian, or bisexual) sexual orientation in adulthood. In previous work, nonstraight twins reported more childhood gender nonconformity than their genetically identical, but straight, cotwins. However, self-reports could be biased. We…

Both genes and the environment are important for individual differences in expertise, but little is known about gene-environment interactions underlying domain-specific achievement. Here we explored this issue in a large Swedish twin cohort (N = 6,610), using moderator modeling with musical expertise as a model domain. Specifically, we tested…

Most study samples show less variability in key variables than do their source populations due most often to indirect selection into study participation associated with a wide range of personal and circumstantial characteristics. Formulas exist to correct the distortions of population-level correlations created. Formula accuracy has been tested…

We examined whether attained socioeconomic status (SES) moderated genetic and environmental sources of individual differences in cognitive performance using pooled data from 9 adult twin studies. Prior work concerning SES moderation of cognitive performance has focused on rearing SES. The current adult sample of 12,196 individuals (aged 27-98…