Individual differences in music traits are heritable and correlated with the development of cognitive and communication skills, but little is known about whether diverse modes of music engagement (e.g., playing instruments vs. singing) reflect similar underlying genetic/environmental influences. Moreover, the biological etiology underlying the…

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…

This twin study examined the genetic and environmental etiology of vocabulary, syntax, and their association in first graders. French-speaking same-sex twins (n = 555) completed two vocabulary tests, and two scores of syntax were calculated from their spontaneous speech at 7 years of age. Multivariate latent factor genetic analyses showed that…

Purpose: This study investigates the heritability of language, speech, and nonverbal cognitive development of twins at 4 and 6 years of age. Possible confounding effects of twinning and zygosity, evident at 2 years, were investigated among other possible predictors of outcomes. Method: The population-based twin sample included 627 twin pairs and 1…

A fairly recent definition of reading disability (RD) is that in the form of a hybrid model. The model views RD as a latent construct that is manifested through various observable unexpected impairments in reading-related skills and through inadequate response to intervention. The current report evaluated this new conceptualization of RD from an…

There has been significant interest in examining the developmental factors that predispose individuals to chronic criminal offending. This body of research has identified some social-environmental risk factors as potentially important. At the same time, the research producing these results has generally failed to employ genetically sensitive…