title: Genetic and Environmental Contributions to Behavioral Stability and Change in Children 6-36 months of Age Using Louisville Twin Study Data.
abstract: The Infant Behavior Record (IBR) from the Bayley Scales of Infant Development has been used to study behavioral development since the 1960s. Matheny (1983) examined behavioral development at 6, 12, 18, and 24 months from the Louisville Twin Study (LTS). The extracted temperament scales included Task Orientation, Affect-Extraversion, and Activity. He concluded that monozygotic twins were more similar than same-sex dizygotic twins on these dimensions. Since this seminal work was published, a larger LTS sample and more advanced analytical methods are available. In the current analyses, Choleksy decomposition was applied to behavioral data (n = 1231) from twins 6-36 months. Different patterns of genetic continuity vs genetic innovations were identified for each IBR scale. Single common genetic and shared environmental factors explained cross-age twin similarity in the Activity scale. Multiple shared environmental factors and a single genetic factor coming on line at age 18 months contributed to Affect-Extraversion. A single shared environmental factor and multiple genetic factors explained cross-age twin similarity in Task Orientation.
authors.affiliation: Department of Pediatrics, University of Louisville School of Medicine, 571 S. Floyd Street, Suite 412, Louisville, KY, USA. deborah.davis@louisville.edu.
authors.forename: Deborah Winders
authors.initials: DW
authors.lastname: Davis
authors.affiliation: School of Social Sciences, Indiana University Southeast, New Albany, IN, USA.
authors.forename: Deborah
authors.initials: D
authors.lastname: Finkel
authors.affiliation: Department of Psychology, University of Virginia, Charlottesville, VA, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Turkheimer
authors.affiliation: Department of Economics, Northeastern University, Boston, MA, USA.
authors.forename: William
authors.initials: W
authors.lastname: Dickens
mesh_terms: D001519:Behavior; D002657:Child Development; D002675:Child, Preschool; D005260:Female; D059647:Gene-Environment Interaction; D006801:Humans; D007223:Infant; D008297:Male; D014429:Twins, Dizygotic / Q000235:genetics; D014430:Twins, Monozygotic / Q000235:genetics
keywords: Behavior; Childhood; Longitudinal; Louisville Twin Study; Twin studies