0000000000958680
AUTHOR
Elina Vierikko
Sex differences in genetic and environmental effects on aggression
The aim of the present study was to investigate the genetic and environmental factors influencing teacher and parental rated aggression in boys and girls, asking whether the magnitude of these effects is similar across rater and sex. The study is part of an ongoing nationwide twin-family study of behavioral development and health habits carried out in Finland. The sample consisted of 1651 twin pairs (264 monozygotic male, 300 monozygotic female, 292 dizygotic male, 278 dizygotic female, and 517 dizygotic opposite-sex twin pairs), representing subsets of five 11- to 12-year-old twin cohorts (b. 1983-1987). The data were collected using the teacher and parental rating forms of the Multidimens…
Genetic and Environmental Influences on the Relationship Between Aggression and Hyperactivity-impulsivity as Rated by Teachers and Parents
This study examined genetic and environmental contributions to the covariance between aggression and hyperactivity-impulsivity as rated by twins' teachers and parents. Sex-differences in these genetic and environmental contributions and rater bias/sibling interaction effects were of interest as well. Part of an ongoing nation-wide twin-family study of behavioral development and health habits, the sample consisted of 1636 Finnish twin pairs ascertained from five consecutive and complete twin birth cohorts. Data were collected at ages 11-12, using teacher and parental rating forms of the Multidimensional Peer Nomination Inventory. Bivariate analyses were performed using structural equation mo…
Genetic and environmental sources of continuity and change in teacher-rated aggression during early adolescence
Genetic and environmental sources of continuity and change in aggression were studied in a sample of 1,041 twin pairs (364 monozygotic; 348 same-sex dizygotic; and 329 opposite-sex dizygotic) as part of an ongoing, population-based Finnish twin-family study. At ages 12 and 14, the twins' aggression was assessed by their classroom teachers, using a rating form of the Multidimensional Peer Nomination Inventory. Genetic and environmental sources of continuity and change were studied by fitting a longitudinal bivariate Cholesky decomposition model. Longitudinal model-fitting results indicated that both genetic and environmental factors influenced continuity in aggression during this 2-year peri…