Examined family influences on vocational interest development. Hypothesized that parents with similar interests were more likely to have adolescents who also developed those interests than were parents whose interests were very divergent. To "unconfound" genetic and environmental influences, parent-child interest difference scores were compared…

The mother, father, and adolescent siblings from 675 families were observed interacting in problem-solving sessions. Siblings were monozygotic twins, dyzygotic twins, or full siblings in nondivorced families and full, half, and unrelated siblings in stepfamilies. Results suggested a greater genetic component to adolescent behavior than to parent…

Parents of Swedish twin pairs ages 7 to 9 years and of British twin pairs ages 8 to 16 years completed the Child Behavior Checklist. Found that genetic factors influenced aggressive antisocial behavior to a greater extent than nonaggressive antisocial behavior, which was also significantly influenced by the shared environment. There was a…

Examined genetic and environmental contribution to self-reported peer-group characteristics among adoptive and nonadoptive adolescent sibling pairs. Found that although peer preference is influenced, in large part, by nonshared environment factors, genetic influence is present. Substantial genetic influence emerged for college orientation, and…

Used data from sibling pairs from the National Longitudinal Study of Adolescent Health to examine how parental education moderated the genetic and environmental contributions to variation in verbal IQ. Found that the variance estimate for heritability was greater than that for shared environment for the whole sample. Both estimates were moderated…

Examined low interrater agreement by decomposing common and unique variance among parent, adolescent, and observer reports of parental warmth and negativity into genetic and environmental factors. Model-fitting analyses findings generally supported predictions for warmth and negativity at Family and Individual levels. At the Social level, genetic…

Examines the findings of 53 studies of sex differences in propositional logic, combinatorial reasoning, and proportional reasoning tasks. Finds sex differences for the latter two tasks to be vulnerable to Rosenthal's "file drawer" problem and effect size to be small for all tasks. Discusses possible explanations for sex differences in…

This behavioral genetic study examined perceived competence and self-worth in same-sex twins, siblings, and stepsiblings 10 to 18 years old, and again 3 years later. Findings at second assessment showed six of seven subscales heritable. Genetic contributions to stability were found for perceived scholastic competence, athletic competence, physical…

Examined three theories for predicting risk for delinquency during adolescence with sixth- and seventh-grade students: an individual difference perspective, social interactional model, and social contextual approach. Found that lack of nurturant and involved parenting indirectly predicted delinquency by increasing antisocial behavior and deviant…

Examined whether differentiating processes existed for 7 composite indices of positive and negative adolescent adjustment in 720 sibling pairs. Found that siblings born 1 year apart at Time 1 were more similar to each other than were siblings born 2 years apart, suggesting that shared environmental influences counteract sibling differentiation…