Reviews of behavioral genetic studies note that "control" aspects of parenting yield low estimates of heritability, while "affective" aspects (parental feelings) yield moderate estimates. Research to date has not specifically considered whether positive and negative aspects of parenting--for both feelings and control--may…

Prosocial behavior is important for the functioning of society. This study investigates the extent to which environment shared by family members, nonshared environment, and genetics account for children's prosocial behavior. The prosocial behavior of twins (9,424 pairs) was rated by their parents at the ages of 2, 3, 4, and 7 and by their teachers…

The genetic and environmental contributions to the development of general cognitive ability throughout the first 16 years of life were examined using sibling data from the Colorado Adoption Project. Correlations were analyzed along with structural equation models to characterize the genetic and environmental influences on longitudinal stability…

Language development was studied in 310 pairs of 4-year-old twins. Rotated factor analyses indicated presence of a general language factor (L) and a general nonverbal factor (NV). Moderate genetic influence was found for L and NV abilities. Bivariate genetic analysis estimated a genetic correlation of .63 between L and NV abilities. Results…

Data from Colorado Adoption Project were used to examine hypothesis that association between parental divorce and children's adjustment is mediated by genetic factors. Findings for psychopathology were consistent with an environmentally mediated explanation for the association. Findings for achievement and social adjustment were consistent with a…

One of the major changes in developmental psychology during the past 50 years has been the acceptance of the important role of nature (genetics) as well as nurture (environment). Past research consisting of twin and adoption studies has shown that genetic influence is substantial for most domains of developmental psychology. Present research…

Examined the genetic and environmental contributions to the predictive association between parenting and adolescent adjustment in identical and fraternal twins, and full, half, and genetically unrelated siblings in nondivorced and stepfamilies. Found that cross-lagged associations between parental conflict-negativity and adolescent antisocial…

Collected data on twins' performance on 13 cognitive variables measured three times at three-year intervals. Twins were monozygotic or dizygotic pairs reared together or apart and were in six cohorts ranging in age from 41 through 84 years. Found stable mean cognitive performance across time on eight measures for the younger cohorts, and…

Focuses on possibility that correlations between measures of environment and child devleopment can be mediated genetically as well as environmentally. Proposing an elementary model to test this hypothesis, data from classical adoption studies and new data from the Colorado Adoption Project are used to illustrate the model and provide quantitative…

Explored origins of individual differences in infant shyness by studying its relationship to parental shyness, sociability, and introversion-extraversion. Full adoption design examined role of both genetic and family environmental influences as possible etiological factors in development of infant shyness. Results indicate genetic influences and…

Parent/infant relationships were investigated among 50 biologically related families selected to provide a control group for an adoption study of rate differences in communicative development in infancy. In addition, a path analysis of genetic and environmental influences on communicative development is presented incorporating the overall sample.…

Results indicated significant genetic influence on eight Family Environment Scales that had been altered to obtain retrospective perceptions of family environment in childhood. The combined twin and adoption design was used with four groups of twins whose average age was 59 years. (RH)

Used the Sibling Inventory of Differential Experience with 396 adolescent and young adult children to determine the extent to which genetic differences between siblings or sibling differences in family constellation variables were responsible for differential experiences. (HOD)

This study of 707 sibling pairs, 10- to 18-years-old, examined parent-child and sibling interactions to determine the effects of genetics on family environment. The sample included identical and fraternal twins and full siblings in nondivorced families, as well as full, half, and unrelated siblings in divorced families. Found significant genetic…

A twin analysis was applied to infants' social behavior in standardized situations that permitted the comparison of social responding to mother and a stranger in different contexts. Twenty-one identical twin pairs and twenty-five fraternal twin pairs were observed in their homes using time-sampled observations of specific behaviors. (Author/SS)