Virtuous character development in children is correlated with parenting behavior, but the role of genetic influences in this association has not been examined. Using a longitudinal twin/sibling study (N = 720; Time 1 (T1) M[subscript age] = 12-14 years, Time 3 (T3) M[subscript age] = 25-27 years), the current report examines associations among…

It has recently been argued that shared environmental influences are moderate, identifiable, and persistent sources of individual differences in most forms of child and adolescent psychopathology, including antisocial behavior. Unfortunately, prior studies examining the stability of shared environmental influences over time were limited by…

SES has long interested researchers investigating school achievement. Its effects are often addressed by studying predictors of achievement in economically disadvantaged samples living primarily in biological families, confounding genetic and environmental influences. Little is known about SES's purely environmental effects. We measured them in…

The home environment of nonadoptive and adoptive sibling pairs was assessed using the Home Observation for Measurement of the Environment when each sibling was one and two years of age. Correlations between home environment scores for nonadoptive siblings were greater than those for adoptive siblings. (BC)

Pooled sibling attachment data to compare attachment relationships to mothers for 138 sibling pairs. Found that sibling relationships were significantly concordant when classified as secure/nonsecure but not when further subcategorized. Maternal insensitivity to both siblings was associated with concordance of sibling nonsecurity. Same gender…

Whether genetic and environmental effects on academic achievement changed as a function of the quality of children's environment was studied with 1664 pairs of full siblings, 366 pairs of half siblings, and 752 pairs of cousins. Little evidence was found of genotype-environment interactions. (SLD)

Virtual twins are unrelated siblings of the same age who are reared together from early infancy (UST-SA). Study uses a sample of 90 UST-SA pairs to comparatively assess the similarity of IQ subtest profile correlations for UST-SAs and twin pairs. Findings support explanatory models of intelligence that include genetic factors, demonstrating that…

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…

Two studies of twin, sibling, and cousin pairs among children attempted to extend a model, called DF analysis, which separates hereditary and shared environmental influences. First study supported the validity of DF analysis applied to kinship height and weight data. The second study showed that spanking, reading, and quality of home environment…

Studied continuity and change in general cognitive ability from infancy to adolescence in adoptees (107 children), biological siblings (87 pairs), and twins (224 monozygotic and 189 dyzygotic pairs). Findings generally support previous findings about genetic and environmental factors, with the exception that in the transition to adolescence,…

Pairs of genetically unrelated children reared as same-age siblings offer a design for investigating genetic and environmental influences on behavior. Results with 21 pairs support an explanatory model of intelligence that includes genetic factors. Shared environment appeared to have a very small effect on intellectual development. (SLD)

Hypothesizes that a child's realization of genetic potential for intellectual development depends on socioeconomic environment. Peabody Picture Vocabulary Test results were examined for a large sibling sample of African American and White adolescents from the National Longitudinal Study of Adolescent Health. When SES factors were considered…

Conducted a trivariate genetic analysis of the Home Observation for Measurement of the Environment (HOME), Mental Development Index (MDI), and Task Orientation (TO). Found that for 101 nonadoptive and 92 adoptive sibling pairs at 12 and 24 months of age, TO explained the remaining genetic variance on the HOME not explained by the MDI. (MDM)

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…