A behavioral genetic analysis of general writing ability was conducted using teacher assessments based on UK National Curriculum criteria for a sample of 3296 same-sex pairs of 7-year-old twins. Writing was highly heritable within the normal range (0.66) and at the low extreme (0.70). Environmental influences were almost all non-shared, with…

The genetic and environmental etiologies of 3 aspects of low mathematical performance (math disability) and the full range of variability (math ability) were compared for boys and girls in a sample of 5,348 children age 10 years (members of 2,674 pairs of same-sex and opposite-sex twins) from the United Kingdom (UK). The measures, which we…

Anxiety and conduct problems covary, yet studies have not explored the genetic and environmental origins of this association. We analyzed parent-reported anxiety and conduct problems in 6,783 pairs of twins at 2-, 3-, and 4-years of age. As anxiety and conduct problems were fairly stable across the three ages (average 1-year correlation was .53),…

Although prior research has examined children's perceptions of the classroom environment as related to academic achievement, genetically sensitive designs have not been employed. In the first study of its kind for the primary school classroom environment, data were collected for 3,020 pairs of nine-year-old identical and fraternal twin pairs in…

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…

Examines the modifiability and heritability of reflection-impulsivity as measured by Matching Familar Figures. A Cotwin control method was used to study the modifiability of reflection-impulsivity and a twin study to assess its heritability. (Author/DEP)

Twin children were videotaped hitting an inflated clown figure. Three behaviors (number of hits, intensity of hits, and number of quadrants hit) showed adequate response characteristics, rater reliability, and test-retest reliability. Twin analyses of the three behavioral ratings yielded no evidence of hereditary influence. (Author)

Despite the importance of learning abilities and disabilities in education and child development, little is known about their genetic and environmental origins in the early school years. We report results for English (which includes reading, writing, and speaking), mathematics, and science as well as general cognitive ability in a large and…

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…

Multivariate genetic analysis was used to examine the genetic and environmental aetiology of the interrelationships of diverse linguistic skills. This study used data from a large sample of 4 1/2-year-old twins who were tested on measures assessing articulation, phonology, grammar, vocabulary, and verbal memory. Phenotypic analysis suggested two…

Obtained objective measures of activity, fidgeting, vigilance, selective attention, and aggression for a sample of 87 twin pairs in late childhood. Little evidence for genetic influence on behavior was found. Between-family environmental sources of variance were far more important than within-family factors. (Author/RH)

Genetic research on intelligence has moved beyond the nature-nurture controversy to investigate developmental change and continuity, associations among cognitive abilities, and the developmental interface between nature and nurture. Advances in molecular genetics are leading to a new era of research. (Author/SLD)

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,…

Examined infant verbal and nonverbal cognitive development for 1,937 pairs of same-sex 2-year-old twins. Found that verbal and nonverbal development correlated .42. Genetic factors were responsible for less than half of this phenotypic correlation. The genetic correlation between verbal and nonverbal abilities was only .30, suggesting that genetic…

The genetic and environmental etiologies of sex-typed behavior were examined during the preschool years in a sample of 3,990 three- to four-year-old twin and nontwin sibling pairs. Results showed moderate genetic and significant shared environmental influence for boys and substantial genetic and moderate shared environmental influence for girls.…