IQ scores from five kinship categories of 7- to 12-year-olds were analyzed into genetic and environmental components. The common environmental effects were larger for older children than younger children. Overall, the Genetic and Common Environment Sources each accounted for approximately 40% of the IQ variability in the data. (Author/LMO)

Examines the mental development scores for two groups of at-risk infants throughout their childhood--those classified as small for gestational age (SGA) and those twins falling below 1,750g birth weight--and determines that SGA twins showed only a modest deficit in IQ scores as compared to the full twin samples. (HOD)

Investigated through direct observation in the home whether mothers socialize differently boys and girls growing up as opposite-sexed twins, triplets, and quadruplets as a function of their different genders. Children and mothers were rated on behaviors about which contradictory evidence had been reported in the literature. (Author/DB)

The Eysenck Personality Questionnaire (EPQ) and the Sensation-Seeking Scale were administered to 219 American undergraduates and 879 English twins. Sensation-seeking was positively correlated to EPQ-measured traits of extraversion and psychoticism. There was no relationship between sensation-seeking and the trait dimension of neuroticism.…

Influences of heredity and environment on educational and occupational choice in mid-life and elderly cohorts were studied using longitudinal twin data (413 pairs). For both education and occupation there is a trend toward increasing genetic variance for females in comparison to males in the younger cohort. (SLD)

This study investigated associations between selected infant and maternal characteristics and autism risk in 4381 California children with autism. Increased risk factors were observed for males, multiple births, and children born to black mothers. Risk increased as maternal age and maternal education increased. Children of immigrant mothers had…

Children who used chloride-deficient soy-based infant formulas (Neo-Mull-Soy and Cho-Free) have been found to exhibit expressive language disorders. Medical studies of such children are reviewed, and a case study compares the language development deficits of an eight-year-old boy who used the formula with that of his fraternal twin who did not.…

Investigates conversational characteristics (discourse features, illocutionary force and style parameters) of mothers of two-year-old twins and mothers of two-year-old singletons with older siblings. Finds significant differences in conversational characteristics, and between twins' and singletons' language scores on measures of language…

The Infant Behavior Record (IBR) assessed the temperament of 95 nonadoptive and 80 adoptive sibling pairs at 1 and 2 years of age. Data from this and an earlier similar study of identical and fraternal twins yielded evidence for genetic influence for IBR factors of extraversion, activity, and task orientation. (BC)

Examined the etiology of individual differences in literacy, phonological awareness, and language ability in monozygotic and dizygotic twins. Found that there was no genetic link between phonological awareness and literacy independent of general language ability. Individual differences in literacy ability were substantially influenced by genetics…

A study of 20 multiple birth children (MBC) (ages 7-8) and 20 controls found MBC performed significantly more poorly on some tasks of phonological processing, and early phonological skills of MBC were correlated with poor performance on visual rhyme recognition, word repetition, and phoneme detection tasks five years later. (Author/CR)

Used quantitative genetic design to examine between- and within-family variations and gene-environment processes in parent-child mutuality among 3-year-old identical and same-sex fraternal twins. Found that greater mutuality was associated with higher socioeconomic status. Moderate sibling similarity in parent-child mutuality was accounted for by…

To examine the development of triplets, 23 sets of triplets were matched with 23 sets of twins and 23 singletons (N138). Maternal sensitivity was observed at newborn, 3, 6, and 12 months, and infants' cognitive and symbolic skills at 1 year. Triplets received lower maternal sensitivity across infancy and exhibited poorer cognitive competencies…

This report presents data on 9-month-old twin pairs (n[MZ]=172; n[DZ]=333) from the Early Childhood Longitudinal Study, demonstrating that the role of genetic variation among infants is trivial and the shared and nonshared environment is substantial in accounting for the observed quality of infant-caregiver relationships. In contrast, maternal…