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…

In this study of the origins of individual differences in theory of mind (ToM), the Environmental Risk (E-Risk) Longitudinal Twin Study sample of 1,116 sixty-month-old twin pairs completed a comprehensive battery of ToM tasks. Individual differences in ToM were striking and strongly associated with verbal ability. Behavioral genetic models of the…

Parents of multiple birth children frequently wonder whether it is best for their children to be separated or placed together in school. This guide from the National Organization of Mothers of Twins Clubs (NOMTC) asserts that research and expert opinion demonstrate that mandatory separation of multiple birth children is ineffective and can be…

The appropriate-for-gestational-age (AGA) and small-for-gestational-age (SGA) infants from 30 pairs of full-term and 15 pairs of preterm same-sex twins were compared for neonatal temperament. The evaluation of neonatal temperament included ratings of irritability, resistance to soothing, activity level, reactivity, and reinforcement value. Results…

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)

Based on a PhD dissertation submitted to Teachers College, Columbia University.

The physical growth of 46 school-aged twins with academic difficulties was examined and compared with that of matched controls. (Author/DLS)

Examined longitudinal changes in cognitive functioning for aging twins. Found that those who were considered demented in old age had achieved lower test scores 20 years prior to diagnosis and experienced greater declines in vocabulary and forward digit span over time than those without dementia. Suggests that dementia may develop very slowly.…

Ninety-two adult twin-pairs were recruited. Twin zygosity was determined by self-report inventory. Monozygotic twins resembled one another more than dizygotic twins in most measures of both level and lability of mood, which provides modest evidence for a genetic influence on subclinical levels of depression. (Author/ABB)

A battery of information processing measures and psychometric tests of specific and general cognitive abilities was administered to 34 monozygotic and 13 dizygotic reared apart twin pairs or triplets. Correlations between information processing parameters and psychometric abilities as well as twin resemblances for the information processing…

Genetic and environmental influences on heart rate were studied in samples of twin pairs in middle childhood. Heart rate was measured in resting situation and under two task conditions. Heart rate was related to parental ratings of shyness, emotionality, and selective attention measure. Multivariate analysis suggested that covariance between heart…

Parents of multiple birth children frequently encounter school policies requiring separation of their children in school, regardless of the circumstances, thereby eliminating parents and their children from the decision-making process. This guide from the National Organization of Mothers of Twins Clubs (NOMTC) asserts that research and expert…

One of the most common parenting issues faced by families with multiple birth children is that of the dynamics involved in sibling cooperation and competition. This document compiles stories from the Mothers of Twins Club "Notebook" examining the issue of cooperation versus competition. The first story discusses the impact of the twin…