A study involving 356 twin pairs with early language delay found environmental influences shared by both twins were more substantial than genetic factors. Heritability was significantly higher in those with persisting difficulties but only when assessed in terms of parental concern at 3 years or professional involvement at 4 years. (Contains…

Composite reading performance data from 223 pairs of identical twins and 169 same-gender fraternal twins in which at least one member was classified with reading disability were subjected to multiple regression analysis. Results indicated that the genetic etiology of reading disability differs as a linear function of IQ. (Contains extensive…

Background: Dissociation--a pattern of general disruption in memory and consciousness--has been found to be an important cognitive component of children's and adults' coping with severe trauma. Dissociative experiences include amnesia, identity disturbance, age regression, difficulty with concentration, and trance states. Stable individual…

Standardized clinical assessments from the point of view of children are rare. A standardized narrative assessment measure, developed to assess children's perceptions of their caregiving environments, the Narrative Story-Stem Technique (NSST), was used with two fraternal twins, age 8, with histories of severe maltreatment and multiple foster…

We use a genetically sensitive design to examine the relationship between language and nonverbal ability at 4 and a half and reading skills at 7 years of age in a sample of more than 1,000 children participating in the Twins Early Development Study. We find that nonphonological as well as phonological measures of early language make significant…

Using a longitudinal, large-scale sample of British twins, we addressed the prediction of both cognitive abilities and behavioral adjustment from eight domains of environmental risk: minority status, socio-economic status, maternal medical factors, twin medical factors, maternal depression, chaos within the home environment, and parental feelings…

Using multiple births as an exogenous shift in family size, I investigate the impact of the number of children on child investment and child well-being. Using data from the 1980 US Census Five-Percent Public Use Micro Sample, 2SLS results demonstrate that parents facing a change in family size reallocate resources in a way consistent with Becker's…

Biosocial influences on sex differences, found for school achievement test results in grades 3 and 6, have been studied by means of opposite-sex twin pairs and singleton controls, attending the same classes as the twins. As expected the opposite-sex twin pairs tend to be more similar in achievement test results in Swedish and mathematics than…

A review of the twin literature and analyses of two large twin samples found identical twin correlations higher than fraternal twin correlations by about .20 for a variety of traits of ability, personality and interests. This was interpreted as indicating that about half of the variation among people in a broad spectrum of psychological traits is…

Lower birth weight babies have worse outcomes, both short-run in terms of one year mortality rates and longer run in terms of educational attainment and earnings. However, recent research has called into question whether birth weight itself is important or whether it simply reflects other hard-to-measure characteristics. By applying within twin…

In studies of relatives, conventional multiple regression may not be appropriate because observations are not independent. Obtaining estimates of regression coefficients and correct standard errors from these populations through a structural equation modeling framework is discussed and illustrated with data from twins. (SLD)

Background: Given the importance of parenting for the child's early socio-emotional development, parenting perceptions and behaviours, and their correlates, should be assessed as early as possible in the child's life. The goals of the present study were 1) to confirm, in two parallel population-based samples, including a large sample of twins, the…

Experimental research suggests the differentiation of "nice" and "nasty" theory of mind (ToM). Over 5000 parents from the Twins Early Development Study reported on nice (e.g., being considerate) and nasty (e.g., blaming others) behaviours following their twins' second, third, and fourth birthdays. Factor analyses yielded four factors and it was…

Do child development professionals have expectations about what it will be like to parent twins based on their professional experiences? Does their professional knowledge influence their approach to caregiving? And do their personal experiences as parents of twins change their research interests or how they work with children and families? To…

The incidence of multiple births has increased dramatically in the past two decades. Given this trend, it seems reasonable to assume that many teachers will have twins and other multiple siblings in their classes at some point in their classroom careers. This Digest offers some pointers for educators facing the challenges of educating multiples.…