We compared dyad-focused maternal speech (protoconversations and maternal speech describing the dyad) in interactions of mothers with their twin and singleton infants. Nine twins and nine singletons, coming from urban areas of Crete (Greece), were video-recorded at home in spontaneous face-to-face interactions with their mothers, from the 2nd to…

Many topics of interest to developmental scientists are informed by behavioural genetic findings and their implications. First, behavioural genetic theory and methods will be briefly outlined. Next, findings will be illustrated by considering two disparate areas--general cognitive ability (IQ), and children's self-conceptions. These topics have…

Background: Despite the well-replicated relationship between the home literacy environment and expressive vocabulary, few studies have examined the extent to which the home literacy environment is associated with the development of early vocabulary ability in the context of genetic influences. This study examined the influence of the home literacy…

Background: Families of children with attention-deficit/hyperactivity disorder (ADHD) report higher rates of conflict within the family and more negative parent-child relationships. This study aimed to test whether negative parent-child relationships have a risk effect on ADHD symptoms using two complementary designs. Method: The first sample…

The authors explore the contributions of social and genetic influences to religious attitudes and practices in a population-based sample of 11-18 year olds and their mothers who responded to a Religious Attitudes and Practices Inventory and Religious Rearing Practices Inventory respectively. Contrary to genetic studies examining adult religious…

This study presents an extended children-of-twins model, which allowed the authors to test the direction of the association between parenting and child adjustment. Three mechanisms were examined: direct phenotypic influence of parenting on child behavior (controlling for both parental and child genotype), passive genotype-environment correlation,…

Background: Bullied children are at risk for later emotional and behavioural problems. "Resilient" children function better than would be expected given their experience of bullying victimisation. This study examined the role of families in promoting resilience following bullying victimisation in primary school. Method: Data were from the…

Investigates differences in the language learning environments of six twin pairs and 12 singleton toddlers (all firstborn) with special reference to pragamatic factors that might be expected to differ in dyadic and triadic interactive situations. (HOD)

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…

To study the social-emotional development of triplets, 23 sets of triplets, 23 sets of twins, and 23 singleton infants (N=138) were followed from birth to 2 years. Maternal depression and social support were assessed in the postpartum period, mother-infant and father-infant interaction and the home environment were observed at 3 months, a…