Accurate understanding of environmental moderation of genetic influences is vital to advancing the science of cognitive development as well as for designing interventions. One widely-reported idea is increasing genetic influence on cognition for children raised in higher socioeconomic status families, including recent proposals that the pattern is…

Impulsivity and inattention are key constructs at the interface of temperament and domains of childhood behavioral problems, such as ADHD and ODD. A multi-method, multi-source assessment of impulsivity and inattention was conducted with 256 families of twins at a mean age of 8-9 years from an epidemiologically defined community sample. Analysis of…

Background: Childhood psychopathology is associated with both high and low levels of prosocial behaviour. It has been proposed that the development of prosocial behaviour shows emerging and consolidating individual differences as children grow older. The influences on these individual differences have not previously been examined in children and…

A set of tri-zygotic quadruplets, three girls and one boy, participated in weekly observations from 1;2 to 1;10 (years;months), a period of transition from prelinguistic gesture to 50 words. In the study, one girl served as a genetic mate to her identical twin and a biological risk mate to her fraternal sister. The biological risk mates achieved…

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…