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Boomsma D. I., van Baal G. C. M.
Genetic influences on childhood IQ study in 5- and 7-year old Dutch twins
(resume)
IQ of 5- and 7-year old Dutch twins was measured
in order to study changes in the genetic
architecture of cognitive functioning. The
continuity and dynamics in genetic and
environmental influences were examined by means of
development model of data processing. The results
show that genetic influences persist during this
age interval and greatly gain in relative
importance. Shared family background influences IQ
in early childhood but their relative importance
becomes smaller. Unique environment manifests
itself age-specifically and accounts for about a
quarter of total variance of IQ in both 5- and
7-year old twins.
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