کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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365291 | 621118 | 2008 | 13 صفحه PDF | دانلود رایگان |
In this paper we assess the presence of assortative mating, gene–environment interaction and the heritability of intelligence in childhood using a twin family design with twins, their siblings and parents from 112 families. We evaluate two competing hypotheses about the cause of assortative mating in intelligence: social homogamy and phenotypic assortment, and their implications for the heritability estimate of intelligence. The Raven Progressive Matrices test was used to assess general intelligence (IQ) and a persons IQ was estimated using a Rasch model. There was a substantial correlation between spouses for IQ (r = .33) and resemblance in identical twins was higher than in first-degree relatives (parents and offspring, fraternal twins and siblings). A model assuming phenotypic assortment fitted the data better than a model assuming social homogamy. The main influence on IQ variation was genetic. Controlled for scale unreliability, additive genetic effects accounted for 67% of the population variance. There was no evidence for cultural transmission between generations. The results suggested that an additional 9% of observed IQ test variation was due to gene–environment interaction, with environment being more important in children with a genetic predisposition for low intelligence.
Journal: Learning and Individual Differences - Volume 18, Issue 1, 2008, Pages 76–88