From Aporia, a preprint from a paper out of King's College, London. I don't recognise the name of the lead author Damien Morris (likely my ignorance), but Ritchie and Plomin are both big names in genetics.
Mechanisms of developmental change in genetic and environmental influences on intelligence. Damien Morris and colleagues re-examine the Wilson effect, the rising heritability of intelligence with age. Analysing longitudinal data for 10,535 twin pairs, they find that heritability rises from 24% at age 2 to 50% at age 16, while shared environmental influence declines from 65% to 10%. Non-shared environmental influence also rises.
This general model is coming to be preferred - at least by people doing actual research, not the journalists, educators, social workers, etc who wield so much influence over children: The effect of genes rises as we grow older. This study is useful because it covers the years of childhood only, when children are usually in a setting controlled by adults, usually parents. To oversimplify, twins reflect their environment(green) more than their genes(blue) at first, and have very little nonshared environmental(red) influence. As they get older, the genes assert their dominance gradually. The nonshared environment - different friends, different available hobbies, different teachers - grows in influence as well. By age sixteen, the parental influence on the intelligence of children is pretty much spent.
The pattern holds for other traits, but not as dramatically as with intelligence.
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