Meta‑analytic and longitudinal evidence shows the proportion of IQ variance explained by genetics increases from childhood into adulthood while the influence of shared family environment largely fades. That means the causes of adult cognitive differences are not the same mix as those most apparent in early childhood test scores.
— This matters because it reframes expectations for when and how educational or social interventions might alter life outcomes tied to measured cognitive ability.
Steve Stewart-Williams
2026.04.18
60% relevant
Plomin’s 'first law' and the discussion of heritability varying across time and place aligns with the existing idea that genetic influence often increases across development; the article sets up that pattern even as it defers some specifics to later items.
2026.04.04
100% relevant
Article item #2: 'The heritability of IQ increases from childhood to adulthood...the effect of the shared family environment largely fades away.'
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