A meta-analysis of longitudinal twin and adoption studies finds that new genetic influences on cognition appear mainly in early childhood but quickly wane, while preexisting genetic influences are amplified over time — and this amplification after about age 8 drives the observed increase in heritability. The result comes from pooled models of 11,500 reared‑together twin and sibling pairs measured between 6 months and 18 years.
— If genetic effects are amplified rather than continuously novel across development, policy and intervention debates should focus on how environments interact with early genetic differences and when interventions might be most or least effective.
Steve Sailer
2026.04.16
85% relevant
Reich et al.'s longitudinal ancient‑DNA results provide empirical evidence that selection in the past ~10,000 years acted on standing variation and shifted allele frequencies, a mechanism (amplification) that can raise observed heritability for cognitive traits over generations — directly supporting the claim that recent evolution can increase genetic influence on cognition.
BeauHD
2026.04.16
60% relevant
The paper reports selection signals on variants linked to traits such as years of schooling and other complex traits; such directional selection over recent millennia is a concrete mechanism that can change genetic variance and thus contribute to observed increases in trait heritability (claim: selection on schooling‑linked variants).
Davide Piffer
2026.04.09
88% relevant
The article tests whether temporal increases in educational‑attainment polygenic scores reflect an 'amplification' process tied to changing social environments (civilization stage) rather than only genetic selection over time; Piffer’s method — coding archaeological stages and controlling for absolute date using the AADR ancient‑DNA dataset — directly engages the amplification explanation for rising heritability.
2026.04.04
100% relevant
Meta-analysis of 16 articles / 11 unique samples (11,500 twin and sibling pairs) showing innovation predominates in early childhood but amplification accounts for increasing heritability after age 8.