With heritability well below 1.00, IQ must be subject to substantial environmental influences, though genetic influence increases with age while shared family environment effects shrink by late adolescence.
Evidence
Intelligence: Knowns and Unknowns (American Psychologist (APA Task Force))
Categorization
- corroborated: 5 independent passages support this claim
- XREF: connects to: Intelligence is malleable and shaped by environment, not fixed by heredity — Harriet A. Washington, A Terrible Thing to Waste, 54; Toxocara canis infection lowers IQ independent of socioeconomic and racial factors — Harriet A. Washington, A Terrible Thing to Waste, 980; Intelligence develops from environment and experience rather than genetic inheritance (+5 more)
Related
- With heritability well below 1.00, IQ must be subject to substantial environmental influences, though genetic influence increases with age while shared family environment effects shrink by late adolescence. (similarity 0.93)
- Twin and adoption studies estimate genetic contribution to intelligence at 50–70% heritability, though molecular GWAS estimates run lower. (similarity 0.88)
- Intelligence develops from environment and experience rather than genetic inheritance (similarity 0.88)
- IQ’s link to income mostly reflects environment’s link to both (similarity 0.86)
- Large positive and negative trends in cohort IQ operate within as well as across families, implying at most a minor role for genes, with environment as the main driver. (similarity 0.85)
- High heritability of individual differences and large environmental effects on population-level IQ are mathematically compatible under a reciprocal gene-environment coupling model (Dickens & Flynn). (similarity 0.84)
- The generational rise in IQ scores is attributed to environmental factors like improved nutrition, education, and reduced toxin exposure. (similarity 0.83)
- How a character works differs from its long-term genetic effects (similarity 0.83)
- Intelligence is malleable and shaped by environment, not fixed by heredity (similarity 0.83)
- Genetic causation of a trait does not imply the trait is unchangeable (similarity 0.83)
- IQ has risen across generations worldwide, and the effect must be environmental since genetic mutation could not act that fast, amounting to about 15 IQ points per generation on fluid tests. (similarity 0.82)
- MZ twins correlate at ~.85 for IQ versus .55 for DZ twins, giving heritability estimates of 50–80% in adults, with heritability rising from childhood to adulthood. (similarity 0.81)
- Mixed-race children’s IQ tracks rearing environment, not racial genetics (similarity 0.81)
- IQ predicts job performance, academic achievement, and mortality better than any known psychological factor (similarity 0.80)
- Rapid IQ gains from reduced disease burden rule out genetic explanations (similarity 0.80)