Intelligence develops from environment and experience rather than genetic inheritance

Evidence

IQ is not innate. Studies that compare the IQs of mixed-race children reveal the determinant role of their various environments. In Germany, children with one parent of African descent and one of European descent who were raised in white households (such as the offspring of African American or African soldiers whose fathers return to the States and whose mothers subsequently marry white Germans) scored higher on IQ tests than mixed-race children from similar backgrounds who were raised in black households. The same thing happened when comparing mixed-race children in the United States.12 — Harriet A. Washington, A Terrible Thing to Waste, 119 (#exemplifies, via linked claim)

Categorization

• corroborated: 2 independent passages support this claim
• XREF: connects to: Mixed-race children’s IQ tracks rearing environment, not racial genetics — Harriet A. Washington, A Terrible Thing to Waste, 119; Rapid IQ gains from reduced disease burden rule out genetic explanations — Harriet A. Washington, A Terrible Thing to Waste, 945; Toxocara canis infection lowers IQ independent of socioeconomic and racial factors — Harriet A. Washington, A Terrible Thing to Waste, 980 (+23 more)

Related

• Mixed-race children’s IQ tracks rearing environment, not racial genetics (similarity 0.94)
• IQ’s link to income mostly reflects environment’s link to both (similarity 0.88)
• 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… (similarity 0.88)
• Mixed-race IQ patterns refute claims of inherited racial intelligence differences. (similarity 0.85)
• Rapid IQ gains from reduced disease burden rule out genetic explanations (similarity 0.85)
• Twin and adoption studies estimate genetic contribution to intelligence at 50–70% heritability, though molecular GWAS estimates run lower. (similarity 0.84)
• Intelligence is malleable and shaped by environment, not fixed by heredity (similarity 0.84)
• 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 0.83)
• 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 0.83)
• Genetic causation of a trait does not imply the trait is unchangeable (similarity 0.82)
• Eugenic ideology suppressed research into infectious causes of low IQ (similarity 0.82)
• Intelligence quotient significantly influences important life outcomes (similarity 0.81)
• How a character works differs from its long-term genetic effects (similarity 0.81)
• The generational rise in IQ scores is attributed to environmental factors like improved nutrition, education, and reduced toxin exposure. (similarity 0.80)
• Toxocara canis infection lowers IQ independent of socioeconomic and racial factors (similarity 0.80)

Library Connections

• Mixed-race children’s IQ tracks rearing environment, not racial genetics #exemplifies (0.88) — Harriet A. Washington, A Terrible Thing to Waste, 119
• Iodine deficiency is a major unrecognized cause of lowered intelligence #exemplifies (0.87) — Harriet A. Washington, A Terrible Thing to Waste, 21
• Toxocara canis infection lowers IQ independent of socioeconomic and racial factors #exemplifies (0.85) — Harriet A. Washington, A Terrible Thing to Waste, 980
• Rapid IQ gains from reduced disease burden rule out genetic explanations #corroborates (0.82) — Harriet A. Washington, A Terrible Thing to Waste, 945
• Targeted interventions can raise a nation’s average intelligence level #expands (0.80)