Rapid IQ gains from reduced disease burden rule out genetic explanations

Evidence

Just as adding iodine to the diets of 1920s Americans raised the IQs of “dullard” areas by 15 points, the average Kenyan IQ rose 14 points between 1984 and 1998 in parts of the country that enjoyed improvements in health, including reduced disability from untreated infectious disease. Parasite stress explains this, but genetics does not: the IQ gains were too high and too rapid to be explained by evolutionary and genetic mechanisms. — Harriet A. Washington, A Terrible Thing to Waste, 945

Categorization

• corroborated: 2 independent passages support this claim — Harriet A. Washington, A Terrible Thing to Waste, 945
• 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; Population IQ scores have risen rapidly over decades, refuting fixed-IQ claims — Harriet A. Washington, A Terrible Thing to Waste, 124 (+18 more)

Related

• Disease-reduction interventions like vaccination and clean water could raise national IQ scores #corroborates (0.80) — The Flynn Effect and IQ Disparities Among Races, Ethnicities, and Nations: Are There Common Links?

Library Connections

• Adding iodine to salt in 1924 raised average U.S. IQ scores #exemplifies (0.85) — Did iodized salt raise the IQ of 50 million Americans by 15 points?
• Iodine deficiency is a major unrecognized cause of lowered intelligence #exemplifies (0.80) — Harriet A. Washington, A Terrible Thing to Waste, 21
• Targeted interventions can raise a nation’s average intelligence level #corroborates (0.80)

Broader Connections

• Mixed-race children’s IQ tracks rearing environment, not racial genetics #corroborates (0.75) — Harriet A. Washington, A Terrible Thing to Waste, 119