Population IQ scores have risen rapidly over decades, refuting fixed-IQ claims

Evidence

In fact, this IQ increase is a variant of the “Flynn effect,” named for James R. Flynn, whose 2012 book, Are We Getting Smarter? Rising IQ in the Twenty-First Century, documented an average IQ rise of three points per decade between 1932 and 1978 in the United States and some other Western nations. Subsequent analyses have confirmed this, such as a 2014 meta-analysis in the Psychological Bulletin, which calculated the same IQ gains between 1972 and 2006.15 This suggests that the scores reflect not innate intelligence but acquired skills. — Harriet A. Washington, A Terrible Thing to Waste, 124

Categorization

• corroborated: 2 independent passages support this claim — Harriet A. Washington, A Terrible Thing to Waste, 124
• recurring: this claim recurs 2 times within its source
• XREF: connects to: Intelligence is malleable and shaped by environment, not fixed by heredity — Harriet A. Washington, A Terrible Thing to Waste, 54; Genetic causation of a trait does not imply the trait is unchangeable — Harriet A. Washington, A Terrible Thing to Waste, 157; Rapid IQ gains from reduced disease burden rule out genetic explanations — Harriet A. Washington, A Terrible Thing to Waste, 945 (+10 more)

Library Connections

• Rapid IQ gains from reduced disease burden rule out genetic explanations #expands (0.85) — Harriet A. Washington, A Terrible Thing to Waste, 945

Broader Connections

• Adding iodine to salt in 1924 raised average U.S. IQ scores #exemplifies (0.75) — Did iodized salt raise the IQ of 50 million Americans by 15 points?
• National infectious disease burden strongly predicts average national IQ #expands (0.72) — Harriet A. Washington, A Terrible Thing to Waste, 937