The Politics of Intelligence · Episode 7 of 9 · 56 min
The Logical Error at the Heart of the Race-and-IQ Argument
The core rebuttal to the race-and-IQ argument is a point of logic. How heritable a trait is within a group says nothing about why two groups differ, as Richard Lewontin argued in 1970 with his seeds-in-soil example. The episode explains that gap and tests it against evidence including postwar German children, transracial adoption studies and the rise in IQ scores over the twentieth century.
Who's who
- Richard Lewontin+2 more episodesHarvard geneticist who stated the within- versus between-group error in 1970
- Arthur Jensen+7 more episodesBerkeley psychologist whose 1969 argument Lewontin answered
- James R. Flynn+1 more episodeResearcher who documented large rises in IQ scores over generations
- Klaus EyferthGerman psychologist who studied children of postwar American servicemen
- Sandra Scarr+1 more episodeMinnesota psychologist; co-author of the transracial adoption study
- Richard A. WeinbergMinnesota psychologist; co-author of the transracial adoption study
- John C. DeFriesBehavioral geneticist who proposed a between-group heritability formula
Where it happens
- University of Minnesota+1 more episodeSite of the Minnesota Transracial Adoption Study
- Hamburg, Germany+1 more episodeWhere Eyferth studied children of Black and white servicemen
Timeline
- 1961Eyferth finds roughly equal scores among postwar German children of Black and white GIs
- March 1970Lewontin publishes 'Race and Intelligence'
- 1972DeFries proposes a between-group heritability formula
- 1976Scarr and Weinberg publish the first transracial adoption study
- 1984Flynn documents massive IQ gains across generations
- 2024PNAS paper generalizes Lewontin's argument and shows the DeFries formula fails
Still debated
Hereditarians have answered Lewontin seriously, citing the DeFries formula, attenuated adoption gains by adolescence, and selection among servicemen in Eyferth's study. Critics reply that key quantities cannot be estimated without environmental controls.
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