The Flynn Effect and IQ Disparities Among Races, Ethnicities, and Nations: Are There Common Links?

Connecting the Flynn Effect to racial, ethnic, and national disparities in IQ

By Scott Barry Kaufman

https://www.psychologytoday.com/us/blog/beautiful-minds/201008/the-flynn-effect-and-iq-disparities-among-races-ethnicities-and-nations

 …The importance of being able to read for performance on an IQ test cannot be understated. Instead of measuring ‘intelligence' in an illiterate test-taker, the test is measuring that person's inability to read. While ‘intelligence' may certainly influence an individual's ability to read, society has a lot of influence on how many inhabitants even get the chance to read in the first place regardless of the intelligence level of any single individual. Therefore, reading skills may exert important effects on particular races and nationalities that have historically undergone much discrimination and as a result, limited opportunity for literacy development.

…Psychologist  David Marks systematically analyzed the association between literacy skills and IQ across time, nationality, and race (Marks, 2010)…He found that the higher the literacy rate of a population, the higher that population's mean IQ, and the higher that population's mean IQ, the higher the literacy rate of that population. When literacy rates declined, mean IQ also declined. Marks also found evidence for unequal improvements across the entire IQ spectrum: the greatest effects of increased literacy rates were on those in the lower half of the IQ distribution.

…It should also be noted that Mark's findings only speak to populations (not individuals) and do not say much about causation. The findings can only definitively say that some not-yet-identified variable is causing both literacy and IQ scores to change. To really test for causation, future experimental studies should be conducted to look at the effect of literacy intervention on IQ scores in comparison with a control group not receiving literacy intervention and should also investigate intervening variables that affect both literacy and IQ. Still, the result that population level literacy changes with population IQ is suggestive that increased literacy is causing increased IQ.

…The Marks study suggests a crucial environmental factor is literacy. If this is so, then interventions that increase literacy will also narrow the IQ gap found between different races and nationalities.