National IQs Are Valid - Cremieux Recueil
If you follow me here or on Twitter/X, I’m sure you’ve seen a map like this, showing country-level differences in average IQs:
The figures in this map are derived from a raft of studies compiled by Richard Lynn and Tatu Vanhanen in their 2002 book IQ and the Wealth of Nations. The book itself is little more than a compilation and discussion of these studies, all of which are IQ estimates from samples located in different countries or based on diasporas (e.g., refugees) from those countries.
To get this out of the way, the estimates from IQ and the Wealth of Nations hold up. They are replicable and they are meaningful. At the same time, they are contentious. Lynn and Vanhanen’s estimates have many detractors, but virtually all of the negative arguments have one thing in common: they’re based on the idea that the estimates feel wrong, rather than with any actual inaccuracies with them.
One of the most common arguments against Lynn and Vanhanen’s national IQ estimates is that it is simply impossible for whole countries’ mean IQs to be what people often consider to be so low that they’re considered prima facie evidence of mental retardation. This feeling is based on misconceptions about how mental retardation is diagnosed and defined, and misunderstandings about the meanings of very low IQs across populations. Let’s tackle definition first.
