Replicating Richard Lynn's "IQ and the Wealth of Nations"

A third of a century ago, the late psychologist Richard Lynn started working on an audacious project: assembling a database of national average cognitive test scores, and then seeing whether intelligence positively correlates with GDP per capita. Lynn and Tatu Vanhanen published in 2002 the landmark IQ and the Wealth of Nations. (My book review is featured in my new anthology Noticing.)

Now, the downsides of Lynn’s work are that he tended to make a fair number of minor typo-level errors, his judgment about what studies to include wasn’t flawless, and he had certain prejudices (notably, as an Orangeman against Irish Catholics).

A coterie of Science Denial activists are attempting to use Lynn’s shortcomings as an excuse to cancel all his work out of ideological spite.

But like most IQ research, Lynn’s results have overall replicated much better than many more famous studies from other psychological fields from that era before the Replication Crisis began to improve standards.

In particular, Lynn’s national average cognitive test score work has been repeatedly replicated using a different type of test. While Lynn initially focused on IQ tests, other researchers have since focused on the growing number of school achievement tests such as PISA.

We now live in an era with an abundance of fairly high quality cognitive test data from around the world … and it comes out looking pretty much like Lynn reported all those years ago. For example, here is a graph I made in 2022 from the World Bank’s spectacular Harmonized Learning Outcomes database. The results don’t differ all that much from Lynn and Vanhanen’s 20 years earlier.

I used various colors to denote populations tracing to different parts of the world: e.g., Singapore is demographically dominated by Han Chinese from northeast Asia (yellow), whereas Estonia is in Europe (blue).

For the methodology and notes about unusual scores (does China really only score 441?), see my 2022 Taki’s Magazine column.