National IQ and the Wealth of Nations in chart

NIQ and (log) GDP capita from the Maddison project shows a strong relationship over 200 years!

Here are some of my comments on the hereditarian theory of economic growth /thread

But before we get to my comments here is the same chart but slowed down for 1950-2015

Under the hereditarian theory. Genes cause National IQ which causes GDP per capita.

If you doubt the first part check out Gregory Christainsen's papers or Davide Piffer (2019) showing educational polygenic scores correlate +0.9 with population IQ.
https://www.mdpi.com/2624-8611/1/1/5 

So what are the main predictions of this theory?
1. The relationship between NIQ and GDP is strong and stable over time.

2. Variation in measures of national IQ/cognitive human capital should be stable overtime

If we look at the the correlation between GDP per capita and national IQ we can see the relationship is in fact rather stable for over 200 years!

However the sample is small and changing before 1950 and the data quality is poorer. There's also randomness in the early 20th century (WW1, depression, WW2).

You can also see the fall of the USSR in the graph (Maddison data overestimates the USSR's GDP) https://www.unz.com/akarlin/maddison-project-2020-new-historical-gdp-estimates/

Why was the NIQ GDP correlation so low in 1950 and why has it increased since.

1. Colonies are added to the sample in 1950 - under western rule they punched above their national IQ!

2. East Asia copied western tech, institutions and markets causing them to catch up

Broadly, the main outliers in the chart are because of
1. Resource wealth
2. Communism
3. Colonialism (smart fraction or good institutions is good for GDP).

As for the second hypotheses in the theory - variation in phenotypic intelligence/human capital is slow moving over long periods of time?

Well the threads getting long so we'll leave that for another day...