Take any population on earth.
For several generations, remove their most physically capable members by force and sell them abroad.
Destroy their existing political institutions and replace them with administrative structures designed to extract rather than develop.
Draw their borders to maximize ethnic conflict and minimize political coherence.
Extract their mineral and agricultural wealth for a century at prices you set unilaterally.
When you leave, install governments that serve your economic interests rather than their populations.
Fund civil wars when those governments are threatened by leaders who want to redirect resource revenues toward domestic development.
Then, three generations later, administer a cognitive test.
Compare the scores to those of the populations who spent the same period accumulating capital, building universities, developing public health infrastructure, and compounding the advantages of political stability.
Put the results on a map.
Call the map a "nature documentary."
Tell yourself the scores show something biological.
Tell yourself the history had nothing to do with it.
Tell yourself you arrived at this conclusion by following the evidence.
You did not follow the evidence.
You followed the map to the place you had already decided to go.
And the evidence, the entire, documented, sourced, cross-disciplinary evidence, is the invoice you refused to open.