Malthusian theory predicts that as the ability of a nation increases linearly, the population of said nation increases exponentially, causing food shortages and massive social unrest.

This seems to be true for most of sub-Saharan Africa and a lot of the developing world. However, highly industrialised countries/regions like Japan and Western Europe, are paradoxically enjoying declining native birth rates.

However, in Western Europe for example, it is measured that the birth rate of immigrants from Africa and/or the Middle East is higher. Immigrants from China and such do not show this behaviour.

Therefore, the primal urge to breed like rabbits and IQ must be linked. This means that by importing immigrants, western nations will, over time, become as the population of sub Saharan Africa and, because of that, enjoy aforementioned social instability.