Anatoly Karlin writes: There is a wealth of evidence implying an exponential relationship between average IQ and income and wealth in the United States.
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There is likewise a wealth of evidence – from Lynn, Rindermann, La Griffe du Lion, your humble servant, etc. – that shows an exponential relationship between levels of average national IQ and GDP per capita (PPP adjusted). When you throw out countries with a legacy of Communism and the ruinous central planning they practiced (China, the Ex-USSR and Eastern Europe, etc), and countries benefitting disproportionately from a resource windfall (Saudi Arabia, the UAE, etc), there is an amazing R2=0.84 correlation between performance in the PISA international standardized student tests and GDP (PPP) per capita. (In sociology, anything about R2=0.3 is a good result).
The reasons for this might be the case are quite intuitive. At the most basic level, intelligent people can get things done better and more quickly. In sufficiently dull societies, certain things can’t get done at all. To loosely borrow an example from Gregory Clark’s A Farewell to Alms, assume a relatively simple widget that requires ten manufacturing steps that have to be done just right to make it commercially viable. Say an 85 IQ laborer has a failure rate of 5% for any one step, while a 100 IQ laborer has a failure rate of 1%. This does not sound like that big or cardinal of a difference. But repeated ten times, some 40% of the duller worker’s production ends up being a dud, compared to only 10% of the brighter worker’s. Consequently, one is competitive on the global markets, whereas the other is not (if labor costs are equal; hence, of course, they are not)…
Average IQ = 70 – Per capita GDP of ~$4,000 in the more optimally governed countries of this class, such as Ghana (note however that many countries in this class are not yet fully done with their Malthusian transitions, which will depress their per capita output somewhat – see below).
Average IQ = 85 – Per capita GDP of ~$16,000 in the more optimally governed countries of this class, such as Brazil.
Average IQ = 100 Per capita GDP of ~45,000 in the more optimally governed countries of this class, or approximately the level of core EU/US/Japan.
Average IQ = 107 – Per capita GDP of potentially $80,000, as in Singapore (and it doesn’t seem to have even finished growing rapidly yet). Similar figures for elite/financial EU cities (e.g. Frankfurt, Milan) and US cities (e.g. San Francisco, Seattle, Boston).
Average IQ = 115 – Largely a theoretical construct, but that might be the sort of average IQ you’d get in, say, Inner London – the center of the global investment banking industry. The GDP per capita there is a cool $152,000.
Countries with bigger than normal “smart fractions” (the US, India, Israel) tend to have a bigger GDP per capita than what could be assumed from just from their average national IQ. This stands to reason because a group of people equally split between 85 IQers and 115 IQers will have higher cognitive potential than a room composed of an equivalent number of 100 IQers. Countries with high average IQs but smaller than normal S.D.’s, such as Finland, have a slightly smaller GDP per capita that what you might expect just from average national IQs.
