The Flynn effect presumably started before there were IQ tests to measure it.
Prenatal and early childhood malnutrition generally lower IQ, as does catching certain diseases in pregnancy or early childhood. Child labour might be bad for IQ too—not sure about this one though because a lot of modern schools are basically equivalent to child labour but being in school is not generally thought to lower IQ. So knocking a population out of Malthusian equilibrium would be expected to result in IQ rises.
Better health and nutrition could plausibly have led to higher average intelligence, good point.
However, I think a large part of the Flynn effect is not actual raw intelligence increasing, but better education that leads people to score better on formal intelligence tests.
The Flynn effect presumably started before there were IQ tests to measure it.
Prenatal and early childhood malnutrition generally lower IQ, as does catching certain diseases in pregnancy or early childhood. Child labour might be bad for IQ too—not sure about this one though because a lot of modern schools are basically equivalent to child labour but being in school is not generally thought to lower IQ. So knocking a population out of Malthusian equilibrium would be expected to result in IQ rises.
Related: here is an essay about how the Black Death may have triggered the Rennaissance by reducing Europe’s population enough to temporarily knock everyone out of Malthusian equilibrium. https://www.nhd.org/sites/default/files/Franke_Senior_Paper.pdf
Better health and nutrition could plausibly have led to higher average intelligence, good point.
However, I think a large part of the Flynn effect is not actual raw intelligence increasing, but better education that leads people to score better on formal intelligence tests.