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.
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.