I've always thought the Flynn Effect was yet another Moore's Law, and both demonstrate Goodhart's Law. We didn't get transistor density doubling year over year because this was a natural tendency of some physical law, we got it because of mountains of money and engineering effort poured into doing that. Similarly, we didn't get rises in a measure of what society considers intelligence because of some genetic or uncorrelated environmental factor, we got it because what we're actually measuring with IQ, since it was invented by Binet, is education and selection of minds toward a particular category of reasoning tasks. I think Binet did something impressive when he distilled the priorities of the entire education system into a psychometrically-evaluable quantity that's relatively stable across individuals, but the way people overstate the generality and broad applicability of this metric baffles me. Like people will point out that IQ correlates with lifetime income and also SAT scores. But those two things not only correlate with each other for a much clearer reason (We gate educational outcomes with standardized tests that resemble IQ tests, and also gate economic outcomes with educational credentials), but that reason also is a causal explanation that mostly amounts to a decision made by human institutional policy, rather than some grand enduring fact about the nature of intelligence

Like look, I get how people get so attached to this stuff. I've got a high enough IQ score to be beyond the statistical sensitivity of Raven's Progressive Matrices which mostly seems to mean that I'm great at test-taking and puzzle-solving, and I get that IQ seems like this really powerful explanation of variance on vibes from an internal perspective. It feels like people above a certain point on the curve are just so much more vibrant and curious sometimes! But I've come to believe that this is more an artifact of how we shunt certain people within the education system than some deep difference between people on some generally-applicable measure of capability. Lots of social science theories about assortative mating and such seem to observe that people with brains that work similarly will also tend to like each other more, and we have vast edifices that determine other socialization-determining factors based on these kinds of heavily-correlated metrics.