[ZeroGravitas]

The Flynn effect has its own little nurture vs nature debate within it.

Was it better medicine and food that stopped both your height and your brain from being stunted?

Or was it people being trained from birth for a world where doing abstract brain teaser tests was important.

Notably both cause problems for the typical racist's use of IQs. If you can improve the scores with such interventions it makes a lot of their genocidal policy recommendations seem less scientifically sound, so they put a lot of effort into denying that IQ scores can be improved by interventions. Even though they have been, for decades.

[sokoloff]

It seems obvious that IQ test scores can be improved with interventions and further that actual [as opposed to measured] general intelligence can be affected by environmental factors that shape whether the brain develops under good, neutral, or damaging conditions (nutrition, sleep, language usage, stress, etc.).

With all the energy that's been spent on the topic, I'm slightly surprised that this isn't entirely settled by now and any opposing view being relegated to fringe/flat-earth territory.

[wizzwizz4]

I don't see why it's surprising: IQ is one of the few tools that modern scientific racists have in their toolbox. One wouldn't expect them to let such trifling concerns as "evidence" and "testable models with successful predictions" take that away from them.

[djaro]

There is such a thing as general intelligence which differs between different people. Arguing that IQ isn't real because IQ tests are imperfect, is like arguing in the year 1500 that temperature isn't real because all thermometers are imperfect.

Our lack of ability to precisely measure something does not mean the underlying thing is not real. There is such a thing as general intelligence which correlates strongly with almost every type of performance and life outcomes.

[wizzwizz4]

IQ tests are useful for measuring features of populations, but they're a very noisy measure of an individual's "general intelligence" (if such a thing even exists), with several confounders: whether you've trained to pass IQ tests, TDTPSATDIBCA [1], how well-rested you are, how stressed you are, how hungry you are, whether environmental conditions are distracting you… Many of these are also a factor in group averages, although in the context of measuring children's educational attainment, this is a feature rather than a bug: in that setting, IQ tests are a good measure (to the extent that educational attainment is something we want to be optimising for, which is another question entirely).

However, in this thread, we were discussing "the typical racist's use of IQs". Nobody was "arguing that IQ isn't real": you brought that up, unprompted. The lady doth protest too much, methinks.

[1]: https://hotelconcierge.tumblr.com/post/113360634364/the-stan...

[Qem]

> Was it better medicine and food that stopped both your height and your brain from being stunted?

The ban on leaded petrol probably also helped.

[sokoloff]

The timeline doesn't match.

The Flynn Effect covers from around 1930s to 1980s and the phase out of leaded gasoline happened during the very end of that timeline, meaning adolescent IQ measurements during the time the Flynn Effect covers would have all been raised in an environment where leaded fuel was either dominant or at least common.