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American IQ scores have rapidly dropped, proving the 'Reverse Flynn effect'

(www.popularmechanics.com)
256 points hirundo | 2 comments | 10 Apr 23 13:00 UTC | HN request time: 0.498s | source
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rahimnathwani ◴[10 Apr 23 16:58 UTC] No.35514446[source]▶
This blog post asserts that IQ scores didn't drop for the population as a whole, and that the drop for each individual group is due to changing composition of that group:

https://emilkirkegaard.dk/en/2023/03/new-study-didnt-really-...

For example, if the % of people who do a postgraduate degree goes doubles, it's no longer such a select group, so you'd expect the average IQ of postgraduate degree holders to go down. This doesn't mean IQ scores are going down for the population as a whole.

One more thing: why do so many papers that present charts that show how a mean or median changes over time, without also presenting charts that show how the distribution has changed over time?

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1. verteu ◴[10 Apr 23 23:14 UTC] No.35518556[source]▶
The blogger is wrong. Supplementary tables S10 and S11 [1] show IQ scores dropped as a whole (stratified by gender only). The result is statistically significant.

[1] Pages 16 and 17 of the Word document under "Appendix A. Supplementary data" at https://www.sciencedirect.com/science/article/pii/S016028962...

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2. AstralStorm ◴[11 Apr 23 07:32 UTC] No.35521980[source]▶
The interesting part is the partial conclusion:

> The steepest slopes occurred for ages 18–22 and lower levels of education.

So they're blaming faulty education for people being bad at the test. Now I want to see the RCT to prove this hypothesis. (With controls for experimenter effect.)