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

(www.popularmechanics.com)
256 points hirundo | 1 comments | 10 Apr 23 13:00 UTC | HN request time: 0.208s | 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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tptacek ◴[10 Apr 23 21:42 UTC] No.35517739[source]▶
It's worth looking up whose blog this is before trusting any of its analysis.
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rahimnathwani ◴[10 Apr 23 22:05 UTC] No.35517966[source]▶
I'd never heard of this person before finding this blog post via Google. So I trust the post as much as I trust any random blog post that seems to make a reasonable argument :)
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tedivm ◴[10 Apr 23 22:11 UTC] No.35518005[source]▶
You trust one of these random people enough to promote it. It's not unreasonable for people to point out that the author is quite infamous for his viewpoints.
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nostrademons ◴[10 Apr 23 22:33 UTC] No.35518200[source]▶
It's an ad-hominem (in the original sense of the word: an ad-hominem fallacy is one where the truth or falsity of an argument is determined by the trustworthiness of its proponent rather than by the content of the argument itself).

Is he right? The argument is plausible: the study measures online IQ tests. Certainly in my experience the average person online has gotten dumber in the 30 years I've been on the Internet, because Internet access has expanded and it's now the general population rather than just upper-middle-class academics. But we'd need to see comparisons vs. offline IQ tests, given to a randomly-sampled selection of the population, to be sure.

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Dylan16807 ◴[10 Apr 23 22:49 UTC] No.35518338[source]▶
It's not a fallacy to attack someone's historical reliability in making arguments.
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nostrademons ◴[10 Apr 23 23:15 UTC] No.35518579[source]▶
It is literally a fallacy [1] in that it's invalid logical reasoning.

There are many types of argumentation that are useful for drawing practical conclusions about the world but are not, strictly speaking, valid logic. For example, "correlation doesn't equal causation, but it does waggle its eyebrows suggestively" [2]. If you know nothing about the truth or falsity of a statement, knowing who's saying it can provide some information that might tilt your opinion one way or another. But the person saying something does not make the argument true or false, otherwise I could make myself as detestable as possible to some group of people and then kill them off by giving them common-sense advice like "go to the doctor" or "eat healthy". (Come to think of it, this is exactly what happened to Republicans during COVID, where somehow wearing masks & getting vaccines became politicized.)

Bringing it back to the topic at hand - I found the digression about who Emil O Kierkegard is to be momentarily interesting, but I'd still like to know if he's right or not. The idea that this article might be due to Simpson's Paradox is plausible, and it invalidates the central conclusion of the study if it is.

[1] https://en.wikipedia.org/wiki/List_of_fallacies

[2] https://xkcd.com/552/

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1. ramblenode ◴[11 Apr 23 02:24 UTC] No.35519984[source]▶
Something can be a logical fallacy while still being epistemologically justified. That's because logic is not an a priori description of reality; it's just a system for making inferences that happen to often be useful models of reality. But if I change my system of logic (e.g. move from accepting to rejecting the law of the excluded middle) then one set of fallacies disappears and another appears.