[Houshalter]

The papers abstract is a bit more interesting than this summary. It looks like they compared 14 studies of reaction time over decades, not just Galtons: https://www.sciencedirect.com/science/article/pii/S016028961...

>The Victorian era was marked by an explosion of innovation and genius, per capita rates of which appear to have declined subsequently. The presence of dysgenic fertility for IQ amongst Western nations, starting in the 19th century, suggests that these trends might be related to declining IQ. This is because high-IQ people are more productive and more creative. We tested the hypothesis that the Victorians were cleverer than modern populations, using high-quality instruments, namely measures of simple visual reaction time in a meta-analytic study. Simple reaction time measures correlate substantially with measures of general intelligence (g) and are considered elementary measures of cognition. In this study we used the data on the secular slowing of simple reaction time described in a meta-analysis of 14 age-matched studies from Western countries conducted between 1889 and 2004 to estimate the decline in g that may have resulted from the presence of dysgenic fertility. Using psychometric meta-analysis we computed the true correlation between simple reaction time and g, yielding a decline of − 1.16 IQ points per decade or − 13.35 IQ points since Victorian times. These findings strongly indicate that with respect to g the Victorians were substantially cleverer than modern Western populations.

It's not terribly convincing just by itself. He's done newer work showing that other proxies for IQ like vocabulary have also decreased over time: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4404736/ And math SAT scores have dropped over time: https://brainsize.wordpress.com/tag/michael-a-woodley/ But we are only just starting to be able to test for genes that correlate with intelligence to see if they have decreased over time.

[iguy]

One complaint IIRC was that the Victorian sample might have been more skewed towards the elite than the current ones -- people attending science lectures, or something.

I haven't read the paper linked, Woodley-teNijenhuis-Murphy, but do they address this?

[AstralStorm]

Oh boy, where do we even begin... Let's try this: http://archive.is/YcIDb

[AstralStorm]

Did he even bother checking error bars due to multiple test correction when verifying the correlations in pooled data?

We could ask Cochrane what they find. They tend to use many more studies than 14 as input with clear inclusion and exclusion criteria.

I suspect the author misuses statistics and fails to check internal and external validity of his measures.

How did he even get the real IQ points when the test had been changed and regraded about every 20 years? How does he convert the numbers to g? Is it general or slanted? Is his measure verified to be consistent even in a single generation across cultures? Etc.

Unfortunately, the other paper is behind the paywall.

[jacobolus]

> may have resulted from the presence of dysgenic fertility

The effects might be interesting, but it seems like an entirely unsupported logical leap to attribute any effect to this cause.

[pjc50]

Other way round : the author is a eugenicist looking for evidence. https://rationalwiki.org/wiki/Michael_A._Woodley_of_Menie

[jacobolus]

Yes that was my point, that sentence seemed quite out of place, and was sufficient to make me skeptical of the author’s motives.

[Houshalter]

Rationalwiki isnt exactly an unbiased resource to put it lightly.

[AstralStorm]

However, the previous cowritten papers are openly accessible and linked from there.