[eesmith]

I tried to track that down. It seems to be a poster and preprint by Bob Uttl, Victoria Violo, Lacey Gibson, available at https://www.scienceopen.com/document_file/5fb398f5-274e-4729... .

If so, Google Scholar finds only two citations to it, neither interesting, which tells me the conclusions haven't been really examined by others in the field.

I bring this up because my first thought was to wonder how they handled any implicit cultural bias which might have been in the 1950s-era tests. If the IQ tests favored well-off white students, which were over-represented in college students back then, then IQ result would be excessively high for the 1950s students.

The alternative explanation for the secular decrease in student IQ is that IQ tests became less culturally biased over the same period of time.

I saw no discussion of this possibility in the paper.

[cholantesh]

Thanks for this; it seemed like a particularly dubious claim.