{"id":16162,"date":"2026-10-15T04:04:00","date_gmt":"2026-10-15T03:04:00","guid":{"rendered":"https:\/\/emilkirkegaard.dk\/en\/?p=16162"},"modified":"2026-10-15T04:04:00","modified_gmt":"2026-10-15T03:04:00","slug":"adult-cognitive-gaps-in-the-piaac","status":"publish","type":"post","link":"https:\/\/emilkirkegaard.dk\/en\/2026\/10\/adult-cognitive-gaps-in-the-piaac\/","title":{"rendered":"Adult cognitive gaps in the PIAAC"},"content":{"rendered":"

For fun, I posted some results for sex differences in cognitive tests from taketest.xyz on Twitter<\/a>. Replotted, they look like this:<\/p>\n

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Most tests show male advantages, and only 3 show a female advantage, all of them quite small, below 0.2 d (multilingual vocabulary, color sorting, eye reading). By contrast, many of the male advantages are quite large, many above 0.5 d. These results thus suggest a general male advantage but focused on certain kinds of tests. The differences in these less general abilities than general intelligence are not surprising or new, though occasionally denied or questioned by feminists (e.g. male advantage in math). However, there is another potential explanation. The users on the site are obviously not representative but rather self-selection for high intelligence. It is possible that the male takers are more selected than the female ones.<\/p>\n

To get around this somewhat I decided to analyze the large public datasets that the OECD has published from their PIAAC studies<\/a>. This is the adult version of PISA. There’s data on 3 tests across 2 waves, and the gaps look like this, pooled across countries:<\/p>\n

\"\"<\/a><\/p>\n

The difference in literacy was ~0, men scored about 0.20-0.26 better on math, and 0.08-0.10 d better on ‘problem solving’. Thus, again, consistent with a general male advantage. Obviously, the OECD aren’t big fans of Richard Lynn, so you can be quite sure they tried to get rid of these gaps in their item designs, but didn’t quite make it. For good measure, I ran my own item response theory models and checked for test bias, though it was quite minor.<\/p>\n

The gaps also vary quite a bit across countries, wave 1:<\/p>\n

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Wave 2:<\/p>\n

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Insofar as age is concerned, the two waves don’t agree entirely:<\/p>\n

\"\"<\/a><\/p>\n

In the first wave, the male advantage appears to be growing with age, but not in wave 2. I am not sure what would be the cause of this. Usually these kinds of abrupt changes are due to changes to the tests, mode of delivery, scoring, and not real differences. The datasets are far too large for these differences to be due to random sampling error. The cohort (birth year) gaps seen between the waves suggest a change in measurement or sampling.<\/p>\n

From a Richard Lynn perspective, the findings aren’t that surprising in general, the male advantage overall would be quite small, an unweighted mean of about 1.5-2 IQ. His general proposed model concerns how to resolve the question of why we see a much greater male brain size, which is seen in every population, and which remains substantial controlling for height, with the known causal effect of brain size on intelligence, with supposedly no difference in general intelligence. This would only be the case if women have some compensating brain advantage, or men’s extra brain size occurs in areas unrelated to intelligence. As far as I know, there is no known candidate for such a female advantage, and brain imaging studies find that the entire brain, more or less, is involved in intelligence. So Lynn’s solution is that researchers had just made an error and men really do have such an advantage in line with the brain size advantage. This resolves the overall problem, but creates a new one. If men are smarter in general because of a larger brain, then why do we see such variation in the size of this advantage? It doesn’t make a lot of sense if this advantage has deep ancestral roots and should be more of a human universal than something that varies between populations and their cultures. I’m afraid I don’t know what the resolution to this question is.<\/p>\n","protected":false},"excerpt":{"rendered":"

For fun, I posted some results for sex differences in cognitive tests from taketest.xyz on Twitter. Replotted, they look like this: Most tests show male advantages, and only 3 show a female advantage, all of them quite small, below 0.2 d (multilingual vocabulary, color sorting, eye reading). By contrast, many of the male advantages are […]<\/p>\n","protected":false},"author":17,"featured_media":16163,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2591],"tags":[3101,2931],"class_list":["post-16162","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-intelligence-iq-cognitive-ability","tag-piaac","tag-sex-difference-in-intelligence","entry","has-media"],"_links":{"self":[{"href":"https:\/\/emilkirkegaard.dk\/en\/wp-json\/wp\/v2\/posts\/16162","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/emilkirkegaard.dk\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/emilkirkegaard.dk\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/emilkirkegaard.dk\/en\/wp-json\/wp\/v2\/users\/17"}],"replies":[{"embeddable":true,"href":"https:\/\/emilkirkegaard.dk\/en\/wp-json\/wp\/v2\/comments?post=16162"}],"version-history":[{"count":3,"href":"https:\/\/emilkirkegaard.dk\/en\/wp-json\/wp\/v2\/posts\/16162\/revisions"}],"predecessor-version":[{"id":16170,"href":"https:\/\/emilkirkegaard.dk\/en\/wp-json\/wp\/v2\/posts\/16162\/revisions\/16170"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/emilkirkegaard.dk\/en\/wp-json\/wp\/v2\/media\/16163"}],"wp:attachment":[{"href":"https:\/\/emilkirkegaard.dk\/en\/wp-json\/wp\/v2\/media?parent=16162"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/emilkirkegaard.dk\/en\/wp-json\/wp\/v2\/categories?post=16162"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/emilkirkegaard.dk\/en\/wp-json\/wp\/v2\/tags?post=16162"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}