Skin color and intelligence in Latin America
Skin color (lightness or brightness) has been used as a proxy for genetic ancestry for over 100 years. It works alright in many cases. Take this study (Parra et al…
Race, intelligence, and inequality in Brazil
Many years ago I discovered that Brazil publishes the subject level data for many scale testing efforts. These also come with rich surveys concerning the children's homes. The main tests…
Genetic evidence of Ashkenazi intelligence
There are long standing questions about the source of Jewish achievement. Most of this achievement relates to the Ashkenazi subgroup, less so the other Jews. This tells us that the…
Explaining economic growth since 2000
Some days ago I posted some cumulative growth charts for OECD countries, like this one: These results are somewhat affected by the usual GDP issues relating to tax haven (Ireland…
American Jewish gentile differences
Jews are an extraordinarily successful ethnic group in almost everything they choose to engage in, from physics to politics with the curious exception of US presidencies. Seb Jensen compiled a…
Assessment of the Confidence Calibration Test + new test
Yesterday, I posted a new cognitive test on taketest.xyz, the Confidence Calibration Test. If you want to take the test without biased results, take it now before reading further. You…
Which countries are best at esports? 2026 update
Given the ease of obtaining scraped datasets with Claude Code, I thought we could update my 2019 study of mental sports with the newest data and better methods. The primary…
Meta-Analysis of American Race Differences in Intelligence
So our new meta-analysis of the American race gaps in IQ is published! Kirkegaard, E. & Jensen, S. (2025). Meta-Analysis of American Race Differences in Intelligence. Mankind Quarterly, 66(2), 290-300.…
Dysgenics for whom?
Some time ago, we published studies showing that the negative correlation between intelligence and fertility varies by other factors. Specifically, we found that it varies by religiousness and conservatism, in…
Motivated reasoning and intelligence
Years ago, a very flashy finding by Kahan and colleagues (2017) got popular (1200+ citations). It goes like this, you give people some matrices of fake study data like these:…
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