Semen quality and intelligence
Back in the 2000s, there was some interest in semen quality and intelligence: Arden, R., Gottfredson, L. S., Miller, G., & Pierce, A. (2009). Intelligence and semen quality are positively…
Explore psychological correlations at taketest.xyz
Have just finished a neat update to the site. On the correlations page you can now see the matrix of cross-test sample sizes: You can click any of the green…
Race differences in reaction time: data from NHANES 3
Whenever race differences in cognitive ability broadly speaking are brought up, they encounter huge skeptical and emotional opposition. This is understandable, though not grounded in science. One common claim is…
Migrant performance on PISA worldwide
There are some data memes floating around like this one: In German, it shows the performance of Turks on PISA math by year and destination country. It can be seen…
Top universities and national intelligence
We all know that universities differ in quality. But what exactly do we mean by that? How do we determine which are the top universities? There are a number of…
Is the EU’s single market and Eurozone even good for economic growth?
Since I can remember I've been told that prominent economists say that the European Single Market (tariff free zone) is good for business and the economy at large. And the…
Occupations, fertility, men, and politics
In response to my prior post on the fertility rates of American women by occupation, some asked for the results for men, and others pointed out that there seems to…
Want children? Marry a telemarketer or maid, avoid librarians and web developers
In a world of declining fertility, we have to ask ourselves why it is so declining. I've spent many posts on that question. We could also ask instead, how do…
Tracking ancestry and social inequality using American surnames
Our big project was finally published: Van Pelt, D., & Kirkegaard, E. O. (2026). Big Data, Deep Roots: Correlating Surname Genetic Ancestry and Socioeconomic Status across Millions of Americans. Comparative…
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…
- 1
- 2
- 3
- 4
- …
- 6
- Go to the next page