In my last column, I reviewed the findings of Butovskaya et al. (2015) on testosterone and polygyny in two East African peoples: - Testosterone levels were higher in the polygynous Datoga than in the monogamous Hadza. This difference is innate. - Datoga men were more aggressive than Hadza men on all measures used (physical aggression,... Read More

Humans differ in paternal investment—the degree to which fathers help mothers care for their offspring. They differ in this way between individuals, between populations, and between stages of cultural evolution. During the earliest stage, when all humans were hunter-gatherers, men invested more in their offspring with increasing distance from the equator. Longer, colder winters made... Read More

In a mixed group, women become quieter, less assertive, and more compliant. This deference is shown only to men and not to other women in the group. A related phenomenon is the sex gap in self-esteem: women tend to feel less self-esteem in all social settings. The gap begins at puberty and is greatest in... Read More

There has been much talk here about Chanda Chisala's article "The IQ gap is no longer a black and white issue." Much of the article focuses on the Igbo (known also as Ibo), a people who live in the Niger Delta and "are well known to be high academic achievers within Nigeria." In the United... Read More