Stupid? No. Unfamiliar? Yes. The meaning of low mean IQs in developing nations

Illiterate people’s thinking probably remains grounded in their everyday experience. When these people take a test that solely measures abstract thinking, they perform poorly. This does not make them stupid. Instead, it shows the disconnect between their natural mode of thought and the unfamiliar test content.

The most important graph in educational psychology

The most important graph in educational psychology is buried in an appendix of an article, but it explains so much about how individual differences have important consequences in adulthood. The graph comes from an article by Jonathan Wai and his colleagues (2009, p. 834) and is shown below. The graph is based on data from

The “fifty million Frenchmen can’t be wrong” replication fallacy

Last week’s post about the flimsy evidence regarding stereotype threat (and the massive amounts of money wasted chasing stereotype threat effects) was far more popular than I expected. The tweet where I publicized it was my most viewed tweet in over a year, and already it is one my most popular blog posts ever. So,

Analysis of introductory psychology textbooks: 2 years later

Exactly two years ago today, my colleagues and I published an article in Archives of Scientific Psychology in which we analyzed the discussion about intelligence in each book and screened it for inaccuracies and logical fallacies (Warne et al., 2018). We found that over three-quarters of introductory psychology textbooks had at least one factual error

Intelligence research: An example of Thomas Kuhn’s “normal science”

Psychology is a mess. And I don’t say that because of the consequences of the replication crisis. No, compared to biology and the physical sciences, psychology is a mess because it has no unifying theory. Biology has evolutionary theory as a powerful framework for understanding everything from ecology to genetics. Chemistry has atomic theory, which