Revisiting Moore’s transracial adoption study

Transracial adoption studies are a powerful methodology for examining the relative contribution of genetics and environment to average differences in IQ across racial and ethnic groups. The best — and most famous — transracial adoption study was the Minnesota Transracial Adoption Study (MTAS) conducted by Sandra Scarr and her colleagues (Scarr & Weinberg, 1976; Weinberg

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.

Implications of average group differences for the design of intelligence tests

[NOTE: After publishing this post, I was informed (first by Avraham Eisenberg and later by Emil Kirkegaard) that some the following information was incorrect. For the sake of transparency, I am leaving the incorrect text posted but crossed out so that people can see my original error and understand that I no longer stand by

Notes on videos of Arthur Jensen defending his work

The most important name in intelligence research in the second half of the 20th century is educational psychologist Arthur Jensen (1923-2012). From the late 1960s until his death, Jensen was the world’s foremost intelligence researcher who singlehandedly made methodological and scientific breakthroughs that greatly advanced intelligence research. I never got to meet Arthur Jensen, but

Comparing the 1975 and 1996 APA statements on intelligence

One of the most highly cited articles in intelligence research is a 1996 report commissioned by the American Psychological Association’s Board of Scientific Affairs to provide an authoritative statement on the science of intelligence (Neisser et al., 1996). What many people do not know, though, is that this was not the first time APA’s Board

The $67.5 million wasted on stereotype threat research

One popular topic in psychology when discussing test performance is the idea of stereotype threat. First proposed by Claude Steele and Joshua Aronson in 1995, the stereotype threat is phenomenon where a person who belongs to a stereotyped demographic group performs in accordance with the stereotype after being reminded of it. Usually this is suggested