Declining US IQ?

Shelby Kearns:

A recent study suggests that, for the first time in nearly 100 years, Americans’ average intelligence quotient (IQ) is declining. 

The professors who authored the study theorize that the quality of education could play a role in reversing the IQ gains enjoyed by previous generations.

The study, published in a spring 2023 edition of Intelligence, measures IQ test results among 18- to 60-year-olds to examine the phenomenon first observed by philosopher James Flynn

Professors from Northwestern University in Evanston, Ill., and the University of Oregon in Eugene explain the Flynn effect: starting in 1932, average IQ scores increased roughly three to five points per decade. In other words, “younger generations are expected to have higher IQ scores than the previous cohort.”

Data from the sample of U.S. adults, however, imply that there is a reverse Flynn effect. From 2006 to 2018, the age groups measured generally saw declines in the IQ test used by the study, the International Cognitive Ability Resource (ICAR).

Overall declines held true across age groups after controlling for educational attainment and gender, but the study shows that the loss in cognitive abilities is steeper for younger participants. “[T]he greatest differences in annual scores were observed for 18- to 22-year-olds,” the authors write.