A new study revealed a declining trend in American IQ test scores in 13 years. Here is everything you need to know.
IQ test scores dropping among Americans
A new study published in the Journal of Intelligence reveals a drop in the recent 13-year period of American IQ test scores compared to most of the 20th century. The study is titled ‘Looking for Flynn effects in a recent online U.S. adult sample: Examining shifts within the SAPA Project’. The remarkable study found evidence of a reverse ‘Flynn effect’ in the sample containing 400,000 individuals between 2006 to 2018. The Flynn effect is an established finding of consistent increase in IQ scores through most of the 20th century. It is important to note that the Flynn effect is not evidence of a genetic increase in intelligence over time. Rather, it suggests that changes in the environment and culture are contributing to the observed increases in IQ scores.
The authors analyzed data from the Synthetic Aperture Personality Assessment (SAPA) Project. SAPA is an online test tapping into 27 personality traits. Ability scores among Americans dropped in verbal reasoning, letter and number series, and matrix reasoning. However, scores in spatial reasoning, especially 3D rotation saw a rise.
Despite the decline, Elizabeth M. Dworak, a senior author cautioned against interpreting it as “Americans are getting less intelligent.” “It doesn’t mean their mental ability is lower or higher; it’s just a difference in scores that are favoring older or newer samples. It could just be that they’re getting worse at taking tests or specifically worse at taking these kinds of tests,” stated Dowak. Dowak is an assistant professor of medical social sciences and research at Northwestern University Feinberg School of Medicine.
What is the reason behind the decline?
The study does not reveal the reason for the declining IQ scores in the period. Some explanations include a shift in educational emphases and practices, differences in the motivation of test takers, and a biased set of test takers. “There’s debate about what’s causing it, but not every domain is going down; one of them is going up. If all the scores were going in the same direction, you could make a nice little narrative about it, but that’s not the case. We need to do more to dig into it,” explained Dowak. However, further research will help in better explaining the trend in IQ scores. Dowak and her colleagues are currently examining a dataset with 40 years of information as a part of a follow-up study.