This is according to a study from scientists at Northwestern University and the University of Oregon published in the journal Intelligence, which indicates that IQ levels, especially for those with less education in the 18 to 22 years age group, has lowered.
The researchers looked at the test results of online IQ tests taken by 394,378 adults. These tests were taken from 2006 to 2018 to see whether the researchers could find evidence of what is known as the Flynn effect. (Related: Education Department report shows school shutdowns caused HISTORIC learning losses for students nationwide.)
The Flynn effect is a theory that suggests the IQ of a population generally appears to increase each generation. As the study authors themselves noted, IQ scores have "substantially increased since 1932 and through the 20th century." Per decade, average IQ points would increase by three to five points.
The researchers noted that there have been very few, if any, studies focusing on average IQ in the United States when compared to studies in European countries.
Instead of proving the validity of the Flynn effect, the researchers found the exact opposite of what they were looking for. Overall, the results suggest that IQ points from 2006 to 2018 have declined.
Declines were seen widely across the board irrespective of either age or gender, but the steepest decline in IQ was found among people with lower levels of completed education and participants between the ages of 18 and 22.
The study authors did note that people with higher levels of education, such as four-year degree holders, had less of a decline.
Of the five test categories in the IQ tests the researchers studied, they only saw improvements in one category: 3d spatial reasoning. Scores for the 3d spatial reasoning portion of the tests increased from 2011 to 2018. Other test categories – verbal reasoning, visual problem solving, inductive reasoning and numerical reasoning – all dropped.
While the researchers didn't explicitly make any conclusions as to why the IQ of Americans has dropped over the years, they did speculate that it might have to do with changes in education in the United States.
"It could be the case that our results indicate a change of quality or content of education and test-taking skills within this large United States sample," the study authors wrote in the conclusion. "As scores were lower for more recent participants across all levels of education, this might suggest that either the caliber of education has decreased across this study's sample and/or that there has been a shift in the perceived value of certain cognitive skills."
Learn more about the latest research in the field of science at Research.news.
Watch this clip from "War Room: Pandemic" on Real America's Voice as host Steve Bannon and his guest, Liz Yore, discuss how IQ dropped dramatically during the Wuhan coronavirus (COVID-19) pandemic.