Are Humans Dumber? Study Finds IQ Scores Have Been Dropping for Decades, and the Media Might Be to Blame

High school students during a testing session on June 17, 2015, in Paris. A Norwegian study published Monday found a seven-point dip in IQ test scores per generation among men born from 1962 to 1991. Martin Bureau/AFP/Getty Images

Critics of video gamers, Netflix fanatics and social media mavens, rejoice: There's mounting evidence that Western IQ scores are on the decline, and media exposure might be to blame.

A Norwegian study published Monday found a seven-point dip in IQ test scores per generation among men born from 1962 to 1991. The results suggest a reversal in the Flynn effect, an observed increase in IQ scores throughout the 20th century in developed countries.

Researchers Bernt Bratsberg and Ole Rogeberg took test results from Norwegian men entering the country's military draft born between 1962 and 1991. Boys born in the first observation period, 1962 to 1975, gained almost 0.3 IQ points per year, but those in the cohort born after 1975 saw a steady decline in scores.

The study attributed the decline to changes in quality of education, increased exposure to media and poor nutrition. Because they couldn't find consistent trends among families, Bratsberg and Rogeberg argued that environmental family factors—such as parental educational attainment and family size, increased immigration and dysgenic fertility—were not significant causes.

They aren't the first to suggest a global dip in intelligence. In 2009, James Flynn, for whom the Flynn effect is named, studied Piagetian test scores of British teenagers and found that the average 14-year-old's IQ dropped by two points over 28 years, while the average middle-class child's IQ dropped six points during the test period.

"It looks like there is something screwy among British teenagers," he told the Telegraph. "What we know is that the youth culture is more visually oriented around computer games than they are in terms of reading and holding conversations."

While brain-training games like Lumosity are advertised as scientifically-proven ways to improve cognitive performance, one study suggests users experience placebo effects: Consumers expect to boost their IQ, so while participants performed well on intelligence tests after just one hour of training, the results were likely self-induced, researchers claimed.

The good news? There's evidence IQ is most malleable at adolescence. In 2011, British professor Cathy Price tested a small group of teenagers twice, four years apart, and found their scores jumped or dropped up to 20 points between test periods. The brain's plasticity in youth could spell trouble or success for future educational attainment and employment, she said.

"[These results] are encouraging to those whose intellectual potential may improve, and a warning that early achievers may not maintain their potential," Price wrote.