It's official: We're not getting any smarter. Worse, media exposure might be to blame. Researchers analyzed 730,000 IQ scores of Norwegian men entering the country's military draft who were born between 1962 and 1991, per ScienceAlert. They found that IQ scores rose almost 0.3 points per year among men born between 1962 and 1975, then declined for men born after 1975. Overall there was a 7-point dip per generation, reports Newsweek. And the Norway study is no outlier: Other studies by European and Scandinavian researchers have noted a similar trend, notes CNN. The investigators believe the environment, rather than genetics, is responsible because they saw the same IQ drop within families, between brothers and sons. Parental education and family size did not seem to play a role in the decline.
For most of the 20th century, IQ scores had been increasing, presumably because of better access to education. The researchers suggest the trend could be due to lifestyle factors, including changes in nutrition, how children are educated, media exposure, and how kids spend their free time. It's also possible that IQ tests, which tend to emphasize formally taught critical thinking, simply haven't been adapted to capture changes in the ways people think. As one psychology professor told CNN: "We need to recognize that as time changes and people are exposed to different intellectual experiences, such as changes in the use of technology, for example, social media, the way intelligence is expressed also changes. Educational methods need to adapt to such changes." (Read more intelligence stories.)