IQ levels have been gradually dropping since the 1970s, researchers from the Norwegian Ragnar Frisch Center for Economic Research have found. According to the researchers, the decline amounted to an average of 7 points per generation.
The research team led by Bernt Bratsberg and Ole Rogeberg analyzed IQ test results from a total of 730,000 draftees entering Norwegian service between 1970 and 2009. Their findings were published in the Proceedings of the National Academy of Sciences.
Previously, population intelligence quotients were known to have increased throughout most of the 20th century, a phenomenon commonly known as the Flynn effect named for New Zealand researcher James Robert Flynn, who discovered a rapid rise of IQ at a rate of about 3 points per decade. The brightening of the human mind has been attributed to several factors, such as better nutrition, healthcare, education and others.
Using data spanning three generations, the Norwegian researchers witnessed the Flynn effect, its turning point and subsequent decline. In the research, differences between family groups were also found, suggesting that at least some of the decline may be linked to environmental factors. A change of lifestyle was another possible explanation, with children reading less and playing video games more, as well as generally leaning more heavily on electronic devices. Changes in pedagogical methods, including teaching math and languages, were also identified as one of the possible reasons.
Across the globe, research teams have recently arrived at similar conclusions. A British team recently found IQ test results falling by 2.5 to 4.3 points every decade since the end of World War II.
Incidentally, Flynn himself claimed decreasing IQ levels to be part of a global trend in a 2017 interview with Swedish magazine "Forskning & Framsteg ("Research & Progress"). Flynn argued that school education has become increasingly less demanding in many countries, pointing out that students spend less time doing homework and reading "thick" books.