It's not your imagination: The world is getting dumber. Scientists have discovered that IQ scores have been dropping worldwide, reversing a century of gains. They say environmental factors — not stupid people reproducing like rabbits — are to blame.
Norwegian scientists looked at the IQ scores of Norwegian men born between 1962 and 1991 and found that scores rose nearly 3 percentage points each decade for those born between 1962 to 1975. But they've steadily declined in children born after 1975.
Studies in Denmark, Britain, France, the Netherlands, Finland and Estonia have shown a similar decline in IQ scores, said Ole Rogeberg, a senior research fellow at the Ragnar Frisch Center for Economic Research in Norway and co-author of the new study.
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Why are IQ scores falling?
For decades, scientists have studied intelligence with the assumption that it's genetic. But the researchers behind the new study don't believe genetics are responsible for the score decline; different IQ scores were found in siblings born in different years. "It's not that dumb people are having more kids than smart people, to put it crudely. It's something to do with the environment, because we're seeing the same differences within families," said Rogeberg.
Those environmental factors could include the education system, media, nutrition, a decline in reading and increased time spent online, Rogeberg said, adding that more research is needed.
IQ scores rose steadily through throughout the 20th century, because of improved access to and methods of education. A reversal in that trend could be cause for alarm among educators and an overhaul in the scientific study of intelligence.
Are the IQ scores accurate?
But some researchers suspect that the IQ test itself may be the problem — it might be outmoded, unable to accurately measure intelligence in the digital age.
"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," said Robin Morris, a professor of psychology at Kings College in London.