Declining IQ Scores Caused By Environmental Factors, Study Says

Technology, Bad Food And Nutrition Causing Drop In IQ, Don't Blame Genetics



External factors like changes in the education system or increased time spent on the internet may play a bigger role than genetics.


While IQ scores increased through most of the 20th century, they have been steadily falling over the past few decades. Furthermore, our genetics may not be the only culprit, according to researchers Bernt Bratsberg and Ole Rogeberg.

Their new study titled "Flynn effect and its reversal are both environmentally caused" was published in the journal Proceedings of the National Academy of Sciences on June 11.

The Flynn effect, named after academic James R. Flynn, refers to the trend in which IQ scores increased over time from one generation to the next. This effect was observed in numerous countries during the 20th century.

For the new study, the researchers analyzed the IQ scores of 730,000 Norwegian men who were born between 1962 and 1991. Their findings revealed a trend of increasing IQ scores for men who were born between 1962 and 1975. However, they noted a steady decline in scores among men born after 1975.

The researchers noted that studies conducted in Britain, France, the Netherlands, Denmark, Finland, and Estonia also found a similar trend in IQ scores. As for the cause behind the Flynn effect as well as its possible reversal, our genes may not be entirely to blame.

"The causes in IQ increases over time and now the decline is due to environmental factors," said Rogeburg, a senior research fellow from the Frisch Centre, Norway. "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."

The study focused on families with siblings in order to compare the IQ scores of brothers born in different years. If genetics played a significant role, the scores would have been similar. Instead, the scores seemed to vary between brothers from the same family.

Such trends found within the families were the ones found across the population, said Rogeberg. This did not imply that genes have no impact, but that environmental factors seem to have a greater influence. These may include changes in the education system, dietary patterns, increased exposure to screen devices, better standards of living, etc.

On the other hand, some believe that IQ tests cannot solely determine intelligence and that it may not account for different types of intelligence. Robin Morris, a professor of psychology at Kings College London, U.K., also said that they may not be accurate enough given the pace of technological development today.

"In my view, 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," Morris said.

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