(CNN) — IQ scores have been steadily falling for the past few decades, and environmental factors are to blame, a new study says.

The research suggests that genes aren’t what’s driving the decline in IQ scores, according to the study, published Monday.

Norwegian researchers analyzed the IQ scores of Norwegian men born between 1962 and 1991 and found that scores increased by almost 3 percentage points each decade for those born between 1962 to 1975 — but then saw a steady decline among those born after 1975.

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Similar studies in Denmark, Britain, France, the Netherlands, Finland and Estonia have demonstrated a similar downward trend 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.

“The causes in IQ increases over time and now the decline is due to environmental factors,” said Rogeburg, who believes the change is not due to genetics.

“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,” he said.

These environmental factors could include changes in the education system and media environment, nutrition, reading less and being online more, Rogeberg said.

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The earlier rise in IQ scores follows the “Flynn effect,” a term for the long-term increase in intelligence levels that occurred during the 21st century, arguably the result of better access to education, according to Stuart Ritchie, a postdoctoral fellow in cognitive ageing at the University of Edinburgh whose research explores IQ scores and intelligence and who was not involved in the new study.

Researchers have long preferred to use genes to explain variations in intelligence over environmental factors. However, the new study turns this thinking on its head.

Intelligence is heritable, and for a long time, researchers assumed that people with high IQ scores would have kids who also scored above average. Moreover, it was thought that people with lower scores would have more kids than people with high IQ scores, which would contribute to a decline in IQ scores over time and a “dumbing down” of the general population, according to Rogeberg.

Anyone who has seen the film “Idiocracy” might already be familiar with these ideas. In the scientific community, the idea of unintelligent parents having more kids and dumbing-down the population is known as the dysgenic fertility theory, according to Ritchie.

The study looked at the IQ scores of brothers who were born in different years. Researchers found that, instead of being similar as suggested by a genetic explanation, IQ scores often differed significantly between the siblings.

“The main exciting finding isn’t that there was a decline in IQ,” Ritchie said. “The interesting thing about this paper is that they were able to show a difference in IQ scores within the same families.”

The study not only showed IQ variance between children the same parents, but because the authors had the IQ scores of various parents, it demonstrated that parents with higher IQs tended to have more kids, ruling out the dysgenic fertility theory as a driver of falling IQ scores and highlighting the role of environmental factors instead.

What specific environmental factors cause changes in intelligence remains relatively unexplored.

Access to education is currently the most conclusive factor explaining disparities in intelligence, according to Ritchie. In a separate study that has not been released, he and his colleagues looked at existing research in an effort to demonstrate that staying in school longer directly equates to higher IQ scores.

But more research is needed to better understand other environmental factors thought to be linked to intelligence. Robin Morris, a professor of psychology at Kings College in London who was not involved in Ritchie’s research, suggests that traditional measures of intelligence, such as the IQ test, might be outmoded in today’s fast-paced world of constant technological change.

“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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Comments (36)
  1. The biggest enemy of liberalism is critical thinking and high IQ.

  2. Mark Mullins says:

    You can thank decades of progressive indoctrination for the dumbing down of society.
    The left required a public that was poorly prepared to be competent, who’s judgment was so impaired that people would be incapable of making good decisions and who as a result, would be necessarily dependent on government for their every need.

    1. Jim Goad says:

      “Dumbing down,” etc. You misspelled “whose,” dude.

  3. This is what you get when you allow uneducated people swarm into a civilized country. It’s getting harder and harder to deal with the under 80 points rabble. I think the longer and longer you spend looking at your phone also reduces intelligence. I refuse to suffer fools.

  4. It’s the fluoride in the water. Dumbs humans down.

  5. zapman2016 says:

    Progressive education focusing on equality of results, and the concentration on teaching diversity and social justice thru social engineering in schools rather than science and engineering is the problem. Political correctness blinds these researchers from the simple answers. Concentrate on reading, writing and arithmetic and problem solving at young ages and IQ’s will rise again.

  6. The culprit is liberalism. It has infected the school system, yes, but everything else, too.

  7. Kelley Eidem says:

    The two biggest causes are fluoridated water, a known pineal gland ossifier, and less well known, the harmful ions generated from our electrical world. Those ions lower cell voltage by interfering with our ATP. The ions make the ATP inactive.

    Your brain is made up of cell batteries. Picture a flashlight with weak batteries. Our brains respond the same way. When the fifth generation (5G is turned on by the end of this year in mostly major cities we can fully expect to see widespread amnesia, confusion, ect., in those cities.

    It’s quite possible that Nancy Pelosi’s recent falls into the rabbit hole with her garbled words and memory lapses are due to Washington, D.C.’s beta testing of 5G in a very small way.

    This winter it’ll be much worse in 30+ cities.

    By the way have you ever seen the rash of local TV news reporters of all ages suddenly turn into frightened mush mouths? They are being beamed with lots of electronics and harmful during those short shoots. Why are there so many examples of that happening in recent years? Sometimes their brains just can’t handle the ions.

    5G will increase the exposure 1,000 fold for many people. I predict lots of car accidents in the minutes and hours after 5G is turned on in a given area, as well as people folks wandering around lost.

    People who are already compromised are likely to collapse right in front of you – or you might collapse in front of them.

  8. Environment has no effect on IQ. IQ is a genetically inherited trait. Average IQ scores are dropping because low-IQ people from the low-IQ third world populations are invading high-IQ white civilization.

    1. Kelley Eidem says:

      The Center for Neo-Marxist privilege awareness” is where you work?? I was about to skewer you for the thoroughly ignorant comment you made, but what would be the point? Engaging with anyone who would have any sort of association with a group like would be a waste of breath.

  9. Blame politically correct education or Common Core. The drop in IQ seems to correspond with “New Math” which was the last disastrous change in education prior to Common Core. What is wrong with the old 3 R’s?

  10. Ra Su says:

    Idiots: you allow low IQ illegal immigrants into USA and EU: you are diluting your gene pool to lower the average IQ.

    California state has approximately 25-30% illegal immigrants based on population: they have one the lowest average IQ in USA.

  11. cicorp says:

    TM, non-religious relaxation for 20 minutes morning and evening helps to increase IQ.

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