Researchers find IQ scores dropping since the 1970s

Credit: CC0 Public Domain

A pair of researchers with the Ragnar Frisch Centre for Economic Research in Norway has found that IQ test scores have been slowly dropping over the past several decades. In their paper published in Proceedings of the National Academy of Sciences, Bernt Bratsberg and Ole Rogeberg describe their study and the results they found. They also offer some possible explanations for their findings.

Prior studies have shown that people grew smarter over the first part of last century, as measured by the intelligence quotient—a trend that was dubbed the Flynn effect. Various theories have been proposed to explain this apparent brightening of the human mind, such as better nutrition, health care, education, etc, all factors that might help people grow into smarter adults than they would have otherwise. But, now, according to the researchers in Norway, that trend has ended. Instead of getting smarter, humans have started getting dumber.

The study by the team consisted of analyzing IQ test results from young men entering Norway's national service (compulsory military duty) during the years 1970 to 2009. In all, 730,000 test results were accounted for. In studying the data, the researchers found that scores declined by an average of seven points per generation, a clear reversal of results going back approximately 70 years.

But it was not all bad news. The researchers also found some differences between family groups, suggesting that some of the decline might be due to environmental factors. But they also suggest that lifestyle changes could account for some of the decline, as well, such as changes in the education system and children reading less and playing video games more. Sadly, other researchers have found similar results. A British team recently found IQ score results falling by 2.5 to 4.3 points every decade since approximately the end of the second world war. And this past December, another group from the U.S. found that children who grew up eating a lot of fish tended to have higher IQs—and they slept better, too, which is another factor involved in adult intelligence levels. Notably, children in many countries in the modern era eat very little fish.

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More information: Bernt Bratsberg et al. Flynn effect and its reversal are both environmentally caused, Proceedings of the National Academy of Sciences (2018). DOI: 10.1073/pnas.1718793115

Population intelligence quotients increased throughout the 20th century—a phenomenon known as the Flynn effect—although recent years have seen a slowdown or reversal of this trend in several countries. To distinguish between the large set of proposed explanations, we categorize hypothesized causal factors by whether they accommodate the existence of within-family Flynn effects. Using administrative register data and cognitive ability scores from military conscription data covering three decades of Norwegian birth cohorts (1962–1991), we show that the observed Flynn effect, its turning point, and subsequent decline can all be fully recovered from within-family variation. The analysis controls for all factors shared by siblings and finds no evidence for prominent causal hypotheses of the decline implicating genes and environmental factors that vary between, but not within, families.

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Citation: Researchers find IQ scores dropping since the 1970s (2018, June 12) retrieved 23 October 2019 from
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Jun 12, 2018
Running back to the dark ages.

This is the real meaning of post-truth.

The Flynn effect does not hold to the current situation: more obesity, more suicide, less reading, more racism, etc. It always sounded to me as he was lying and wanted to gain political power by alluring to people's pride.

Jun 12, 2018
If you watch 'the century of the self' and 'the American ruling class', you can see where western oligarchy became scared enough of the 'flower power' of the late 60's...that they banded together (bilderburgs, etc), and embarked on a rough plan...and that was to reign in any 'commoner' attempt to usurp their quiet and clandestine control of overall human society and culture.

Within those two documentary issuances (4 hrs and 1.5 hrs) you will see the full explanation of names, dates, places of a more hidden but real oligarchical group.

In the the 'American' you will have hard questions that are answered directly on this subject. From actual ruling class members, all the way up to James Baker.

This is an oligarchical factional war, and one group is working to lower lower intelligence in the proletariat, to hold the line of willful/enforced human ignorance in a worker class. Seriously.

Then the unfolding starts to get strange. Really really...out there. But all too real.

Jun 12, 2018

If anyone has seen the first few minutes of Idiocracy, then you know the answer as to why.

Jun 12, 2018
Given that black and brown-skinned people score lower than whites, for whatever reason, not necessarily due to race, and given that the birth rate among whites is lower, it's possible there's just more test subjects among races that score lower, and nothing fundamentally has changed at all.

I don't think you can ignore the difference in IQ scores from sub-Saharan Africa and Chinese, let's say, even if you believe the supposed DNA based explanation is flat out racist. That score differential does exist, and the birth rates are inversely correlated between the lowest scoring regions and the highest.

Jun 12, 2018
Anyone who has reared animals (pets) knows that an animal becomes as smart as it needs to be. Humans are no different. Before leading the pack an animal must first be able to keep up with it. The period from 1900 to ~1970 saw tremendous increases in technology and social structure. Anyone not keeping up was dropped from the herd. But, since ~1970 the level of knowledge needed to get along and prosper has dropped, and so has the average IQ score. Research tells us that IQ is variable and responds to pressures of all natures. IQ rises when stresses require it to rise. In a world of less challenge there is no need for higher IQ.

Jun 12, 2018
Among other things, there can be another explanation for the "Flynn effect". People through the century have been taking tests, or "tests", based on a prior schema. The designers of the first tests, evidently, were using themselves as a base and so they developed tests guaranteed to make them appear geniuses. They could answer the third president of the U.S., so they said that anyone who knew that had a high IQ. Most in the early part of the 20th Century couldn't answer the questions on the early IQ tests, but, later on, they could.
The decay in intelligence every generation now, is definite.
A point, though. The article states that "children in many countries in the modern era eat very little fish". Then why are there so many warnings about the oceans becoming "fished out"? And, if only a specific group is eating most of the fish, why don't they display such so called intelligence?

Jun 12, 2018
I opinionate these results are caused by the inherent prejudices of those who write the tests. As the test writers were confronted on their rigging the tests, a series of reforms over the last couple of generations has improved the accuracy and honesty of the test outcomes. Still a system needing further reform.

In other words. It is not that people are getting more stupid but that the tests are now evaluating everybody with a higher degree of reliability.

For a century now, the students of the correct race and economic circumstances were awarded higher scores than their inferiors. Thus receiving the extra-privileges of their notable status.

And, who is to say that there were not beneficial results from a caste system? Well, except for the grumblers from low-caste discriminated against.

Yes, our parents lied to us. The results lied to them by our teachers. Who had been lied to by the test makers. Expressing the lies of those paying for the testing.

Jun 12, 2018
more racism

Or is it low-IQ 3rd world immigrants bringing down the average?

Jun 12, 2018
To track down whether decline is caused by environment or genetic selection, one should test IQ of parents as well as their children. If the cause is by environment, then IQ of a child is not average of his/her parents but lower.

Jun 12, 2018
Bertie Wooster was right! It's all about the fish. That's why Jeeves was so smart. Eat more fish.

Jun 12, 2018
One says we are as smart as we need to be.....well....maybe. Welfare states dole out as they are budgeted to folks that usually receive bare subsistance & little else. This cements an underperforming underclass of whatever ethnic or many ethnics sharing one condition, poverty re-inforced by lack of education and lately even the opportunity for education. Paranoia of underclass' possession of computer skills or chemistry/engineering skills for fear that such may rebel and have a fighting chance....were like slave revolt fears in antibellum 'south's ruling nobility'...e.g John Brown.

So we create a large subclass of welfare and do not require them to work. Such do not need to be noted above. AND, such breeds like rabbits imitating economic Malthus' dictum. The resultant of masses of ambitionless sub-pars of every ethnic breeding teeming masses of 'mentally challenged' is inexorable. Maybe welfare will doom us all to revert to little more than apes. Bananas anyone?

Jun 12, 2018
One change in society not noted in the research was that modern subsistance payments for social welfare as a function of percieved state responsibility to those in need essentially was born out of the ashes of the Holocausts >20,000,000(Europe), Holodomyr5,000,000(Ukraine), 'DP camps >3,000,000('Allied' post WWII forced relocation from Soviet occupied Oder-Niesse Silesia[Germany] and Ost-Prussien(Germany1945-), and 40,000,000(Soviets under Stalin relocation and purges), and 2,000,000 Spain & Basque lands in Spanish War1935-38),,more. Born of emergency, these programs took on a life of their own. The rootless progeny of such were easy prey to ravening drug pushers. These children, besides being less intelligent, have less judgement...look at the horrible politicians that prime examples, inbred hicks in SouthEast US, choose to support for Senate and administration. These are the unaccounted changes that mainly occured since 1936. Do the math: 80 years to species idiocy!

Jun 12, 2018
How can we be certain that the tests are consistent enough to reflect a real "intelligence" quotient over two generations?

Jun 12, 2018
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Jun 12, 2018
That's diversity for ya.

Jun 12, 2018
Liberalism and teacher's union are murdering our education system. Every one is a sick shame on America.

Jun 12, 2018
It seems fairly obvious that the combination of opportunity at the beginning of the the 20th century, as well as the the adversity both of the past and during the world wars provoked a Darwinian increase in measured IQs. As societies have become more socialist, and survival has become less focused on the individual, it is only reasonable that it would decline. What I find perplexing, and disturbing, is that the same problems come up again and again in sociology, but are never directly talked about. Do we want the happiest population or the most capable. Do we want the happiest population or the largest. What do we want the future to be for our grandchildren, and does, or should, that even really matter to us?

Jun 13, 2018
Researchers find IQ scores dropping since the 1970s

well that certainly explains the juxtaposition of global warming and neo-marxism.

Jun 13, 2018
Anyone who has reared animals (pets) knows that an animal becomes as smart as it needs to be..
Just curious; have any of them become smart enough to shout "NO!" where and when they need to become that smart?

Jun 13, 2018
Shootist---you make a lot of sense. From the 1970's we have also see a gradual increase in believing in global warming. The dumber the population, the more people will believe in it.

Jun 13, 2018
We have been spreading a segment of humanity that is severely inbred. Happening more in Europe than America.

Jun 13, 2018
On a more serious note than my last comment....I doubt this has a lot to do with it, but I wonder if there is any correlation to rising indoor CO2 levels indoors. Homes/school/offices have become more energy efficient leading to tighter barriers that some let as much fresh outdoor in. Cognitive function decreases as CO2 levels increase. This starts happening around 800 ppm. Indoor areas are routinely 1000+ ppm and can be as high as 3000 ppm.

Jun 13, 2018
Good grief in the US you just have to look at the US educational system to find the answer. While the amount of money/child has skyrocketed achievement has plummeted. Younger cashiers do not even know how to make change without a digital readout. Reading and math scores in major cities are pitiful. To get an education for your child you either have to move out of the cities or pay for a private school.

The progressive movement and courts have tailored the curriculum to serve the lowest common denominator.

Jun 13, 2018
Uhh, and here I hadn't known that teachers got any say in what their students are taught. I thought it was generations of conservative dominated school boards making the decisions about curriculum and book purchases.

Oh well, the bigots have to whine about their fear of allowing the melanin-endowed to compete on an honest playing field.

The altright fairytails cowardly embrace of fake patriotism and false superstitions to excuse their mistreatment of ambitious competitors. Their crocodile tears of rage that basically, they just don't measure up to the rising standards of an evolving technological society.

The machines don't give a trump about gender or class or ethnicity or ideology. I suspect the whiners in the comments above? The most "scientific" act they perform all day is to push the buttons on their game controller!

Jun 13, 2018
Lower IQ........could be!


Jun 13, 2018
"Uhh, and here I hadn't known that teachers got any say in what their students are taught. I thought it was generations of conservative dominated school boards making the decisions about curriculum and book purchases."

In the major cities the school boards are 90% Democrats just like the teachers. No wonder the system is failing.

Jun 13, 2018
Before you all jump to conclusions, the Norwegian conscripts aren't a representative sample of population for several reasons.

First of all, while about 60,000 people a year get the call, only about 10,000 are actually selected for service - people give all sorts of excuses to avoid it, one of which is enrolling into an university.

It's technically mandatory, but not really. If you don't want to go, you can always get someone to write you a paper that say you don't have to. Hence, the smartest people skip military service.

Jun 13, 2018
Besides, since there's not enough funding to keep a large standing army, they basically ask "do you want to serve?" - and if you say no they put you at the back of the list, and you're unlikely to get selected.

And they test only those conscripts that make the short list for being selected, so again, you get mostly people who -want- to be in the army, and have nothing better to do, don't have major physical impediments like weak joints of exceedingly poor eyesight... etc. which biases the selection tremendously.

Jun 13, 2018
Oh, and if you do end up on the short list despite saying you don't want to, one major way people dodge the draft is by...

...intentionally failing the tests.


It's not surprising that the motivation for the average guy to enter service dropped considerably between 1970 - 1991: the cold war ended with the dissolution of the Soviet Union.

Jun 17, 2018
Coincidentally, average, inflation-adjusted worker wages have remained flat since the '70s...

Jun 18, 2018
Remember leaded gasoline? Spewing lead everywhere? Stopped that in 1980 or there abouts but c'mon. When large samples like this show an IQ deviation you have to think environmental causes. Lead is a neurotoxin.

Jun 18, 2018
Considering that IQ testing has changed a lot of the past half century, it could be very difficult to match IQ test results closer than say 5%. Oh, wait that would mean the study was meaningless.

Jun 26, 2018
I read more about the testing methods. Totally bogus. They compared older siblings with younger ones when they became the same age. But it is a very well known fact that earlier born siblings do better than the later born ones.

The main reasons are that the first born gets far more adult attention in those very early years. And being carefully watched they injure themselves much less. They also try to make younger siblings feel inferior because they are doing less advanced schoolwork because it is a lower grade. They also cause more brain damage during roughhousing. The young ones are knocked down easily and bang their heads on all sorts of things. These small incidents add up, as we now know. Really out of control older siblings use strangle holds, stick their finger between cranial plates, or shake the heads of their siblings. And there is more of this, if there is only one parent to keep them in check.

Jun 26, 2018
If there is a decline, it is due to bad advise during pregnancy: to avoid fish, to avoid the sun, to avoid salt (iodized salt has the much needed iodine), to avoid nuts, to eat more vegetables and less fruit, less grain less red meat...
Recent studies say we need double or more of the currently recommended choline. That 7 servings of fruit a day during pregnancy yields 7 more IQ points!

Statistically, countries that eat more fish have less murders. Likely because of Iodine which is not just important for IQ but is critical for a well developed conscience. Other seafood may do the same thing.

Vitamin D acts not just as a vitamin but as something that promotes cellular differentiation. Failed neural cellular differentiation is what Autism spectrum is all about. Telling pregnant women to avoid the sun unless they have sunblock is stupid. Sure, there are probably some genes involved, but I think Autism rates exploded for a reason...and it certainly was not vaccinations.

Jun 26, 2018
The use of hardwood flooring instead of the thick wall to wall carpeting of the past probably causes more head trauma. Maybe we should even have carpet on the walls 4 feet up to protect the little least in the play room.

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