Why do intelligent people reproduce less?

Are we getting more and more stupid?

Those who achieve an intelligence quotient (IQ) of 100 today are only considered to be mediocre. At the beginning of the 20th century, however, a similar performance would have been enough for about 130 points - which corresponded to a gifted person.

The reasons for this shift: For a long time, the number of points achieved in such tests only knew the upward direction. Since IQ tests have existed, people in Europe have become smarter and smarter.

The phenomenon is known as the Flynn effect, after the American political scientist James Flynn, who discovered it in the 1980s. For a long time the increase in performance averaged 0.3 IQ points per year. That doesn't sound like a lot, but in just 100 years it makes up 30 points - the difference between average intelligence and giftedness.

Experts attribute the Flynn Effect to improvements in diet and medical care. And on expanding the education system. The irritating thing: In recent times, the performance curves have been pointing down again.

Be it in Norway, Switzerland, Germany, the Netherlands, France or Austria: The average IQ of the population is falling again. Experts speak consequently of the anti-Flynn effect. How could it possibly come this far?

Well-educated people usually have only a few children, but less intelligent people often have very many, argue right-wing populists such as the controversial best-selling author Thilo Sarrazin. Since intelligence is hereditary to a certain extent, the gene pool gradually loses quality - and the average IQ falls.

Researchers refer to the migration figures in recent years: Uneducated immigrants (with many children) would level the IQ in Europe downwards. It should be examined whether a high level of immigration from countries with a less well-developed education system has a negative impact on the IQ results in the receiving country.

Test before military service

Economists working with Ole Rogeberg from the Frisch Center in Oslo approached the question indirectly: up to the 1991 age group, young Norwegians had to take an IQ test before doing military service.

The researchers were therefore able to analyze the test results of 30 consecutive cohorts since the 1960s, from a total of more than 700,000 Norwegians without a migration background. They also compared the achievements of siblings.

They found that the anti-Flynn effect was determined by the performance gap within families: towards the end of the period under review, the younger brothers performed significantly worse on average than their older siblings a few years earlier.

"This suggests that it was not changes in the gene pool, but environmental influences that influenced intelligence," says Ole Rogeberg. Otherwise one would not have found such clear differences in performance between close relatives. "Our research puts an end to the notion that the anti-Flynn effect came about because less smart people have more children than smart people," says Rogeberg.

In addition, the results speak against the fact that immigration caused a decline in intelligence in Norway. "If migration were the reason," says Rogeberg, "we would not have noticed the trend described widespread in Norwegian families."

No influence from migration

Special case Norway? The psychologist Jakob Pietschnig from the University of Vienna put the IQ test results from 50 years and 21 countries in relation to the immigration figures. He also found no influence due to migration.

What if more migration flows to Europe? "Supplementary studies have shown that IQ differences between different population groups in a country, as soon as they have comparable educational opportunities, usually even out within a generation," says Pietschnig.

A study by Dutch researchers on different groups of immigrants (from Indonesia, Turkey, Suriname, Morocco and other countries) found in 2004 that their average intelligence level quickly matched that of the locals, regardless of whether they were stronger or weaker on previous IQ tests when these cut off.

Perhaps the reason for the anti-Flynn effect lies elsewhere? In the past, important dates in world history were known by heart. Today is googled. Some experts believe that GPS systems make you stupid: people can memorize huge networks of paths. According to the psychologist Julia Frankenstein from the University of Darmstadt, however, this ability withers away if you use navigation systems for orientation.

"Digitization is changing the way we think," says Jakob Pietschnig. Whether the intelligence is weakened or ultimately even promoted is open. In video games, where you have to find your way in virtual worlds, spatial imagination is trained.

Improving in parade discipline

Pietschnig suspects another reason for the declining performance in IQ tests: such tests measure performance in areas as diverse as a feeling for language, abstract thinking or spatial imagination - and the results are ultimately used to calculate general intelligence. The Flynn effect was based heavily on improvements in individual areas.

Most people only got better in their favorite discipline. Since industrialization, the world of work has demanded ever greater specializations from people, according to the researcher. And many school reforms in recent times have also worked in this direction, says Pietschnig.

"Even young people today should learn to recognize and develop their strengths." The ideal of comprehensive education that promotes all aspects of intelligence equally is receding into the background.

But why should the IQ suddenly drop as a result? "It's a bit like a decathlon," says the Viennese psychologist. "If you train intensively to run, your performance in the relevant disciplines increases. You may neglect discus throwing, on the other hand. You will then become a little weaker. But that is hardly noticeable and your overall score increases."

Attention span decreases

At a certain point, however, the improvements in the parade discipline are only tiny. Then the deficits in other areas would become noticeable - until the total number of points achieved in the competition finally drops again, says Pietschnig.

"The attention span is decreasing," says neuropsychologist Lutz Jäncke from the University of Zurich. That doesn't surprise him. "A lot of young people in particular are chatting on Whatsapp, watching Youtube and listening to music at the same time." That promotes difficulty concentrating. Jäncke fears that this problem will have an increasingly negative impact on IQ tests in the future. Then maybe humanity will soon be dumber than it was 100 years ago. (Till Hein, November 10, 2019)