Flynn effect: Are we getting more stupid?

Updated: Jul 25

The Flynn effect – named after Professor James Flynn of the University of Otago in New Zealand – refers to a phenomenon of rising IQ scores of abstract and visuo-spatial skills over time.

Flynn (1987) analysed the trend of rising IQ in 14 countries between 1932 and 1978, providing evidence for rising IQ scores of abstract and visuo-spatial skills: a 13.8-point increase in IQ scores. It means a 0.3-point increase per year, or approximately 3 points per decade.

So, in the last century, each generation performed significantly better on tests of intelligence, suggesting that we (humans) were getting cleverer.

Reversed Flynn Effect

However, at the end of the 20th century, the IQ gains faltered. Flynn & Shayer (2018) reported important national differences:

  • Losses in Nordic nations after 1995 average at 6.85 IQ points when projected over thirty years.

Piagetian trends provide information conventional tests do not: that the largest losses may be at the top of the curve. On Piagetian tests:

  • Britain shows decimation among high scorers on three tests and overall losses on one.

  • The US sustained its gain (0.3 points per year) through 2014.

  • The Netherlands shows no change in preschoolers, mild losses at high school, and possible gains by adults.

  • Dutch trends show that IQ gains vary by age.

  • Australia and France offer weak evidence of losses at school and by adults respectively.

  • German speakers show verbal gains and spatial losses among adults.

  • South Korea, a latecomer to industrialization, is gaining at twice the US rate.

When a later cohort is compared to an earlier cohort, IQ trends vary dramatically by age. Piagetian trends indicate that a decrease in top scores may be accompanied by gains in cognitive ability below the median. Piagetian tests may be more sensitive to detecting this phenomenon (Flynn & Shayer 2018).

In a very large sample of Norwegians, since the late 1970s there’s been a dramatic fall in mean IQ scores (Bratsberg & Rogeberg 2018).

Using a measure of fluid intelligence, Platt et al. (2019) compared scores normed in 1989 and 2003 among 10,073 American adolescents. Overall, the Flynn Effect was not significant; however, effects varied substantially by age and ability level:

  • IQs increased 2.3 points at age 13, but decreased 1.6 points at age 18.

  • IQs decreased 4.9 points for those with IQ<70, but increased 3.5 points for those with IQ>130.

Using nine years of data from the National Database for Autism Research, Billeiter et al. (2021) examined whether general intelligence changed significantly from 1998 to 2006. Their analyses demonstrated that a downward trend is 0.27. The mean IQ is 92.74 for years 1-3; 91.54 for years 4-6, and 87.34 for years 7-9 – indicating a reverse Flynn effect of 5.4 points per decade. (Though the standard IQ tests are not designed to measure autistic intelligence.)

What has happened to us? Are we getting more stupid?

The decline started with people born in the late 1970s and has continued ever since. What happened to these generations that made such a difference?

Several hypotheses of IQ decline have been put forward, such as, for example: changes in educational exposure or quality, changing media exposure, worsening nutrition or health, over-reliance on computer-acquired information and others.

In their paper (entitled ‘Flynn effect and its reversal are both environmentally caused’), Bratsberg & Rogeberg (2021) suggest that changes in lifestyle could be what's behind the lower IQs, perhaps due to the way children are educated, the way they're brought up, and the things they spend time doing more and less (the types of play they engage in, whether they read books, and so on).

Reversed Flynn effect in education

In the past, school achievements in most developed countries were on the rise and so were intelligence scores (Flynn, 1984). Now students in schools and universities show constantly deteriorating basic academic skills and competencies. Dramatic decreases in basic literacy levels among college and university students in numerous countries have been reported (e.g., Torgesen et al. 2017). As a result, some professions struggle to get appropriately skilled workers. One of the most burning issues in this line of thought is the deteriorating quality of teachers (Zysberg 2019).

A recent OECD* report (2015) suggests that 2-7% of the school graduates in the developed countries are practically illiterate (OECD 2015).

An intentional sample of 9 OECD countries (2019) was taken from the general pool of included countries/ regions. Singapore, Japan and South Korea represented developed countries in the east; the USA, the UK and Germany represented modern western countries and Poland, Russia and Greece represented more traditional developed countries. The results reveal that for the vast majority of sample countries (with the exemption of Russia, which shows a marked improvement in its indicators) either declined or stayed more or less as they were.

Take the UK, for example: The OECD report in 2016 placed the UK 22nd out of 23 developed nations for numeracy. A Loughborough University research project showed a grade B in Maths from the 2010s was equivalent to an E in the 1960s.

It is not very cheerful, is it?

Is there any hope to reverse the reversed Flynn effect in a few generations or is it the beginning of the end of our civilisation as we know it?


* The Organisation for Economic Co-operation and Development (OECD) is an international organisation that works to build better policies for better lives. The OECD is a group of 38 member countries that discuss and develop economic and social policy.

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