Getting dumber: the reverse Flynn effect and the politics of denial

The greatest of follies is to imagine that we can remain wise while ceasing to learn. -Francis Bacon

Once upon a time, human beings appeared to be getting cleverer. Year after year, decade after decade, IQ scores crept upward, a steady, reassuring rise that came to be known as the Flynn Effect, after the New Zealand philosopher-psychologist James R. Flynn, who first documented it in the 1980s.

Flynn found that average IQ scores rose about three IQ points every ten years or so. If you were born in 1980, you would have outscored your parents on the same test. By the 2000s, great-grandparents would have struggled to keep up with the average teenager. It was as if each generation had been drinking from a secret well of enlightenment.

As a species, we were evolving, not through genetic mutation, but through universal education, improved nutrition, and perhaps more affordable books and television. Intelligence was becoming an ever-increasing resource. And then, something happened. The Flynn Effect reversed; IQ scores began to fall. Was it all a mirage, or did the course of human intellectual development really change?

Measuring intelligence

Modern intelligence testing began in Paris in 1905, when the French education department commissioned Alfred Binet to devise a test to identify pupils who could benefit from remedial education.

Psychologists soon expanded Binet's ideas, and his test escaped the classroom and went forth to assess almost everyone: military recruits, factory workers, immigrants, and even the occasional genius. Intelligence had been given a number, simple, seductive, and impossible to resist.

Fast forward to the 1980s. James Flynn noticed that intelligence test numbers weren't static. People in many countries were steadily scoring higher than earlier generations. They were not just memorising more facts; people were reasoning differently. The modern mind, Flynn argued, had learned to think more abstractly. People had learned to deal with symbols, understand graphs, and reason using hypothetical situations.

Flynn's theory was flattering. The modern world, schools, offices, and communications have trained human beings to think like scientists. We weren't just getting smarter; we were becoming more rational. According to Flynn, we learned to classify, reason abstractly, and think hypothetically, skills our ancestors rarely needed.

It was a lovely story: the triumph of environment over heredity, of culture over biology. Intelligence wasn't fixed; human progress was potentially boundless.

To understand what Flynn discovered, we have to peek inside the test itself. IQ is always standardised. This means the average score in any generation is fixed at 100. When Flynn said IQs were rising, he meant that people were answering more questions correctly on the same test than earlier generations did. If you gave your grandmother the 2020 test, she might score 85. Give yourself her 1950 version, and you would probably score 115. To keep the average IQ score at 100, test designers had to make the questions steadily harder.

For decades, it seemed that people were becoming smarter, but around the turn of the millennium, the graphs began to bend the wrong way. People were getting fewer correct answers on the same tests than their parents did. The treadmill of intelligence had reversed. In Norway, Denmark, Finland, Britain, and Australia, places not generally known for intellectual collapse, average IQ scores stopped rising and began to fall.

The trend isn't huge, but it's consistent. Average Norwegian twenty-year-olds today score roughly five to seven points lower than their fathers did at the same age. In the United States, Northwestern University researchers found declines between 2006 and 2018 in three of four cognitive domains tested.