Research claims we have been getting dumber since the 1970s

New research has suggested that people have been getting progressively dumber since the 1970s, with IQ scores falling steadily across the decades since.

The worrying trend has been revealed in a new study, which claims that average human intelligence reached its peak around 1975 and it has been on a downward trajectory ever since.

After World War II scientists observed a rapid rise in intelligence at a rate of about three IQ points per decade, which became known as the Flynn effect, named in honour of the work of New Zealand research James Flynn. But it seems those days have passed us by as the new findings suggest that IQ scores are getting lower and lower.

Environmental factors, such as a change in the way we teach math, science and language, and the question of whether traditional IQ tests are suited to capturing intelligence in the digital era, have been credited with causing the suspected decline in intellect.

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Researchers from the Ragnar Frisch Centre for Economic Research in Norway analysed 730,000 IQ test results and discovered that the Flynn effect reached its highest point for people born during the mid-1970s, and has significantly declined ever since.

The analysed tests were completed between 1970 and 2009 and researchers noticed a clear turning point for the Flynn effect occurring after 1975, with each subsequent generation losing seven IQ points. Those born in 1991 scored on average five points lower than those born in 1975, and three points lower than those born in 1962.

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Writing in the Proceedings of the National Academy of Sciences, the researchers said: “Recent years have seen a slowdown or reversal of this trend in several countries.

“Using administrative register data with information on family relationships and cognitive ability for three decades of Norwegian male birth cohorts, we show that the increase, turning point, and decline of the Flynn effect can be recovered from within-family variation in intelligence scores.

“This establishes that the large changes in average cohort intelligence reflect environmental factors and not changing composition of parents, which in turn rules out several prominent hypotheses for retrograde Flynn effects.”

Psychologist Stuart Ritchie, from the University of Edinburgh, told The Times: “This is the most convincing evidence yet of a reversal of the Flynn effect. If you assume their model is correct, the results are impressive, and pretty worrying.”

What do you think? Were the 1970s the peak of human intelligence?