IQ scores in some western nations appear to be falling after years of improvement, new research has suggested.
A peer-reviewed study published by scientific journal Intelligence reveals that notable progress in education made over previous decades could now be in reverse - but gives no explanation as to why.
The study, titled 'IQ decline and Piaget: Does the rot start at the top?' shows that IQ in some Nordic countries will have fallen as much as seven points by 2025, while the scores of Britain's highest-achieving children have also dropped according to numerous benchmarks.
The United States' educational improvement has also stagnated but avoided similar reversals in test scores.
This contrasts with other developing nations which have recorded significant gains in IQ and general intelligence. According to the study, South Korea is gaining at twice the rate as the United States.
The alarming findings were made by Otago University's professor emeritus James Flynn. His work gave name to the so-called 'Flynn effect', a phenomenon which recorded large rise in IQ scores across western societies during the 20th century. He claimed that children born during this period would be considered "geniuses" by their great-grandparents, owing to their vastly superior IQs.
His observations encouraged education professionals to claim the gains were down to improved standards and better teaching methods. Flynn's contribution also showed IQ was not immutable and could be improved over time so long as investment in education was maintained.
It seems Flynn may be changing his mind, however. The reversal in fortunes in some European countries has been traced back to the mid-nineties when the rate of improvement began to slow.
What Flynn highlights is that IQ scores can go forward as well as back, and says more must be done to halt the slide over the past ten years.
While scores may be declining overall, it is possible that improvements in some areas, such as reading or literacy, are offset by declines in numeracy and spatial skills – an event noticed in scores of German-speakers.
Age plays a part too as in the Netherlands, which has seen IQ reduction in school-going children, increases in adults and little notable change in pre-schoolers.
Bryan Roche, a senior lecturer at Maynooth University, told IBTimes UK that the findings are not entirely surprising and indicated that "a one size fits all" educational policy may be harming bright, high-achieving students.
"More resources are rightly being directed to help students at the bottom end of the educational attainment spectrum, but at the cost of students at the high end", he said. "As education becomes increasingly homogeneous, we would fully expect to see a decrease in the excellence of students at the top end."
As Roche points out however, IQ scores are only useful to predict academic success rather than being an end in itself.
"So long as we are happy with the educational attainment of our children, we can reassess whether IQ tests are doing a good job in indexing that ability," he said.