Are traditional IQ tests still fit for purpose?
IQ scores are falling across the world, provoking headlines of ‘‘dumbing down’’. But what does it measure anyway, asks David Olusoga , of The Observer.
IQ tests have a troubled history. Although their inventor, the intellectually cautious Frenchman Alfred Binet, understood and acknowledged their limitations, many of those who went on to deploy and develop his ideas did not.
Within years of their emergence, IQ tests were being used by US eugenicists to weed out the ‘‘feebleminded’’, and by politicians keen to cloak their calls for greater racial segregation and changes to American immigration laws with a degree of scientific legitimacy.
From the start, Binet’s tests were also drawn into the debate over whether human intelligence is predominantly hereditary or better understood as a reflection of environmental factors such as education — one part of the sprawling nature v nurture debate.
Some of the problem with IQ tests stems from the inescapable reality that human intelligence is staggeringly complex and multifaceted. In one attempt to reflect this, modern researchers draw a distinction between crystallised intelligence, the fruits of learning and training, and fluid intelligence, the capacity of an individual to recognise patterns and problemsolve using logic.
Although modern IQ tests are much more sophisticated than those developed by Binet in the early 20th century, so many factors have been shown to apparently influence the results — everything from eating fish once a week to simply practising the types of question the tests are based on — that some reject the whole contention that IQ offers a meaningful, stable and reliable measure of intelligence.
Those of us outside these debates tend to be less sniffy about IQ tests, particularly when the dispatches from the frontline of intelligence research are flattering, as they were for much of the latter 20th century. The good news then was that, in the decades after the Second World War, improvements in measured intelligence were regularly recorded in various nations around the world. Each postwar decade saw an increase of about three points.
The trend is known as the Flynn effect, after Prof James R. Flynn, a leading New Zealand researcher. While the increases were warmly welcomed, the underlying reasons were never properly understood with multiple explanations being put forward. But in recent years, successive studies have delivered the sobering news the boom years are over. We have passed peak Flynn, and test scores are falling.
The most recent study, published last month, was carried out by Ole Rogeberg and Bernt Bratsberg, of the Ragnar Frisch Centre for Economic Research in Oslo. Their work makes use of a readymade data set, a huge sample of 730,000 18 to 19yearold Norwegian men who did compulsory national service between 1970 and 2009. Part of their training and assessment involved taking standardised IQ tests.
Comparing the scores of successive generations of Norwegian draftees, Rogeberg and Bratsberg discovered those born in 1991 scored about five points lower than those born in 1975, their fathers’ generation. The research even showed declines within families, with sons achieving lower scores than their fathers had managed earlier.
All this might be dismissed as a problem for the Norwegian army, were it not for studies in France, Denmark, Finland, the Netherlands and the UK that have all detected similar trends.
Some researchers suggest this is merely the flatlining of an uptick. For much of the 20th century, people in the West have been getting taller — the average height of men in the Netherlands is now about 184cm, making them 19cm taller than their 19thcentury ancestors. But noone expects this to continue indefinitely, until Dutch males are at risk of posing a threat to air traffic. Already, there are signs similar height increases among Americans, recorded over the course of the 20th century, are drawing to an end.
The reasons for the decline in IQ scores are unknown and disputed. But the Norwegian researchers were quick to state the probable causes were environmental rather than genetic, and, like most scientific papers, theirs concluded by calling for further research and careful consideration. To some sections of the British press and in the more rabid corners of social media, that sort of academic rigour was just not good enough. What they wanted was not intellectual caution but for science to legitimise the rehashing of old arguments and old political obsessions.
That the Oslo report coincides with a new series of Love Island in the UK has created the perfect tabloid storm. By skipping the complex and unhelpfully nuanced parts of the Norwegian report, it was possible, with a following wind and stiff drink, to take the research and blame a decline in IQ test results in the Norwegian army on childfocused teaching methods, calculators in maths exams and (for good measure) the internet and gaming. Had the findings come in 1978, the blame would have been apportioned to colour TV and the Sex Pistols.
But, as with so many of these stories, the most interesting questions that remain, after the political posturing is over, are about IQ tests themselves. As the Oslo academics acknowledge, what their research might indicate is not that Norwegians born in the 1990s are less intelligent than those born in the 1970s, but that a testing system designed more than a century ago may be approaching its sellby date.
What needs to be debated is whether IQ tests, as currently designed, are fit for purpose, and capable of measuring the changing nature of intelligence in the 21st century among generations brought up with digital technology and different learning habits.