Average IQs are rising sharply from generation to generation, a phenomenon known as the "Flynn effect". Helen Joyce talks to James Flynn, the man who spotted the trend and has been working to explain it ...

From INTELLIGENT LIFE magazine, December 2007

James Flynn is not the sort of man to go quietly into retirement. A professor emeritus at the University of Otago in New Zealand, he still teaches and researches energetically at 73. He speaks on finance and tax for the left-of-centre Alliance Party. He has a book in preparation that will be his own last word on the relation between race and IQ. In autumn he was touring the world talking about "What is Intelligence", a book published in October, in which he sets out his explanation for a mysterious phenomenon that bears his name: the rise in IQ from generation to generation. Your IQ is likely to be higher than those of your parents, and your children's IQs is likely to be higher than yours.

"Our advantage over our ancestors is relatively uniform at all ages from the cradle to the grave," says Flynn. Nobody knows if the gains will persist, but "there is no doubt that they dominated the 20th century and that their existence and size were quite unexpected."

He is not afraid to offend. In July, when a journalist asked him about New Zealand census figures showing that less-educated women were bearing more children, he said the trend would exert downward pressure on average intelligence--just as average heights would fall if short people had more children than taller ones.

Flynn went on to speculate that if future scientific advances meant contraceptives could be put in the water, so that an antidote had to be taken before becoming pregnant, then every child would be a wanted child. Another academic described his ideas as "totally repugnant". New Zealand's children's commissioner said he was wandering into "dangerous territory". And Flynn? He said he was just too old to be worrying about offending anyone.

Which makes Flynn's ideas on intelligence, race and politics all the more striking for their liberalism. They had their genesis in his time at the University of Chicago half a century ago. In 1951, aged 17, he had travelled to the Midwest from his home town of Washington, DC, to study politics. Liberal ideas were in the air. Nine years earlier, some of the university's students had helped found the Congress of Racial Equality (CORE). Precociously clever, Flynn was awarded a BA after just one year, and went on to do a master's degree and then a doctorate.

In his first academic job, at the University of Eastern Kentucky, he became chairman of a chapter of CORE--and, as a result, found his job untenable. He moved north, to Lake Forest, a liberal-arts college back in Chicago, only to find that his socialist politics meant he didn't fit in there either.

So in 1963 he moved to New Zealand, taking his interest in liberal ideas with him. And in 1980 he wrote a book, "Race, IQ and Jensen", arguing that the reason American blacks' IQs lagged behind whites' was not a genetic inferiority, as claimed by some intelligence researchers including Jensen.

The gap was caused, Flynn thought, by the huge differences between the two groups' environments. Hence it could be closed. He discussed how, between the two world wars, blacks had narrowed the gap with whites on tests of mental ability that the American military used to screen recruits. His opponents had retorted that such tests merely registered school-taught knowledge, and that the gap would remain unchanged on any purer test of cognitive ability. To prove them wrong, Flynn needed to show that the military tests truly measured intelligence, and not just learning.

He started wading through the manuals for the two most widely used IQ tests to see how well they correlated with the ones the military used. Both the Stanford-Binet and the Wechsler tests were seen as good measures of native intelligence--so, if the same people tended to do well on both the IQ tests and the military ones, it would strengthen his case that there had been cognitive gains among black Americans.

Flynn found nothing relevant to his search, but he did spot something else, something very strange. IQ tests are updated periodically, to replace out-of-date questions ("typewriters" have given way to "computers"; da ted words like "delectable" have been jettisoned for modern jargon like "operational"). Whenever a test was updated, a single group of people would take both versions--the obsolete and the replacement--to check that each ranked people in a similar order.

As a matter of completeness, the groups' average scores on both versions would be published in the test manuals. And, pretty much always, the group would score higher on the old test. An IQ score shows how a candidate does in comparison with a large "standardisation sample" of people who took the test when it was first introduced. Flynn's discovery indicated that the people who were used to calibrate the earlier tests were consistently easier for test-takers to beat.

Now Flynn found himself with a much bolder hypothesis. Rather than just one disadvantaged group--black Americans--having made cognitive gains, could the average person be getting smarter? He looked up every study in which a single group had been given two tests, one calibrated before the other. By 1984 he had compiled results from more than 7,000 subjects, and about a dozen combinations of tests. And they pointed to a startling conclusion: that white Americans had been steadily gaining around three-tenths of an IQ point a year for almost half a century.

In 1984 he published a paper saying so. It didn't convince his critics. As far as they were concerned, all he had proved was that IQ tests were far more influenced by general improvements in schooling, and far less good at picking up native ability, than had previously been thought. IQ scores tend to remain fairly stable throughout a person's adult life, and studies of twins who had been separated at birth suggested that genetic inheritance had a greater influence than any environmental factor. That Americans--white Americans, no less--could genuinely be getting smarter, and astonishingly quickly, seemed inconceivable.

Flynn looked farther afield. "I had got some notoriety because of my '84 article," he explains. "So I felt I could write the military authorities in every country that gave mental tests, and all the testing agencies around the world that I knew of." Not all of them answered, but some did. And it was the reply he got on a dull November Saturday in 1984, from P.A. Vroon, a Dutch psychologist, that convinced Flynn he was on to something of profound significance.

It contained the results of a test called Raven's Progressive Matrices, administered to 18-year-old Dutch conscripts from 1952 to 1982. This is one of the purest tests of innate intelligence. The task is to spot logical patterns in groups of shapes and fill in the missing ones. There are no words, no school-taught skills and no general knowledge. In those three decades the average score had gone up by 20 points.

This was a huge gain. It meant that an 18-year-old with a middling score in 1982 did better than all but a tenth of the young men of the same age who had been tested three decades earlier. Just as tellingly, a random sample of the most recent group had been matched with their own fathers, and the sons had scored 18 points higher. Over the following year Flynn received data from another 13 countries, all of them showing IQ gains.

Today, no doubt remains: IQs have gone up throughout the 20th century. Almost 30 countries, some developed, some developing, have recorded gains. The whole world got smarter, and fast. But no one knew how, or why, or what this meant.

Paradoxes abounded. "Why are we not struck by the extraordinary subtlety of our children's conversation?" asks Flynn. "Why do we not have to make allowances for the limitations of our parents?" If you project IQ gains back to 1900, the average score would be less than 70 on current norms. "That's the cut-off for a diagnosis of mental retardation," says Flynn. If people in 1900 were as thick-skulled as that, how on earth did they manage to run a modern society?

Then there was the puzzle of how such massive gains could have occurred at all. Everything that was known about IQ suggested that by far the strongest influence on it was genetic: parents and their children tend to have similar IQs; the IQs of identical twins are closer than those of fraternal twins; and the effects on IQ of environmental factors such as better schooling tend to fade. "And yet, IQ gains are so great as to signal the existence of environmental factors of enormous potency." How could environment be so feeble and so potent at the same time?

For two decades, Flynn thought about these questions, in between teaching and carrying out research in politics and moral philosophy. Many others thought about them too. Some rejected the very notion of IQ. It had always been controversial anyway, from its early links with eugenics to its later use to justify the place of white men at the top of pretty much every hierarchy. If IQ was meaningless, then its increase would be meaningless too.

But Flynn was sure that rising IQs did matter. IQ is a pretty good predictor of academic success. Scores on IQ tests tend to match teachers' opinions of their students. People with low IQs are rarely found in jobs that require creativity or autonomy. Although plenty of other ingredients are needed for success in life, an above-average IQ seems to help.

Among those who took rising IQs seriously, some thought the cause might be better diet, or smaller families, or more liberal child-rearing. But none of these theories accounted for the size or extent of the phenomenon. And none could explain the odd pattern of the gains.

Most IQ tests contain a collection of subtests, each of which picks up on a different mental skill. And only some of the subtests showed an increase in scores. The average person had become much better at completing geometric patterns, at spotting abstract similarities and at re-ordering scrambled picture cards to tell a story. But people were no better at memorising lists of numbers, and their vocabulary and general knowledge had not expanded at all.

Why would better-fed children, or those with fewer siblings, or those who were more gently reared, grow into adults who had improved so much on some intellectual tasks, but not on others? The rise in IQs was a mass phenomenon, but by no means all children were better-fed.

Although the components of an IQ test measure different skills, someone who is good at one tends to be good at the others too. The same people who are good at spotting the missing piece of a pattern tend also to be good at arithmetic and to amass large vocabularies and stores of general knowledge. This common element, known as "g" for "general intelligence factor", is what IQ tests are meant to measure.

Some subtests are better single measures of the overall score than others. This is not surprising: you could imagine testing people on their ability to cook different dishes. Those who cooked one dish beautifully would be most likely to cook other ones well too, so there would be a "general cooking factor", but the truly excellent cooks would open up a bigger lead when making soufflé than when frying an egg.

Likewise, the most cognitively complex tasks are better predictors of g than more straightforward ones--but some of the most complex tasks showed very large gains, and others, none at all. If each of a pair of tests was supposed to be equally closely related to innate intelligence, how could people have got so much better at one of them but not the other?

It was this puzzling patchiness that started Flynn thinking along the right lines. He likes to use sporting analogies to illustrate his ideas. Suppose we had long been in the habit of subjecting children to a battery of tests for athleticism: long jump, high jump, sprint, and so on. As with mental abilities, so physical abilities would tend to be linked. Someone who can run fast can usually also run a long way, and jump high and far. So we could calculate a "physical g".

But over time priorities change. Satellite television becomes widespread; broadcasters bid up the rights to athletic events; advertisers find that some events attract viewers so they pay more for those events and sponsor the athletes who excel at them. The 100-metre sprint, say, becomes the most popular event in schools and sports clubs; training improves. Even though human bodies and human genes have not changed, and even though excellence in sprinting is still just as closely related as it ever was to excellence in other events, sprinting improves massively, whereas performance in other events barely changes.

By reverse-engineering the pattern of improvement in IQ tests, you can tell how mental priorities have changed over the century. It turns out that we, far more than our recent ancestors, take seriously the ability to find abstract similarities between objects (Question: how are dogs and rabbits alike? Answer: they are both mammals). And we are better at applying logic to finding abstract patterns, as in Raven's Progressive Matrices.

"At that point I began to get excited", says Flynn, "because I began to feel that I was bridging the gulf between our minds and the minds of our ancestors. We weren't more intelligent than they, but we had learnt to apply our intelligence to a new set of problems. We had detached logic from the concrete, we were willing to deal with the hypothetical, and we thought the world was a place to be classified and understood scientifically rather than to be manipulated."

Flynn cites his own father, who was 50 when he was born in 1934. "He was a highly intelligent man. But he had only an intermediate school education; he and all his brothers had gone into factory work between the ages of 12 and 14. I don't think he would have taken a 'matrices' problem seriously. He wouldn't have had any practice in his everyday life at finding logical patterns in abstract shapes; he could do logic all right, but it was mainly applied to concrete situations."

Saying that the rise in IQ scores has been caused by shifting social priorities may seem like dismissing it as mildly interesting, but ultimately trivial. This would be to miss the point. Changes in what we take seriously, and what we use our minds for, are just as real and meaningful as changes in the speed with which we process thoughts, or how much we can remember.

"I reject the idea that either these are intelligence gains or else they're insignificant," says Flynn. "They're not in any simple sense intelligence gains, but they are still highly significant." His father was also rather unwilling to waste his time on profitless speculation. "I remember frustrating occasions when it was natural for me to take hypothetical situations seriously and he thought of this as silly. We might argue about race, and I would say: 'What would you think if your skin turned black?' And his response would be: 'Who has ever heard of such a thing?' Most moral argument cannot get off the ground unless you take the hypothetical seriously."

And when he looks at his two-year-old grandson, he sees social priorities shifting still further. "His parents have enlisted in the great crusade of intellectual stimulation. If he identifies something they immediately pounce on it. A parent 30 years ago who was looking at a book with their child, if the child said, 'that's a cow'; they would say, 'you're right, it's a cow.' Today's parent will add, 'And what noise does a cow make? How many legs does a cow have?' And away they go."

I tell him that this story makes me think of my own 18-month-old son, who, when I took him to his room the night before our conversation, had turned the light switch on and off, again and again, until finally, to his disgust, I had pulled him away to put him in his cot. "Exactly! Merely being surrounded by mechanical contrivances prepares you to have a different mindset. They are artificial causal networks. That in itself helps to free the mind."

There is still the puzzle of how environmental differences can be so weak when we compare individuals born at the same time, but so strong over time. The key, which Flynn attributes to fruitful discussions with his collaborator, William Dickens, an economist at the Brookings Institution in Flynn's home town of Washington, DC, lies in the observation that superior genes cause superior performance by co-opting superior environments.

To illustrate, he recounts another sporting analogy; this time-as is practically mandatory in all discussion of the roles of genes and environment--a fable about identical twins, separated at birth.

These particular twins were born in Indiana, and adopted by unconnected families in the vicinity. They share genes that make them grow a bit taller and stronger than average. In that basketball-mad state, both, like all neighbouring children, shoot hoops in the yard and in school, and, being tall and strong, they are both rather good. This is pleasurable, so they play more and get better still. Each makes his high-school team, enjoys good coaching, puts in a great deal of practice, and goes on to play for his college team too. Both men started with a slight shared genetic advantage. But even tall, strong players are bad before they are trained and it was their genes' ability to recruit an ideal environment that explains how this translated into an enormous superiority.

Everything falls into place with the observation that, for the first time in human history, some people's superior mental abilities are making superior mental environments available to everyone. Humans are social animals. The most important part of the environment that created your mind is other people's minds. Before the 20th century, only the privileged had easy access to ideas. Now, when one person thinks something worthwhile, we can all think it and that thought changes all of us.

This process does not have to be "intellectual" to have an effect. In his book "Everything Bad is Good for You", Steven Johnson analyses the way popular entertainment has changed as people have got better at using their brains quickly and logically. Computer games such as "Civilisation" and "The Sims" reward players who obey the coherent internal logic of virtual realities. Popular television shows weave together multiple characters and storylines, in narrative arcs that extend over many episodes. Think of "24", or "Heroes", which require the audience to hold unanswered questions in their minds through entire series.

These days, film and television viewers are expected to work more out for themselves. Baddies no longer wear black hats; plucky kids lost in the wood no longer turn to one another and say "let's split up"; the presence of an intruder is no longer signalled by repeated shots of a door left ajar.

The Flynn effect is not a story of pure gains. There are signs that children are missing concrete experiences that help develop some mental abilities. Michael Shayer, a psychologist at King's College, London, has spent most of his working life studying the foundations of mathematical ability. In 1976 he tested children on their understanding of volume and shape, an understanding thought by many to underlie all future mathematical ability. When he repeated the tests in 2003, 11-year-olds performed only as well as eight-year-olds had done 30 years earlier.

Flynn's thesis does, though, provide a dignified escape from fruitless arguments about nature and nurture. And it points towards a satisfying answer to his original question: why do black Americans still perform worse on IQ tests than whites do, even when matched for poverty and other disadvantages? It is perfectly possible that in a still-biased society their genes can only co-opt inferior environments.

Most importantly, it shows that whole societies can get better at thinking. The next step will be to build on IQ gains to become wiser too. Flynn reels off abstractions that are now part of our intellectual capital: concepts such as "market", "placebo" and "control group". "If only we trained students to use these properly, that would...give them more critical intelligence and allow them to test truth in the world around them." The mind is supple and the Flynn effect shows that what we value gets stronger.