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Why are children smarter than their parents?

IQ test scores have been creeping upwards for a century, writes Karl Kruszelnicki.

IQ tests indicate children are adapting well to a contemporary environment. – ShapeChange / Getty Images

We’ve all heard of intelligence quotient (IQ) tests. Psychologists see IQ as our “fluid and crystallised intelligence” – our ability to solve problems and to reason deeply and speedily. But surprisingly, averaged around the world, the typical IQ is not fixed. IQ seems to be creeping upwards, at about three IQ points every decade.

This story begins back in 1948 when R. D. Tuddenham, a psychologist, examined the IQ scores of American conscripts between the years 1917 and 1943. He showed that their IQ scores increased by about 4.4 points every decade.

Today it’s known as the Flynn effect, named after moral philosopher James R Flynn who rediscovered the effect in 1984 (and is now Emeritus Professor of Political Studies at the University of Otago in New Zealand).

IQ tests are limited in scope. You can see this by looking at a typical IQ test, the Wechsler Intelligence Scale for Children (or WISC). The WISC tries to measure 10 different “aspects” of this strange beast we call IQ including information (“On what continent is India?”), arithmetic (“If three toys cost four dollars, how much do seven toys cost?”), vocabulary (the words we use in everyday life), comprehension (“Why are houses in a street given numbers?”), picture completion (in which you find the missing part in a picture) and similarities (“How are dogs and rabbits related?”).

Another widely used test is Raven’s Progressive Matrices, suitable for children aged five and up. It uses patterns in an attempt to measure on-the-spot problem solving ability. There are 60 multiple-choice questions which get progressively more difficult. In each question you are asked to point out the missing element to complete a given pattern. Ability to do the test seems to be largely independent of the culture you live in, or your education.

Getting back to the WISC – over the past 70 years or so it’s been recalibrated three times to make sure that the average measured IQ of children was always 100. The original WISC was released in 1947. It was recalibrated (or “renormed”) upward in the early 1970s and renamed the WISC-R, and renormed up again in the late 1980s and called the WISC-III. Most recently it was renormed up in the early 2000s, and renamed the WISC-IV. Each version was harder than the one before it. (And then the WISC-V, the WISC-VI, etc.)

And here’s the essence of the Flynn effect. If you give a child of today one of the WISC IQ tests of the past, on average, that child will score more than 100.

But if you look at each of the 10 components that make up the WISC, you’ll see differences in their scores over time. On one hand there has been virtually no increase in “arithmetic” scores over the decades. But over the same time, there has been a huge measured increase in “similarities” scores. We’re not sure why.

A similar increase has been seen in the non-mathematical and non-verbal Raven’s Progressive Matrices. Indeed, the Raven’s Progressive Matrices shows some of the highest gains in measured IQ.

So IQ is a measure of how well we can deal with the society we inhabit.

So what’s causing the Flynn effect? We don’t know for sure, but many explanations are offered.

Compared to a century ago, our brains have to work within an environment that is more abstract. Today’s world is loaded with synthetic visual imagery – televisions, computers and video games. So results on an abstract category such as “similarities” could be improved more than “arithmetic”.

Another set of changes over time involves the home and physical health. Children now get better nutrition during their formative years when the brain is growing. Smaller families mean that parents can theoretically spend more time with and money on the fewer kids. A higher standard of living can mean fewer infections, so children’s potential growth is not hindered. A 2010 study showed a strong link between early childhood vaccinations and the average IQ of a nation.

The Flynn effect also seems to kick in strongly when countries achieve a certain level of health, education and welfare.

Another way to interpret this is to see your IQ not as something set in stone and unchangeable but, rather, more like a muscle that can alter itself and adapt to a changing environment. So IQ is a measure of how well we can deal with the society we inhabit. In other words, perhaps it’s a measure of how “modern” we are.

But we still don’t understand the full ramifications of the Flynn effect. According to Flynn, if these gains in IQ are actual and real, “Why aren’t we undergoing a renaissance unparalleled in human history? Why aren’t we duplicating the golden days of Athens or the Italian Renaissance?” Perhaps we are, but we can’t see it because we are in the middle of it.

So OK, it’s not as easy as ABC to test IQ ... And maybe teenagers were right all along, and they really do know more than their parents.

Edited extract from House of Karls, Macmillan 2014

Contrib drkarl.jpg?ixlib=rails 2.1
Karl Kruszelnicki is an author and science commentator.
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