Saturday 23 May 2009

Disadvantages of high IQ


Having a high IQ is not always good news

Mensa Magazine June 2009 pp 34-5

Bruce G Charlton


There are so many advantages to having a high IQ that the disadvantages are sometimes neglected – and I don’t mean just short-sightedness, which is commoner among the highly intelligent. It really is true that people who wear glasses tend to be smarter!

High IQ is, mostly, good for you

First it is worth emphasizing that high IQ is mostly very good for you.
This has been known since Lewis Terman’s 1920s follow-up study of Californian high IQ children revealed that they were not just cleverer but also taller, healthier and more athletic than average; and mostly grew-up to become wealthy and successful.

Professor Ian Deary of Edinburgh University has confirmed that both health and life-expectancy improve along with increasing IQ. So that, remarkably, a single childhood IQ test done on one morning in Scotland in 1932 made significantly-valid statistical predictions about when people would die many decades later.
And other studies have shown that higher IQ people tend to be less violent, so smarter people usually make less-troublesome neighbours.

Indeed, Geoffrey Miller has put forward the idea that IQ is a measure of biological fitness. Since it takes about half of our genes to make and operate the brain, most damaging genetic mutations will show-up in reduced intelligence. So it would have made sense for our ancestors to choose their mates on the basis of intelligence, because a good brain implies good genes.

Sidis and the problems of ultra-high IQ

However, high IQ is not always beneficial. Terman’s study of the highest IQ group among his cohort revealed that more than one third grew up to be ‘maladjusted’ in some way: for example having significant problems of anxiety, depression, personality disorder or experience of ‘nervous breakdowns’.

This applied to William James Sidis (1898-1944), who is often considered to have had the highest-ever IQ (about 250-300). Sidis was a child prodigy, famous throughout the USA as having enrolling at Harvard aged 11 and graduated at 16. Yet he was certainly ‘maladjusted’, and had a chaotic, troubled and short life. Indeed, Sidis was widely considered to have been a failure as an adult – although this failure has been exaggerated, since it turns out that Sidis published a number of interesting books and articles anonymously.

In fact, there seems to be a consensus among psychometricians (and among the possessors of ultra-high IQ themselves) that - while an IQ of about 120-150 is mostly advantageous - extremely high IQ levels above this may prove to be as often of a curse as a benefit from the perspective of leading a happy and fulfilling life.

On the one hand, the ranks of genius are often recruited from amongst the more creative and stable of ultra-high IQ people; but on the other hand there are also a high proportion of chronically-disaffected ultra-high IQ people that have been termed ‘The Outsiders’ in a famous essay of that title by Grady M Towers
( )

Socialism, atheism and low-fertility

Sidis himself demonstrated, in exaggerated form, three traits which I put forward as being aspects of high IQ which are potentially disadvantageous: socialism, atheism and low-fertility.

1. Socialism

Higher IQ is probably associated with socialism via the personality trait called Openness-to-experience, which is modestly but significantly correlated with IQ. (To be more exact, left wing political views and voting patterns are characteristic of the highest and lowest IQ groups – the elite and the underclass - and right wingers tend to be in the mid-range.)

Openness summarizes such attributes as imagination, aesthetic sensitivity, preference for variety and intellectual curiosity – it also (among high IQ people in Western societies) predicts left-wing political views. Sidis was an extreme socialist, who received a prison sentence for participating in a May Day parade which became a riot (in the event, he ‘served his time’ in a sanatorium).

Now, of course, not everyone would agree that socialism is wrong (indeed, Mensa members reading this are quite likely to be socialists). But if socialism is regarded as a mistaken ideology (as I personally would argue!), then it could be said that high IQ people are more likely to be politically wrong. But whether correct or wrong, the point is that high IQ people do seem to have a built-in psychological and political bias.

2. Atheism

Something similar applies to atheism. Sidis was an atheist, and it has been pretty conclusively demonstrated by Richard Lynn that increasing IQ is correlated with increasing likelihood of atheism. The most famous atheists – like Richard Dawkins and Daniel Dennett – are ferociously intelligent individuals.

Again, whether atheism is a disadvantage is a matter of opinion (to put it mildly!) – but what is not merely opinion is that religious people are on average more altruistic in terms of measures such as giving to charity, giving blood, and volunteering time for good causes.

So, higher IQ may be associated with greater selfishness. In other words, smarter neighbours may be less troublesome on average, but they may also be less helpful.

3. Fertility

However the biggest and least-controversial disadvantage of high IQ is reduced fertility. Again Sidis serves as an example: as a teenager he published a vow of celibacy, and he neither married nor had children.

Pioneer intelligence researchers such as Francis Galton (1822-1911) noticed that (since the invention of contraception) increasing intelligence usually meant fewer offspring. Terman confirmed this, especially among women – so the group of the highest IQ women had only about a quarter of the number of children required for replacement fertility.

This trend has, if anything, increased in recent years as ever-more high IQ women delay reproduction in order to pursue higher education and professional careers. Indeed, more than 30 percent of women college graduates in the UK and Europe have no children at all – and more than half of women now attend college.

Since IQ is highly heritable, this low fertility implies that over time high IQ will tend to select itself out of the population.

The bad news and the good news

So much for the bad news about high IQ.

The good news is that while the advantages of high IQ are built-in; the disadvantages of high IQ are mostly a matter of choice.

People can potentially change their political and religious views. For example, Sidis apparently changed from being a socialist to a libertarian, indeed many adult conservatives went through a socialist phase during their youth (declaration of interest: this applies to me).

And religious conversions among the high IQ are not unknown (declaration of interest: this applies to me). For instance, GK Chesterton and C.S Lewis being famous examples of atheists who became the two greatest Christian apologists of the twentieth century.

Indeed, although it does not often happen, smart people can also choose to be more fertile. One example is the Mormons in the USA, whose average IQ and fertility are both above the national average, and where the wealthiest Mormons also have the biggest families. Presumably - since wealth and IQ are positively correlated - this means that for US Mormons higher IQ leads to higher fertility.

So, on the whole it remains good news to have a high IQ - although perhaps not too-high an IQ. But perhaps the high IQ community needs to take a more careful look at the question of low fertility. It may be that, under modern conditions, high intelligence is stopping people from ‘doing what comes naturally’ and having large families.

Human reproduction could be one situation where the application of intelligence may be needed to over-ride our spontaneous emotions or the prevailing societal incentives.

Or else at some point in the future, high IQ could become very rare indeed.


For more on IQ see: