Disease and intelligence

Mens sana in corpore sano


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Readers' comments



Two caveats:

IQ is not a good proxy for "intelligence".

What about the obvious issue of food?

A Finn

So, some of you still want to believe IQ tests reveal the truth about intelligence, ok go o,n whatever makes you happy. I would not, however, rely on the mega study results collected by a professor [T. Vanhanen] famous for his eugenic opinions. He just might not like African and Middle-East natives.

But even if he was right and knew the IQs of all the nations of the world, at least I am a little bit scared. Where did this nonsense of dividing peoples lead last time in Germany, Rwanda,...


The appearance of intellectual gifted intelligences remain purely random at the present level of our scientific knowledgement-you know that one individual is geniuses only after his/her work well done and fully recognized ,at least by History! .Otherwise, they are just “wizards” (well trained, remember Salieri,Bill Gates and the superstrings physicists!-joke!).However cultural backgrounds are decisive for nurturing a fully and successful geniuses development ,even at a random environment (just thinking on Mozart, Albert Einstein and Alexander Magnus and their higher well prepared preceptors and Universities and Isaac Newton ,Michael Faraday or Mendeleev that arose from the peasantry!.All that geniuses really need are free access to good Libraries (The society cultural backbone!) and to survive to the envious and corrupters “Hooligans” on Academia and high schools(the Society virtues!).That is why advanced countries are advanced countries!.


I like the article which has certainly given me new insights! Still I miss two factors that may well play a role here as well: race and inbreeding.

The first - race - is very sensitive but should be addressed. We see the Chinese scoring really well despite the less-than-Western health standards. In fact they score higher than all the 'white' countries. I as a white dutchman wouldn't feel offended at all if this would lead to the conclusion that the Chinese outsmart the Dutch, any more than I would derive a superiority-complex from the fact that the black countries score lower than The Netherlands. So I hope this taboo will be broken at some point in time.

The second - inbreeding - is important I think because in some places in the world it is quite common (cousins marrying) and it definitely has many bad effects. And: like health but unlike race it can be influenced by governments.

A Finn

Yeah, sure I understand this kind of stories are just politics. The poor should be ashamed and not try to get rid of the stripes. Once and a while someone needs to remind the outliers who they really are and average IQs of the nationalities are a fine way to do this.

I think it is kind a common wisdom that malnutrition, malaria etc cause too much brain damages which is an important issue to know. But trying to find correlations with IQs are too stereotypic and dangerous way to go further. Furthermore brain damages caused by deceases are not hereditary, so what it has to do with genes.

Someone may want back the "good old times" when the Finns stared like a wild game through the leaves in the forests more sophisticated Swedes. Or some Italian still would be happy if Britons still hadn't musical abilities. As well, some Americans still would enjoy looking black men with big white lips dancing like maniacs. I have seen, some men still like women to stand 50cm behind, smiling.

Finland rose from poverty partly because we have one of the most equal school system (and women rights) in the world; the school system that does not measure any IQs, at least nowadays, but gives way to the outliers. However, equal school system producing strong outliers may threat some people proud of their high status. So, that is why this article in this paper (?)

Linda VF

This study reminded me of all the research done years ago on African American slaves and the effect of the flatworm parasite on their IQ, an interesting topic we read about in my Economic History course at Uni.

I would say that the point of view taken in this study at least makes more sense than many of the other ones presented by other studies on this topic.

A Finn

Oh, my dear "KPATOS" and "Boethius", I cannot say if you are right or wrong, but wonder why it is so important to know better. Some people have green eyes and some some grey ones, some run fast and some keep the couch warm. We might be different but the same, after all. But not quite, sorry, I am not a Mr (still "Mr plodding PC Finn" sounds quite cute, I would change my profile name immediately if only possible).

We in Finland really have just few immigrants compared to rest of the western world. So, I might not understand properly your immigrant problems. However, we have never brought slaves by boats to serve us. Still 150 years ago Swedes, our landlords thought we were just stupid forest people incapable to learn academic skills or poetry etc. I think it was the Romans who considered the British people very much the same and furthermore incapable to understand music at all many more centuries earlier.

And what was said about educating women who belonged between a kitchen and a fist.I would not try to be too wise to know better what the future will reveal. I happened to call Madonna a one hit singer when saw her first video in the 80's. Formula driver Mika Häkkinen was doomed to be looser at our school about the same time. Anyway, I do not like formula. My daughter got an early acceptance to Harvard among the 80 others in the world though I was unsuccessful biology researcher, too poor to buy toilet paper over ten years ago. During teacher's education we were taught never to reveal our negative expectations to pupils. Any expectations, positive or negative, may harm the child more than you should expect.

I understand in your comments you speak about averages but we should not when it is about intelligence. Hearing too much about the stereotypic averages will push back the outliers.

...and still Ghana rules not so typical nation in football semifinals...


If average IQ at birth would be the same for all racial and ethnic groups but for differences in childhood diseases, we would expect these differences to disappear as soon as members of those groups migrated to healthier or unhealthier locations. However, at least within the United States, the disparity between higher-scoring Asians and lower scoring Africans persists over many generations.


Intriguing correlations, and almost certainly causal connections as well. Tony Ryan congratulates himself on having got on to the underlying policy requirement in 1975. What a pity he didn't know raw untutored human nature well enough to forsee the trashing of so many of those 4WD vehicles!

Mr plodding PC Finn doesn't like IQ tests... (oh dear, I didn't realise that Finns, with their relatively high average IQs were becoming as conformist PC plodders as the Norwegians. Perhaps they need even more Third World immigrants to act as grit in the pearl shell with learning about reality the product).

Plenty of people who score high on IQ tests live foolish lives and have poor judgment. Some people with modest scores on IQ tests live materially and socially successful lives but you won't find them making important scientific discoveries, or even being serious scientists or innovators in business. If you haven't got the high speed of mind and short-term memory capacity that are part of what are measured by well-designed and validated IQ tests you won't be likely to contribute much to the wealth of nations or the progress of civilisation. In short other people who aren't friends or family can probably do without you although success less highly correlated with IQ, such as weightlifting, might make you the gold medal winning pride of your country.

Sure emotional intelligence etc. are good but all kinds of intelligence test prove to correlate with the g (for general intelligence factor) which is the common factor extracted from all adequate IQ tests. Other things being equal, and on average, higher IQ is better.

So, unsurprisingly, it will help raise the cognitive abilities needed to run a modern country and make its economy work for the diseases and parasites which afflict Africa to be combated effectively. But don't sneer at the Finnish PM's old-fashioned idea that heritable IQ differences (and who doubts that intelligent people on average have more intelligent children by whatever definition you like than less intelligent people do). None of the work outlined in the article explains why Afican-American IQs have remained a whole standard deviation below those of the rest of the population for 90 years in which the Flynn Effect has been manifested by increasing tested IQ scores in nearly all countries.

Nor is the clear evidence that Ashkenazi Jews, over a period of several hundred years, evolved average IQs variously estimated at one standard deviation or half a standard deviation above the general Northern European average explained by anything to do with infections or parasites.

Anyone commenting piously on these issues ought to know at least the work of James R. Flynn whose quite recent book "What is Intelligence; Beyonnd the Flynn Effect" expresses some interesting views on why IQ scores as measured by successively standardised IQ tests over the last century have shown rises in scores which could not be attributable to genetic change. He probably doesn't give enough weight to infections and their remedies and their a number of other explanations such as test sophistication, the speeding up of people's reactions by listening to broadcast entertainment etc. which I would add to his idea that we are increasingly educated to employ scientific abstraction.

Anyone willing to bet me that neuro-science and genetics won't within 10 years have demonstrated that most of the descendants of the people who left Africa in prehistoric times have genetic causes of their higher cognitive abilities, just as there are genetic causes for West African sprinting ability and East African distance running ability? (Mind you plenty of East Africans would point to their IQ advantages over "Bantu"). By then the Papal authority will have been so undermined that genetic engineering can begin. A long haul, but Chinese and Indian influence should prevail over the Mullahs and Bishops.

Bimbi Balcha

To begin with, I have a very strong reservation, if not objection, to measuring intelligence in IQ. But even with that aside, the average IQs slapped on the countries on the list couldn't feel any more random.
And as an African who did exceedingly well in a European School (ahead of all the Europeans and Asians in my class), I couldn't feel any more insulted by this -condescending make-up of a self-serving truth for a situation they have no proper explanation for- sort of "study".

AB ve

Sitting a cubical all day, tapping keys, reading from a screen, I am sure my health and intelligence are going down ;)

Have fun outdoors on the weekend.

Tony Ryan

I have known some remarkably stupid PhDs, some highly intelligent blacks, and some abysmally thick Chinese. If you meet enough people from enough places, you beconme increasingly unempressed with IQ tests and racial stereotypes.

The truth is, the IQ test has been a con from the outset.

It was originally invented to identify mentally retarded children. The French inventor said it had no application beyond that. As he pointed out to the US eugenics movement, intelligence is not linear, therefore it cannot be measured.

However, the eugenics elitists saw IQ tests as a means of creating a meal ticket, providing they invented a new IQ test, and placed their own profile at the top of the scale.

Thus, a bunch of neurotic, stupid, socially retarded technicians became the intellectual elite of the world, colonising universities and nabbing expert roles.

Sadly for them, you can fool a lot of the people all of the time, but ultimately if you are stupid but posing as intelligent, it is only a matter of time before the stupidity becomes too obvious for anyone to ignore.

This finally happend over AGW, with scientists and academics making AGW an act of faith, with the remaining 80% of humanity rejecting this absurd theory.

The writers of this paper showing a correlation between disease and intelligence probably constitute the second source of self-ridicule.

It may interest this intelligentsia to know that in 1975 I convinced Australia's Dept of Aboriginal Affairs to fund 4wd vehicles to facilitate access to clan homelands and bush food, which would improve nutrition over and above the mission store rubbish till then available.

The ultimate intention was to improve educational potential.

I might add, I was covering no new ground then either. This is all so old hat.

A Finn

"Random Scientist", you might be quite right. However that was not the point with immigrants in Finland. I might have not written my comment clearly. School performance of 15-year-old immigrants worldwide were studied in Pisa test as well as other things. Immigrants in Finland did better on average than immigrants in other countries of the Pisa study. So we in Finland are not genetically any different but our educational system might still be more equal and immigrant may have better opportunities to excel academically than in countries with more hierarchical educational system. At least we have very few schools with fees in Finland and the best schools are all free of charge.

Furthermore, in Finland most schools do not try to get rid of pupils with several problems to make their performance numbers look better. I think this may be the hidden big problem in some schools elsewhere. And at least we think that makes the difference.

This is not quite the issue of the article but I just needed to make clear my point that our genes are very much the same.


Which intelligence, we are talking about? To some extent, the concept is so relative that the smartest and brightest guy can appear more than stupid.
To get it right, solving problems intelligence refers to the practice and the repetition. Start to list the type of intelligence will be a good starting(emotional, organisational and so on) before to shortcut by the IQ and disease.
It does not make sense to apply regressive analysis and conclude on that complicated issue.
I bet you the smartest Christopher LANGAN won't be able to solve the basic problem in some parts in world, where a child can come up the most effective and efficient solution.
Please, the Economist as source serious newspaper should update coz how such weak paper can be termed "scientific paper".

Random Scientist

About immigrants in Finland and elsewhere.

Studies on immigrants could reveal uncomfortable truth that immigrants are on average more intelligent than natives. An immigrant by definition must have vision, determination and resources to break out of his/her own country. Western Europeans should find that, if given really equal start, children of immigrants excel at school.

Random Scientist

To readers wondering why Asians score so high?

IQ tests heavily rely on comparing abstract pictures. Cultures using pictograms are much more familiar with them. It is long known relationship.

Comparing IQ in disease-ridden rural regions and healthy urban-dwellers in a country like China would be more meaningful. It would also give an ammunition to those willing to invest in sanitation and medicine for the poor.

A Finn

At university during many courses we were warned about this kind of studies "how ice cream consumption correlates with deaths by drowning". Warm summer might has something to do in all this in Finland. This study mentioned in the Economist has not much to do with proper science. We cannot just try to find correlations between our favorite tables of numbers.

If we in the rich world put our children live in some poor villages with malaria etc from the very beginning of their lives without health care and education like ours, would they excel at school. Instead studying IQ related things one should focus on finding out why immigrants in Finnish school system perform better than immigrants in average do elsewhere.

May I, as well as Jared Diamond and so many others, suggest we are very much products of our environments. Proper education and health care system might help intelligence to blossom everywhere.

I hope not to see studies of Tatu Vanhanen mentioned in a positive light in the Economist any more. Vanhanen has suggested whites and Asians, with higher IQs, should lead Africa forward instead of African themselves. Of course some whites and Asians excel in Africa because white and Asian immigrants in Africa usually have better educational and health care background than an average African. Furthermore these immigrants in Africa quite seldom educate their offspring in the worst schools of slums.

With these IQs one should be very cautious or just forget the whole IQ issue and try to find better ideas to think about or study.


@TonyEmo- The numeral system, including the zero, was developed in India. It was introduced to the Europeans by the Arabs who acted as a bridge. For Algebra, however, they did undertake the development of the concepts existing in the earlier civilizations.

Gurinder Shahi

Intriguing findings...

While exposure to infectious diseases in early life can certainly take its toll on mental (and physical) development, other factors may help explain the findings of the study such as ethnic and socio-cultural differences between the countries that fared badly (mostly in Africa) and those that did best (mostly in East Asia). Among other possibilities, the reality that Oriental societies tend to place a premium on education and literacy may help overcome the negative impact of poverty, under-development and infectious disease on intelligence as measured using IQ tests...


This research had well founded arguments and if taken into it's prospectus
it will eradicate the much needed thinkings of the government's and for the
world organizations.


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