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Archive: August 31, 2003

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IQ and Populations

Sunday,  08/31/03  11:35 AM

The other day I came across this table of National IQs for all the countries in the world.  (Drawn from Richard Lynn's and Tatu Vanhanen's "Intelligence and the Wealth and Poverty of Nations", via Gweilo, via razib.)  This is fascinating information, particularly when combined with population growth rates.

For the purposes of this discussion, let's stipulate that someone's IQ is just something you can measure, which may or may not have some correlation to anything else you can measure.  Whether it has anything to do with intelligence or any particular cognitive ability will not be addressed.

The U.S. Census Bureau has a terrific website called the International Data Base (IDB).  This includes a facility to create a table of National populations for any year between 1950 and 2050.  Let's assume that countries are (first-order) self-breeding and that measured IQ was/will be stable in each country during the 100 year period.  Combining all these data yields the following graph:

world IQ over time

The dark blue line is the average IQ of the world.  I've also plotted the population growth of the five most populous countries, India, China, the U.S., Indonesia, and Nigeria; the average IQ of each of these countries is in parenthesis.  (Nigeria is currently ninth, with Brazil (87), Pakistan (81), Russia (96), and Bangladesh (81) intervening, but by 2050 it will be fifth.)  As you can see, in a 100 year period the world's average IQ will have dropped from 92 to 86, a change of 6%.  That is pretty darn significant.  And all because of differential population growth.

I extrapolated the population growth of each country another 50 years to the year 2100 (lightly shaded region of graph).  At that time the world's average IQ will have dropped below 84.  Within this time period of 150 years, extremely short by any evolutionary standard, an incredibly significant change in this key metric will have occurred.  And there is no sign of the trend bottoming out, because the growth rate of countries with lower IQs exceeds the growth rate of countries with higher IQs.  The most populous country today is China, which has a high IQ (100), but its growth is actually projected to be negative because of their "one child" policy.  After about 2030 India will be the most populous country, and it has relatively low IQ (81).  At current growth rates by 2100 Nigeria will be the third most populous country, and it has a low IQ (67).

If you're interested in playing with these numbers yourself, here's the Excel spreadsheet with all these data.  If you publish further analysis or commentary, I would appreciate it if you'd link back to this page.

There were two assumptions we made up front, and I'd like to revisit them.  First, we assumed countries are self-breeding.  With modern vehicles and opportunities for travel this is becoming less and less true, but for the bulk of the world's population it is definitely a safe assumption.  The two largest countries, China and India, are both relatively undeveloped and by-and-large people do not travel in or out of them.  The third largest country, the U.S., is the only possible exception to this assumption, because so many people immigrate into the U.S. (in 1990 8% of the U.S. population was foreign-born).

The second assumption is more interesting; we assumed measured IQ was/will be stable in each country.  The Flynn Effect predicts this is false, and that measured IQ will increase over time.  (Historical data provide significant evidence for this.)  Many explanations have been offered for this effect, including steady improvement in testing procedures, and there is some evidence that in recent years the Flynn Effect has diminished.  If the overall world IQ changes due to differential birth rates among populations with different IQs (that is, separate countries), then it seems plausible that a country's IQ could change due to differential birth rates within its sub-populations as well.  In most countries and under most circumstances the birth rate of poorer and less educated people is significantly higher than the birth rate among wealthier and more educated people.  (China is the primary exception; due to their "one child" policies the birth rate within all sub-populations is essentially the same.)  Given the positive correlation between measured IQ and wealth, and between measured IQ and education, these differential birth rates would suggest that individual countries' IQs would decrease as populations expand.  If true, this would obviously accelerate the overall decrease in world IQ over time.

There are other factors at work.  For example, AIDS is presently the most common cause of death in Nigeria, which is one of the most populous and fastest growing countries.  Wealthier and more educated people are less likely to become infected by AIDS, because of awareness of the known transmission mechanisms and available protections, and also more likely to survive infection, because of availability of treatment (at least to the point of having and raising healthy children).  Because of this the effective birth rate among wealthier and more educated people in Nigeria is probably higher than poorer, less educated people.  There is a substantial correlation between wealth, education, and measured IQ.  Thus the AIDS epidemic may have the effect of raising the average IQ of Nigerians.

The human race has been in existence for approximately 150,000 years, during which time natural selection has incrementally increased human intelligence and cognitive ability.  It is not possible to give IQ tests to humans from 100,000 years ago - at least not yet :) - so we can only surmise that there would have been a corresponding increase in measured IQ as well.  Only recently - within the last 10,000 years or so - has this trend been halted, primarily by organized agriculture which enabled a small group of humans to provide food for a larger group.  It now appears that very recently - within the last 100 years or so - this trend has been reversed.  I call this Unnatural Selection, since it appears that societal rather than evolutionary effects are at work.  The consequences of this overall decrease in world IQ have yet to be quantified, but they are bound to be significant.


© 2003-2017 Ole Eichhorn


Sunday,  08/31/03  11:52 PM

In the wake of the Challenger disaster, CNN reports that Experts suggest extreme measures for NASA.  I suggest something really extreme: disband NASA, support commercial development of space as much as possible, and watch what happens.

But NASA keeps on ticking; they have plans for a light orbital plane to replace the space shuttle.  And this appears to have strong public support; "The survey found that 81 percent of Americans consider space exploration very important or somewhat important to the country's future."

Okay, so here's a cool idea: the idea a day site, "where ideas are free".  There are already 1109 ideas out there.  No RSS feed, but I've bookmarked it...  [ via Andrerib ]

Revolve - the bible for teenage girlsAnd here's an off-the-wall idea: a bible especially for teenage girls.  From the marketing pitch, "it's quite likely you'll see teen girls sporting the newest, hippest Bible this summer - from the beach to the mall, this magazine-style Bible is the most innovative concept in Bible publishing in the last twenty years."  Are you kidding me?  And no, I am not making this up.  [ via godless, who headlines her post "this is not the Onion"... ]

Yippee, another great book series coming to the silver screen.  This fall Russell Crowe becomes Jack Aubrey in Master and Commander, the initial episode of Patrick O'Brian's fantastic Aubrey-Maturin series.  If you haven't read the books, start now, that way you'll have read the first one by the time the movie comes out...

We're used to talking about the "brain drain" from Africa - smart young Africans go to school elsewhere, and stay there - but the Economist writes about the "brawn drain".  Interesting.  The markets for everything are becoming global, including skilled people.  [ via razib ]

bromine and raisinetteI found 101-365 in my referral log, and I like it!  Check it out, I mean bromine and raisinette, you can't really top that, can you?  (Bromine is bad stuff, but Chris' raisinette appears to be perhaps equally poisonous :)

Yesterday I linked a review of the new Archos Mediabox, and I wondered about an iPod A/V.  Well, here's the rumor.  If Apple could sell Quicktime-encoded downloadable movies through the iTunes store, they'd be able to print money.  And it would be time to short Blockbuster.

spider webThis is cool: Scientists Crack Secret Strength of Silk.  Spider silk is one of the most amazing things.  Aside from the material itself, which is amazingly strong and light, the 3D structure in which it is organized is amazing.  The elasticity of spider silk is actually a property of the way it is spun, not the material; essentially there are tiny "coils" of silk like beads on a string which act as springs.  And then there are the webs themselves, which have some amazing topological properties.  Richard Dawkins goes into some depth about spider silk in his terrific book Climbing Mount Improbable, check it out if you're interested in learning more.

Microsoft has an endless stream of great downloads available, monitorable with this RSS feed.  Of course 99% of them are uninteresting to any one user, but the other 1% are great.  Like this one, Inside the Microsoft .NET Framework.  If you've ever said "I don't get .NET", then this is for you.  Dr. GUI takes you on a magic tour through the .NET kingdom, with zero marketing BS.  Warning, it is 94MB, broadbanders only.

weapon of choicestick-figure ninjaAnd here we have - the stick-figure ninja!  Awesome flash animation, check it out.  A perfect stick-figure copy of this Fatboy Slim video, featuring Christopher Walkin.  (it is cool, too...)  [ via Bigwig ]

Want to read or share old Apple anecdotes?  Then visit the Apple Computer History Weblog.  { This is one of those things where I'm just glad it's out there.  I won't visit it often or bookmark it, but Google will know about it, and one of these days I'll be looking for something and poof!, there it is... }


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Correlation vs. Causality
The Tyranny of Email
Unnatural Selection
Aperio's Mission = Automating Pathology
On Blame
Try, or Try Not
Books and Wine
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Moving Mount Fuji The Nest Rock 'n Roll
IQ and Populations
Are You a Bright?
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Religion vs IQ
In the Wet
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On the Persistence of Bad Design...
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almost famous design and stochastic debugging
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world population map
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introducing eyesFinder
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