04 March 2012

IQ Research: Limited Lasting Benefit from Early Childhood Intervention

Approximate Average IQs by Nation / Region

It is generally felt among IQ researchers that the heritability of IQ is somewhat lower in children from families of low socioeconomic (SES) status. If true, the possibility for raising IQ through early childhood intervention provides hope for narrowing IQ gaps between groups that statistically tend to populate different SES strata.

A recent UK IQ study by SES, of 8716 twin pairs, suggests that we should view earlier research on this topic critically -- particularly if it was performed with fewer than 5,000 twin pairs.
If heritability is lower in lower-SES families, it suggests that environmental interventions might be more effective in boosting cognitive development for children in lower-SES families. The present study, which is based on a large UK-representative sample of children followed longitudinally, leads to a similar implication. Although the genetic influence on IQ is the same in lower-SES families, shared environmental influence appears to be greater in lower-SES families, suggesting that family-based environmental interventions might be more effective in these families. However, two further aspects of the results temper the policy implications of this finding. First, shared environmental influence is found in both lower- and higher-SES families and the difference in shared environmental influence between them is modest. Second, shared environmental influences on IQ decline from childhood to adulthood so that these influences might not have an impact in the long run. _PLoS: SES and Children's IQ
The above study when combined with an earlier study by some of the same authors, looking for the quantitative effect of specific genes on IQ, suggests that we should not expect to develop any magical intervention for permanently raising IQ in the near future -- from either environmental or genetic interventions.

This is bad news for groups which occupy the low rung of the SES ladder -- either as sub-populations within a particular country, or as low ranking countries within the community of nations, eg sub-Saharan African countries.

Hope springs eternal, however. Here is a look at the prospects for development in sub-Saharan Africa from an Indian perspective:
Samir Brahmachari, Director General of India's Council for Scientific and Industrial Research, CSIR, knows that intellectually, Africa is a goldmine. "Of every thousand Africans, one has an IQ of 140" he says. That sort of brilliance can't be put down, all it needs is a push in the right direction.

But he also knows India is in the best position to help. "I was part of the team that first mapped the Indian genome", he says. "And we found that among all the ethnic groups of the world, Indians have the maximum number of genes similar to Africans". _ibnlive.in
Is it true that one out of 1,000 sub-Saharan Africans has an IQ of 140? Let's try to find out.

Below you will find a Z score probability calculator which will let you test this assertion for yourself. Set the calculator to compute the area under the "right" tail (rather than the default setting of "left"). Now you will need to enter a "Z" score -- what should you enter? The Z score is simply the number of standard deviations from the mean for which you are seeking a probability. So we want to know what the mean IQ of sub-Saharan Africans is, so that we can calculate how many standard deviations from the mean the score of "140" happens to be.

The most likely IQ mean for SS Africa is 75 points, which is 65 points away from 140. Dividing 65 by a standard deviation of 15 gives a Z score of 4.333... But the calculator does not allow you to enter a value higher than 4, so enter 4 as the Z value. The result for the area (probability) of the curve at or above approx. 140, is given as 0.000032.

Is a probability of 0.000032 the same as 1 in 1,000? No, 1 in 1,000 would correspond to a probability of 0.001. The actual likelihood of finding a sub-Saharan African at random with an IQ at or above 140, is about 3 in 100,000. Not exactly the "gold mine" which the CSIR's Brahmachari claims -- more like tin.

What if Brahmachari was referring to North Africans, with an average IQ of 85? That would put a score of 140 about 55 points from the mean of 85, giving us a Z score of 3.666... If we enter a Z score of 3.67 in the box, we obtain an area of 0.000121, or a probability of about 0.0001. Is that 1 in 1000? No, it is about 1 in 10,000. Still not a gold mine, but perhaps copper.

For Brahmachari's assertion to be true, he would have to be referring to a population with a mean IQ of about 95 -- where a score of 140 would have a Z value just above 3. That is very close to the mean IQ of the United States or Russia, and considerably above the mean IQ of any part of Africa -- or even India. I wonder what Brahmachari was thinking? Does the CSIR have secret plans to colonise Russia or the US?

By zscorecalculator.com
The average population IQ of a nation leads to important consequences in terms of national GDP, and national competitiveness. The map at the top of this entry suggests one reason why some nations have better economic prospects than others.

Unfortunately, it looks as if will be a matter of decades, at least, before science can do anything to change that picture.

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Blogger Matt M said...

Early Childhood intervention turns out to be very expensive childcare.

Tuesday, 06 March, 2012  

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“During times of universal deceit, telling the truth becomes a revolutionary act” _George Orwell

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