One of the great mysteries in IQ research is why Indian Americans are such super achievers despite the fact that India reportedly has an IQ of only 82 according to the book IQ and Wealth of Nations.

And yet Indians in North America are known for their high intelligence and scholastic achievement, and despite being new to America, are already slightly over-represented on Forbes list of the 400 richest Americans. In some parts of Canada (particularly the maritime provinces like Newfoundland) if you’re Indian, all the white will people will assume you’re a doctor.

So how can Indians in North America be so smart when India’s average IQ is not great? Many people in the HBD-blogosphere invoke the theory that India is nation of many micro-races (castes) and that largely the smartest castes migrate to America, but the truth is usually much simpler.

Of the 2.8 million Indians in America, probably no more than 25% (700,000) are the ones who initially gained immigration (and the remaining 75% are the spouces, siblings, parents, and children, who came alone for the ride). But these 700,000 who actually gained immigration for themselves and their families are probably roughly the most occupationally successful 700,000 Indians out of a population of nearly 1.3 billion. In other words, they are above the +3.3 standard deviation mark in occupational status, and are on on average +3.5 SD. Since occupational status (mostly a function of education and income) correlates 0.7 with IQ, we should expect their IQ’s to be 3.5(0.7) = 2.45 SD higher than the average Indian (assuming Indians have a mean IQ of 82 and an SD 15, those who initially gain immigration to America should have an IQ of 119).

But because the IQ correlation between a parent and his adult offspring is about 0.45, the children of these high achieving immigrants from India should regress precipitously to the Indian mean:

0.45(119 – 82) + 82 = 99

Thus we should expect second-generation Indians born in America to have IQ’s around the U.S. average which is inconsistent with their incredible achievements. Can their achievements thus be explained by Tiger Moms? According to excellent Jamaican American blogger JayMan, parenting has zero impact.

So how do we explain the high achievements of second generation Indian immigrants? Nutrition. Blogger Steve Sailer was perhaps the first to notice that even un-mixed black Americans who have lived in the United States for centuries are several inches taller and about 13 IQ points smarter than black Africans. This suggests that first world nutrition adds about 13 IQ points (and several inches of height) to people of third world ancestry.

So the children of these high achieving immigrants would only have had an average IQ of 99 if born in India. Since they’re born in America, they should have IQ’s of 99 + 13 = 112.

Is it really plausible that Indian Americans could really have an IQ that high? Forbes magazine writes:

Just how smart are Indian Americans? We don’t know with much certainty. Most data sets with information on ethnic groups do not include IQ scores, and the few that do rarely include enough cases to provide interpretable results for such a small portion of the population.

The only direct evidence we have comes from the 2003 New Immigrant Survey, in which a basic cognitive test called “digit span” was administered to a sample of newly arrived immigrant children. It is an excellent test for comparing people with disparate language and educational backgrounds, since the test taker need only repeat lengthening sequences of digits read by the examiner. Repeating the digits forward is simply a test of short-term memory, but repeating them backward is much more mentally taxing, hence a rough measure of intelligence.

When statistical adjustments are used to convert the backward digit span results to full-scale IQ scores, Indian Americans place at about 112 on a bell-shaped IQ distribution, with white Americans at 100. 112 is the 79th percentile of the white distribution. For more context, consider that Ashkenazi Jews are a famously intelligent ethnic group, and their mean IQ is somewhere around 110.

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