Why the high intelligence of Indian Americans?
I reproduce below a well-informed answer to the above question. I disagree with his conclusion that it is all due to nutrition however. Other work finds only 5 IQ points attributable to nutrition. The suggestion of 15 IQ points is therefore startling. So I think we need to look at other possibilities. I think that the Indian advantage is probably a compound of several factors.
The treatment of Indians as a single group is of course absurd. Almost any Indian will regale you with stories about the great gaps between the castes. And the castes do seem to have a racial and historic origin. A Brahman and a Dalit are worlds apart in all sorts of ways, including skin color. And it is usually held that the differences arose from the Northern Brahmins being in fact late "Aryan" invaders on top of an original Dravidian population. So we would expect Brahmins to have higher IQs. And Brahmins seem well-represented in Indian immigrants to America.
Everything in the above paragraph is however subject to controversy so how much caste accounts for higher IQs in Indian Americans remains "under study". Something that would reveal the effect (or not) of caste would be a study of Indian diaspora populations in places such as Fiji, where the Indians there are the descendants of coolies imported to act as agricultural labourers. If they have high IQs, there is no caste effect. But I can find no data on such populations. It is however true that Indians run just about everything in Fiji these days.
The next possibility is related to the one above: A general selective effect of immigration. Diaspora populations are not always brighter than the home population but when we are looking at poor countries they probably are. To get yourself out of a poor country to a rich one surely requires brains. So regardless of caste, diaspora Indians should be brighter.
The third possibility is one shown up by the Flynn effect: Education. Education does have an effect on at least some measures of intelligence. How that works is speculative but the most plausible explanation is that doing tests and exams in the course of a long education develops test-taking skills (e.g. guessing when uncertain) that generalize to IQ tests. And the Indian education system is woeful so a transition to the less woeful U.S. system should confer an advantage.
A fourth factor that is rarely mentioned in these discussions is regional differences within India. The Indian South seems to be much brighter, particularly where mathematical ability is concerned. The great concentration of Indian IT knowledge is in Bengaluru (Bangalore), which is in the South. And it was almost entirely Southern engineers who were behind the quite remarkable Indian Mars shot.
I am not going to say much about why the Southerners are smarter but I note that they hate one-another. Keralans despise Tamils, for instance. And that is related to the long history of warfare between them. And dummies are the least likely to survive wars. So warfare has dragged up the average IQ of most of the South.
But getting back to Indians in America: I have seen no figures on it but I gather that a huge proportion of Indians came to America to work in IT. If that is so, they would mostly have come from the South -- because that is where the IT ability is. So the Indian immigrants to the USA came from a (Southern) population that was ALREADY pretty high on IQ. So from that starting point, the various advantages (already mentioned) of life in the USA could easily have added one third of a standard deviation -- which could explain what we see. It could in fact explain the whole of what we see.
And regardless of where they come from in India, being employed to work in IT is a HUGE selective pressure. To code easily in languages like C and its derivatives requires an IQ within about the top 2%. If that doesn't bring up the average, nothing would.
So I would summarize that the high IQs of Indians in the USA is the combined effect of nutrition, education, caste, an immigrant effect, an effect of regional origin and an effect of occupation.
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.