Indian IQ: Contained within is an alternative to the rec1man model of Indian IQ - it is not very structured but instead a mess of observations as a citizen.
First off, I think we can all agree that the 81 figure in Lynn &Vanhanen's 2002 is deeply suspect, and does not tally with the historical record of highly advanced Indian civilization. Noted here is the fact that malnutrition at the moment in India exceeds that in sub-Saharan Africa by a significant margin, and the simple removal of that malnutrition certainly makes up a huge portion of the 1 S.D. gain of blacks from Africa to the U.S.A.
And Lynn & Vanhanen emphasize the role of nutrition in raising average IQs (including micronutrients -- South Asians suffer a lot from iodine shortages, which can lead to cretinism).
IQ is segregrated by caste. Castes are still chiefly endogamous even in relatively modernized areas, and thus there is genetic IQ difference. It seems likely that Brahmin > Kshatriya/Vaishya should be the usual IQ stratification among the upper castes or dwijas.
After this broad division - contrary to what most would say - the subdivisions are very murky. Parsis perform on a Brahmin level or above it. The Kayasth - an administrative Kshatriya subcaste - have contributed 1 nobel laureate - Amartya Sen - and are competitive with Bengali Brahmins in Bengal. They seem to have done well in the sciences - Satyen Bose of Higgs boson fame for instance. Tamil Brahmins dominate the IITs , as well as hard sciences and mathematics. Compare with the Bengalis, who have nobels in economics and literature.
Visual-Verbal split ? Quite likely, imo. The backward castes and dalits follow the forward castes. Backward castes do quite well in some places - dalits not so much.
Factors depressing Indian IQ at the moment include poor literacy and nutrition, but also Islam. Nutrition as I noted earlier is worse than SS Africa. Literacy is rising, and with any luck will keep maintaining the strong growth it has now. [ Incidentally, it would be interesting to study Sri Lankan IQ - highly literate, low malnutrition, similar racial makeup with South India...and the only study we have is one way back in 1954 with a sample size of 46, that too on eight year olds, when IQ is not very heritable. The figure of 79 it gives is quite meaningless in the present context. ]
Islam needs a whole book unto itself. It promotes intellectual coma to a degree that no other religion can. I am positive that the Middle-Eastern IQ would be higher if those nations simply converted to something like Judaism. Sephardim , I think, illustrate my point by outscoring Arabs comfortably
There are various racial minorities in India. Of note is the fact that Mongoloid populations in the NE region - similar to Thailand/Tibetan/Burmese people underperform compared to the rest of the country. All these regions fall below average income and are not very developed. Since Thai IQ is 91, this puts a floor on true Indian IQ of somewhat above 91.
Interestingly, the eastern city of Kolkata has held a sizeable minority of Chinese. They do not have any history of academic excellence per se, and are more famous for bringing their cuisine to India. Perhaps a segment of the left half of the Chinese curve, as I do not believe that Indians have a mean IQ above 105.
Raw Income/IQ/Academic data from the diaspora
With the significant retarding effects on Indian IQ in India, we must look elsewhere.
In the U.S.A, Indian Americans outperform the Chinese. But they are highly selected and barely representative, and hence unsuitable as samples.
In the U.K., the Indian sample is quite representative of India. Lynn in his Race Differences in Intelligence gives some figures for Indians in Britain -
87 - 1967 , 91 - 1978 , 94 - 1983 , 97 - 1985 , 87 - 1992 [ 97 data point for Indians resident in Britain for 4+ years - the study used FoB immigrants scoring 83 as a comparison. Since this shows clear environmental influence, the FoB score which has presumably been environmentally deflated has been removed. ]
Unfortunately, Lynn has fudged the original Mackintosh data points, as Mackintosh mentioned in his review of the book.
Using Mackintosh's review as a basis, the data points become 87, 91, 94 , 97, 97, 91. You can read the relevant portions of his review at Dienekes :
Well, you have to massage the data to account for the Flynn Effect. But that makes it more likely for errors to creep into the process.
The IQ in the UK averages out to 93, which does not square with the Indians outperforming whites in terms of education and income. Perhaps a further relative flynn has taken place since 1992 ? Or perhaps culture is a huge bonus for Indians.
British school tests have a huge gender gap, with girls badly outperforming boys within each racial group. I don't know whether there's something wrong with the tests or with boys in Britain.
Mauritius - Mauritius is a mostly lower caste-based sample of Indians and may be taken as a lower estimate. The Mauritian IQ is 89 for Indians and creoles. Indians are 70% of the sample and have a mean IQ of 2.5 points more than the creoles. Using basic algebra, we find that the Indo-Mauritian IQ is 90. Note that Mauritius is far from a selective migration case - calculations are basing off Lynn's Race Differences in Intelligence.
Singapore : No IQ data here. But according to the 2005 Singstat income data -
Median income monthly : Chinese - 2500 Malay - 1800 Indian - 2480
Average income monthly : Chinese - 3610 Malay - 2200 Indian - 3660
Malaysia : IQ data of 88 just after the heyday of NEP which widely discriminated vs Chinese and Indians in Malaysia, hence testing those children who suffered under it. The chinese of course were not hit as hard. The Malays at the same time averaged 89. During this time the Indian economic situation put them in a very bad state. Now however the Indians perform midway between Malays and Chinese in income - see http://www.malaysianews.net/story/308459 . Plotting Chinese IQ as 105 and using a crude linear basis, the Indian IQ from that distribution is 96.
For a diaspora of plantation workers, 96 is quite impressive.
In sum, the true Indian IQ should be around 94 corrected for environment and very multi-modal. India's prospects in the 21st century in terms of IQ, while worse off than China's 105, are not that bad, primarily as Verbal IQ is more helpful in terms of GDP prediction than IQ - see La Griffe Du Lion's revised SFT - and East Asians lack verbal IQ comparatively.
Finally, allow me to mention two studies of Indian IQ that have not drawn much attention :
http://www.ncbi.nlm.nih.gov/pubmed/8240214 - note control group IQ
http://www.ncbi.nlm.nih.gov/pubmed/15004297 , http://www.ncbi.nlm.nih.gov/pubmed/10740303 - two studies, same cohort - note control group IQ
Indian IQ deserves a book length treatment, considering how diverse India is. What are your thoughts on Indian IQ ?