In comments on a previous post, I mentioned that I had seen a study of the IQ of immigrants to the Netherlands.

Here is the full reference:

Jan te Nijenhuis and Henk van der Flier: ‘Group differences in mean intelligence for the Dutch and Third World immigrants’, Journal of Biosocial Science, 33 (2001), 469-475.

The authors’ Summary is as follows:

“Evidence from eleven samples indicates that the mean IQ of third world immigrants in the Netherlands is lower than the Dutch mean by approximately one standard deviation for Surinamese and Antillians, and by approximately one and a half standard deviations for Turks and Moroccans. Since IQ tests provide the best prediction of success in school and organizations, it could be that the immigrants’ lower mean IQ is an important factor in their low status on the Dutch labour market. The IQs of second-generation immigrants are rising.”

For more details……

The article is a review of Dutch studies of immigrant IQs. It is stated that ‘only studies of acceptable methodological quality were included in the review’. Unfortunately not much is said about the tests used, which are identified by their (Dutch?) acronyms, such as ‘RAKIT’, ‘GATB’, or ‘DAT’. If any Dutch readers know what these are, please tell!

The four immigrant groups studied are Turks, Moroccans, Surinamese, and Antillians. You all know who Turks and Moroccans are, but Surinamese are from the South American former Dutch colony of Surinam (Dutch Guiana), and Antillians are from the Dutch Antilles islands in the Caribbean. The Surinamese and Antillians are predominantly black, with maybe a touch of white and Amerindian ancestry.

It is not explictly stated whether mixed-race individuals are excluded from the studies. Clearly it would be misleading to describe them simply as ‘Turkish’, etc., if they are Turkish-Dutch. If anyone has access to the original Dutch studies maybe they could check?

The data from the various studies are given in a table. There are a few studies of adults, and more of children. The children’s studies are classified as ‘1st generation’, ‘2nd generation’, or ‘Mixed generations’.

I give the key results below. A = Antillians, S = Surinamese, T = Turkish, M = Moroccan. In some of the studies Surinamese and Antillians are grouped together, and in some Turks and Moroccans are grouped together. I have omitted two studies which cover ‘various’ immigrant groups. [For those who consult the original table, I have assumed that the study by van der Vijver covers Surinamese and Antillians, like the one immediately above it in the list.]

You can all group and average the data however you wish. I have calculated averages for Surinamese and Antillians together, and for Turks and Moroccans together, if only because many of the raw data are grouped in this way. For children, I have averaged 2nd generation and mixed generations combined, as there are so few studies which distinguish 2nd generation as such.

So here are the data. The mean IQ of the samples is stated in standard deviations below the Dutch mean:

Surinamese and Antillians
S: 1.05, 1.08. A: 1.17. Average: 1.1
Turks and Moroccans
T: 1.43 M: 1.86 Average: 1.5

Children (1st generation)
Surinamese and Antillians
S: 0.93, S & A: 1.09 Average: 1.01
Turks and Moroccans
T: 1.45. M: 1.70. T & M: 1.13. Average: 1.43

Children (2nd generation and mixed generations)
Surinamese and Antillians
S & A: 0.77 (2nd gen.), 0.81 (2nd gen.), 0.22 (mix), 0.67 (mix), S: 0.70 (mix),
A: 0.21 (mix) Average: 0.56
Turks and Moroccans
T: 1.20 (2nd gen.), 1.16 (mix), 1.47 (mix), 0.60 (mix) M: 1.43 (2nd gen.), 0.82 (mix), 1.38 (mix), 0.79 (mix). T & M: 0.89 (mix) Average: 1.08.

It will be seen that Turks and Moroccans perform considerably worse than Surinamese and Antillians. Presumably no-one will argue from this that Turks and Moroccans are innately less intelligent than Surinamese and Antillians. The obvious fact is that Surinam and the Antilles are former Dutch colonies, and their people presumably speak reasonable Dutch, while the Turks and Moroccans wouldn’t know Dutch from douche. Both groups perform better after the first generation, as the authors point out.

It is odd that the studies do not cover people of Indonesian origin. As anyone familiar with the Netherlands will know, there is a large Dutch Indonesian community, especially from the Moluccas. Te Nijenhuis and van der Flier say that data on the IQs of various generations of Moluccans are not available. This is surprising.

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