The reviewer does not consider that educational opportunity may reflect underlying differences in IQ. Black African countries lack the cognitive capital to maintain well-resourced schools and even when externally maintained by a high IQ minority like in South Africa and Rhodesia, there are intrinsically few intelligent students able to reach high educational level. Similarly, in countries where whites are a majority and there is equal educational opportunity, like the US, average wealth and other socioeconomic indicators correlate strongly with IQ in a Black, Hispanic, gentile white, East Asian, and Ashkenazi Jew continuum.
Yes – both this critique and (to a lesser extent) the original argument end up simplifying things overmuch by treating all of these variables as independent. Though I have not read ‘IQ and the Wealth of Nations’, I wonder whether it accounts for the possibility that greater national wealth leads to increased IQ (until the Flynn effect is explained satisfactorily, this cannot be ruled out). The critique is even lamer though: it treats fertility as a variable independent of IQ (along with educational achievement and some other things). Yeah, sure – if I want to pretend that the number of children per family and the level of education attained are somehow separate from and uninfluenced by IQ, then I can magically make its effects on national wealth seem to disappear.