It's extremely difficult, and maybe impossible, to make an IQ test that gives equal chances for everyone on this planet. There is always something cultural in these tests. An example: A psychologist talked to a Mexican child.
Q: What would happen if I would blindfold you? A: I wouldn't be able to see. (right!)
Q: What if they would cut your ears off? A: I wouldn't be able to see. (wrong!)
Q: WHY? A: My hat would come down and blind me.
In fact, this was a very intelligent answer, and better than the psychologist could think of. Without ear shells one could still hear.
Agreed.
But initially you said that it's the difference between IQ tests that is important and now you are saying that its adopted cultural perceptions that could make a difference.
I do agree with that, yes.
Well, while that would make sense given (1) brain drain from poorer to richer nations and (2) lower levels of education and skilled labor leading to a lower level of cognitive functioning for entire areas over time, I have a hard time accepting the data presented in that map. The average person in Zaire (and several other nearby nations) is mentally retarded (IQ 70 is generally the cut-off between borderline and retarded)? I don't buy it.
I don't buy it either.
For some countries the IQ was simply estimated based on the IQ of neighbouring nations.
"For 104 of the 185 nations, no studies were available. In those cases, the authors have used an estimated value by taking averages of the IQs of neighboring or comparable nations. For example, the authors arrived at a figure of 84 for El Salvador by averaging their calculations of 79 for Guatemala and 88 for Colombia. Including those estimated IQs, the correlation of IQ and GDP is 0.62.
To obtain a figure for South Africa, the authors averaged IQ studies done on different ethnic groups, resulting in a figure of 72. The figures for Colombia, Peru, and Singapore were arrived at in a similar manner."