Raising this on behalf of fellow IN-posters who have bravely mentioned this in passing but I guess haven't had the courage to expand on their arguments.
Here is what I hope will be a credible organization that compiles this kind of data, ranking IQ's by country. You may want to check where you are positioned just by your nationality - very interesting.
In essence, East Asians are by far our most intelligent cousins while the Africans are apparently the least smart of the lot. One could argue that "this explains a lot" or "this is why the data doesn't hold".
Simplistically speaking, is there a correlation between skin colour and intellectual capability? Thoughts? True? False? Perhaps?