Funnily enough, I recently posted some comments on exactly the IQ 70 Africa claim against the usual view that that is impossible, quoting a LWer's blog post about working in Haiti:

"It has proven hard for me to appreciate exactly how confused the Haitians are about some things. Gail, our program director, explained that she has a lot of trouble with her Haitian office staff because they don't understand the concept of sorting numerically. Not just "they don't want to do it" or "it never occurred to them", but after months and months of attempted explanation they don't understand that sorting alphabetically or numerically is even a thing. Not only has this messed up her office work, but it makes dealing with the Haitian bureaucracy - harrowing at the best of times - positively unbearable. Gail told the story of the time she asked a city office for some paperwork regarding Doctors Without Borders. The local official took out a drawer full of paperwork and looked through every single paper individually to see if it was the one she wanted. Then he started looking for the next drawer. After five hours, the official finally said that the paper wasn't in his office."