The country of Botswana has a per capita income of $13,392 — one of the highest in Africa. (It’s neighbor’s GDPs are closer to $1000/year) This is remarkable because culturally, Botswana is much like any other Sub-Saharan African country in dealing with issues such as the world’s highest HIV/AIDS rate and millions of refuges from Zimbabwe. If you want to know why Africa lags behind the rest of the world, there’s no need to study colonialism, psychology, tribal myths, political bickering, natural resources, or racial IQ levels. As one blogger notes, just observe that the constitution of Botswana prohibits the nationalization of private property and it is the freest economy in mainland Africa.
(Edit: My GDP statistic is for purchasing power parity and not the nominal income.)