"Maybe Africa needs a different theory of political centralization":
Roots of Political Centralization in Africa, by Daron Acemoglu and James Robinson: Seen from a wider perspective, the development of the strong central state we described in our previous post in Rwanda is anomalous in African history. Though states did form in pre-colonial Africa, for example around the Niger bend in the late middle ages, and in many parts of West, Central and East Central Africa after the 17th century, it is clear that these processes lagged those which took place in Eurasia. One can get some quantitative picture of this via the data coded by Louis Putterman and his collaborators (see this paper).
The lagged development of political centralization in Africa is an important part of the puzzle about why Africa developed less slowly than the rest of the world (see also this paper and this paper).
What can explain this retarded political centralization? Scholars of European political development, notably Charles Tilly in Coercion, Capital and the European State, have advanced several hypotheses which, they claim, can explain the development of European states. Tilly’s boldest claim was “states made war and war made states”. He argued that it was the intense inter-state warfare of Europe which led to political centralization. Other scholars have instead emphasized high population density and trade and commerce.
A natural approach to explaining why political centralization lagged in Africa is therefore to argue that the factors that led to such centralization in Europe were absent in the African continent. Jeffrey Herbst in his book States and Power in Africa did exactly this, arguing that African had not developed powerful centralized states because it had low population density and inter-state warfare was absent.
Is this the right answer to the puzzle? ...[continue reading]...
They don't believe that it is (see the evidence in the graphs they present in the post).