I found this in another thread on the internet asking the same question:
Seems like a fair answer:
Link
Some Africans and others say that the Africans did have some sort of great civilisation in the past. However the evidence is scanty.
Various reasons have been suggested for the undeveloped state of the continent despite the fertile climate of much of it, the presence of enormous mineral wealth etc. Much the same sort of paradox is evident with the indigenous peoples of N. America where the civilisations of Central America never seemed to spread to the north, just as Egyptian civilisation never caught on to the south.
I list, without implying agreement or disagreement with any of them, some of the suggested reasons.
1)...Making a living was just too easy. Where hunting & gathering or subsistence agriculture easily supply year-round food, there is no obvious incentive to change things.
2)...The local culture was hostile to the idea of living in large agglomerations - much as the European Celts preferred to live in loosely organised small settlements and resisted the Roman habit of city-dwelling. The Celts, though not primitive (their woodwork and metalwork were in some ways better than that of the Romans), were also, by comparison, economically underdeveloped.
3)...Recurrent local conflict between tribes, resulting in periodic genocide which made it hard to consolidate advances in knowledge and technique. This is possible, but why it should have this effect in Africa and not in the equally tribal societies of primitive Europe and Asia is hard to explain.
4)...Linguistic problems. I am not a specialist in African studies, but I am told that some parts of Africa have a large number of local languages, making sharing knowledge between communities awkward. Again, the lack of any written language might have made it hard to preserve knowledge or transmit it over distances.
5)...Communities were locally based and travel rare. If this is true (again, I appeal to any specialists to supply accurate information) it would limit cross-fertilisation of ideas. This explanation begs the question of why long-distance trade, analogous to the tin trade in Europe or the silk route from China, did not develop in Africa.
6)...Disease. The same conditions which make it easy for humans to make a living also provide ideal conditions for various pathogens and for the insects, snails etc. which carry them. If their vitality were reduced by debilitating endemic diseases, the locals may have had reduced intellectual as well as physical energy, making it harder for them to advance.
But it looks like it has been moved to the proper forum.
