Two theories have been advanced that explain the spread of the earliest modern humans across the globe. Their names are: Multiregional and Out-of-Africa. which one is favored by researchers and why.

The Out-of-Africa theory is favored by researchers because it has more reliable genetic evidence, but neither model has been conclusively confirmed to the exclusion of the other one. Neither has been conclusively refuted as well.

Both models agree on the roots of human evolution being in Africa. But they differ on the time frame and the evolutionary participation from Homo erectus.