[chx]

While there's little doubt of a "recent" spread of humanity out of Africa, 100 000 years ago or so and also development of earlier humans there. This is perhaps what you've learned. But this article talks about an earlier period of time, it discusses some fossils in Greece / Bulgaria that are some 7 million year old and are more human than ape. It's possible that the well known and documented development of humanity in Africa was preceded by a migration of these into Africa perhaps seeking warmer places during a cooler period millions of years ago. We simple do not know much about the transition from ape to human and this might be an important step. An emphasis on might. We know little.