Answer:
The tools and the glaciers
Step-by-step explanation:
The different ice ages of the late Pleistocene era (Palaeolithic) marked a decisive phase in the history of Man. The animal existence (primal food supply) depended on the advance and retreat of glaciers. In the latter they allowed for the spread of vegetation and thus the presence of animals like the mammoths. This made it possible for human beings to live outside the warmer equatorial regions in Africa.
So they did, somewhere between 100.000 and 60.000 years ago they start spreading north and eastwards and reached the Arabic peninsula where Jebel Faya is situated.
The climate changes and the fact that the tools that were found at Jebel Faya were similar to those found in Africa, confirm the theory that African people moved to Arabia.