What did stone tool making capacity have to do with human pop expansion out of africa after 2.0million yrs ago

Question

What did stone tool making capacity have to do with human pop expansion out of africa after 2.0million yrs ago

Answer 1

Not just stone tools, but it would be technology.

-Technology enabled people to farm.

-Because people could farm, they didn't need to move around for food

-People were able to settle down and form villages

-Technology and knowledge advanced

-Small villages turned into cities

-Cities are home to large populations

-Many cities formed=large population

Answer 2

The first of the two "out of Africa" migrations (assuming you are not a fan of the Multiregional hypothesis) was not by anatomically modern Homo sapiens sapiens (who did not evolve until probably ~70,000 ybp), but by Homo erectus. Probably, lithic technology (stone tools) had little to do with this particular migration, as lithic technology of H. erectus did not change much either before the exodus or after (although new data from China may change this). Rather, the exodus was more likely due to the fact that the Suez/Sinai land bridge connecting Afric to Eurasia was most likely under water before that time due to differences in Paleoclimate and some tectonic differences in the orientation of the major plates. H. erectus did, however, have a decent lithic technology mainly consisting of simple flake tools and cores/core tools. They also may have had the use of fire (suggested by evidence from Zhougodian and other caves in China), and may have had an advance multi generational social system (see articles on the "grandmothering hypothesis" by James F. O'Connell and Kristen Hawkes from the University of Utah). In the end, it was most probably a combination of these things that help H. erectus to expand out of Africa and survive in the different environments they encountered in Eurasia.