Actually both theory turned out to be correct which is the way science sometimes works. Most of our ancestry is traced back to Africa, but the various populations outside of Africa are a mix of African and the various related human species that had been living in the area. For example modern Europeans and East Asian peoples are a hybrid of African humans and Neanderthal human populations [1]. The modern Austronesian peoples (most likely the descendants of the cave painters) are a three way hybrid between African, Neanderthal and the Denisovian humans [2]. I find this all really interesting.

[1] http://en.wikipedia.org/wiki/Archaic_human_admixture_with_mo...

[2] http://en.wikipedia.org/wiki/Denisovan