David Reich is exploring a theory that Neanderthals are culturally modern humans, despite being genetically mostly archaic, due to a modern human expansion 200,000-300,000 years ago that introduced Middle Stone Age technology and key genetic material.

A recent study by David Reich's lab identified approximately 7,200 positions in the human genome with at least a 50% confidence of being under natural selection, estimating that about 3,600 of these are real signals.

Europeans and East Asians descend from a common ancestral population that came out of Africa and the Middle East approximately 40,000 to 50,000 years ago.