Out of Africa: The dispersal of the earliest technical systems reconsidered

This paper deals with the question of human dispersals out of Africa. Some hypotheses concerning dispersals for both Mode 1 and Mode 2 technologies ar e presented. We suggest that early humans were technically split into at le ast two groups, those producing Oldowan (Mode 1) and those producing the mo re advanced Acheulean (Mode 2). Environmental changes caused a major faunal dispersal at around 1 my, which may have facilitated the first human dispe rsal toward Eurasia. However, this first dispersal involved only Mode 1 tec hnology, although Mode 2 was already well developed. Therefore, we suggest that the main cause for this dispersal must have involved differential subs istence strategies, such as the competition for resources between Mode 1- a nd Mode 2-producing populations, which drove the former, but not the latter populations out of the Rift System to other areas. Although Mode 1 technol ogy was highly effective in successfully facing the new Eurasian environmen ts, when the African areas with Mode 2 became saturated, this technical sys tem started to spread, replacing Mode 1 technology in Eurasia long after it s initial settling. (C) 1999 Academic Press.