ABSTRACT
The Middle Pleistocene period has emerged recently as of equal importance for the understanding of human evolution as its immediate quaternary neighbours. It now matches in interest the archaeologically flashier Upper Pleistocene of modern humans and the epochal strides in hominin bauplans made at the Pliocene-Pleistocene boundary. The archaeological model of a cultural revolution that accompanied Homo sapiens' first dispersal from Africa has been successfully challenged. While the African species factory is a combination of tropical diversity and a fluctuating wet-dry desert, its equivalent in Southeast Asia combines tropical diversity with fluctuating sea level. The impact of climate and environmental change is mediated through global, continental and regional scales. The manner in which they interlock produces mechanisms in deep history that drive population growth, movement and decline. The capacity to persist for longer in the face of climatic change was the adaptive basis which allowed a threshold in hominin behaviour to be crossed in the Late Middle Pleistocene.
