Alison Brooks and John Yellen
May 1, 2015
Alison S. Brooks (George Washington University) and John E Yellen (National Science Foundation) are members of the Smithsonian’s Human Origins Program and its Olorgesailie Research Project, both led by Rick Potts.
What constitutes the essential behavior of our species? When, where and under what conditions did we develop complex technologies, symbolic communication and the ethnic and social divisions and interactions that characterize modern human societies and nations? Recent discoveries in southern and northern Africa suggest that these behaviors were widespread on that continent by sometime after 100,000 years ago, just prior to the spread of our ancestors from Africa to the rest of the old world. The longest, relatively continuous records of human behavioral development, however, are found in eastern Africa, which has also yielded the earliest fossil remains attributed to Homo sapiens. Archaeological sites in the Olorgesailie basin in the southern Kenya Rift Valley, span about 1.2 million years and provide a direct record of changing behavior over time. While Olorgesailie is famous for concentrations of hand axes and other Early Stone Age archaeological materials dating to >500,000 years ago, the recently-discovered sequence of younger deposits yielding “Middle Stone Age” materials speaks directly to the question of modern human behavioral origins during the later Middle Pleistocene: 400-200,000 years ago. In this presentation we set the “modern behavior question” in a broader theoretical and geographic context, provide an overview and relevant data from the Olorgesailie project and suggest underlying processes with explanatory potential.