Eastern African Stone Age
This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Anthropology. Please check back later for the full article.
The Stone Age record in eastern Africa appears to be longer and better documented than any other region worldwide. Rich archaeological and fossil evidence derives particularly from sites within the Rift Valley of the region, often with secure radiometric age estimates. Despite a relatively late start and disproportionate focus on earlier time periods and open-air sites within the rift, scientific research into the region’s Stone Age record continues to play a central role in our understanding of human evolution.
Putative stone tools and modified bones from two Late Pliocene (3.6–2.58 million years ago, or Ma) contexts are exclusive to eastern Africa, as is conclusive evidence for these starting around the Plio-Pleistocene boundary (2.6–2.5 Ma). The earliest indisputable technological traces appear in the form of simple flakes and core tools, as well as surface-modified bones. It is not clear what triggered this invention, or whether hominins with this technology hunted or only scavenged carcasses. Neither is it certain whether late australopithecines made and used stone tools. Archaeological occurrences predating ~2 Ma are limited to sites in Ethiopia and Kenya, becoming more common afterwards across eastern Africa and beyond.
By 1.75 Ma, lithic technologies that included heavy-duty and large cutting tools appeared at two sites, in Ethiopia and Kenya. Details about these larger and more diverse stone tool forms are still inadequately understood, although their appearance in eastern Africa roughly coincides with the appearance of Homo erectus. These technologies represent by far the longest-lived Stone Age tradition that endured ~1.6 million years. Hominins with these technologies successfully inhabited high altitude (>2,300 m above sea level) environments starting ~1.5 Ma and expanded within and beyond the region starting even earlier.
Small-sized and highly diverse tool forms gradually and variably started to replace heavy-duty and large cutting tools beginning ~300 thousand years ago (ka). Conventional wisdom associates this extremely variable shift in toolkit with the evolution of Homo sapiens, although the oldest undisputed representatives of our species continued to make and use large cutting tools in eastern Africa well after 200 ka. In addition to the dominance of small retouched tools, such as pointed pieces, scrapers, and blades, significant innovations such as hafting and ranged weaponry emerged during the length of this technological tradition. Increasingly complex socio-cultural behaviors, including mortuary practices, mark the later part of this period in eastern Africa. The consolidation of such technological and socio-cultural skills, as well as environmental and demographic dynamics may have enabled the hypothesized, ultimately decisive out-of-Africa dispersal of our species from eastern Africa, ~50–80 ka.
Even smaller and more diverse stone tool forms and other socio-cultural innovations evolved in many areas of eastern Africa by ~50 ka. Miniaturization and diversification allowed the adoption of different complex technologies, including tools intentionally partially dulled and other microlithic tool forms used as parts of sophisticated composite implements, such as the bow and arrow. Complex behaviors involving personal ornamentation, symbolism, and rituals that resembled the lifeways of ethnographically known hunter-gatherer populations were similarly adopted, although relatively later than in northern and southern Africa. These led eventually to new technological and economic developments marked by the inception of agriculture and attendant lifeways.