Middle Stone Age begins

The Middle Stone Age is the long phase of African prehistory, from roughly 300,000 to 50,000 years ago, in which toolmakers moved away from the big hand axe toward smaller, more varied tools, often made by hafting stone points to handles. One of the best views of the start comes from Olorgesailie in southern Kenya, where a team led by Alison Brooks and Richard Potts reported in 2018 that the change was under way by about 320,000 years ago. The layers there show smaller points and blades, as well as lumps of black and red pigment, within a short time of the last hand axes.

What stands out is the evidence for long-distance contact. Obsidian, a volcanic glass that makes extremely sharp edges, was carried to the site from sources up to 95 kilometers away, while the older layers used only local stone. Moving rock that far suggests exchange between groups, or very large territories, and some form of social network. The pigments, ground from iron-rich rock, hint at symbolic use, such as body decoration, though that is an interpretation, not proven. The shift also coincides with big environmental changes: large grazing animals in the older layers gave way to smaller animals, and the toolkit may have been a flexible response to a more unpredictable climate.

The timing matters because the earliest known fossils of our own species, from Jebel Irhoud in Morocco, are about 315,000 years old. The Middle Stone Age is therefore the toolkit of the first Homo sapiens, though the toolmakers may have included other humans as well, and scientists disagree on who made which tools. Over the next 250,000 years, African groups developed ever more complex technology, including heat-treated stone, bone tools, ochre paint, shell beads and eventually arrows, long before similar behaviors showed up in Europe.