Another long silence, alas. My apologies once again. I’ve been completely preoccupied with finishing the first draft of a book manuscript (of which more in a few months), which is now being disemboweled by experts. I promise more regular blogs in coming weeks.

A momentary distraction came with the announcement of the discovery of tools made with blade technology dating to at least 285,000 years ago. Startling at first glance, especially when you reflect that there is pretty general agreement that Homo sapiens, ourselves, first appeared in tropical Africa about 200,000 years ago. The date, obtained by the argon-argon method, which is far more accurate than the long-established potassium argon technique, comes from Gademotta in Ethiopia’s Rift Valley, known to be a crucible of human evolution. It coincides remarkably well with a second site, Kapthurin in Kenya, which dates to about the same time.

Both Gademotta and Kapthurin have yielded small and sophisticated blades and spear points, very different from the large hand axes and cleaving tools so widely used in Africa at the time. The Gademotta tools are made from obsidian, a fine-grained volcanic glass and come from below and above a volcanic layer, which yielded the date of 280,000 years ago.

For generations, archaeologists have equated stone technologies based on small, basically parallel-sided blades with modern humans. They’ve found them in Southern Africa dating to around 70,000 years ago, where such tools appear and disappear, as if the technology was used, then abandoned, perhaps in response to changing environmental conditions, notably drought. Now what is claimed to be blade technology dates back thousands of years earlier. What does this mean in human terms? Did the cognitive skills associated with modern humans develop gradually over a long period of time, or are these artifacts temporary developments, reflecting times of experimentation or purely local needs, or even the availability of exceptionally find raw materials?

We don’t know, of course, but it’s clear from Gademotta and Kapthurin that the development of modern humans both culturally and biologically was more complicated than perhaps we realize.

And so the archaeological dance goes on. . . .