The world's oldest social network
Welcome to Cosmographia. This post is part of our Cartography of Networks series. For the full map of posts, see here.
Globalisation — the increasing interconnection between societies and economies — is often portrayed as an entirely modern phenomenon. In truth, it’s a process that has waxed and waned for time immemorial, having far deeper roots than many of us know.
Homo sapiens seem to have evolved, both anatomically and behaviourally, in a patchwork of semi-connected populations across Africa. Despite inhabiting disparate ends of the Mother Continent, it seems these groups were able to maintain loose connections across distances measuring in the thousands of kilometres.
We can see this in the distribution of ostrich eggshell beads, which are among the earliest ornaments created by our species. The beads, thought to have conferred social status and used as a medium of exchange, were manufactured in a torus shape (like a donut), and then threaded together on strings to make bracelets, necklaces, and other items. There’s some evidence of their use as much as 75,000 years ago; remarkably, some indigenous African communities still make them to this day.
Genetic studies have revealed that eastern and southern African lineages diverged somewhere between 350,000-70,000 years ago. One would suspect that given the genetic drift between the groups, there would be little social exchange happening between them. After all, when human groups come together, they tend to mate. However, despite the lack of interbreeding, it seems links between the eastern and southern African communities existed for tens of thousands of years.
To piece together the details of a historical network, archaeologists must find a tangible good, preferably one that can weather the ravages of time, that will allow them to track exchange across geographies. Ostrich eggshell beads are perfect in this respect: they are human-made, so cannot occur naturally; differences in style can identify separate groups and allow us to track cultural diffusion; and they last for millennia.
In 2022, a group of German scientists mapped bead exchange across Africa, and in so doing uncovered what is perhaps the oldest long-range human network in history.