Stone ‘Swiss Army knives’ show early humans had long-distance social networks

Archaeologists have found that around 65,000 years ago, knives were made to a very similar template across thousands of kilometres and multiple environmental niches

Humans are the only species to live in every environmental niche in the world — from the icesheets to the deserts, rainforests to savannahs. As individuals we are rather puny, but when we are socially connected, we are the most dominant species on the planet.

New evidence from stone tools in southern Africa shows these social connections were stronger and wider than we had thought among our ancestors who lived around 65,000 years ago, shortly before the large “out of Africa” migration in which they began to spread across the world.

The early humans weren’t always so connected. The first humans to leave Africa died out without this migratory success and without leaving any genetic trace among us today.

But for the ancestors of today’s people living outside of Africa, it was a different story. Within a few thousand years they had migrated into and adapted to every type of environmental zone across the planet.

Archaeologists think the development of social networks and the ability to share knowledge between different groups was the key to this success. But how do we observe these social networks in the deep past?

To address this question, archaeologists examine tools and other human-made objects that still survive today. We assume that the people who made those objects, like people today, were social creatures who made objects with cultural meanings.

A small, common stone tool gave us an opportunity to test this idea in southern Africa, during a period known as the Howiesons Poort around 65,000 years ago. Archaeologists call these sharp, multipurpose tools “backed artefacts”, but you can think of them as a “stone Swiss Army knife”: the kind of useful tool you carry around to do various jobs you can’t do by hand.