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(CNN)Thousands of years before Facebook, Twitter and TikTok, tiny beads helped humans make social connections.
A decade-long study of more than 1,500 beads made from ostrich eggshells and found across Africa has revealed a 50,000-year-old social network, archaeologists say.
The donut-shaped beads are among the earliest kinds of personal adornment found in the archaeological record -- and some traditional, hunter-gatherer groups in southern Africa still make and use the beads today.
"People made them to communicate symbolic messages, the way that today we might wear a wedding ring, to indicate something about social status, wealth or position in society," said Jennifer Miller, a postdoctoral researcher in the department of archaeology at the Max Planck Institute for the Science of Human History, in Jena, Germany.
They studied 1,516 beads (1,238 of which were described for the first time) that originated from 31 different sites across southern and eastern Africa and spanned the last 50,000 years.
Comparing the different characteristics of the beads -- the diameter and thickness -- they found that between 33,000 and 50,000 years ago, people at sites across southern and eastern Africa -- spanning a distance of more than 3,000 kilometers (1,864 miles) -- were using almost identical beads.
"We know that genetically these groups had some sort of contact, but there so far has been no cultural evidence," said Miller, who was an author of the study, which published on Monday in the journal Nature.
"It's kind of mind-boggling that these people, who lived 40,000 to 50,000 years ago, would have had some kind of social network that spread over such a long distance."
The oldest beads come from East Africa, the study found, and likely spread south across the continent from there. The authors described it as the oldest social network ever identified and the furthest Stone Age "stylistic connection" ever documented.
While it's possible the beads could have been directly exchanged in some way, Miller thought more likely it was the knowledge of how to make them that was exchanged.
"Based on what we're seeing, it loo