These etched fragments of ostrich egg are perhaps the earliest example of ‘symbolic representation’.

According to a new paper from PNAS, a collection of 270 shells unearthed in South Africa shows not only single geometric patterns but “complex use of symbols to mediate social interactions”. Pierre-Jean Texier, of the University of Bordeaux, and colleagues date the shells to around 60,000 years ago and say they were likely used daily by hunter-gatherers.

“The lines are crossed at right angles or oblique angles by hatching. By the repetition of this motif, early humans were trying to communicate something. Perhaps they were trying to express the identity of the individual or the group,” Texier told the BBC.

The most common pattern is two long parallel lines, intersected by shorter lines. Another common pattern is made up of straight but sub-parallel lines.

“The standardized production of repetitive patterns, including a hatched band motif, suggests a system of symbolic representation in which collective identities and individual expressions are clearly communicated, suggesting social, cultural, and cognitive underpinnings that overlap with those of modern people,” they write.

Image: Pierre-Jean Texier, Diepkloof project