Why Researchers Believe These 100,000-Year-Old Etchings Weren’t Symbolic

In a new study, the markings — which resemble hashtags —were not found to be distinctive based on time and geography

Christopher S. Henshilwood & Francesco d'Errico

Some 52,000 to 109,000 years ago, an ancient human carved etchings onto red ochre stones in a South African cave. Looking at the markings found in the famed archaeological site of the Blombos Cave through a modern eye, the patterns almost appear to resemble a hashtag.

Was the prehistoric creator designing a work steeped in symbolic intent and tradition? It’s a tantalizing question, but as Michael Erard reports for Science, a new study, “The adaptive cognitive evolution of the Blombos and Diepkloof engravings” suggests that’s not the case. Instead, the markings appear to have been made as decoration or for enjoyment.

To investigate the significance of the patterns on the rocks, a team of cognitive scientists and archaeologists from Aarhus University, University of Western Australia and University of Johannesburg asked 65 Danish university students to study 24 images of stone markings and sort or copy the lines they saw.

The idea was to find out if people could distinguish the marks from those at other sites, and if they could copy them by only looking at them briefly. If the markings carried symbolic meaning— if they represented something — then they hypothesized etchings would be distinct based on time and geography, Erard reports.

While newer etchings were more clearly defined than older ones, the students weren’t able to distinguish the etchings from others, failing the researchers’ basic test for symbolic status.

“That suggests that we’re not looking at a symbolic system in the sense that each marking has an individual meaning,” lead researcher Kristian Tylén said at Evolang, a biannual conference on the evolution of language, last week.

But the findings are not conclusive. Instead, as Erard notes, they offer another way to consider early human engravings.

Back in 2014, the discovery of 13 marks in Gibraltar’s Gorham’s Cave believed to be by Neanderthals also excited attention about early “rock hashtags.” But as Iain Davidson, emeritus professor of humanities at the University of New England, cautions in The Conversation, determining the intent of the scratched patterns is complicated.

What’s less complicated? The modern history of the hashtag. Now used as a symbol to identify a group of tweets around the same topic, the hashtag, or pound sign, has a fascinating history, as Ben Panko reported for Smithsonian.com last year. It is believed to date back to the Romans, who wrote “lb” with a horizontal line, or tilde, above the letters, to denote an abbreviation. It was later used as a symbol for numbers and then as a symbol on telephones before becoming ubiquitous on social media.

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