Hashtags have become a standard in communication. They emerged as a way to organize and identify content on social media and evolved into an entire experience of subspeak. It was a suggestion from technologist Chris Messina that a gained a momentum of its own. People use hashtags to tag and organize their content and find and follow information, but also to add descriptions or color to their commentary which can range from sarcasm to sentimentality. Archaeologists have uncovered what may be the world’s oldest example of the ubitquitous cross-hatched pattern drawn on a silcrete flake in the Blombos Cave in South Africa. Yes, we’re seeing what we want to see in an abstract drawing. I think we can say with certainty that the creators of this instance of the symbol did not attribute the same meaning or significance to it that we do. What is exciting about this find — aside from its connection to the forms of media that hold our attention today — is that it represents the oldest example of abstract art that we have uncovered.
The Blombos Cave has been undergoing excavation since 1991 with deposits that range from the Middle Stone Age (about 100,000 to 72,000 years ago) to the Later Stone Age (about 42,000 years ago to 2,000 years BCE). The Middle Stone Age deposits include artifacts linked to the Still Bay complex, a technology characterized by the use of heat to manipulate stones used for tool production. Members of the Still Bay culture heated the flakes they intended to shape, which increased the length of the flakes that could be removed and increased the precision of fractures by causing the stone to react more uniformly to breaks when hit. This would have meant cleaner cuts by the creator. Artifacts recovered from the Middle Stone Age deposit include bone awls and spear points from the Still Bay culture, as well as beads made from Nassarius kruassianus shells (which are also a favorite of hermit crabs), and engraved pieces of ochre.
Ochre is a naturally occurring pigment derived from iron oxide with which we, as a species, have a long history. The artwork of the Lascaux Caves is a prominent example of prehistoric use of the pigment for drawing and imagery, but it has been used throughout our history for drawings, to decorate pottery, and for tattoos — and potentially as a medicine and glue additive. It can range in color from yellow to red with color intensity determined by oxidation and hydration. The Middle Stone Age layer of Blombos contains a lot of naturally occurring ochre, used ochre, and engraved ochre. (The latter is literally what it sounds like: ochre specimens with carvings etched into them.) The oldest Middle Stone Age layer also revealed a toolkit designed to create a pigmented compound that could be stored in abalone shells. The supplementary evidence retrieved demonstrates the potential for creativity.
The now famous cross-hatch is evident on a silcrete flake retrieved from the “newer” Middle Stone Age layers at Blombos, which dates it closer to 72,000 years old. In the image above, the hashtag is the image on the left — it’s harder to see than in the article itself which pulls it out into a line drawing. The flake was discovered in 2011 (#thatishowlongitcantakeresearchtobepublished #seriously), and based on the exterior characteristics of the artifact, researchers can tell it was a constructed implement. The side on which the drawing is displayed is smoother than the other sides and contains microscopic haematite-rich residues — the flake itself was likely a grindstone for processing ochre. How do we know then that the markings are intentional then and not left over ochre that happens to display a pattern that we’ve recognized? Experimental recreation revealed that the pattern of the symbol is consistent with ochre crayon use. Researchers recreated the image using ochre crayons and ochre paint and found that the discontinuous nature of the drawing more closely matched crayon use. Think if the pressure generated when a crayon is applied to a hard surface as opposed to a sheet of paper: there are often breaks or gaps in the coloration as the crayon meets resistance from the material. Researchers were also able to determine that the width of the lines indicated the number of crayon strokes used to generate the marking. For example, the thickness of one the lines on the right indicate that several strokes were necessary for the imprint while only one stroke was used for the other lines.
Prehistoric artwork fascinates us because it gives us insight into the imaginations (and experiences) of our evolutionary ancestors. Recovered artifacts of prehistoric abstract engravings generally pre-date the Later Stone Age (~42,000 years ago) in Africa and the Upper Paleolithic (~44,000 years ago) in Europe. For example, an engraved shell from Trinil dates to 540,000 years ago and engraved ostrich egg shells from Diepkloof and Klipdrift Shelter date to 65,000 – 59,000 years ago. The oldest known examples of abstract art, however, are generally from younger sites that post-date 42,000 years ago, such as Chauvet (~32,000 years old) and Maros (~39,000 years old). This example from Blombos is at least 30,000 years older than this find .
The artifacts and artwork at Blombos tell us that early humans were engaged in creative expression. They were creating markings and coloring for their own purposes but they were doing so using recognized techniques. The Blombos hashtag shows us that they were able to apply similar designs to multiple media. While it’s exciting to think about this find in terms of what this symbol means to us today, ultimately it’s an abstract marking to which we ascribed a more relevant meaning. We want to see ourselves in the past. It justifies who we are and makes us comfortable with our behavior. The find not any less exciting on it own, however. Any evidence we find of early human activity helps us better evolutionary past, and that is always newsworthy.