Long before writing, people in southern Africa were carving ostrich eggshells with geometric designs that followed clear rules, according to a new study led by researchers at the University of Bologna.
Archaeologists have found hundreds of engraved ostrich eggshell fragments, more than 60,000 years old, at sites in South Africa and Namibia. The study, published in PLOS One, says the markings were far more organized than simple scratches or improvised decoration.
Researchers examined 112 fragments from Diepkloof and Klipdrift in South Africa, and Apollo 11 in Namibia. The ostrich eggshells were probably used as containers for carrying or storing water.
Using geometric and statistical techniques, the team reconstructed the directions, angles and paths of the engraved lines. They found that more than 80 percent of the configurations contained consistent spatial patterns.
Angles close to 90 degrees appeared repeatedly, along with sets of parallel lines. The researchers also identified hatched bands, grids and diamond-shaped motifs that showed rotation, translation, repetition and “embedding,” which the study describes as the ability to build hierarchical levels of signs within the same surface.
“These signs reveal a surprisingly structured, geometric way of thinking,” said Silvia Ferrara, professor at the University of Bologna’s Department of Classical Philology and Italian Studies, who coordinated the study.
“We are talking about people who did not simply draw lines, but organized them according to recurring principles, parallelisms, grids, rotations and systematic repetitions: a visual grammar in embryo.”
Ferrara said the engravings showed “mastery of geometric relationships”.
“There is not only a process of repeating signs: there is real visuo-spatial planning, as if the authors already had an overall image of the figure in mind before engraving it,” she said.
The researchers said the findings point to the mental abilities needed to create visual designs according to consistent rules.
“Our analysis shows that Homo sapiens 60,000 years ago already possessed a remarkable ability to organize visual space according to abstract principles,” said Valentina Decembrini, a PhD student at the University of Bologna’s Department of Classical Philology and Italian Studies and first author of the study.
“Transforming simple forms into complex systems by following defined rules is a deeply human trait that has characterized our history over millennia, from the creation of decorations to the development of symbolic systems and, ultimately, writing.”
The study is titled Earliest Geometries. A Cognitive Investigation of Howiesons Poort Engraved Ostrich Eggshells. The authors are Valentina Decembrini, Ludovica Ottaviano, Mattia Cartolano, Enza Elena Spinapolice and Silvia Ferrara.
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