Ancient Engravings on Ostrich Eggshells Highlight Early Abstract Thought in Homo Sapiens

Archaeologists in southern Africa have uncovered hundreds of engraved ostrich eggshell fragments dating back over 60,000 years, created by early Homo sapiens. A study led by researchers at the University of Bologna reveals that these engravings exhibit a structured geometric order, challenging previous assumptions that they were merely random scratches or decorative patterns.

Published in PLOS One, the research analyzes 112 fragments from archaeological sites in South Africa—specifically Diepkloof and Klipdrift—and one site in Namibia known as Apollo 11. The ostrich eggshells, likely used for carrying or storing water, display organized engravings that follow geometric principles, such as parallel lines and right-angle relationships.

Professor Silvia Ferrara, who coordinated the study, noted, “These signs reveal a surprisingly structured, geometric way of thinking. 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.”

Geometric Patterns and Statistical Analysis

The researchers employed geometric and statistical methods previously unapplied to such artifacts to reconstruct the paths, angles, and orientations of the engraved lines. The analysis uncovered that over 80% of the configurations demonstrated consistent spatial patterns, with frequent appearances of angles close to 90° and sets of parallel lines. Some designs, featuring hatched bands and diamond motifs, also showed complex attributes such as rotation, translation, and hierarchical embedding.

“These engravings are organized and consistent, and show mastery of geometric relationships,” Ferrara adds. “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.”

Significance of Early Abstract Thought

The study underscores that the significance of these engravings extends beyond their individual meanings. The ability to create visual designs with consistent rules points to a developing capacity for abstract thought among early humans.

Valentina Decembrini, a PhD student and first author of the study, stated, “Our analysis shows that Homo sapiens 60,000 years ago already possessed a remarkable ability to organize visual space according to abstract principles. Transforming simple forms into complex systems by following defined rules is a deeply human trait that has characterized our history over millennia.”

The findings are part of a broader project titled SAPIENCE—Symbols, Preliteracy and Code Evolution—led by Professor Silvia Ferrara in collaboration with Professor Enza Spinapolice from Sapienza University of Rome. The study is published under the title “Earliest Geometries. A Cognitive Investigation of Howiesons Poort Engraved Ostrich Eggshells.”