Ancient ostrich-eggshell art reveals rule-based geometry in early humans

Researchers have shown that 60,000-year-old ostrich-eggshell engravings from southern Africa follow systematic geometric rules, indicating sophisticated visual cognition.

Archaeologists working at Diepkloof, Klipdrift and the Apollo 11 site uncovered hundreds of ostrich-eggshell pieces dated to more than 60,000 years ago. Using quantitative geometric and statistical methods, a University of Bologna team reconstructed the line directions and angles on 112 fragments, finding that over 80 % displayed consistent spatial patterns such as parallel lines, right-angle relationships and grid-like arrangements.

The researchers interpret these regularities as evidence that the engravers mentally planned complex designs, employing concepts like rotation, translation and hierarchical embedding. Lead author Valentina Decembrini and colleagues argue that this level of visual planning marks an early emergence of abstract, rule-governed thought in Homo sapiens. The paper, titled “Earliest Geometries,” appears in PLOS One and was produced under the FIS Advanced SAPIENCE project in collaboration with Sapienza University of Rome.