An analysis of the markings found on hundreds of eggshell fragments dating back more than 60,000 years, unearthed between South Africa and Namibia, has revealed our ancestors’ remarkable ability to organize visual space according to abstract principles
Peer-Reviewed PublicationAt several archaeological sites in southern Africa, hundreds of highly unusual fragments of ostrich eggs have been found. Dating back more than 60,000 years, the shells were engraved by groups of Homo sapiens who lived in that region.
A new investigation, led by researchers from the University of Bologna, has now revealed for the first time that these engravings on ostrich eggshells were not random or improvised, but followed recurring and surprisingly organised geometric rules. The study — published in the journal PLOS One — shows the presence of a genuine cognitive organisation of forms, based on parallelism, orthogonality and the repetition of lines and regular patterns.
“These signs reveal a surprisingly structured, geometric way of thinking,” says 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 organised them according to recurring principles — parallelisms, grids, rotations and systematic repetitions: a visual grammar in embryo.”
The ostrich eggshells were most likely used as water containers. The researchers carried out a quantitative and systematic investigation of 112 fragments from two South African archaeological sites (Diepkloof and Klipdrift) and one site in Namibia (Apollo 11). By applying methods of geometric and statistical analysis never previously used on these artefacts, the study made it possible to reconstruct in detail the lines, angles and trajectories of the markings.
The results show that more than 80% of the configurations analysed display coherent spatial regularities, with repeated use of angles close to 90° and groups of parallel lines. The most complex compositions — such as hatched bands, grids and diamond-shaped motifs — reveal cognitive operations of rotation, translation, repetition and “embedding”, i.e. the ability to build hierarchical levels of signs within the same surface.
“These engravings are organised and consistent, and show mastery of geometric relationships,” Ferrara explains. “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.”
Beyond the possible meanings of the markings, the authors stress that the implications of the study concern above all the cognitive foundations that made it possible to create these decorations. The ability to construct visual configurations structured according to specific rules can be seen as a key indicator of the emergence of abstract thought — a crucial step in the evolution of human thinking.
“Our analysis shows that Homo sapiens 60,000 years ago already possessed a remarkable ability to organise visual space according to abstract principles,” notes Valentina Decembrini, 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 characterised our history over millennia, from the creation of decorations to the development of symbolic systems and, ultimately, writing.”
The study was published in PLOS One under the title “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.
The research was carried out as part of the FIS Advanced project SAPIENCE – Symbols, Preliteracy and Code Evolution, directed by Professor Silvia Ferrara, in collaboration with Professor Enza Spinapolice of Sapienza University of Rome.
Journal
PLOS One
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