40,000-year-old signs show humans were recording information long before writing

Using computational techniques, the researchers analyzed more than 3,000 signs carved into 260 Paleolithic artifacts to better understand how writing may have evolved. Their results, which were published in PNAS, were clear -- and even the team did not expect such a close comparison to early writing systems.

Paleolithic Symbols in the Swabian Jura

Artifacts dating from 34,000 to 45,000 years ago feature recurring patterns of lines, dots, notches, and crosses. Many were found in caves in the Swabian Jura region of southwestern Germany. In Vogelherd Cave in Lone Valley, for example, archaeologists uncovered a small mammoth figurine carved from mammoth ivory. Its surface is marked with rows of crosses and dots.

Other objects from the same region also contain similar engravings. The 'Adorant', a mammoth ivory plaque discovered in Geißenklösterle Cave in the Ach Valley, shows a lion-human hybrid figure and is covered with rows of dots and notches. Another well known sculpture, the Lion Human from Hohlenstein-Stadel Cave in Lone Valley, includes evenly spaced notches along one arm.

Researchers now conclude that these markings were purposeful. Stone Age people likely used them to communicate or store information. "Our research is helping us uncover the unique statistical properties -- or statistical fingerprint -- of these sign systems, which are an early predecessor to writing," says Professor Christian Bentz.

A Widespread Stone Age Sign Tradition

According to Dutkiewicz, the Swabian Jura is just one of several key areas where such symbols appear. "The Swabian Jura is one of the regions where objects with this type of sign have been found most frequently, but there are, of course, other important regions. Countless tools and sculptures from the Palaeolithic, or the Old Stone Age, bear intentional sign sequences," she explains.

The researchers travel across Europe to museums and archaeological sites to identify additional examples. "There are many sign sequences to be found on artifacts. We've only just scratched the surface," says Dutkiewicz, who serves as a research associate and curator of the Stone Age department at the Staatliche Museen zu Berlin.

These artifacts come from a time long before formal writing, when Homo sapiens had recently migrated from Africa into Europe and encountered Neanderthals. Supported by funding from the European Research Council, the research team is investigating how early humans encoded information through visual symbols.

Information Density Comparable to Proto Cuneiform

The team examined more than 3,000 geometric signs across roughly 260 objects using computational analysis. Their goal was not to decipher the symbols, which remain undecoded, but to measure their structural properties. "There are plenty of theories, but until now there has been very little empirical work carried out on the basic, measurable characteristics of the signs," Bentz explains.

By studying how frequently signs appear and how predictable they are within sequences, Bentz compared these Paleolithic markings to proto-cuneiform and modern writing systems. "Our analyses demonstrate that these sign sequences have nothing to do with the writing systems of today, which represent spoken languages and are characterized by high information density. In contrast, the signs on the archaeological objects are frequently repeated -- cross, cross, cross, line, line, line. This type of repetition is not a feature found in spoken language," he says.

Even so, the overall information density of the Paleolithic signs closely matches that of the earliest proto-cuneiform tablets from ancient Mesopotamia, which emerged about 40,000 years later. "Sign sequences in proto-cuneiform script are also repetitive and the individual signs are repeated at a similar rate. In terms of complexity, the sign sequences are comparable," Bentz adds. Dutkiewicz notes, "Figurines exhibit higher informational density than do tools."

The similarity surprised the researchers. "We hypothesized that the early proto-cuneiform script would be more similar to the writing systems of today, especially due to their relative proximity in time. Yet the more we studied them, the clearer it became that the early proto-cuneiform script is very similar to the much older Paleolithic sign sequences." Bentz explains that around 5,000 years ago, a new writing system emerged that directly represented spoken language and displayed very different statistical patterns.

Computational Tools Reveal Ancient Encoding Systems

To conduct their analysis, the team digitized the sign sequences into a database and evaluated them using tools from quantitative linguistics, including statistical modelling and machine learning classification algorithms. They assessed how much information the signs could potentially convey and compared that capacity with early cuneiform and modern writing.

"Because of the high rate of repetitions and the high predictability of the next sign, we were able to show that the entropy -- a measure of information density -- is comparable to that of proto-cuneiform, which came much later," says Bentz. He emphasizes that the human ability to encode information developed gradually over tens of thousands of years. "The human ability to encode information in signs and symbols was developed over many thousands of years. Writing is only one specific form in a long series of sign systems."

Bentz also points out that encoding remains fundamental to modern technology. "We continue to develop new systems for encoding information. Encoding is also the basis of computer systems." Large language models, a prominent form of artificial intelligence, rely on the predictability of language sequences to determine which part of a word is likely to appear next.

What Were Stone Age Humans Recording

The study does not determine exactly what information these symbols conveyed. "But the findings can help us to narrow down potential interpretations," says Dutkiewicz. Although modern societies benefit from thousands of years of accumulated knowledge, anatomically modern humans of the Paleolithic period had cognitive abilities comparable to ours.

The ability to record and share information may have helped early humans coordinate groups and survive. The objects themselves suggest portability. 'They were highly skilled craftspeople. You are able to see that they carried the objects with them. A lot of the objects fit right in the palm of your hand. That is another way in which the objects are similar to proto-cuneiform tablets,' Dutkiewicz explains.

This research is part of the project 'The Evolution of Visual Information Encoding' (EVINE), funded by an ERC Starting Grant from the European Research Council. Professor Christian Bentz joined Saarland University in 2025 and now leads the EVINE project. The initiative began at the University of Tübingen and later continued at the University of Passau at the Chair of Multilingual Computational Linguistics. Bentz and Dutkiewicz are working to trace how visual information systems evolved from the earliest symbolic markings to modern writing. (ERC, EVINE, 101117111).