Ana Reif
A major reevaluation of radiocarbon dating narrows down the period when Neandertals and modern humans may have exchanged cultures in France and Northern Spain.
The Châtelperronian tradition is a culture localized to France and Northern Spain around 45,000-40,000 years ago. The culture is particularly interesting to scientists studying Neandertal/modern human relationships, as it may be evidence that populations of the two groups lived side-by-side for a time. Though it bears remarkable similarities to contemporaneous modern human cultures, the Châtelperronian tradition is usually attributed to Neandertals, as scientists assume no modern humans were present in the area at the time it was invented. There are a few different interpretations of the similarities between this culture and modern human cultures. First, it is possible that Neandertals, being cognitively similar to modern humans, made technological innovations in parallel to modern human cultures. Alternatively, because certain innovations usually associated with modern humans like thin, precise blades have only so far appeared in later Châtelperronian caches, some argue that a brief intrusion of modern humans into Neandertal territories resulted in Neandertals trading, looting, or learning how to make modern human tools. Otherwise, it is possible that the Châtelperronian tradition is not a distinct Neandertal culture, but instead separate depositions of Mousterian (Neandertal) and Aurignacian (modern human) cultures that scientists have mistakenly attributed to the same time period because post-depositional disturbances.
Châtelperronian artifacts from Grotte du Renne in France
Aurignacian artifacts from southern France
Recently, scientists have been reevaluating radiocarbon dates from around 40,000 years ago due to the discovery of the Laschamp event– a short reversal of the Earth’s magnetic field– which would have messed with the amounts of Carbon-14 in the atmosphere, resulting in the inaccurate dating of fossils from around this time. Recognizing this revelation’s relevancy to the Châtelperronian problem, Djakovic et al. (2022) set out to redate many of the Neandertal and modern human fossils in the Châtelperronian region using a new calibration standard that corrects for the Laschamp event. They chose the earliest modern human and latest Neandertal direct dates to make a conservative estimate of overlap, and then used Bayesian models to estimate the start and end dates of Châtelperronian and (presumed intruding) Aurignacian cultures with the same dataset. These dates combined suggested a population overlap between 1,400-2,900 years in the region, plenty of time for not only genetic but cultural diffusion between populations.
These findings do not support any theory concerning the origins of the Châtelperronian tradition over others, they simply narrow the Neandertal/modern human overlap in this specific region to a period of a few thousand years and reaffirm that cultural exchange is one likely scenario. Additionally, these findings are significant as there is plenty of evidence of interaction between modern humans and Neandertals in the form of genetic exchange, but little consensus on where or when this exchange occurred.
Read more:
Djakovic, I., Key, A. & Soressi, M. Optimal linear estimation models predict 1400–2900 years of overlap between Homo sapiens and Neandertals prior to their disappearance from France and northern Spain. Sci Rep 12, 15000 (2022). https://doi.org/10.1038/s41598-022-19162-z