This news is important in its own right:
Surprisingly old stone points found in a Mexican cave are the latest intriguing discovery among many to raise questions about when humans really arrived in the Americas.
For most of the 20th century archaeologists generally agreed that humans who had crossed the Beringia land bridge from Siberia to North America only ventured further into the continent only when retreating ice sheets opened a migration corridor, about 13,000 years ago. But a few decades ago, researchers began discovering sites across the Americas that were older, pushing back the first Americans’ arrival by a few thousand years. Now, the authors of a new study at Mexico’s Chiquihuite cave suggest that human history in the Americas may be twice that long. Put forth by Ciprian Ardelean, an archaeologist at the Autonomous University of Zacatecas (Mexico), and his colleagues, the new paper suggests people were living in central Mexico at least 26,500 years ago.
Ardelean’s work was published in Nature and paired with another study that presented a broader look at 42 known early human sites across North America from the Bering Strait to Virginia. Data from those sites were used to model a much earlier peopling of the Americas, and help scientists reimagine not only when but how the first people reached and populated the New World. The model features a number of archaeological sites, including Chiquihuite cave, which are intriguing but controversial enough, as experts disagree whether the sites actually evidence human occupation.
Here is the Smithsonian article. Of course I also wonder what is the rational Bayesian update? That it takes longer to build a civilization than we had thought? That people are more mobile than we had thought? How much mobility precedes civilization? All seem to be true. Perhaps the truly scarce input in human history is “conceptual categories, understood properly in the relevant context.” If those categories are very difficult to come by, it would help explain why the flowering of civilizations indeed did not follow immediately from these migrations, or indeed from the origin of mankind. So this is partly a victory for Paul Romer’s theories, noting that the necessity of context may mean these ideas are not pure public goods in any simple sense. You can’t just drop into Mexico, circa B.C. 3000 and bark out “here’s what the Mayans and Aztecs did!”. Arguably the context as the scarce part is more important than the idea proper.