A research group led by Daniel Adler of the University of Connecticut have overturned long-held wisdom about the spread of tool-making technology among Stone-Age populations. Ancient humans in Africa and Eurasia created sharp flake-based stone tools about 400,000-200,000 years ago, a distinctive technological advance from earlier hand-axes. Paleoanthropologists previously hypothesized that humans in Africa invented this technology, then migrated to Europe (bringing the stone-making techniques with them). Now, however, Adler et al. have evidence that this technology arose multiple times independently.

Flake tools, known as Levallois tools, are smaller and slightly different than African ones. Further, Levallois tools in a site in modern-day Armenia (the Nor Geghi region) were preserved next to old bifacial (hand-ax) tools. Adler et al. argue that ifLevallois tools had swept in from Africa, a superior technology brought by migrating humans, we would not have observed simultaneous production and use of both types of tools.

In short, Levallois tool use in different populations was analagous, not homologous. This technology was not a "'technical breakthrough' that spread from a single point of origin," but it instead "resulted from the gradual synthesis of stone knapping behaviors shared among hominins in Africa and those indigenous to the Acheulian dispersal area in Eurasia. Consequently, the development of Levallois technology within Late Acheulian contexts represents instances of technological convergence."

If the authors are correct, and this technology sprang from "deep-rooted evolutionary processes based on a common technological ancestry," this raises questions about evolutionary history and cultural development. Does shared evolutionary history lead to roughly similar cognitive tracks? Were the limitations of human dexterity, mental processing, and material availability such that they dictated our tool-making strategies? If given the proper nudges and a similar environment, would American Crows produce the same magnificent tools that their New Caledonian cousins create?