Location of Discovery
Researchers at Columbia University's Lamont-Doherty Earth Institute recently dated Acheulean tools found in Lake Turkana, Kenya as 1.76 million years old, making them the oldest known specimens of this type. Previously, Acheulean tools were believed to have developed between 1.4 to 1.6 million years old.
The tools were discovered in a sediment level which also contained Homo erectus skulls, indicating that this species was responsible for their production. Interestingly, Oldowan artifacts were found alongside the Acheulean ones. The Oldowan tools consisted of sharp stone flakes and rock cores. Oldowan technology, described as "earlier and simpler" in the New York Times Article "Earliest Signs of Advanced Tools Found," is believed to have originated around 2.6 million years ago.
The idea that the two technologies could coexist should not be surprising, yet the Times article makes a point of stating, "It was possible that the Acheulean technology was imported from a place yet to be identified," before acknowledging the possibility that it originated within the area. Even after the idea of local development is addressed, the article quotes "archaeologists and geologists" involved in the discovery as "concluding that there may have been multiple groups of hominids 'distinguished by separate stone-tool-making behaviors and dispersal strategies' co-existing in Africa 1.76 million years ago."
The article does not (probably deliberately) incorporate terms associated with a linear archaeological timeline, such as Old Stone Age, Early Stone Age, or even Modes 1 and 2 (terms which correspond, respectively, to Oldowan and Acheulean technologies). However, the references to Acheulean tools as "more advanced" and "more sophisticated" than the Oldowan ones indicate the pervasiveness of the underlying assumption that evolution follows a linear progression.
The article's subject, the discovery of the coexistence of both types of tools, contests this assumption, yet the author still manages to incorporate it. The idea that the Acheulean technology must have either been brought in from an outside source or developed by groups separate from those using Oldowan technology ignores the possibility that one group could be using both types of tools at once. Perhaps Oldowan tools were better suited for certain purposes, they were easier to make, or the materials used to make them were more readily available and thus groups continued to make them alongside the Acheulean ones.
Dr. Ian Tattersall of the American Museum of Natural History was quoted in the article as being surprised that "the Acheulean evidently didn't catch on widely for several hundred thousand years after it was invented." It makes sense that he would be surprised if the existence of a linear timeline is taken for granted - why would anyone continue to use an outdated and rudimentary tool when given the option of a newer model? The fact that the two types coexisted indicates that there is no linear progression from one to the other, and therefore it is inaccurate to classify Oldowan technology as less advanced just because it developed first.
In fact, Mode 5 microliths, often classified as the "most advanced" form of Stone Age tools, have been discovered at Howieson's Poort and Stillbay in South Africa dated between 70,000 and 65,000 years ago. However, the use of these microliths disappeared, and the Mode 3 technology returned. The Mode 5 microlithic technology did not reappear again until thousands of years later. The Mode 3 prepared cores must have served some purpose, then that the Mode 5 tools could not fulfill at the time, indicating that the Mode 5 microliths are not necessarily more useful or more refined. This example demonstrates the incompatibility of a purely linear framework with archaeological evidence.
The assumption that certain technologies are inherently better than others is especially problematic given that certain groups still use stone tools in their everyday lives. Ethnographic analysis of these groups, then, can place them in the past without acknowledging their histories and their change over time. Although archaeologists have attempted to move beyond C.J. Thomsen's Three-Age System, they have, for the most part, simply created new idioms for their linear timelines. Even when the archaeological evidence visibly contests this notion, there can be a tendency to try to interpret it in a way that remains in accordance with these deeply embedded assumptions. In order to accurately analyze the actions of ancient hominids, how can we rid ourselves of the restrictions inherent in linear thinking?