Is the accuracy of lithic use-wear studies unacceptable?

Stone tools are frequently examined microscopically to locate, identify and interpret use-wear traces.  Since the 1970s lithic assemblages have been studied this way by various labs, using different microscopic techniques to reconstruct their functions. However, the objective nature of these analyses can be, and have been, questioned and a recent paper by Adrian Evans stresses the need for a wider use of blind-testing in lithic functional studies.

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20 blind testing studies have been conducted so far, showing an interesting chronological pattern. The majority were conducted throughout the 1980’s and early 1990’s with only a few recent studies, all performed by the same researcher. This indicates the general perception that the method has reached a stage of maturity where less methodological check-ups are required. Evans describes the varying designs of these blind tests and then goes on to compare their results (as far as possible) for the identification of four main worked materials: wood, antler, bone and hide. The blind test results average around 42.7%, although the author correctly points out this figure cannot be extrapolated to applied use-wear studies. It is interesting how wood and bone/antler working are frequently mistaken for each other. Stone tools used in bone working are commonly interpreted as unused and identifying hide working seems to be hard since it is commonly mistaken for various other use-wear traces.

Evans refutes several critiques of previous blind tests and points out their common use in other disciplines such as faunal analysis, palynology and human osteology. Overall, the take away message is the need for a wider dataset of blind test results to be able to upgrade current methodological practices. A great example is radiocarbon dating where inter-laboratory comparisons are commonplace, labs go through anonymous tests, and the results are used to infer the accuracy of the method.  Evans states that if micro-wear analysis is to become an accepted archaeological science real steps in understanding and methodological development must be made.

This paper fits in nicely with recent work by Rots and Plisson which questions how impact traces can be identified. We seem to have reached a point for a new methodological reevaluation of lithic functional studies and of great importance is the creation of a new large, comparable set of blind-test data, which can hopefully help reduce the subjectivity of lithic use-wear analyses in the (near) future.

Reference: Adrian A. Evans. On the importance of blind testing: the example from lithic functional studies.
Journal of Archaeological Science, Available online 1 December 2013.

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One thought on “Is the accuracy of lithic use-wear studies unacceptable?

  1. It’s an interesting paper. Nevertheless wear identification process is complex and most of the time you can only identify part of it. I’ll explain myself. Use-wear identification is completely dependent on preservation, intensity and duration of activity, and the material which has been processed. Sometimes you have enough elements to correctly identify material and task, but when you are working with paleolithic materials, most of the time you can infer the movement or the relative hardness of the worked material. There is something I call the confidence pyramid, at the top you have the correct and complete identification, at the bottom the pieces where you are only able to identify that they have been use. Maybe you are not getting ALL the information, but you still have some useful data. Of course derived interpretation will be more or less robust. It is similar with faunal analysis. You can have a huge collection of bone fragments, where you can identify some of them, in some cases the anatomical part, for some others the species, but sometimes you can only say medium herbivore or simply that they are bone fragments. We should be aware of the robustness of our identifications and be honest with the interpretations we are building from them.

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