Fast and slow science and the Palaeolithic dating game

Abstract

Accurate and precise dating is critical to our ordering of human fossils and the Palaeolithic behavioural record. Only with such secure dating can we understand the sequence of human evolution and dispersals across the old and new worlds, and the behavioural innovations that constitute the major changes within the Palaeolithic; we are then able to view these in the context of the remarkably unstable climatic conditions that characterise the Pleistocene. For the last 50 000 years of the Upper Pleistocene (the latter part of the Middle Palaeolithic and the Upper Palaeolithic), radiocarbon dating—these days almost entirely undertaken with accelerator mass spectrometry (AMS)—forms the most accurate and precise, and hence preferred, chronometric method. The above paper by Kuzmin (2019) reflects a recurring question in relation to this method—what kind of bone sample should produce the most accurate dates: those on general collagen or those on a specific single amino acid extracted from that collagen? The debate relates to whether the latter should be adopted, on the basis that, as this amino acid derives only from bone, the technique effectively eliminates any contamination that would affect the accuracy of the determined ages. When the AMS radiocarbon dating of bone collagen was being developed in the 1980s, the amount of bone required for the process was too large to facilitate the dating of valuable fossils. This situation soon changed as chemical pre-treatment methods reduced the necessary sample size. Similarly, although it was possible in the 1990s to extract single amino acids, the amount of bone required precluded the use of this particular method on all but the largest of herbivore bones. Now, in turn, radiocarbon dating based on single amino-acid samples has come to represent the next generation of radiocarbon dating. The questions that Kuzmin poses about dating based on single amino acids are: is it accurate? Is it a suitably reliable replacement for ‘generic’ collagen dating? And, should we discard the dates produced by other methods? There are several issues here that should concern us. First, I have ethical reservations about the ease with which the finite number of Palaeolithic human remains known to us are repeatedly re-drilled and re-dated whenever a new pre-treatment method becomes available. Why run straight to the hominin fossils when techniques should surely be tested extensively on the far more abundant animal remains first? I am concerned that, in the name of dating, the surfaces of a number of these, usually very small and precious, remains increasingly resemble a pocked lunar surface. My ethical concerns about this high-profile Palaeolithic ‘dating game’ result from the focus on (decontextualised) human remains and the limited research agendas around them. As Kuzmin correctly implies, these too often seem to be ‘how old is this human sample, and might it be found to be older than the last