The Backbone of Archaeological Dating

Seriation, Stratigraphy, and Index Fossils: The Backbone of Archaeological Dating by Michael J. O’Brien and R. Lee Lyman presents a distinctly New World take on chronology building, an activity central to archaeological inquiry. The authors are prolific evolutionary archaeologists whose interest in chronology building links them to the New World culture historians of the early twentieth century and puts them in opposition to the synchronic functionalist tendencies of the New Archaeology cum processualism that flourished in the second half of the century.

The book begins with a chapter that presents some general thoughts on time and dating, followed by a chapter on constructing time-sensitive artifact classifications. Seriation is covered in two chapters, with a chapter on phyletic seriation followed by one on frequency and occurrence seriation. Chapters on stratigraphy and cross dating are followed by a concluding discussion that contrasts efforts to measure time continuously and discontinuously.

Perhaps the best way to read this book is as an attempt to resurrect the goal of historical inference for New World archaeology by dispelling the hangover from a generation of reactionary processualism, when New World archaeologists typically ignored or disparaged historical inference. A big part of O’Brien and Lyman’s program is to pick up the threads of culture history that Robert Dunnell, a student of the eminent culture historian Ben Rouse at Yale, wove into the evolutionary archaeology he championed in opposition to processualism. O’Brien and Lyman have authored many books and articles on New World culture history and much of that material finds its way into this book. This material is often fascinating and useful for the practice of historical inference, but the reader expecting a primer on the backbone of archaeological dating might tire of these long historical digressions.

The book strongly reflects its New World perspective and mostly ignores archaeological practice in the Old World, where processualism’s pernicious anti-historicism had less effect. I found it jarring that the chapter on stratigraphy doesn’t mention the Harris Matrix, which was developed on urban sites in England to account for the complexity of cultural stratification there. Harris’s Principles of Archaeological Stratigraphy, first published in 1979, clearly sets out the laws of archaeological stratigraphy that are applicable everywhere, including the stratigraphically simpler sites of the New World. Here, the long history of stratigraphic excavation in the New World and the question of whether or not, and how, stratigraphic excavation revolutionized New World archaeology lead to a stern warning about the supposed dangers of measuring time discontinuously based on stratigraphic boundaries. Well, yes, it is possible to misinterpret stratigraphic evidence and artifact assemblages defined on the basis of stratigraphic evidence, but more important than these caveats are the ways archaeologists have made productive use of contextual information to further the cause of historical inference, where it plays a crucial role. Old World archaeologists have a long practice of deductively correlating stratigraphically defined artifact assemblages with reference to periods defined by assemblages excavated at a type site—a topic ignored in this book. Here, the peculiar history of New World archaeological practice makes it difficult to maintain a focus on the pragmatic goal.

Another topic conspicuously missing from this book is Bayesian calibration. Bayesian calibration defines a statistical procedure for combining information from the backbone of archaeological dating with various absolute dating techniques to derive age estimates that help place historical inference on the strongest possible chronological footing. This absence is reasonable due to several factors: the authors’ choice to limit the book to the practice of deductive correlation based on comparisons of artifact assemblages and not to discuss inductive correlation based on absolute dating; the novelty of Bayesian calibration in 1999 when this book was published; and New World archaeologists’ reticence to adopt Bayesian calibration, an attitude that continues to retard the diffusion of this now common Old World practice to the New World.

Similarly, the long chapters on seriation do a good job detailing its historical development in the New World, but omit any discussion of seriation by correspondence analysis which was then, and continues to be, the preferred technique used by Old World archaeologists to seriate artifact assemblages.

This is a good book that continues to fill an important niche in the archaeological literature. It was, however, a book clearly produced in response to the hangover from the excesses of New World processualism. It does an admirable job resurrecting the important threads of culture history rashly dismissed by the New Archaeologists cum processualists. However, the hangover had the effect of muddling the presentation by neglecting important advances in Old World practice whose uptake in the New World had been slowed by the sway of processualism.

New World archaeologists might benefit from the sympathetic review of the book by the Old World archaeologist and Bayesian, Andrew Millard.