MEASURING CHRONOLOGICAL UNCERTAINTY IN INTENSIVE SURVEY FINDS: A CASE STUDY FROM ANTIKYTHERA,GREECE*

This paper considers how to make the most out of the rather imprecise chronological knowledge that we often have about the past. We focus here on the relative dating of artefacts during archaeological fieldwork, with particular emphasis on new ways to express and analyse chronological uncertainty. A probabilistic method for assigning artefacts to particular chronological periods is advocated and implemented for a large pottery data set from an intensive survey of the Greek island of Antikythera. We also highlight several statistical methods for exploring how uncertainty is shared amongst different periods in this data set and how these observed associations can prompt more sensitive interpretations of landscape‐scale patterns. The concluding discussion re‐emphasizes why these issues are relevant to wider methodological debates in archaeological field practice.     

A probabilistic framework for assessing spatio-temporal point patterns in the archaeological record

The assessment of spatial patterns in archaeology is hampered by a number of constraints, one of the most serious of which is the intrinsic temporal uncertainty associated with most of the archaeological record. Different types of chronological definition or different degrees of temporal knowledge will suggest different kinds of spatial pattern, ultimately obscuring and restricting our interpretation of the background process, especially in cases where we are seeking a diachronic perspective. This paper addresses these problems by adopting both a probabilistic approach and a more standardised framework for diachronic analysis. First, we define the notion of temporal uncertainty and explore its analytical consequences. Second, we consider two methods by which it might be formally quantified, emphasising (a) the advantages of probability-weighted spatial analysis and (b) the comparison of alternative spatio-temporal patterns via Monte-Carlo simulation. Finally, we apply these methods to a case study that considers the distribution of Middle to Late Jomon (ca.5000–3000 BP) pithouses recorded in the Chiba New Town area of Japan.     

Spatio‐Temporal Modelling As A Way to Reconstruct Patterns of Past Human Activities

This paper examines the possibilities of creating quantified models of past human activities in both time and space. The study area lies in the south‐eastern Czech Republic and western Slovakia. The spatio‐temporal model of behavioural categories was calculated with the help of Monte Carlo simulations and statistical testing. One of the main advantages of our approach is that it admits the probabilistic nature of input data, quantifies them and provides probabilistic results comparable with other proxies. It also presents a less biased way of how archaeological data from regions and periods with low numbers of ¹⁴C datings can be incorporated into models of past population dynamics.     

Geographic Visualization in Archaeology

Archaeologists are often considered frontrunners in employing spatial approaches within the social sciences and humanities, including geospatial technologies such as geographic information systems (GIS) that are now routinely used in archaeology. Since the late 1980s, GIS has mainly been used to support data collection and management as well as spatial analysis and modeling. While fruitful, these efforts have arguably neglected the potential contribution of advanced visualization methods to the generation of broader archaeological knowledge. This paper reviews the use of GIS in archaeology from a geographic visualization (geovisual) perspective and examines how these methods can broaden the scope of archaeological research in an era of more user-friendly cyber-infrastructures. Like most computational databases, GIS do not easily support temporal data. This limitation is particularly problematic in archaeology because processes and events are best understood in space and time. To deal with such shortcomings in existing tools, archaeologists often end up having to reduce the diversity and complexity of archaeological phenomena. Recent developments in geographic visualization begin to address some of these issues and are pertinent in the globalized world as archaeologists amass vast new bodies of georeferenced information and work towards integrating them with traditional archaeological data. Greater effort in developing geovisualization and geovisual analytics appropriate for archaeological data can create opportunities to visualize, navigate, and assess different sources of information within the larger archaeological community, thus enhancing possibilities for collaborative research and new forms of critical inquiry.     

SahulTime: Rethinking Archaeological Representation in the Digital Age

SahulTime is an experimental development project to explore how archaeological knowledge might best be represented within a digitally native mode. The system incorporates an interactive, zoomable timeline with a changing geographic view, time-aware icons and detail-boxes that can themselves express temporal visualisations. The core knowledge domain currently represented is Australian archaeology in the context of changing sea-level, but the visualisation concepts developed are more generally applicable at a global level on all timescales, and may offer a first step towards the ‘Digital Earth’ vision of a top-down interface for exploring the world and its history.     

Confidence Factor?

Eurocode 8 Part 3 (EC8-3) is devoted to assessment and retrofitting of existing buildings. In order to take into account the uncertainty in the knowledge of structural properties, EC8-3 defines, analogously to the ordinary material partial factors, an adjustment factor, called “confidence factor (CF),” whose value depends on the level of knowledge (KL) of properties such as geometry, reinforcement layout and detailing, and materials. This solution is plausible from a logical point of view but it cannot yet profit from the experience of its use in practice, hence it needs to be substantiated by a higher level probabilistic analysis accounting for and propagating epistemic uncertainty (i.e., incomplete knowledge of a structure) throughout the seismic assessment procedure. This article investigates the soundness of the format proposed in EC8-3. The approach taken rests on the simulation of the entire assessment procedure and the evaluation of the distribution of the assessment results (distance from the limit state of interest) conditional on the acquired knowledge. Based on this distribution, a criterion is employed to calibrate the CF values. The obtained values are then critically examined and compared with code-specified ones. The results pinpoint a number of deficiencies that appear to somewhat invalidate the approach. The methodological significance of the work extends beyond the assessment procedure in EC8-3, since similar factors appear in other international guidelines (e.g., the knowledge factor of FEMA356).     

Snapshots of History and the Nature of the Archaeological Image

By its very definition, archaeology is situated at the intersection of the material and the temporal worlds. Photography is similarly positioned, and yet it can be manipulated to produce constructed contexts according a photographer’s agenda. In order to explore how the abilities and limitations of archaeology and photography are entwined I examine the representational power of the photograph and the phenomenon of Japanese tourist photography. I then discuss the construction of archaeological photographs, both in practice and in the prescribed theory contained archaeological methods textbooks, as well as how photographs are used to represent the embodied, physical performance of archaeology.     

The Importance of Multiple 14C Dates from Significant Archaeological Contexts

Radiocarbon (¹⁴C) dates are the most important means for determining the age of Holocene archaeological deposits. The theoretical physical basis of this method is by now unassailable, having been consistently tested and refined over two generations. However, the means by which this method has been applied and the interpretation of these results remain as key issues, particularly for complex archaeological discoveries that substantially affect our understanding of world prehistory and social evolution. Many factors can produce uncertainty or variation in the ¹⁴C concentrations of samples, even those that have been selected from the same archaeological context or event. A number of recent studies have also addressed the ways in which ambiguities and irregularities in the ¹⁴C calibration curve can affect the interpretation of archaeological dates and temporal patterns. Of greatest concern, however, is a growing practice of using only one or two samples to date a significant prehistoric context or event. The date of these events, usually relative to other human activities, often holds important theoretical implications for evolutionary anthropology and related disciplines. In this article, we demonstrate that such a practice is rarely adequate or acceptable. Rather, proper procedure requires a suite of dates that permit statistical verification that the deposit or event itself is being correctly dated. We present a detailed case study that highlights the importance of analyzing multiple samples of ¹⁴C from significant archaeological contexts.     

Caribou Crossings and Cultural Meanings: Placing Traditional Knowledge and Archaeology in Context in an Inuit Landscape

Meaning is conveyed by context. Northern landscapes associated with oral traditions provide rich contexts for understanding archaeological features and their spatial and temporal distribution. At the same time, traditional knowledge, including place names, is supported by the persistence of an integral archaeological landscape. The lower Kazan River, Nunavut Territory, Canada, preserves a record of land use for a hunting-trapping society in archaeological remains and traditional knowledge. The record shows that traditions of knowledge are manifest in the archaeological landscape. These traditions include commemoration of people and events in monuments, enduring practices (land skills) that are associated with a traditional time, and principles of spatial differentiation and orientation based on relations between people and caribou.     

Lithic production,site formation and Middle Palaeolithic palimpsest analysis: in search of human occupation episodes at Abric del Pastor Stratigraphic Unit IV (Alicante,Spain)

We present the results of an exercise in Middle Palaeolithic palimpsest analysis geared toward the identification of human occupation episodes. It is based on a combined reading of the archaeosedimentary deposit and the archaeological record of Stratigraphic Unit IV from Abric del Pastor (Alcoy, Alicante, Spain), chronologically framed within MIS 4–5. A study of site formation processes coupled with archaeostratigraphic analysis of the lithic record incorporating Raw Material Units (RMU) and refits, as well as with combustion features and faunal remains enabled identification a minimum of 4 and a maximum of 6 human occupation episodes within lithostratigraphic units IVa, IVb and IVc. Through our data it reaches a high resolution temporal frame close to the ethnographic time scale, which constitutes a significant contribution for the knowledge of human occupations types and landscape use in the Mediterranean rim of the Iberian Peninsula during Middle Palaeolithic.     

Radiocarbon dates as data: quantitative strategies for estimating colonization front speeds and event densities

Archaeological analysis of large-scale prehistoric population history requires us to estimate rates of spatial spread during dispersals, and rates and magnitudes of temporal contraction during crashes. Using OxCal’s MCMC sampling routine, I introduce and demonstrate a simple and easily implemented method of estimating front speeds that takes due account of the uncertainty in the archaeological data (in both dates and distances), and argue that this method is more appropriate than those most often used in front speed estimation at present. I also propose a simple and easily implemented method of estimating event densities as a demographic proxy, as an alternative to summed calibrated probability distributions. I argue that this alternative is a significantly better technique, and show that its use also enables us to identify individual archaeological dates that are exerting particularly strong influence on the results, so that we can efficiently allocate our attention when assessing the possible effects of exogenous sampling uncertainty. To illustrate these methods I re-analyse two published datasets relating to the early Paleoindian colonization of North America. My results with the new technique indicate that even with a very noisy dataset, there was clear evidence in the framework of the INTCAL04 calibration curve for a drastic reduction in archaeological event densities following the Younger Dryas onset, followed by a prolonged period of reduced human activity, and a possible renewed phase of rapid growth after the Younger Dryas termination and onset of the Holocene. However, the revised estimate of the Younger Dryas marine reservoir offset in the INTCAL09 calibration curve for ∼12,550–12,900 cal BP changes the picture significantly, by flattening the peak in Clovis-age events and pushing it forward in time into the early Younger Dryas itself.     

Vagueness and Archaeological Interpretation: A Sensuous Approach to Archaeological Knowledge Formation through Finds Analysis

The rapid development of natural scientific methods coupled with the recent popularity of new materialist philosophies in archaeological theory has raised discussion about the possibility of a return to empiricism in archaeology. While empiricism as a pragmatic philosophy is in line with archaeology’s hands-on character, the recent development has left some concerned about the vanishing role of vagueness and ambiguity in archaeological interpretation. In this setting, the exactitude of natural scientific methods is seen as a process of simplification that compromises the tacit dimensions of archaeological knowledge. This article discusses vagueness as an elementary part of all archaeological knowledge formation, with a particular emphasis on the role of perception and senses in finds analysis. Archaeological finds analysis is explored as an example of epistemologically vague and creative hypothesis formation.     

Memory as Archaeology: An Experience of Public Archaeology in the Atacama Desert

Conducting archaeological projects in areas inhabited by Indigenous Communities who dislike both excavations and archaeologists leads to an ethical conundrum, one requiring a reconsideration of the research methodologies utilized in these settings, and a turn toward Public Archaeology as a means to find alternative pathways. This article describes a research project conducted in the Indigenous Atacameño Community of Peine, in the Atacama Desert, Chile, where, through a principal methodology of Participatory Action Research, it became possible to explore the past of this community in ways that were both meaningful and valid for its members. The results drawn from this experience differ markedly from traditional archaeological approaches (i.e. excavations, analysis of material culture), both in terms of the nature of the knowledge recovered and the temporal depth achieved. In this particular instance, collective remembrance and embodied memory featured prominently in accounting for the past of Peine.     

Tracing Teams,Texts, and Topics: Applying Social Network Analysis to Understand Archaeological Knowledge Production at Çatalhöyük

Social network analysis (SNA) is an analytical technique rapidly gaining popularity within archaeology for its applicability to a wide variety of issues relating to past communities. Using the 20-year project at Çatalhöyük, Turkey, as a case study, I demonstrate how SNA can be helpfully used to understand knowledge production in archaeology. Balancing network visualization and computation with contextual knowledge, combining SNA with topic modeling, and concentrating on social structures all work to provide a diachronic view of how information flows between disparate research teams at Çatalhöyük as well as the social structures and specific individuals promoting this flow. SNA has the undeniable potential to provide new perspectives on how dispersed datasets are assembled to produce archaeological knowledge, illustrating the value of retaining focus on the social conditions of scientific practice even as significant insights are being derived from instead investigating objects and ontology.     

Do temporal size differences influence species identification of archaeological albatross remains when using modern reference samples?

Zooarchaeological remains have been identified to species, using identification criteria based on specific morphological variations among modern specimens. However, temporal size changes in bones, due to micro-evolution and/or phenotypic plasticity, could distort identification of archaeological remains according to these criteria. We developed species identification criteria for North Pacific albatrosses (Short-tailed, Laysan and Black-footed Albatrosses) using both mensural- and DNA-based analysis and actually identified many archaeological remains from a site using these criteria. Our mensural-based criteria could accurately discriminate the modern Short-tailed Albatross from modern Laysan and Black-footed Albatrosses and indicated that the archaeological remains included both Short-tailed and Laysan or Black-footed Albatrosses. DNA-based criteria, however, suggested that all remains were Short-tailed Albatross. The most plausible explanation for this inconsistency would be misidentification using mensural-based analysis, due to temporal size changes in bones or existence of birds from extinct population(s) or breeding region(s) with mensurally different bones from recent birds. This is the first study that suggests temporal size changes in bones may distort the species identification of archaeological remains according to modern size variations. Further studies are required to judge if this pattern is unusual or not.     

Historic landscape management: a validation of quantitative soil thin-section analyses

The archaeological interpretation of past land management practices can be greatly enhanced through examination of soil thin sections. Features relating to manuring practice are among those key to interpreting agricultural practices. The sources and the processes leading to the distribution of these manure materials may further improve knowledge of the past landscape utilisation. The use of quantitative analyses to examine soil thin sections opens the possibility of considering these relationships between manured areas in greater detail and to extract more subtle spatial and temporal changes in past management. In this study the validation of this methodology has been tested with quantitative image analysis methods used to examine manure inputs to a well-documented historical landscape of Papa Stour, Shetland, where intensive manuring has been practised until the 1960s. By using both historic and ethnographic evidence to validate the image analysis protocol, differences in spatial and temporal distribution are examined for the practices of manuring with both fuel residues and with turf. The validation of the hypotheses expected from ethnographic and historical data that quantitative soils-based evidence allows the definition of variations in manuring strategies and provides a more secure basis from which to interpret manuring management strategies in archaeological landscapes.     

Knowledge-Based Performance Assessment of Existing RC Buildings

One of the most challenging aspects of the seismic assessment of existing buildings is the characterization of structural modeling uncertainties. Recent codes, such as Eurocode 8, seem to synthesize the effect of structural modeling uncertainties in the so-called confidence factors that are applied to mean material property estimates. The confidence factors are classified and tabulated as a function of discrete knowledge levels acquired based on the results of specific in-situ tests and inspections. In this approach, the effect of the application of the confidence factors on structural assessment is not explicitly stated. This work presents probabilistic performance-based proposals for seismic assessments of RC buildings based on the knowledge levels. These proposals take advantage of the Bayesian framework for updating the probability distributions for structural modeling parameters based on the results of tests and inspections. As structural modeling parameters, both the mechanical material properties and also the structural detailing parameters are considered. These proposals can be categorized based both on the amount of structural analysis effort required and on the type of structural analysis performed. An efficient Bayesian method is presented which relies on simplified assumptions and employs a small sample of structural model realizations and ground motion records in order to provide an estimate of structural reliability. As an alternative proposal suitable for code implementation, the simplified approach implemented in the SAC-FEMA guidelines is adapted to existing structures by employing the efficient Bayesian method. This method takes into account the effect of both ground motion uncertainty and the structural modeling uncertainties on the global performance of the structure, in a closed-form analytical safety-checking format. These alternative proposals are demonstrated for the case study structure which is an existing RC frame. In particular, it is shown how the parameters for the safety-checking format can be estimated and tabulated as a function of knowledge level, outcome of tests, and the type of structural analysis adopted.