EARTH grantee: McLaughlin, T. Rowan

Introduction

My interest in non-industrial agriculture stems from my doctoral studies of dental microwear in European pre-history, where evidence of food and food preparation is provided by direct microscopic examination of human teeth. This document contains details of my research, and how work completed during the 2008 ESF EARTH Program Summer School has proved new ideas and techniques for researching the role of certain foods in prehistoric diets.

Dental microwear

Dental microwear analysis is the study of microscopic damage to teeth caused by abrasive particles in food. The technique has applications in zooarchaeology,palaeontology and biological anthropology and is used to study and understand aspects of past diets. Dental microwear analysis generally involves the examination of occlusal (biting) surfaces of molar teeth using scanning electron microscopy, and quantifying the microscopic wear patterns. Differences between individuals and populations are studied using statistical techniques. Because dental microwear patterns form rapidly, the technique thus offers a useful insight into diet over the short-term. A scanning electron micrograph of dental microwear can be seen in Figure 1, which shows the typical pattern of pits and scratches on the enamel surface.

Figure1. Dental microwear: a microscopic pattern of pits and scratches on tooth surfaces

Human diet does not contain foods that are hard enough to damage tooth enamel directly, yet relatively high occlusal wear rates frequently observed inhuman skeletal remains. This is because food can be loaded abrasive particles whose origins lie in food preparation and processing technologies. Dental microwear analysis can thus document changes in food processing, preparation and storage techniques directly, using human remains, and is thus an ideal proxy to compare with archaeological and historical accounts of dietary change, palaeopathology and isotopic palaeodietary studies. Several microwear studies have been performed that attempt to document dietary change in prehistory using dental microwear. Among Mesolithic hunter-gatherers,dental microwear results tend to vary quite considerably from region to region.However, in the Neolithic period, when cereal farming and animal husbandry first appears in the archaeological record, dental microwear results tend to be less variable, and provide evidence for a diet loaded with larger abrasive particles than those of the preceding Mesolithic period. This idea is based on the assumption that lager abrasive particles cause larger microwear features, and larger microwear features are found on the teeth of Neolithic people. New foods introduced into the dietary spectrum in the Neolithic period thus seem the likely cause of these large microwear features. In turn, the stone tools used to process cereals provide the likely vector for the abrasives to enter food.

EARTH Program Summer School

Reconstructing past diets is a complex undertaking, and careful consideration must be given to a number of factors that influence data generated by analyses such as dental microwear. An understanding of (1) the ecology of food plants and animals, and (2) the principles, practises and beliefs of the people who exploit them, are both crucially important. The EARTH Program Summer School attempted to broach both these topics, with considerable attention to the second set of themes. Hence my interest in the Summer School, where lectures and workshops devoted to the ethnology, landscape geography and material culture of non-industrial agriculture furthered my understanding of how the processes of agriculture and food production work. Lectures were held on the principles of agriculture itself -- how land is prepared,crops sown, harvested processed and stored -- from an ethnographic perspective. These principles were then explored in the context of the archaeological record and the modern-day landscape using a series of seminars, workshops and practical sessions.

In Figure 2, we see one of the possible links between the physical anthropological study of dental surfaces, and the ethnographic studies out during the summer school. This is a photograph of the hydraulic mill near Zureda in Asturias in action. The miller noted that the flour was not to his preference, as it tasted of the millstone. The small fragments of millstone in the flour, as well modifying the taste of the food produced, also have the capacity to damage tooth enamel directly. Similar relations between food, technology and dental anthropology have presumably been in operation since prehistory.

Figure 2. A traditional mill in Asturias in operation

That said, it is simply not valid to use interdisciplinary data without an understanding of the limitations and goals of each discipline, and the Summer School provided insight into several complex issues. The Summer School has thus enabled me to reflect upon my doctoral work and identify important new research goals. I plan to perform a study of dental microwear in the ethnographic present -- an approach which circumvents many of the ambiguities of prehistory -- to see if the kind of between-population differences visible in the archaeological record can be identified among populations whose dietary preferences are already documented using other proxies.