Bioarchaeology of Iron Age Central Thailand

A review of Human Skeletal Health and Dietary Assessment of Metal Age Central Thailand: The Impact of Changing Social Complexity and Regional Variation, by Chin-hsin Liu.

This dissertation by Chin-Hsin Liu is a bioarchaeological exploration and synthesis of the human condition in Iron Age Central Thailand. Liu’s primary interest lies in the changing social structure and increasing social heterogeneity during the Iron Age, as well as the impacts of increasing inequality on health and dietary variation. To these ends, Liu tests two hypotheses: that over time, increasing social complexity would lead to (1) greater variation of skeletal health within different skeletal collections from the same archaeological assemblage; and (2) that dietary variation within chronologically later skeletal collections would increase as well (p. 31). These hypotheses are tested using five skeletal assemblages derived from Iron Age archaeological sites located in Central Thailand: Non Mak La (74 individuals); Ban Mai Chaimongkol (38 individuals); Promtin Tai (35 individuals); Ban Pong Manao (49 individuals); and Kao Sai On-Noen Din (3 individuals). For comparative purposes, human skeletal material recovered from the well-known Late Neolithic site of Khok Phanom Di (ca 2000-15000 BC), located just inland from the Gulf of Thailand, was used as representing a community with minimal social stratification and different dietary opportunities from those available in Central Thailand.

Following a comprehensive overview of the landscapes and environments of Central Thailand in Chapter 2, Chapter 3 is dedicated to the description of the pertinent archaeological contexts as well as the chronologies of the sites investigated in the course of the study. Many of these are multi-component sites with considerable chronological depth, including Bronze Age components in two cases and later historic strata in another. Such chronological depth afforded the author a wonderful opportunity to accurately place each available skeleton from consecutive occupation phases into its proper context, also resulting in Liu’s being able to confidently test her hypotheses within several individual sites. Although each sample is fairly small, I believe that this site-centered approach is the primary strength of Liu’s dissertation. Whenever a bioarchaeologist is faced with modest-sized samples of skeletal material, it becomes tempting to pool the data across multiple archaeological sites to draw temporal and spatial comparisons. Unfortunately, that type of approach more or less ensures that the effects of local environmental settings and sociocultural differences on the human condition in a specific area will be overlooked. Liu’s site-centered bioarchaeology is both rich and nuanced at the same time; her discussion of health and diet changes during the Iron Age is nicely integrated with the archaeological and environmental records of the specific sites.

The author left no aspect of human skeletal biology untouched, exploring the paleo-demographic profiles of the skeletal assemblages used as the subjects of her analyses and synthesis, including achieved adult stature, the chemical signatures of diet in bone samples, various indicators of oral health, and a number of signatures of growth arrest—i. e. linear enamel hypoplasia, skeletal lesions, patterns of trauma, and degenerative joint disease. Tables summarizing the relevant data are comprehensive and represent a remarkable data mining opportunity for scholars interested in meta-analysis.

The results and discussion sections (Chapters 6 to 9) of the dissertation are structured sequentially and include discussions on paleo-demography, sexual dimorphism, childhood physiological stress, dental health, and the pathology of the postcranial skeleton—systemic stress, degenerative joint disease, and traumatic injuries, as well as paleo-dietary signatures in human and animal bone and in tooth samples. The last of these chapters is particularly substantial, giving a detailed account of local dietary patterns for each site. The discussion is thorough, placing the findings of the present thesis into the wider context of both the bioarchaeological and strictly archaeological literatures.

Contrary to initial expectations of increased intra-site health and diet variation as a consequence of developing social inequality during the Iron Age, Liu found little evidence of gross-skeletal pathology of any kind and therefore no detectable change over time in skeletal health. This lack of detectable heterogeneity in pathology is even more surprising, considering that some skeletons in the study came from remarkably wealthy burials. Taking the demographic profile for each site into account and also considering a distinctly low overall degree of sexual dimorphism in pathology, Liu argues that the effect of the osteological paradox is an unlikely explanation for the low incidence of skeletal pathology observed. She infers overall good baseline health for Iron Age communities in Central Thailand. As Liu states in her discussion, this conclusion aligns well with the findings of other bioarchaeological studies conducted in mainland Southeast Asia, where little evidence of pronounced trends in community health associated with agricultural development and the rise of social complexity has been found. It appears that sociocultural changes that are evidenced in the Iron Age archaeological record for Central Thailand had little impact on resource distribution among community members. Another possibility, as Liu suggests, is that the extreme diversity of local environments in Central Thailand overshadowed any effects of increasing social complexity in the area.

Arguably the most exciting finding in Liu’s dissertation is her observation that considerable inter-site variability in terms of dietary signatures was coupled with extremely narrow ranges of these signatures within sites. Consequently, each site in Central Thailand included in the study seems to have been characterized by a unique subsistence specialization, largely determined by the local environment and cultural practices. Further developing ideas recently propounded by White (2011), who argued for deep roots of cultural diversity in Thailand, Liu proposes that local subsistence specialization can be traced to a period as early as the Iron Age.

To conclude, I hope that this thesis will become the foundation of a monograph on the bioarchaeology of Central Thailand.

Kate Pechenkina, Ph. D.
Department of Anthropology
Queens College of the City University of New York

Dissertation Information

University of Florida. 2012. 388 pp. Primary Advisor: John S. Krigbaum.


Image: Promtin Tai village temple, Lopburi, Thailand (photograph by Chin-hsin Liu, 2011).

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