This project will reconstruct patterns of systemic stress among prehistoric Middle-Final Jomon period (5000-2500 BP) foragers from Japan using incremental enamel microstructures (perikymata) found within and between linear enamel hypoplasia (LEH) defects. Results will help explain the biological impact of subsistence diversity among foragers and provide a biocultural framework for interpreting the spread of wet rice economies across the Japanese Islands. Jomon foragers from western Japan occupied an environment of low resource density and consumed foods with poor nutritional yield compared to groups from eastern and northern regions. Wet rice economies were introduced and adopted in western Japan around 2500 BP, followed by diffusion to eastern regions around 2300 BP, but failure to spread northward. Greater prevalence of LEH defects and reduced stature are reported among Jomon foragers from western Japan. This suggests that agricultural diffusion may have been influenced by systemic stress patterning, though the more finite components of stress including chronology, duration, and periodicity are poorly understood. Five hypotheses predicting greater defect prevalence, earlier stress chronology, greater stress duration, reduced time intervals between defects, and seasonal stress patterning for western compared to eastern and northern Jomon people will be tested.
High resolution silicone impressions were collected for more than 1200 teeth from more than 500 Middle-Final Jomon period individuals recovered from over 15 archaeological sites on Hokkaido and Honshu Islands. Tooth replicas will be fashioned from these impressions for microscopic analysis. Perikymata spacing and counts derived from microscopic analysis of tooth replicas will then be used to reconstruct chronology, duration, periodicity and prevalence of stress between regional Jomon samples.
Several aspects of this study contain significant intellectual merit. First, this study highlights the relationship between environmentally mediated behavioral choices and systemic stress in a behaviorally diverse group of foragers. Second, this study helps explain the relationship between systemic stress and phenotypic variation (long bone length). Third, this research explores the relationship between behavior, cultural diffusion, and systemic stress.
Broader impacts of this study are as follows: First, large, widely comparable data-sets will be disseminated on a professional webpage. In addition, data sets accumulated by this study will be used for educational purposes in the classroom, while equipment purchased by this study will provide graduate students access to technological resources that can be used to test independent research hypotheses. Finally, tooth replicas manufactured by this study can be used by other researchers interested in questions involving life history and dental anthropology.
