Abstract
Bioarchaeology, or the study of human health and life experiences in the past, has at its core an interest in the assessment of systemic stress within the biocultural context. Stress can leave impressions on the skeleton such as linear enamel hypoplasia (LEH), small grooves on the surface of the teeth that correlate with periods of impacted growth during early-life development. In bioarchaeology, LEH are a common means of quantifying systemic stress in the past to answer questions about ancient human health. Much of that research assesses differences in LEH frequency and ‘severity’ between groups within a population, often with a focus on sex differences. Previous bioarchaeological studies on the Chinese Eastern Zhou 東周 (771– 221 BCE) have detected accentuated sexual dimorphism in height, male favouritism in diet composition, and a higher number and quality of grave goods in male burials, indicating a rise in male- biased gender inequality (androcentrism) in an increasingly stratified society.
To interrogate the relationship between cultural androcentrism and systemic stress during early life, I assessed LEH in 114 anterior teeth from 39 individuals (3 juveniles and 36 adults) from three Eastern Zhou sites from the Central Plains of China near the ancient city of Zhenghan 郑韩故城: Xiyasi 西亚斯, Tiancheng 天成, and Changxinyuan 畅馨苑. This sample included 13 females, 24 males, and 2 individuals of indeterminate sex. I used the new MicroPoly Sharp© program to apply the Micro Polynomial technique, identifying significant negative deviations on a digitised cross-section of the labial enamel surface. Where these defects co-occurred on two or more teeth, LEH was detected. My results showed that all individuals had at least 2 LEH lesions, and I found no statistically significant differences in LEH presentation between males and females in frequency, percentage of affected enamel, total LEH duration, inter-LEH periodicity, age at first lesion, and average lesion age.
Given that historical, archaeological, and previous bioarchaeological research indicates that androcentrism negatively impacted female health and resulted in male- biased differences in both child-rearing and social status, these results are interesting. The developmental origins of health and disease hypothesis (DOHaD) proposes that during early development, the health of the child largely reflects and depends upon the health of their mother (the maternal-infant nexus). I suggest that the LEH detected in these individuals reflect a cumulative, multi-generational impression of stress experienced by mothers and children in the Eastern Zhou, rather than solely representing the stress of the isolated person as has been interpreted of LEH in the past. This would explain why sex differences in LEH are not observed and indicates that throughout this sample systemic stress levels were consistently high in the mother-infant dyad. Future research comparing microscopically detected LEH by social class as well sex could shed more light on the relationship between LEH, systemic stress, social inequalities, and the maternal-infant nexus.