A multiplicity of identities: The intersections of cranial vault modification, paleodiet, and sex in San Pedro de Atacama, Chile

Objectives: Intentional cranial modification and diet serve as markers of identity. Here, we explore the intersection between the body and social persona in the San Pedro oases through the complex relationship(s) between these markers and other aspects of society and the individual. Methods: Skeletal remains of 1190 individuals were analyzed for evidence of intentional head shaping and classed as unmodified, tabular, or annular. Stable carbon and nitrogen isotope analyses of bone (n = 203) focused on the contribution of C₃ plants, C₄/CAM plants, beans, and terrestrial animal meat per the Bayesian model, FRUITS. Strontium isotope data from dental enamel was considered for more detailed analyses. Results: Cranial modification was present in 520 individuals (43.7%; N = 1190). Modification was significantly more common among females (χ² = 7.403, p = 0.007). There was no significant difference in presence or type between periods. Average values for the four modeled food groupings differ significantly. There is a significant difference in consumption of C₄/CAM plants by those individuals with modified heads consuming more (26.5 ± 9.9% vs. 23.6 ± 9.4%, Wilcoxon signed-rank test, p < 0.05). In the Middle Period sample, males consume significantly more C₄/CAM plants (p < 0.05) and females more C₃ plants (p < 0.01). Four of those with outlier C₄ values were analyzed for strontium, yielding values outside the “local” range. Conclusions: As head shaping is permanently imposed in infancy while dietary patterns are the consequence of ongoing choices and constraints in the social and ecological environment, these markers of identity are not parallel. The numerous points of intersection between these markers and other aspects of identity are highlighted.