Stable isotope analysis has become routine in bioarchaeology and is used to reconstruct diet because it allows comparisons at inter- and intra-individual, as well as at population scales. Isotopic variation between individuals within a population is sometimes attributed to social status, or economic or subsistence specialization. However, we demonstrate that aggregating individuals within even culturally relevant time periods may confuse secular resource availability with behavioral specialization. We use both real data from prehistoric California and simulated data generated from a newly created Bayesian multi-level model to demonstrate how conflation of temporal and population scales can artificially inflate dietary variability for some populations. Our conclusions suggest that stable isotope analyses benefit from intra-individual sampling and AMS radiocarbon pairing, which aids in achieving the temporal resolution needed to infer population-scale specialization or status-based differences.

稳定同位素分析已成为生物考古学中的常规方法，并用于重建饮食，因为它允许在个体间和内部以及人口规模上进行比较。人口中个体之间的同位素变化有时归因于社会地位、经济或生计专业化。然而，我们证明，即使在与文化相关的时间段内聚集个体，也可能会将世俗资源可用性与行为专业化混淆。我们使用来自史前加利福尼亚的真实数据和从新创建的贝叶斯多层次模型生成的模拟数据来证明时间尺度和人口尺度的合并如何人为地夸大某些人群的饮食变异性。