The Effects of Early Childhood Stress on Mortality under Neolithization in the Levant

Abstract

Abstract. This study investigates the causal relationships among early-life health conditions, mortality across the lifespan, and population growth during neolithization in the Levant. We analyze a comprehensive sample of 558 human skeletons, associated with mortuary features from 24 Levantine sites spanning the transition to agriculture, from the Early Natufian period to the Pre-Pottery Neolithic C (Southern Levant) and Pottery Neolithic periods (Northern Levant), mainly covering 13,000-6,000 BC. We find that early-life stress—as preserved in linear enamel hypoplasias (LEH) that we recorded in the study sample—not only increased dramatically in prevalence with the adoption of agriculture and village life. Early-life stress was also strongly associated with mortality in the juvenile, adolescent, and younger-adult life stages (ca. 5-29 years). This statistical link is independent of analysis of raw life-stage-at-death distributions, which may be heavily biased by ancient age or sex-skewed funerary recruitment practices. According to our results, biological well-being deteriorated with the adoption of agriculture and village life between ca. 9,000-6,000 BC. We find that the transition to agriculture raised risks for premature mortality across the Levant. We suggest that in the regional transition to agriculture, mortality and fertility rose together in a fragile dynamic, the balance of which may have shifted in the 7th millennium BC, as a rapid rise in early-life stress exposures reduced average well-being.