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Archaeologists now routinely use summed radiocarbon dates as a measure of past population size, yet few have coupled these measures to theoretical expectations about social organization. To help move the ‘dates as data’ approach from description to explanation, this paper proposes a new integrative theory and method for quan- titative analyses of radiocarbon summed probability distributions (SPDs) in space. We present this new approach to ‘SPDs in space’ with a case study of 3571 geo-referenced radiocarbon dates from Wyoming, USA. We develop a SPD for the Holocene in Wyoming, then analyze the spatial distribution of the SPD as a function of time using a standard nearest-neighbor statistic. We compare population growth and decline throughout the Holocene with expectations for different Ideal Distribution Models from population ecology that predict the relationship be- tween habitat quality and population density. Results suggest that populations in Wyoming were initially clustered and then became increasingly dispersed through the course of the Holocene. These results suggest that Allee-like benefits to aggregation, rather than ideal free-driven dispersion patterns, explain settlement decisions in response to growing populations. Our approach is a first step in constructing a method and theory for de- scribing relationships between social organization and population growth trends derived from archaeological radiocarbon time-series.
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This content will become publicly available on September 20, 2025
Do counts of radiocarbon-dated archaeological sites reflect human population density? A preliminary empirical validation examining spatial variation across late Holocene California
Researchers increasingly rely on aggregations of radiocarbon dates from archaeological sites as proxies for past human populations. This approach has been critiqued on several grounds, including the assumptions that material is deposited, preserved, and sampled in proportion to past population size. However, various attempts to quantitatively assess the approach suggest there may be some validity in assuming date counts reflect relative population size. To add to this conversation, here we conduct a preliminary analysis coupling estimates of ethnographic population density with late Holocene radiocarbon dates across all counties in California. Results show that counts of late Holocene radiocarbon-dated archaeological sites increase significantly as a function of ethnographic population density. This trend is robust across varying sampling windows over the last 5000 BP. Though the majority of variation in dated-site counts remains unexplained by population density. Outliers reveal how departures from the central trend may be influenced by regional differences in research traditions, development-driven contract work, organic preservation, and landscape taphonomy. Overall, this exercise provides some support for the “dates-as-data” approach and offers insights into the conditions where the underlying assumptions may or may not hold.
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- PAR ID:
- 10548457
- Publisher / Repository:
- Radiocarbon
- Date Published:
- Journal Name:
- Radiocarbon
- ISSN:
- 0033-8222
- Page Range / eLocation ID:
- 1 to 14
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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