Correcting temporal frequency distributions for taphonomic bias

Graphs of quantitative data are analytical tools that facilitate visual thinking. In many disciplines, the use of graphs was preceded by tables summarizing quantitative data. Graphs known by North American archaeologists as “battleship curves” are temporal frequency distributions of relative abundances of specimens in each of several artifact types. They are unimodal frequency distributions known as spindle graphs. In the early 1950s, it was suggested that the idea of spindle graphs was borrowed by archaeologists from paleontology. Archaeologists occasionally used bar graphs and line graphs to diagram change in artifact inventories in the early twentieth century. The questions addressed in this volume are: (i) did North American archaeologists borrow the idea of spindle graphs from paleontology, and (ii) what was the frequency of use by North American archaeologists of each of the various graph types to diagram culture change during the early and middle twentieth century?

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Spatiotemporal distribution of Holocene populations in North America

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1505657112 ◽

2015 ◽

Vol 112 (39) ◽

pp. 12127-12132 ◽

Cited By ~ 22

Author(s):

Michelle A. Chaput ◽

Björn Kriesche ◽

Matthew Betts ◽

Andrew Martindale ◽

Rafal Kulik ◽

...

Keyword(s):

North America ◽

North American ◽

Kernel Method ◽

Temporal Frequency ◽

Human Populations ◽

Human Occupation ◽

Migration Routes ◽

Frequency Distributions ◽

Continental Scale ◽

The North

As the Cordilleran and Laurentide Ice Sheets retreated, North America was colonized by human populations; however, the spatial patterns of subsequent population growth are unclear. Temporal frequency distributions of aggregated radiocarbon (14C) dates are used as a proxy of population size and can be used to track this expansion. The Canadian Archaeological Radiocarbon Database contains more than 35,000 14C dates and is used in this study to map the spatiotemporal demographic changes of Holocene populations in North America at a continental scale for the past 13,000 y. We use the kernel method, which converts the spatial distribution of 14C dates into estimates of population density at 500-y intervals. The resulting maps reveal temporally distinct, dynamic patterns associated with paleodemographic trends that correspond well to genetic, archaeological, and ethnohistoric evidence of human occupation. These results have implications for hypothesizing and testing migration routes into and across North America as well as the relative influence of North American populations on the evolution of the North American ecosystem.

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Archaeology Spindle Graphs in the 1930s

Graphing Culture Change in North American Archaeology ◽

10.1093/oso/9780198871156.003.0007 ◽

2021 ◽

pp. 128-147

Author(s):

R. Lee Lyman

Keyword(s):

Probability Theory ◽

Culture Change ◽

Temporal Frequency ◽

American Southwest ◽

Statistical Reasoning ◽

Graph Models ◽

Frequency Distributions ◽

Ultimate Source ◽

Rough Form ◽

Variational Evolution

During the 1930s, archaeological spindle graphs in the form of seriograms (straight-sided spindle graphs) were published. Three of these represent the investigator’s suspicions about culture change rather than being strictly empirical. Stylistically, seriograms were seldom subsequently published, suggesting these graphs minimally influenced later researchers. By the 1920s, based on the basically unimodal frequency distributions observed in frequencies of specimens of various pottery types in the American Southwest, anthropologists had begun to suspect there were so-called stylistic pulses reflecting the vogue or popularity of particular kinds of artifacts. Explanations fell back on probability theory, likely as a result of the influence of Franz Boas’s statistical reasoning; kinds of phenomena simply should display unimodal temporal frequency distributions given probability theory. Although conceptually unsophisticated, graphic models of these stylistic pulses published by anthropologists in the 1920s took the rough form of spindle graphs and represent a then unrecognized nod to the theory of variational evolution. These spindle graph models may be the ultimate source of archaeological spindle graphs, but these models were a bit difficult to decipher. Many graphs of culture change appearing in the 1920s and 1930s imply variational evolution.

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Spatio-temporal variation in the preservation of ancient faunal remains

Biology Letters ◽

10.1098/rsbl.2015.0823 ◽

2016 ◽

Vol 12 (2) ◽

pp. 20150823 ◽

Cited By ~ 2

Author(s):

Todd A. Surovell ◽

Spencer R. Pelton

Keyword(s):

United States ◽

Temporal Frequency ◽

Faunal Remains ◽

Radiocarbon Dates ◽

Frequency Distributions ◽

Arctic Regions ◽

Terrestrial Sediments ◽

Excellent Preservation ◽

Spatio Temporal ◽

Over Time

Palaeodemographic studies of animals using frequency distributions of radiocarbon dates are increasingly used in studies of Quaternary extinction but are complicated by taphonomic bias, or the loss of material through time. Current taphonomic models are based on the temporal frequency distributions of sediments, but bone is potentially lost at greater rates because not all sedimentary contexts preserve bone. We test the hypotheses that (i) the loss of bone over time is greater than that of sediment and (ii) this rate of loss varies geographically at large scales. We compiled radiocarbon dates on Pleistocene-aged bone from eastern Beringia (EB), the contiguous United States (CUSA) and South America (SA), from which we developed models of taphonomic loss. We find that bone is lost at greater rates than terrestrial sediment in general, but only for CUSA and SA. Bone in EB is lost at approximately the same rate as terrestrial sediments, which demonstrates the excellent preservation environments of arctic regions, presumably due to preservative effects of permafrost. These differences between bone and sediment preservation as well as between arctic and non-arctic regions should be taken into account by any research addressing past faunal population dynamics based on temporal frequency distributions.

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Validation of a global model of taphonomic bias using geologic radiocarbon ages

Quaternary Research ◽

10.1017/qua.2018.78 ◽

2018 ◽

Vol 91 (1) ◽

pp. 325-328 ◽

Cited By ~ 1

Author(s):

Lara E. Bluhm ◽

Todd A. Surovell

Keyword(s):

Late Quaternary ◽

Temporal Frequency ◽

Archaeological Sites ◽

Human Populations ◽

Proxy Record ◽

Correction Model ◽

Frequency Distributions ◽

Archaeological Materials ◽

Over Time ◽

Independent Model

AbstractTemporal frequency distributions of radiocarbon ages from archaeological sites can be used as a proxy record for human paleodemography after correction for taphonomic bias, or the time dependent loss of sediments due to erosion. Surovell et al. (2009) presented a global taphonomic correction model based on radiocarbon ages from volcanic deposits that has since been used by several researchers for paleodemographic reconstructions. This method is based on the assumption that the best indicator of relative human population density over time is not the absolute abundance of archaeological materials over time but, instead, the abundance of cultural material relative to geologic contexts in which those materials can occur. To verify the Surovell et al. model, in this paper we take 2457 radiocarbon ages from geologic contexts collected from published literature to create an independent model of taphonomic bias. We find that between 1 and 39 ka, the two curves are largely indistinguishable, but that they diverge in recent times. This suggests that current global models of taphonomic correction can be used to reconstruct human populations for the late Quaternary, but that demographic reconstructions remain challenging for the most recent two millennia.

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