Preservation bias: is rice overrepresented in the archaeological record?

Abstract

Most charring experiments are carried out in the muffle furnace in highly controlled conditions and tackle the taphonomic issues of seed shrinkage and distortion caused by carbonisation. This paper presents the results from charring experiments conducted using real fire conditions. The objective of this study is to reproduce the charring processes that occur naturally and so address the issue of preservation biases which occurred in prehistoric contexts of carbonisation. This is particularly important in addressing the possible overrepresentation of rice over other taxa in the archaeological record. Prior charring experiments focus on Old World crops, but in this study the taxa used are East, South and Southeast Asian cereals and pulses. An ethnographic study conducted in Thailand examining the rice processing stages of dehusking and winnowing is also included since differential preservation may also result from crop processing. Archaeological results from sites in Mainland Southeast Asia are then interpreted using the results of the charring experiments and the ethnographic data.

The Khmer did not live by rice alone: Archaeobotanical investigations at Angkor Wat and Ta Prohm

“…In both sites, the high proportion of rice processing waste products such as spikelet bases and husk fragments indicates that rice was routinely dehusked where people were living since husk and spikelet bases are normally found in higher proportions than rice grains if they resulted from dehusking waste which went on to be burnt. Rice spikelet bases preserve well when charred and are highly visible in the archaeological record (Castillo, 2019), are good indicators of processing stages but also of the domestication status of rice in prehistory. Dehusking rice on a daily basis in a household is still practiced in Southeast Asia, such as at Ban Non Wat in Thailand (Castillo, 2019).…”

“…(For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) modern counterparts as shrinkage occurs probably due to the effects of charring (Castillo, 2019).…”

A microbotanical and microwear perspective to plant processing activities and foodways at Neolithic Çatalhöyük

“…[ 76 , 83 , 85 ]). One possible cause could be a preservation bias since small millets are vulnerable to charring conditions making them less likely to be preserved by this means than other cereals [ 46 , 234 – 238 ]. It is also possible that small millets, being a seasonal resource used when available in the landscape, were treated differently to many other wild resources which were instead stored, thus making them less susceptible to preservation by accidental charring (i.e.…”

Sedimentary unknowns constrain the current use of frequency analysis of radiocarbon data sets in forming regional models of demographic change

“…A key step in improving SPD‐based interpretation of the archaeological record is to expand age databases to promote a move beyond simple temporal correlation to more broadly based assessments. The various proxies used by archaeologists (e.g., radiometric, artefact, ecological and ethnographic data) are all filtered and biased in various ways (e.g., Castillo, 2018) by factors that themselves vary with depositional setting and time (e.g., see also Purnell & Donoghue, 2005). Even proxies derived from any one type of site (e.g., rockshelter, surface scatter, midden) are unlikely to form an appropriate representation for human activity (French & Collins, 2015; Palmisano et al, 2017; Ulm, 2013).…”