Text 1
Anthropologist Maya Laird and colleagues measured carbon and nitrogen isotope ratios in bone collagen from burials in two river valleys. They reported δ13C and δ15N values consistent with heavy reliance on maize by about 500 CE. Laird's team argues that these signatures support a regionwide shift to intensive maize farming and storage, broadly similar to later historical accounts. The authors contend that isotopes provide the clearest line of evidence available for diet and land use at this time, implying that communities had already adopted field systems that could sustain large settlements.
Text 2
Archaeologists David Corbett and Lina Cho maintain that bulk collagen isotopes are often overinterpreted as markers of maize agriculture. Similar values can arise from marine fish consumption, arid-zone plants, or trophic-level changes in freshwater settings. They note that Laird's study did not incorporate compound-specific amino-acid analyses, enamel carbonate data, or plant microfossils from tools and dental calculus, which could separate these possibilities. Corbett and Cho conclude that without such complementary evidence, claims about an early, regionwide maize regime likely rest on an incomplete reading of the available signals.
Based on the texts, how would Corbett and Cho (Text 2) most likely characterize the conclusion presented in Text 1?
