Simple Financial Economic Models of Prehistoric Fremont Maize Storage and an Assessment of External Threat

Purpose – This chapter examines the risk of a hostile incursion as perceived by Fremont farmers living in the Range Creek area of Utah, 700–1700 years ago. Methodology/approach – We build two simple financial portfolio models where agents (Fremont farmers) choose optimal locations to store grain based on a trade-off between ease of access during normal times and difficulty of confiscation during a hostile incursion. We calibrate our model using the observed distances and difficulty of access to granaries measured in caloric costs. Findings – We find that even low or moderate probabilities of an incursion rationalize the use of cliff granaries. Risk on the order of a 5–25% chance per year makes building, maintaining, and transporting grain to a cliff granary worthwhile. Social implications – Our research does not rule out other motives for granary construction. However, it does show that a small threat of hostilities can explain the observed location of granaries in Range Creek and other areas of Fremont habitation. Originality/value of chapter – This research is unique in its application of standard financial portfolio theory (normally dealing with optimal holdings of risky financial assets) to the problem of deducing perceived risk. To our knowledge, this is the first use of these rational financial models in the context of a human population that has left no explicit economic evidence such as prices or transaction records.