The Arena Model: An Account of Human Judgment

Psychology, economics, and behavioral science catalog human judgment through hundreds of disparate cognitive biases. The Arena Model (AM) replaces this disjointed taxonomy with a single account: judgment runs on a low-dimensional projection of a higher-dimensional world. The model derives many canonical heuristics and biases from a few fixed mechanisms. A "bias,'" per the AM account, is what happens when a mind works with fewer dimensions than its environment contains, when a researcher measures dimensions that differ from what the mind used, or when an internal signal is taken to report a property of the world. Many apparent departures from rationality resolve once unmeasured and mismatched dimensions are taken into account. Unlike descriptive frameworks that add a new mechanism for each phenomenon, the AM constrains the space of possible errors and yields clear, falsifiable predictions about the conditions under which biases will and will not appear. It also gives researchers a single, testable account in place of a growing list of unconnected exceptions. I demonstrate consistency across known biases, define the limits of the account, and propose a diagnostic test to evaluate, or invalidate, it.