Empirical findings from fieldwork inform our theories of natural language semantics: what is cross-linguistically possible, what current theories can and cannot account for, what type of representations we need, and so on. Formally precise analyses can also inform our fieldwork, making predictions that need to be tested in the field and providing novel questions to ask. This interrelationship of fieldwork and theory can be mutually beneficial, symbiotic, producing novel avenues for both fieldwork and analysis. This paper discusses an example of such interplay from the author's fieldwork on the semantics of the reflexive/reciprocal construction in Cheyenne (Plains Algonquian). New data led to a novel analysis in terms of underspecification, which in turn led to novel discoveries about the possible interpretations of the Cheyenne reflexive/reciprocal marker (Murray 2007(Murray , 2008.