||Sustainability problems can often be characterized as social dilemmas because the "rational" strategy for an individual's short-term self-interest is suboptimal if everyone follows the same strategy. Such dilemmas may be overcome through social institutions (e.g., common property regimes) and cosmological beliefs (e.g., belief in punitive spirit guardians of nature) that alter the costs and benefits, or at least the perception of costs and benefits. In this dissertation I examine the efficacy of common property institutions and cosmological beliefs for regulating natural resource use among the Miskitu people of an indigenous territory located within the Bosawas Biosphere Reserve, Nicaragua. Using mixed methods and an interdisciplinary approach, I focus on the relationship between individual incentives and prosustainability behavior in a series of studies. First, I analyze de facto enforcement of the local common property regime, concluding that it is weak due to rules that are inherently difficult to enforce and too few individual incentives for enforcers to do so. Second, I test whether individuals who perceive greater resource scarcity or who perceive greater severity or certainty of civic punishment for violating the rules are more likely to comply with them; they are not. Third, I test whether individuals who expect supernatural punishment for overharvesting take less wildlife; they do, but this result is not robust against outlier exclusion. However, since individuals with an inclusive moral circle may weigh the costs and benefits of their actions to nonhumans, I also examine the relationship between wildlife harvests and beliefs in nonhuman personhood (without reference to punishment) and the interconnectedness of humans and the rest of nature. Results show that individuals, especially men, who hold more of these beliefs harvested less wildlife biomass. This suggests that morally inclusive and relational beliefs about nonhumans may alter the way that costs and benefits are tacitly, even if not explicitly, perceived. In light of these results - and in consideration of each study's limitations - several directions for future research are recommended.