This dissertation consists of analyses of a series of common pool resource experiments that I designed and conducted in three regions of Colombia with individuals who face similar dilemmas in their everyday lives as those faced in the experiment. The objectives are to develop an empirical characterization of how individual behavior deviates from purely self-interested Nash behavior, and to further our understanding of the effects of alternative institutions to promote more conservative choices in common pool experiments. The results of this dissertation are organized in three essays. The first essay, What Motivates Common Pool Resource Users?, develops and tests several models of pure Nash strategies of individuals who extract from a common pool resource when they are motivated by combinations of self-interest, altruism, reciprocity, inequity aversion and conformity. The experimental data suggest that a model that balances self-interest with a strong preference for conformity best describes average strategies. The data are inconsistent with a model of pure self-interest, as well as models that combine self-interest with individual preferences for altruism, reciprocity and inequity aversion. The second essay, Communication and Regulation to Conserve Common Pool Resources, tests for complementarities between formal regulations imposed on a community to conserve a local natural resource and non-binding verbal agreements to do the same. The experiments suggest that formal regulations and informal communication are complementary in some instances, but this result is not robust across regions or regulations. Therefore, the hypothesis of a complementary relationship of formal and informal control of local natural resources cannot be supported in general; instead the effects are likely to be community-specific. The third and final essay, Within and Between Group Variation in Individual Strategies in Common Pools, analyzes the relative effects of groups and individuals within groups in explaining variation in individual harvest decisions for particular institutions, and examines how these sources of variation may vary across institutions. Communication serves to effectively coordinate individual strategies within groups, but these coordinated strategies vary considerably among groups. In contrast, regulatory schemes (as well as unregulated open access) produce significant variation in the individual strategies within groups, but these strategies are roughly replicated across groups so that there is little between-group variation.