Some Capuchins are notable for their relatively large brains, complex social traditions, and tool use. These traits are absent in some of their closest phylogenetic relatives, making capuchins an important taxon for understanding why some primates (like humans) favored cognitive solutions to their social and ecological challenges. However, we know surprisingly little about how capuchins use cognition in the wild. With this new project, we focus on the use of social cognition in wild white-faced capuchins (Cebus capucinus) of Costa Rica. We use a combination of observation and playback experiments to understand both the depth (how detailed is their social knowledge?) and breadth (how far does their social knowledge extend?) within and between social groups. We take advantage of our newly established field site, the Taboga Research Exchange (T-REX) where ~10 capuchin groups live in an isolated ‘island’ of tropical dry forest surrounded by sugar-cane farms. The self-contained nature of the forest allows us to precisely track multiple monkey groups, while the available facilities (electricity, internet, endocrine laboratory) enable us to operate much like a captive laboratory with real time analysis. In addition to the capuchin research, we are developing T-REX as the first of its kind: a net-zero field station and field school where we, along with our colleagues from the Universidad Técnica Nacional and SEAS, are piloting and demonstrating sustainable solutions and biological methods.