No one can play a symphony, build a city, or advance scientific understanding entirely on their own. How do humans combine their limited knowledge and resources into something greater than the sum of its parts? My lab studies the cognitive capacities and community dynamics that make human collaboration possible. We approach collaboration at two levels of analysis. Zooming in, our work seeks to understand how individuals navigate collaborations—that is, how individuals learn about their collaborators, share knowledge with one another, and divide labor. Zooming out, our work examines how community-wide dynamics contribute to the success of collaborations. We draw on multiple methods, including behavioral studies with children and adults, Bayesian cognitive models, functional neuroimaging, and analyses of large, naturalistic datasets.