Diffusion studies are taking us a step closer to understanding social learning and cultural transmission in young children. The first half of this article presents a review that focuses on four main cultural issues addressed by diffusion studies: (1) horizontal transmission, including child-to-child learning; (2) learning in children’s everyday environments (“in the wild”); (3) the experience of multiple demonstrations and attempts at mastering new tasks; and (4) the iterative process of learning across multiple cultural “generations.” The second half of the article introduces an open-diffusion experiment. After an initial asocial-learning phase in which children had the chance to discover two possible solutions to a puzzle box, the box was brought into the children’s playgroup, thus allowing observational learning. Although variation of method use occurred in the asocial-learning phase, by the end of the second day of the open diffusion, the group had converged on a single method. The open-diffusion approach allowed the documentation of social interactions not seen in the dyadic studies typical of the field, including both coaction and scrounging, the significance of which for cultural transmission is discussed.