Complex systems are sets of related entities that, when interacting, produce consequences that are more than the sum of their parts. Previous research in the learning sciences tradition has repeatedly suggested these systems are difficult to understand and counterintuitive to students. However, in the face of a long body of work on cognitive diversity across peoples, it is hard to believe that these results generalize across every population in the world. This paper goes beyond traditionally used learning sciences samples to investigate the relationship between cultural epistemologies and practices and reasoning about complex economic phenomena. Samples were taken from a working-class (favela) and a middle-class background in Rio de Janeiro, Brazil. The data suggests that complex systems thinking outcomes are affected by both cultural epistemologies and practices.