Cumulative culture is a cornerstone of human intelligence. Currently, two models give contrasting explanations of how it works. According to one, humans build causal models and innovate by reasoning over them; culture acts as a repository of these accomplishments. According to another, humans engage in high-fidelity imitation of the prevailing thoughts and behaviors, but without necessarily understanding the underlying causal mechanics. Then, a process of blind evolution leads to incremental improvements over time. A key challenge for the field is to integrate these models. I will present work showing how individuals can arbitrate between them, how populations can evolve to favor one or the other strategy, and how the two processes can productively “exchange” information with each other.