It is widely believed that exploration is a mechanism for young children's learning. The present investigation examines preschoolers' beliefs about how learning occurs. We asked 3- to 5-year-olds to articulate how characters in a set of stories learned about a new toy. Younger preschoolers were more likely to overemphasize the role of characters' actions in learning than older children were (Experiment 1, N = 53). Overall performance improved when the stories explicitly stated that characters were originally ignorant and clarified the characters' actions, but general developmental trends remained (Experiment 2, N = 48). These data suggest that explicit metacognitive understanding of the relation between actions and learning is developing during the preschool years, which might have implications for how children learn from exploration.