Proceedings of the Annual Meeting of the Cognitive Science Society

When deciding whether to explore, people must consider both their need for information, and the cost of obtaining it.Thus, to judge why someone explores (or decides not to), we must consider not only their actions, but also the cost ofinformation. Do children attend to the cost of agents exploratory choices when inferring what others know or desireto know? In Experiment 1, four- and five-year-olds judged that an agent who rejected an opportunity to gain low-costinformation must have already known it. In Experiment 2, four- and five-year-olds judged that an agent who incurreda greater cost to gain information had a greater epistemic desire. In two control experiments, we show that these resultscannot be explained by a low-level heuristic linking competence with knowledge. Our results suggest that childrens Theoryof Mind includes expectations about how costs interact with epistemic desires to produce action.