Previous research has shown that when learning categories, adults and young children allocate attention differently. Adults tend to attend selectively, focusing primarily on the most relevant information, whereas young children tend to distribute their attention broadly. Although selective attention is useful in many situations, it also has costs. In addition to ignoring information that may turn out to be useful later, selective attention can have long-term costs, such as learned inattention--ignoring formerly irrelevant sources of information in novel situations. In 2 reported experiments, adults and 4-year-old children completed a category learning task in which an unannounced shift occurred such that information that was most relevant became irrelevant, whereas formerly irrelevant information became relevant. Costs stemming from this shift were assessed. The results indicate that adults exhibit greater costs due to learned inattention than young children. Distributing attention may be adaptive in young children, making them flexible to changing contingencies in the world and facilitating broad information gathering, both of which are useful when general knowledge about the environment is limited.