Ready to Learn: Incidental Exposure Fosters Category Learning.

Our knowledge of the world is populated with categories such as dogs, cups, and chairs. Such categories shape how we perceive, remember, and reason about their members. Much of our exposure to the entities we come to categorize occurs incidentally as we experience and interact with them in our everyday lives, with limited access to explicit teaching. This research investigated whether incidental exposure contributes to building category knowledge by rendering people "ready to learn"-allowing them to rapidly capitalize on brief access to explicit teaching. Across five experiments (N = 438 adults), we found that incidental exposure did produce a ready-to-learn effect, even when learners showed no evidence of robust category learning during exposure. Importantly, this readiness to learn occurred only when categories possessed a rich structure in which many features were correlated within categories. These findings offer a window into how our everyday experiences may contribute to building category knowledge.