When people make decisions, they experience subjective feelings of confidence or uncertainty about whether their choices are the right ones. In my talk, I’ll describe my lab’s research into the basis of these confidence judgments and how people use them to improve their decisions, for example by indicating whether they should seek advice before committing to a choice. Extending this idea, we’ve explored how confidence judgments also allow people to learn about the quality of others’ decisions — i.e., to learn whose advice to trust and whose not to trust — even in the absence of objective feedback. Most of this work has been done in lab settings, but in recent research we’ve begun to apply these approaches to the practical setting of medical decision making.