Metacognition is the ability to introspect and report one's own mental states, or in other words to know how much one knows. It allows us to form a sense of confidence about decisions one makes in daily life, so one can commit to one option if our confidence is high, or seek for more evidence before commitment if our confidence is low. Although this function is crucial to behave adequately in a complex environment, confidence judgments are not always optimal. Notably, individuals with schizophrenia are prone to overconfidence in errors and underconfidence in correct answers. In schizophrenia, confidence is less correlated with performance compared to controls.