Because people lack access to the many unconscious thought processes that influence perception, they often have the experience of seeing things “as they are”. Psychologists have long presumed that this “naïve realism” plays a role in driving human confidence and closed-mindedness. Yet, surprisingly, these intuitive links have not been empirically demonstrated. Presumably, if naïve realism drives confidence and closed-mindedness, then disabusing people of naïve realism should reduce confidence in one’s judgments and instill openness to change. In the present experiment, we found that participants who read about naïve realism and also experienced various perceptual illusions showed reduced confidence in their social judgments and indicated a greater willingness to change their judgments relative to participants who merely read about naïve realism and perceptual illusions, participants who received failure feedback on an earlier task, or participants left in a baseline state. Broadly, the present research provides evidence for an untested origin of human confidence and closed-mindedness and may have broad implications for decision making.