Despite extensive experience, humans have limited metacognitive insight into many aspects of their perception

There is nothing humans have more experience with than their own perception. Accordingly, one may expect that people would be intimately familiar with their perceptual abilities. Here, we demonstrate that, in fact, humans have limited insight into their own perception. We designed a 46-item questionnaire with forced-choice questions regarding perceptual tasks that most people have extensive experience with. For each question, after indicating their response, participants (N=200) rated their confidence. We found that six questions featured below-chance performance, such that participants consistently picked the wrong responses. Further, for two of these questions, we observed a significantly negative confidence-accuracy correlation, such that participants who had higher confidence were more likely to be wrong. In addition to these six questions, there were another three that featured chance-level performance. A total of 24 questions featured confidence-accuracy correlations indistinguishable from zero. Moreover, average confidence stayed roughly constant for questions when considering the most challenging questions (24 out of the 43 non-catch questions). These results demonstrate that extensive experience alone is insufficient for metacognitive knowledge into our perception and suggest that the working of our perceptual systems can only be inferred by cognitive analysis instead of by direct access to the underlying mechanisms.