Illustration of confidence properties.

Correct answers are more likely with higher confidence (left panel), confidence in correct trials is higher (center panel), and, for a given level of discriminability/difficulty, trials with higher confidence should be more accurate (right panel). This figure was simulated using a uniform distribution for discriminability (U(0,1)) and a normal distribution for the perception of discriminability levels (details in [10]). This figure is not a number comparison model (for that, see Fig 5), just an illustration of the confidence properties proposed by [10].