Training attenuates the influence of sensory uncertainty on confidence estimation

Confidence is typically correlated with perceptual sensitivity, but these measures are dissociable. For example, confidence judgements are disproportionately affected by the variability of sensory signals. Here, in a preregistered study we investigate whether this signal variability effect on confidence can be attenuated with training. Participants completed five sessions where they viewed pairs of motion kinematograms and performed comparison judgements on global motion direction, followed by confidence ratings. In pre- and post-training sessions, the range of direction signals within each stimulus was manipulated across four levels. Participants were assigned to one of three training groups, differing as to whether signal range was varied or fixed during training, and whether or not trial-by-trial accuracy feedback was provided. The effect of signal range on confidence was reduced following training, but this result was invariant across the training groups, and did not translate to improved metacognitive insight. These results suggest that the influence of suboptimal heuristics on confidence can be mitigated through experience, but this shift in confidence estimation remains coarse, without improving insight into confidence estimation at the level of individual decisions.