Subjective ratings.

<p>Results of the control behavioural study show that participants were on average less certain of errors in the difficult than in the intermediate condition. Interestingly, ratings in the difficult condition suggest a bias towards the (right-end) error side, as if participants somehow “felt” they had committed an error in this condition. Importantly, participants were also quite certain of their correct responses on Go trials. Horizontal bars represent the S.E.M.