a. Time order error (TOE) as a function of Δt, measured from the behavior. TOE is positive in both groups across all Δt, indicating that the first stimulus is perceived as longer. b. Mean expected value from the model in the last 50 trials. Overall, a higher expected value can be seen in the imaging group (two-samples t-test; t49 = 2.4, p = 0.02). This difference is caused by a larger difference in magnitude between the positive and negative outcomes used for the imaging group (+4/−2), as compared to the behavior-only group (+2.5/−2.5). c. Proportion of discrimination errors grouped by PE-type. No difference in performance is seen between the groups for PE+/- (t51 = 0.8/0.9, p = 0.4/0.37, Bayes-Factor >2.5). However, higher proportion of errors in PE0 was found in the imaging group (t51 = 2.52, p = 0.01, Cohen’s d = 0.185), suggesting a non-zero value assigned to these trials during the main paradigm. Right: Proportion of discrimination errors for PE0 trials in the first and second half of main paradigm in the imaging group. The shallower slope (that is indicating worse discrimination) for later trials may result from the fact that the expected value of a trial becomes non-zero as a result of the imbalance between positive and negative outcomes (+4/−2, see b and c, same Figure). Error bars and error bands represent SEM (n=18, 35 for behavior-only and imaging groups, respectively).