Figure 1

Behavioural performance in stimulus identification during the five training sessions. A: Labeling the speech sound with 20 ms pre-voicing time as ‘mba’ was considered as correct response. The group mean of correct responses increased over training sessions (red line). The group mean frequency of mistakenly labeling the 10-ms pre-voicing sound as ‘mba’ decreased during the training (blue line). (Error bars denote the 95%-confidence limits for the mean). B: The signal discrimination index d-prime (red line) increased significantly between the third and fourth and between the fourth and fifth training session, whereas the performance increase was not significant during the first half of the training. A response bias (blue) was not significant (blue line). C: Individual change in correct responses (red) and false alarms (blue) between the first and last training sessions. D: Individual changes in the signal discrimination index d-prime. Despite individual variability the d-prime measure increased for all participants during the training.