Recalibration of subjective simultaneity between self-generated movement and delayed auditory feedback.

Temporal contingency between motor commands and corresponding auditory feedback is crucial for perception of self-generated sound as well as external auditory events. The present study examined whether delay detection of self-generated sound was affected by the range of delayed auditory feedback used during the experiment. Participants pressed a button with their right index finger and judged whether auditory feedback was delayed compared with the sensation of finger movement. The range of auditory feedback delay was varied across conditions. To calculate the delay detection threshold (DDT), that is, the point at which the delay detection rate was 50%, we fitted a logistic function to the delay-detection probability curve. The DDT was significantly different across conditions (Tukey-Kramer's honestly significant difference test, P<0.01). Specifically, the DDT became longer as the mean delay of the range increased. However, this shift was not observed for the delay range with a minimum delay greater than 250 ms. We propose that the subjective simultaneity of auditory feedback and self-body movement is, to some extent, automatically recalibrated toward the mean delay of the delay range used in the experiment.