Effect of Flanking Sounds on the Auditory Continuity Illusion

Background: The auditory continuity illusion or the perceptual restoration of a target sound briefly interrupted by an extraneous sound has been shown to depend on masking. However, little is known about factors other than masking. Methodology/Principal Findings: We examined whether a sequence of flanking transient sounds affects the apparent continuity of a target tone alternated with a bandpass noise at regular intervals. The flanking sounds significantly increased the limit of perceiving apparent continuity in terms of the maximum target level at a fixed noise level, irrespective of the frequency separation between the target and flanking sounds: the flanking sounds enhanced the continuity illusion. This effect was dependent on the temporal relationship between the flanking sounds and noise bursts. Conclusions/Significance: The spectrotemporal characteristics of the enhancement effect suggest that a mechanism to compensate for exogenous attentional distraction may contribute to the continuity illusion.