Simultaneous grouping and auditory continuity.

Are the conditions for illusory auditory continuity entirely local in frequency, or are judgments of continuity made on auditory objects? Listeners made continuous/pulsating judgments on a variety of complex tones that repeatedly alternated with a 100- to 500-Hz bandpass noise. A sufficiently quiet complex tone was heard as continuous when all its harmonics fell within the frequency range of the noise. Adding harmonics outside the noise's frequency range substantially reduced the impression of continuity, which was largely restored when these additional components were given a different fundamental frequency. Judgments of auditory continuity thus appear to be based on entire simultaneously grouped objects, rather than being determined solely by local criteria based on individual frequency channels.