Illusory continuity of tonal and infratonal periodic sounds

Temporal induction can restore masked or obliterated portions of signals so that tones may seem continuous when alternated with sounds having appropriate spectral composition and intensity. The upper intensity limits for the induction of tones (pulsation thresholds) are related to masking functions and have been used to define the characteristics of frequency domain (place) analysis of tones. The present study has found that induction also occurs for infratonal periodic sounds that require a time domain analysis for perception of acoustic repetition. Limits for temporal induction were determined for iterated frozen noise segments from 10-2000 Hz alternated with a louder on-line noise. Masked thresholds were also obtained for the pulsed signals presented along with continuous noise, and it was found that the relation between induction limits and masking changed with frequency. The results obtained for induction and masking are discussed in terms of general principles governing restoration of obliterated sounds.