The auditory continuity phenomenon: role of temporal sequence structure.

The auditory continuity phenomenon occurs when listening to a series of alternating high- and low-level tones: instead of perceiving this intermittence, listeners often report hearing a continuous tone upon which is superimposed a series of intermittent tones. The temporal limits to the perception of this phenomenon are investigated, as well as effects of task instructions on it. A loudness-matching paradigm developed previously [McAdams et al., J. Acoust. Soc. Am. 130, 1580-1591 (1998)] provided both an objective indication of this phenomenon and an indication of its strength. In the studies reported here, the phenomenon was observed reliably when the low-level tones were at least half the duration of the high-level tones: the greater the duration ratio between low-level and high-level tones, the stronger the phenomenon. Duty-cycle duration did not affect the strength of this phenomenon. It proved to be particularly robust as its strength was unaffected by task instructions, level of expertise, and repetition. A model is proposed in which adjusted levels depend on the relative levels of the high- and low-level tones weighted by relative duration and attentional focusing.