Cues to reduce modulation informational masking.

The detectability of target amplitude modulation (AM) can be reduced by masker AM in the same carrier-frequency region. It can be reduced even further, however, if the masker-AM rate is uncertain [Conroy and Kidd, J. Acoust. Soc. Am. 149, 3665-3673 (2021)]. This study examined the effectiveness of contextual cues in reducing this latter, uncertainty-related effect (modulation informational masking). Observers were tasked with detecting fixed-rate target sinusoidal amplitude modulation (SAM) in the presence of masker SAM applied simultaneously to the same broadband-noise carrier. A single-interval, two-alternative forced-choice detection procedure was used to measure sensitivity for the target SAM; masker-AM-rate uncertainty was created by randomly selecting the AM rate of the masker SAM on each trial. Relative to an uncued condition, a pretrial cue to the masker SAM significantly improved sensitivity for the target SAM; a cue to the target SAM, however, did not. The delay between the cue-interval offset and trial-interval onset did not affect the size of the masker-cue benefit, suggesting that adaptation of the masker SAM was not responsible. A simple model of within-AM-channel masking captured important trends in the psychophysical data, suggesting that reduced masker-AM-rate uncertainty may have played a relatively minor role in the masker-cue benefit.