Comodulation masking release: effects of training and experimental design on use of within- and across-channel cues

The effects of training and experimental design on comodulation masking release (CMR) were assessed. The study of Dau et al. [(2009), J. Acoust. Soc. Am. 125, 2182-2188], which used auditory-grouping manipulations to distinguish the use of within- and across-channel cues to CMR, was replicated in Experiment One but using naive subjects and an experimental design that minimized familiarization with the cues. Subjects made effective use of within- but not across-channel cues. Experiment Two examined training effects over more testing sessions, across four experimental designs (to minimize or maximize repeated exposure to the cues) and using an auditory grouping manipulation ("postcursors") to distinguish the use of within- and across-channel cues. Naive subjects were tested with either two or four flanking bands (FBs), to determine if training effects varied with the amount of FB information. Within-channel cues could be used from the outset, but effective use of across-channel cues required training when they were less salient. Increased repeated exposure enhanced the effects of training. Experiment Three tested naive subjects using two FBs, but with noise presented continuously and a different auditory grouping manipulation, after Grose et al. [(2009), J. Acoust. Soc. Am. 125, 282-293]. CMR was large from the outset.