Older listeners report substantial difficulty understanding a talker when others are speaking simultaneously. This difficulty may reflect changes in auditory perceptual organization, which is based on lower-level (peripheral) and/or higher-level (schema-based) processes. This study investigated the extent to which older listeners’ difficulties in multitalker environments are due to lower-level deficits in perceptual organization and/or the interaction between lower-level and higher-level processes.

Two groups of listeners participated in competing-speech tasks and were evaluated on several measures of auditory and cognitive function. One group of listeners included 17 older adults with varying degrees of hearing loss and the other included five younger adults with normal hearing. The competing-speech tasks used stimuli from the Coordinate Response Measure corpus. On each trial, two messages were simultaneously presented at a 0 dB signal-to-noise ratio and were amplified to ensure audibility for the listeners with hearing loss. Only one of the messages was designated as the target. Listeners had to identify either the message of the target (Task 1) or the talker of the target (Task 2). Identification accuracy was evaluated in terms of (a) the vocal distinctiveness between the two talkers (same talker; different talkers of the same sex; or different sex talkers) and (b) whether the competing message was meaningful (regular or time-reversed presentation). In both tasks, listeners benefited from vocal distinctiveness and showed improved performance with the nonmeaningful competitor. However, the extent to which these manipulations benefited performance differed for younger and older listeners. Furthermore, the variability in performance was considerably greater in the older group of adults. Statistical analyses indicated that a combination of auditory and cognitive predictor variables were able to account for most of this increased variability.

The experimental results were interpreted in the context of an interactive model of competing-speech perception. In this model, perceptual organization is guided by lower-level and higher-level processes and processing resources are shared throughout the system. The current findings suggest that age-related declines in multitalker environments are not due solely to lower-level deficits in perceptual organization, but are also a consequence of the limited availability of processing resources in an interactive system.