Objective: Previous studies have shown that presenting younger listeners with all but the last word of a target anomalous sentence immediately before presenting the full sentence in a noisy background produces a greater release from masking when the masker is two-talker anomalous speech than when it is speech-spectrum noise, thereby demonstrating that an auditory prime can produce a release from informational masking. The purpose of this study was to investigate whether older adults could gain the same benefit from auditory primes as younger adults and what bottom-up auditory factors contribute to the advantage provided by auditory primes in releasing speech from informational masking.
Design: A total of 76 younger adults (university students) and 76 older adults (volunteers from the local community) participated in this study. All participants spoke English as a first language and had normal hearing below 4 kHz.
Results: In experiment 1, younger adults performed better in the presence of the speech masker, whereas older adults performed equivalently under both types of masking, but auditory priming produced an equivalent amount of release from informational masking in both younger and older adults. To examine the degree to which familiarity with the target talker's voice contributed to the priming effects observed in the first experiment, in experiment 2, we primed individuals with sentences that were spoken by the target talker but with lexical content that was unrelated to the target sentences. There was no release from informational masking for either age group. Next, to investigate the extent to which the release from informational masking in the first experiment was due to the amplitude envelope cues provided by the prime, in experiment 3, we noise vocoded the prime (using 3 bands) to remove semantic content while retaining some cues about the prime's amplitude envelope. When the primes were noise vocoded, there was no release from informational masking for either younger or older adults. Finally, to examine whether older adults' performance in the presence of the speech masker in the first experiment was due to an age-related decline in the ability to take advantage of dips in the amplitude envelope of the speech masker, in experiment 4, we noise vocoded the speech masker. We found a significant improvement in performance, but the amount of improvement was equivalent for both age groups.
Conclusions: Auditory priming resulted in equivalent amounts of release from informational masking in both younger and older adults. The benefit provided by auditory primes was not due to cues provided in the prime about the target talker's voice or cues provided in the prime about fluctuations in the amplitude envelope of the target sentences. Importantly, there was an age-related decline in performance in the presence of a two-talker masker relative to a continuous speech-spectrum noise masker; however, this age-related decline in performance cannot be attributed to age-related differences in the ability to take advantage of fluctuations in the amplitude envelope of the speech masker.