Limited learning and adaptation in disfluency processing among older adults.

Listeners adapt to diverse cues in real-time language processing. While younger adults can learn and adapt in complex multitalker settings, it remains uncertain whether this ability persists in older adults, especially when they must accumulate auditory inputs to learn novel statistics. We examined whether older adults adapt to talker-specific patterns using paralinguistic cues such as disfluency. In two experiments, older adults listened to instructions from two talkers: one used disfluency predictively (e.g., always referring to novel objects following disfluency) and the other used disfluency unpredictably (e.g., referring to either familiar or novel objects following disfluency). Experiment 1 examined a single-talker setting (N = 50, between-subjects), and Experiment 2 examined a multitalker setting (N = 50, within-subjects). Participants' eye movements were compared between the predictive and nonpredictive conditions. In Experiment 1, older adults demonstrated partner-specific adaptation by looking at novel images more in the predictive condition than in the nonpredictive condition. However, this partner-specific adaptation was not observed in Experiment 2. The results suggest that while older adults can adapt to simpler single-talker settings, their ability to learn and apply novel statistics specific to each talker diminishes in more complex multitalker settings. This limitation may stem from slower processing speed and decreased cognitive flexibility, which may lead older adults to rely on global statistics rather than partner-specific ones. (PsycInfo Database Record (c) 2025 APA, all rights reserved).