Aging and Distributional Tone Learning: The Role of Pitch Memory in Older Adults’ Discrimination of Mandarin Lexical Tones

Distributional learning enables listeners to form phonetic categories by extracting statistical regularities from speech input. Younger Cantonese speakers can acquire the Mandarin level-falling (T1–T4) contrast through distributional learning, with bimodal exposure facilitating category formation and unimodal exposure suppressing it, and fine-grained pitch sensitivity predicting success. However, aging is associated with declines in pitch sensitivity and phonetic boundary formation, which may disrupt this process. This study examined whether Cantonese-speaking older adults exhibit distributional learning of Mandarin T1–T4 and whether cognitive factors predict success. Sixty-four participants completed a pretest–training–posttest procedure with bimodal or unimodal exposure. While older adults improved in tone discrimination, no group differences emerged. Further analysis showed those with lower pitch-related auditory memory failed to learn from unimodal input. These results suggest a shift from perceptual encoding to memory-based learning and highlight age-related changes in speech perception and the limits of statistical learning in older adulthood.