Cognitive and Linguistic Influences on Dichotic Listening: A Study Across the Lifespan

This study investigated the effects of aging on dichotic listening (DL) performance using native (Brazilian Portuguese) and non-native (English) consonant-vowel stimuli across three age groups: children, young adults, and older adults. The right-ear advantage (REA) was examined under free and directed attention conditions, alongside cognitive tasks assessing attention and working memory. Results revealed a significant REA in children and adults, but not in older adults, providing empirical support for the HAROLD (Hemispheric Asymmetry Reduction in Older Adults) model of reduced hemispheric asymmetry with aging. Adults significantly outperformed both children and older adults in cognitive and DL tasks, demonstrating the combined influences of neurocognitive maturation and age-related decline. Directed attention selectively enhanced the REA in adults, whereas older adults exhibited markedly reduced performance under attentional manipulation, indicating age-related impairments in top-down cognitive control mechanisms. Non-native stimuli elicited stronger top-down cognitive engagement, particularly in children and adults, suggesting increased executive processing demands for unfamiliar linguistic material. These findings underscore the dynamic interplay between bottom-up sensory processing and top-down cognitive control in dichotic listening, with significant implications for understanding auditory processing and hemispheric specialization across the human lifespan.