Efficiency of spoken word recognition slows across the adult lifespan

Abstract

Spoken word recognition is a critical hub during language processing, linking hearing and perception to meaning and syntax. Words must be recognized quickly and efficiently as speech unfolds to be successfully integrated into conversation. This makes word recognition a computationally challenging process even for young, normal hearing adults. Older adults often experience declines in hearing and cognition, which could be linked by age-related declines in the cognitive processes specific to word recognition. However, it is unclear whether changes in word recognition across the lifespan can be accounted for by hearing or domain-general cognition. Participants (N = 107) responded to spoken words in a Visual World Paradigm task while their eyes were tracked to assess the real-time dynamics of word recognition. We examined several indices of word recognition from early adolescence through older adulthood (ages 11–78). The timing and proportion of eye fixations to target and competitor images reveals that spoken word recognition became more efficient through age 25 and began to slow in middle age, accompanied by declines in the ability to resolve competition (e.g., suppressing sandwich to recognize sandal). There was a unique effect of age even after accounting for differences in inhibitory control, processing speed, and hearing thresholds. This suggests a limited age range where listeners are peak performers.