The right visual field advantage for word processing is stronger in older adults

The human brain is functionally asymmetric. Producing and understanding language, for instance, engages the left hemisphere to a larger extent than the right in most people. Recent research showed that lateralization for auditory word processing increases with age. The present study extends these findings to the visual domain. We measured lateralization for visual word processing with the visual half field task in young (20-30 years) and older participants (70-80 years). The older cohort had a larger right visual field advantage in terms of reaction time (p = .016, d_{older adults} = 0.16, d_{younger adults} = 0.13) and accuracy (p = .053, d_{older adults} = 0.73, d_{younger adults} = 0.25). This difference was mainly driven by a weaker performance for words presented in the left visual field. Our findings suggest that hemisphere dominance for language increases with aging. Alternatively, the findings could be explained by delayed inter-hemispheric communication in older adults.