Reading fluency and word segmentation agreement modulate the benefits of word boundary cues for older readers in traditional Chinese.

Nonword segmentation produced a robust interference effect across all reading and oculomotor measures in older readers of traditional Chinese.

• The study tracked eye movements of 76 older readers across three conditions: baseline monocolor, word segmentation (alternating text colors marking words), and nonword segmentation.
• The interference effect from nonword segmentation was described as 'robust' and consistent 'across all reading and oculomotor measures.'
• This finding held regardless of readers' vocabulary knowledge level.
• Traditional Chinese script was used, which is described as 'visually more complex' than simplified Chinese.

Benefits of word segmentation cues were specific to older readers with lower vocabulary knowledge.

• Word segmentation benefits did not generalize to all 76 older readers but were restricted to those with lower vocabulary knowledge.
• The utility of word boundary cues depended on 'a dynamic interplay between visual processing and vocabulary knowledge.'
• Higher vocabulary knowledge readers did not show measurable benefits from word boundary color cues.
• This suggests more proficient older readers can segment words effectively without external cues.

Word segmentation benefits were specific to words with clear, unambiguous boundaries.

• Benefits of word segmentation cues emerged 'only for words with clear, unambiguous boundaries.'
• Words with ambiguous boundaries did not show reading benefits from the alternating color word segmentation condition.
• This indicates that word boundary ambiguity is a key moderator of the effectiveness of typographic word boundary cues.
• The authors conclude that 'models of reading should account for word boundary ambiguity and readers' experience.'

Older readers were chosen as participants because aging-related declines in visual acuity and processing speed may undermine word segmentation ability in unspaced scripts.

• The study included 76 older readers of traditional Chinese.
• Older readers have 'extensive reading experience' but suffer from 'declines in visual acuity and processing speed.'
• Traditional Chinese is an unspaced script, making word segmentation a non-trivial perceptual task.
• Prior research on word boundary cues had focused on simplified Chinese readers, leaving open whether benefits extend to older readers of traditional Chinese.

The findings have practical implications for the development of assistive reading technologies tailored to less proficient readers.

• The authors state that 'development of assistive reading technologies needs to be tailored to the needs of less proficient readers, who benefit most from external support.'
• More proficient older readers did not benefit from word segmentation cues, suggesting one-size-fits-all typographic aids are insufficient.
• The results underscore the need to consider individual differences in vocabulary knowledge when designing reading aids.
• The theoretical implication is that reading models should incorporate both word boundary ambiguity and reader experience.