Effects of Word Frequency, Word Length, and Visual Complexity on Chinese Sentence Oral Reading: An Eye Movement Comparison Study Between Children and Adults

This study investigated how word frequency, word length and visual complexity affect lexical processing during Chinese sentence oral reading, and whether these effects differ between developing and skilled readers. Third-grade children and adults read sentences aloud while their eye movements were recorded with an EyeLink 1000 Plus eye-tracker. Linear mixed-effects models revealed three main findings. First, children showed larger word-frequency and visual-complexity effects than adults, indicating less efficient lexical processing in developing readers. Second, word length moderated the effects of word frequency and visual complexity. Frequency effects were amplified for two-character words, whereas visual-complexity effects were stronger for single-character words on early measures and followed a different pattern on some late measures. Third, at the sentence level, children exhibited shorter forward saccades, more regressions and longer total reading times than adults. These findings provide developmental evidence for the visual and linguistic constraints hypothesis and show how visual recognition and overt phonological output jointly shape foveal lexical processing in Chinese oral reading.