Interaction effects of aging, word frequency, and predictability on saccade length in Chinese reading

BACKGROUND: It was well known that age has an impact on word processing (word frequency or predictability) in terms of fixating time during reading. However, little is known about whether or not age modulates these impacts on saccade behaviors in Chinese reading (i.e., length of incoming/outgoing saccades for a target word). METHODS: Age groups, predictability, and frequency of target words were manipulated in the present study. A larger frequency effect on lexical accessing (i.e., gaze duration) and on context integration (i.e., go-past time, total reading time), as well as larger predictability effects on data of raw total reading time, were observed in older readers when compared with their young counterparts. RESULTS: Effect of predictability and frequency on word skipping and re-fixating rate did not differ across the two age groups. Notably, reliable interaction effects of age, along with word predictability and/or frequency, on the length of the first incoming/outgoing saccade for a target word were also observed. DISCUSSION: Our findings suggest that the word processing function of older Chinese readers in terms of saccade targeting declines with age.