Perceptual span is independent of font size for older and young readers: Evidence from Chinese.

Abstract

Research suggests that visual acuity plays a more important role in parafoveal processing in Chinese reading than in spaced alphabetic languages, such that in Chinese, as the font size increases, the size of the perceptual span decreases. The lack of spaces and the complexity of written Chinese may make characters in eccentric positions particularly hard to process. Older adults generally have poorer visual capabilities than young adults, particularly in parafoveal vision, and so may find large characters in the parafovea particularly hard to process compared with smaller characters because of their greater eccentricity. Therefore, the effect of font size on the perceptual span may be larger for older readers. Crucially, this possibility has not previously been investigated; however, this may represent a unique source of age-related reading difficulty in logographic languages. Accordingly, to explore the relationship between font size and parafoveal processing for both older and young adult readers, we manipulated font size and the amount of parafoveal information available with different masking stimuli in 2 silent-reading experiments. The results show that decreasing the font size disrupted reading behavior more for older readers, such that reading times were longer for smaller characters, but crucially, the influence of font size on the perceptual span was absent for both age groups. These findings provide new insight into age-related reading difficulty in Chinese by revealing that older adults can successfully process substantial parafoveal information across a range of font sizes. This indicates that older adults’ parafoveal processing may be more robust than previously considered.