Effects Of Aging On Chinese Reading:Evidence From Eye Movements

Age-related reading difficulty is well-established for alphabetic languages.Compared to young adults(18-30 years),older adults(65+ years)read more slowly,make more and longer fixations,more regressions,and often appear have greater difficulty identifying lower frequency words.But older readers also skip words more frequently,and make longer forward saccades,and so seem to compensate for their poorer processing of text by employing a more risky reading strategy.However,little is known about effects of aging on eye movement control for non-alphabetic languages,like Chinese,that have very different visual and linguistic characteristics.This raises a basic but important question:how about Chinese older adults reading?The answer to this question would reveal the extent to which age-related changes in reading strategy are universal,and also would be the key point of the cognitive mechanism of the age-related cognitive mechanism changes of Chinese.Furthermore,the solution of this issue will contribute directly to the development in the field of improving the quality of life of the elderly.Five studies including six experiments were carried out.Study 1 used measures of eye movements to investigate adult age differences in Chinese reading and the basic frequency effect,which gave us a general view of Chinese older adults reading.Based on the findings of Study 1,the next 4 studies further investigated how different factors affect the reading of Chinese older adults,including stimulus quality(Study 2),character visual complexity(Study 3),spacing effect(Study 4),perceptual span(Study 5).Young(18-28 years)and older(65+ years)participants were selected to take part in these 5 eye-tracking Studies.In Study 1,high or low frequency target words were inserted into the same sentence frame.Additionally,because aging is associated with sensory declines,effects of reduced stimulus quality were investigated by presenting a specific target word(Experiment 1)or all characters in sentences(Experiment 2)normally or with contrast reduced in the Study 2.With Study 3,we focused on the role of visual complexity,which is a likely source of reading difficulty.Chinese is ideally suited to investigating such effects,as Chinese characters are formed from differing numbers of individual brush-strokes but always occupy the same square area of space,and so effects of visual complexity are not confounded with word length.In Study 3,participants read text containing interchangeable high-complexity or low-complexity two-characters words that were matched for lexical frequency and predictability.Whether this age-related change in reading behavior reflects the specific processing demands of this naturally-unspaced,character-based writing system remains to be established.Moreover,it is unclear if older Chinese readers,like other poorer readers of Chinese,benefit from the addition of spaces between characters to delineate word boundaries.To investigate this issue,in Study 4,we assessed the eye movements of young and older Chinese readers for sentences which were normally(unspaced)or had spaces inserted to group together characters that formed ether words or nonwords.Chinese uses a logographic writing system in which text is printed as a sequence of box-like,pictorial characters.Crucially,Older adults also suffer more from visual crowding,characterized by the impaired recognition of visual objects when closely surrounded by similar objects.Moreover,crowding appears greater for Chinese characters than Latin alphabetic letters and may limit the number of characters that can be identified on each fixation,and so may be a further,specific source of difficulty for older Chinese readers.In Study 5,the perceptual span of the older adults during Chinese reading were investigated using gaze contingent paradigm.To summarize the findings of these studies,the conclusion was made as follows.1)Typical patterns of age-related reading difficulty were observed in all these studies.But,unlike older readers of alphabetic languages,the older Chinese readers skipped words infrequently and made shorter forward saccades than younger readers.Therefore,rather than engaging in risky reading,the older Chinese adults read more cautiously.2)Effects of low-contrast text were greater for the older readers,although unlike in studies with alphabetic languages,this effect of reduced stimulus quality was largely restricted to the visual encoding of text.Effects of aging and stimulus quality on eye movements during reading therefore appear to be language-specific and may reflect the visual and linguistic demands of the writing system.3)Crucially,older readers also had greater difficulty reading high-than low-complexity words compared to young adult readers,suggesting older adults have particular difficulty processing more complex characters due to visual/cognitive declines in older age.We discuss these findings in relations to the specific visual demands of Chinese reading.4)Using spaces to group together characters into words produced no overall benefit for either age-group,but shorter than normal re-reading times for the older adults,suggesting they were less likely to misidentify words when these spaces were included.By comparison,using spaces to segregate nonwords disrupted eye movements similarly for the two age-groups.The indication is that inserting spaces between words does not remediate age-related Chinese reading difficulty.Indeed,while words remain an important unit of processing for Chinese reading across the adult lifespan,it seems clear they are accurately segmented in naturally-unspaced text by both young and older adult readers.5)The older adults have smaller and more symmetric perceptual span than the young adults during Chinese reading.The older adults might utilize more information to the left of fixation than younger adults.