Aging Effects On Perceptual Span And Visual Span During Chinese And English Reading

Reading involves the precise co-ordination and integration of a range of visual,oculomotor,and cognitive processes.It is a complex skill which is acquired early in life and used daily throughout the lifespan.A range of visual and cognitive declines occur with advancing age,which may be particularly relevant to the reading process.Poor reading ability can have a profound impact on daily life.More and more researchers begin to explore this issue and realize the importance of development research across the life.Chinese and English are the major languages of the world,the development research for the two languages has gradually become the focus of the research.In recent years,older readers(aged 65+ years)of both alphabetic and Chinese languages read more slowly than their younger counterparts(aged 18-30 years).What is the mechanism for this reading difficulty? A possible explanation for this slowdown is that,due to age-related visual and cognitive declines,older readers have a smaller perceptual span and so acquire less information on each fixational pause.Therefore,it is very important to determine the acquisition of information on a glance,which may be the main reason of the slow reading speed for older adults.Several methods have been developed to estimate the number of letters that can be recognized on a single glance,each with different conceptual definitions(for a review,see Frey & Bosse,2018).Key concepts are the perceptual span(McConkie & Rayner,1975)and the visual span(O’Regan,1990).The perceptual span is termed as the amount of information that can be acquired on each fixational pause during natural reading.While,the visual span,which is defined as the number of letters that can be recognized reliably without moving the eyes(O’Regan,1990;O’Regan,Levy-Schoen,& Jacobs,1983;Legge,Cheung,Yu,Chung,Lee,& Owens,2007).It is important to note,however,that the perceptual span is defined in terms of the functional demands of reading,and so performance may be influenced by various factors including allocation of attention,use of context and word knowledge.On the contrary,visual span focuses on sensory bottom-up constraints on reading(O’Regan,1990;O’Regan,Levy-Schoen,& Jacobs,1983;Legge,Cheung,Yu,Chung,Lee,& Owens,2007),imposes a sensory bottleneck on reading speed.In order to investigate the disruption of information acquisition more comprehensively,the research about the aging on the perceptual span and visual span helps to reveal this issue and to understand the age-related reading difficulty for older adults.Noteworthily,English is a different writing system from Chinese.To be specific,in alphabetic language reading,older adult readers tend to skip words more frequently and made generally longer forward eye movements.Based on these findings,it is argued that older adults compensate for their poorer processing of text by employing a more “risky” reading strategy in which they are more likely than younger adults to infer the identities of upcoming words using prior context and only partial word information.By contrast with the findings for alphabetic languages,the older adults did not skip words more frequently than the young adults and made shorter,rather than longer,forward eye movements.Together these findings reveal that,rather than engaging in risky reading to compensate for greater reading difficulty,older Chinese readers employ a more careful strategy.The key to understanding possible agedifferential compensation strategies is to determine whether,and if so how,young and old adults differ in the perceptual span.Therefore,the age difference of perceptual span in Chinese and English reading is helpful to explain the aging effect on reading processing in different language reading and to improve the theoretical model of eye movement control in Chinese and English reading.To sum,the main aims of this paper is to explore the mechanism of age-related reading difficulty and to further understand the universality and specialty of age-related information processing ability changes in different script systems by studying the aging effect on the perceptual span and visual span in English and Chinese reading.Based on this,we investigated these issues in eighth experiments.Among these,the thesis conducts the aging effect on the perceptual span with Study 1 and 2.The moving window paradigm is the most classical and commonly used paradigm.Therefore,moving window paradigm is used in Study 1 and 2.A particular concern for the present research was that moving-window paradigms in which letters in words outside of a window are replaced by which kinds of stimuli.This has been a long controversial.To resolve this debate,three experiments were conducted to systematically explore the aging effect on perceptual span in English reading.The pattern mask was used in Experiment 1,visual similar characters in Experiment 2 and the blurring technology in Experiment 3.All the three experiments used a 2(age-group: older adults and young adults)× 2(viewing condition: unmasked and masked)× 5(window size: normal(N),only the fixated word(1W),the fixated word and one word to its left(1W + L1),or the fixated word and one or two words to its right(1W + R1 and 1W + R2))mixed design.Based on the previous study,the comparison of 1W +R1 and 1W + R2 windows will provide a key test of age differences in the perceptual span.Twenty young and 20 older adults were recruited for each Experiment.The results show that older adults had longer reading times and slower reading rates compared to the young adults in all three experiments.The findings also showed that restricting linguistic information to the right and left of the fixated word increased sentence reading times and slowed the reading rates.Importantly,there is no age difference between 1W+R1 and 1W+R2 window conditions on the reading behavior.This suggests that there is no essential difference in rightward of perceptual span for both older and young adults in English reading,and this further indicates that parafoveal processing may be maintained across the lifespan during English reading.To ensure comparability with the findings in Study 1,we conducted Study 2 with moving window to explore the aging effect on perceptual span during Chinese reading.Following the similar procedure as Study 1,we recruited 35 Chinese undergraduate students and 35 Chinese older adults from local communities for each experiment.The only difference is still the masking stimuli(pattern mask(" ※ "),visually similar Chinese characters and blurring technology)for each experiment.The results were basically consistent with the results of Study 1,and there was no difference in acquiring information from parafoveal for both age groups.Taken together,there is no age difference in perceptual span,and this is universal across different script system.In addition,blurring technique is an ideal method to mask the information outside the window in moving window experiment.The current study 1 and 2 provides the evidence that there is no age difference in perceptual span during Chinese and English reading,further indicates that the absence of age difference in acquiring information in the parafoveal.As noted above,the visual span is mainly governed by the visual acuity.The exploration for the age difference in visual span may provide a clearer indication of specifically perceptual limitations on the acquisition of linguistic information and the extent to which reading difficulty is affected by age-related visual acuity.Accordingly,Study 3 and Study 4 examined the size of the visual span in young and older readers of English and Chinese with the trigram task.In study 3,26 older and young adults were randomly selected from those who had participated in Study 1.A trigram task,in which sets of three letters were displayed randomly,then asking the participants to report the three letters from left to right.And in study 4,21 older and young adults were selected from those who had participated in Study 2.A trigram task,in which sets of three similar complexity characters,then asking the participants to report the three characters from left to right.The study 3 and 4 were conducted to explore the age differences in visual span and the relationship between visual span and reading speed in English and Chinese reading separately.The results show that young adults readers recognized more characters than old adult readers for both alphabetic and Chinese script,and also there exists positive correlation between numbers of Characters and reading speed.This suggests that age-related decline in visual ability limits the acquisition of language information and provides a simple perceptual explanation for age related reading difficulty.Moreover,this is universal across languages and has no linguistic specificity.To summarize the findings of these studies,the conclusion was made as follows:1)Compared with young readers,old readers have greater reading difficulties in both alphabetic and Chinese reading.2)Older readers could acquire the same amount of information on each fixation with the young adults.The age-related reading difficulty is due to the depth of parafoveal processing undertaken across the span,rather than a narrow of the perceptual span size.3)The types of masking stimuli affect the perceptual span size,especially visually similar alphabetic or Chinese characters,suggesting that incorrect orthographic information not only interferes with orthographic processing,but also leads to incorrect semantic information,which interferes with normal reading.Compared with pattern mask or visually similar stimuli,blurring technique is an ideal method to mask the information outside the window in moving window experiment.4)When employing the word-based windows as this study,the readers can acquire the information from a similar region in the parafoveal during English and Chinese reading.That is to say,the size of the perceptual span is similar for English and Chinese readers.However,the visual span size is smaller for the Chinese readers than for English readers.5)During Chinese and English natural reading age-related visual limitations reduced the amount of information acquired in parafoveal.In addition,there is a correlation between the visual span size and reading performance in both scripts,the smaller the visual span,the slower the reading speed.This correlation provides a simple perceptual explanation for age-related reading difficulty.