Binocular coordination of the eyes during reading: word frequency and case alternation affect fixation duration but not fixation disparity

This experiment investigated whether properties of the text being read affect binocular coordination of the eyes during reading. Readers' binocular eye movements were recorded while they read sentences that contained high- and low-frequency words. In addition, half of the sentences were presented in normal case, and half were presented in alternating case (i.e., AlTeRnAtInG cAsE). Past research has suggested that the visual system tolerates less binocular fixation disparity with alternating than with normal case (Heller & Radach, 1999). While both word frequency and alternating case produced large effects on fixation durations on the target word, neither manipulation affected the magnitude of fixation disparity. It is concluded that linguistic and visual properties of the text being read do not influence binocular coordination of the eyes during reading. Additional analyses also showed no difference in fixation disparity between reading and a nonlinguistic task. Implications of these results for split-fovea models of reading are discussed.     

Individual differences in working memory during reading with and without parafoveal information: a moving-window study

We examined individual differences in working memory appearing in the effective visual field size while reading Japanese text. Working memory capacity was measured by a Japanese reading span test, and the subjects were divided into high- and low-score groups. Reading performance was measured by reading time, comprehension, and eye movements using a variable moving window through which the subject could read areas of the Japanese text. As the window size decreased, the reading time increased significantly. High-span subjects showed better performance in reading time, comprehension, and fixation duration than low-span subjects even in small visual fields. Interestingly, high-span subjects appear to show better information integration during reading, whereas low-span subjects showed less integration without parafoveal vision. These findings suggest that reading performance was better for subjects with larger working memory resources in a parafoveal restriction condition.     

Masking of foveal and parafoveal vision during eye fixations in reading

A window or visual mask as moved across text in synchrony with the reader's eye movements. The size of the window or mask was varied so that either information in foveal or parafoveal vision was masked on each fixation. In another experiment, the onset of the mask was delayed for a certain amount of time following the end of the saccade. The results of the experiments point out the relative importance of foveal and parafoveal vision for reading and further indicate that most of the visual information necessary for reading can be acquired during the first 50 msec that information is available during an eye fixation.     

Eye movements and the perceptual span in silent and oral reading

Previous research has examined parafoveal processing during silent reading, but little is known about the role of these processes in oral reading. Given that masking parafoveal information slows down silent reading, we asked whether a similar effect also occurs in oral reading. To investigate the role of parafoveal processing in silent and oral reading, we manipulated the parafoveal information available to readers by changing the size of a gaze-contingent moving window. Participants read silently and orally in a one-word window and a three-word window condition as we monitored their eye movements. The lack of parafoveal information slowed reading speed in both oral and silent reading. However, the effects of parafoveal information were larger in silent reading than in oral reading, because of different effects of preview information on both when the eyes move and how often. Parafoveal information benefitted silent reading for faster readers more than for slower readers.     

Parafoveal Magnification: Visual Acuity Does Not Modulate the Perceptual Span in Reading

ABSTRACT— Models of eye guidance in reading rely on the concept of the perceptual span—the amount of information perceived during a single eye fixation, which is considered to be a consequence of visual and attentional constraints. To directly investigate attentional mechanisms underlying the perceptual span, we implemented a new reading paradigm—parafoveal magnification (PM)—that compensates for how visual acuity drops off as a function of retinal eccentricity. On each fixation and in real time, parafoveal text is magnified to equalize its perceptual impact with that of concurrent foveal text. Experiment 1 demonstrated that PM does not increase the amount of text that is processed, supporting an attentional-based account of eye movements in reading. Experiment 2 explored a contentious issue that differentiates competing models of eye movement control and showed that, even when parafoveal information is enlarged, visual attention in reading is allocated in a serial fashion from word to word.     

Eye movement control during reading: Evidence for direct control

In three experiments, subjects read text as their eye movements were monitored and display changes in the text were made contingent upon the eye movements. In one experiment, a window of text moved in synchrony with the eyes. In one condition, the size of the window was constant from fixation to fixation, while in the other condition the size of the window varied from fixation to fixation. In the other experiments, a visual mask was presented at the end of each saccade which delayed the onset of the text, and the length of the delay was varied. The pattern of eye movements was influenced by both the size of the window and the delay of the onset of the text, even when the window size or text delay was varying from fixation to fixation. However, there was also evidence that saccade length was affected by the size of the window on the prior fixation and that certain decisions to move the eye are programmed either before the fixation begins or are programmed during the fixation but without regard to the text fixated on. The results thus provide support for a mixed control model of eye movements in reading, in which decisions about when and where to move the eyes are based on information from the current fixation, the prior fixations, and possibly, other sources as well.     

Parafoveal preview benefits during silent and oral reading: Testing the parafoveal information extraction hypothesis

The preview of a parafoveally visible word conveys benefits when it is subsequently fixated. The current study examined whether these benefits are determined by the effectiveness of parafoveal information extraction, as implied by current models of eye movement control during reading, or by the effectiveness with which extracted information is integrated when a previewed word is fixated. For this, the boundary technique was used to manipulate the extent to which parafoveal information could be extracted, and text was read silently or orally. Consistent with prior work, a parafoveal target word preview conveyed fewer benefits when less parafoveal information could be extracted, target viewing durations were longer during oral than during silent reading, and the two factors interacted in the target fixation data, with smaller preview benefits during oral than during silent reading. Survival analyses indicated that this occurred because parafoveal information use occurred at later point in time during oral reading. Diminished opportunity for parafoveal information extraction also diminished target skipping rate, and it resulted in smaller saccades to target words, but these effects were not influenced by reading mode. Parafoveally extracted information was thus used less effectively during oral reading only when it involved the integration of parafoveally extracted information during subsequent target viewing. The dissociation of extraction from integration challenges current models of eye movement control.     

Covert attention and eye movements during reading

Eye movements were monitored during the reading of spatially transformed text in order to examine covert attentional processes in reading. In some conditions, the sequence of letters within a word was congruent with (i.e. in the same direction as) the sequence of words in the sentence; in other conditions the direction of letters within words and the direction of words in the sentence were incongruent. In addition, the window of visible text was varied so that in some conditions only the fixated word (and all preceding words) were visible, whereas in other conditions the fixated word and the succeeding word were both visible. Readers were able to extract more parafoveal information from text when the words themselves were normal than when the letters within the words were transformed. However, with practice, readers were able to use some parafoveal information even when the words were transformed. The most important finding was that the congruity of the word and letter order had no reliable effect on the ability to extract parafoveal information and influenced reading performance only when the words themselves were normal. We conclude that covert attention in reading is not a letter-by-letter scan that sweeps across the page, but either an asymmetric spotlight held constant on each fixation or a shifting of an attentional spotlight extending across multiletter units (possibly words) with the direction of shifts of attention closely coupled to the direction of eye movements.     

Eye movement guidance in reading: the role of parafoveal letter and space information

The relation between parafoveal letter and space information in eye movement guidance during reading was investigated in 2 experiments. Contingent upon the reader's fixation, the type of parafoveal information available to the right of fixation was varied by (a) space information only, (b) space information with letter information added at some delay, or (c) letter and space information simultaneously. In addition, the onset of the relevant parafoveal information was delayed between 0 and 250 ms into the fixation. The time course of processing the 2 types of information (letters or spaces) differed, as did the nature of their impact on the eye movement record. Although both letter and space information influenced saccade length and initial landing positions within words, only letter information had an effect on fixation duration. In addition, fixation duration was affected only by information entering within the first 50 ms of the fixation, whereas saccade length was affected by information arriving at any time during the fixation. The results are consistent with a model of eye movement control in which 2 independent processes are operating in tandem to determine when and where to move the eyes during reading.     

Effects of foveal processing difficulty on the perceptual span in reading: implications for attention and eye movement control

Two experiments were conducted to examine the effects of foveal processing difficulty on the perceptual span in reading. Subjects read sentences while their eye movements were recorded. By changing the text contingent on the reader's current point of fixation, foveal processing difficulty and the availability of parafoveal word information were independently manipulated. In Experiment 1, foveal processing difficulty was manipulated by lexical frequency, and in Experiment 2 foveal difficulty was manipulated by syntactic complexity. In both experiments, less parafoveal information was acquired when processing in the fovea was difficult. We conclude that the perceptual span is variable and attentionally constrained. We also discuss the implications of the results for current models of the relation between covert visual-spatial attention and eye movement control in reading.     

When preview information starts to matter: Development of the perceptual span in German beginning readers

How is reading development reflected in eye-movement measures? How does the perceptual span change during the initial years of reading instruction? Does parafoveal processing require competence in basic word-decoding processes? We report data from the first cross-sectional measurement of the perceptual span of German beginning readers (n = 139), collected in the context of the large longitudinal PIER (Potsdamer Intrapersonale Entwicklungsrisiken/Potsdam study of intra-personal developmental risk factors) study of intrapersonal developmental risk factors. Using the moving-window paradigm, eye movements of three groups of students (Grades 1–3) were measured with gaze-contingent presentation of a variable amount of text around fixation. Reading rate increased from Grades 1–3, with smaller increases for higher grades. Perceptual-span results showed the expected main effects of grade and window size: fixation durations and refixation probability decreased with grade and window size, whereas reading rate and saccade length increased. Critically, for reading rate, first-fixation duration, saccade length and refixation probability, there were significant interactions of grade and window size that were mainly based on the contrast between Grades 3 and 2 rather than Grades 2 and 1. Taken together, development of the perceptual span only really takes off between Grades 2 and 3, suggesting that efficient parafoveal processing presupposes that basic processes of reading have been mastered.     

中文阅读中副中央凹预加工的范围与程度

在阅读中, 读者既能加工当前注视的中央凹视觉区的信息, 也能从副中央凹视觉区提取信息并利用该信息预先加工下文词汇, 称为预加工或预视。它是熟练阅读的一个关键环节。对副中央凹信息的预加工涉及预视的空间范围和预视程度(即预视量和预视类型)。在拼音文字阅读的研究中, 关于预视范围与预视程度如何受中央凹加工负荷和副中央凹预加工负荷的调节存在争议, 一个主要的原因是拼音文字词长变异大, 在考察预视程度时难以克服预视范围的干扰。而中文词长变化小, 能有效分离预视范围与预视程度。利用中文优势, 采用眼动技术来考察:(1)副中央凹预加工负荷如何影响预视范围, (2)中央凹加工负荷如何影响预视范围与预视程度, (3)阅读能力与阅读效率如何调节预视范围与预视程度, 结果将有助于解决副中央凹预视研究中的理论争论, 为预测阅读能力与衡量阅读效率提供更多有效的眼动行为指标。     

不同年级学生阅读知觉广度及预视效益的眼动研究

本研究以小学五年级学生和大学生为被试, 采用眼动技术, 从阅读知觉广度和副中央凹预视效益相结合的角度考察读者在阅读过程中一次注视获得信息的情况。实验一采用呈现随眼动变化技术探讨了不同年级学生一次注视获取信息的范围, 即阅读知觉广度。实验二采用边界范式进一步考察不同年级学生在知觉广度范围内, 副中央凹预视获取信息的类型。研究发现, 大学生读者知觉广度范围较大, 能够在副中央凹预视中获取字形和语音的信息, 而小学生读者的知觉广度范围较小, 在副中央凹预视中仅能获取字形的信息。上述结果表明, 不同年级学生在注视时, 获取信息的范围及在副中央凹预视时获取信息的类型上均存在一定差异。     

Eye movements when reading: The importance of the word to the left of fixation

In reading, it is well established that word processing can begin in the parafovea while the eyes are fixating the previous word. However, much less is known about the processing of information to the left of fixation. In two experiments, this issue was explored by combining a gaze-contingent display procedure preventing parafoveal preview and a letter detection task. All words were displayed as a series of xs until the reader fixated them, thereby preventing forward parafoveal processing, yet enabling backward parafoveal or postview processing. Results from both experiments revealed that readers were able to detect a target letter embedded in a word that was skipped. In those cases, the letter could only have been identified in postview (to the left of fixation), and detection rate decreased as the distance between the target letter and the eyes' landing position increased. Most importantly, for those skipped words, the typical missing-letter effect was observed with more omissions for target letters embedded in function than in content words. This can be taken as evidence that readers can extract basic prelexical information, such as the presence of a letter, in the parafoveal area to the left of fixation. Implications of these results are discussed in relation to models of eye movement control in reading and also in relation to models of the missing-letter effect.     

Moving window generator for reading experiments

An inexpensive PC-based moving window generator with an eye movement recording system is described. The moving window technique, activated by current eye movements, has an advantage over the fixed window technique in measuring the effective visual field size during reading. A variable rectangular window, through which the subject observes the text, is generated on a PC-controlled CRT screen. The system includes a frame buffer memory, an analog-to-digital conversion unit, and an eye movement recording system. The system works well for measuring approximate field size during reading.     

中文阅读知觉广度的影响因素研究

研究以Eyelink2000车载眼动仪为工具,采用6×3×2×2的四因素混合设计,借助经典的移动窗口技术,探讨了72名被试阅读知觉广度的发展情况,以及材料难度和阅读能力对知觉广度的影响。结果表明:(1)年级、材料难度、阅读能力均各自独立地影响知觉广度。(2)小学三年级被试知觉广度的右侧范围为1~2个字,小学五年级被试接近成人大学生的知觉广度,右侧范围均为2~3个汉字。(3)难度对知觉广度有影响,被试阅读难材料的知觉广度为2~3个汉字,易材料为2~4个汉字。(4)高阅读能力被试的知觉广度大于低阅读能力被试,阅读容易材料时比低阅读能力被试有更大的向右眼跳幅度。     

Binocular coordination of the eyes during reading: Word frequency and case alternation affect fixation duration but not fixation disparity

This experiment investigated whether properties of the text being read affect binocular coordination of the eyes during reading. Readers' binocular eye movements were recorded while they read sentences that contained high- and low-frequency words. In addition, half of the sentences were presented in normal case, and half were presented in alternating case (i.e., AlTeRnAtInG cAsE). Past research has suggested that the visual system tolerates less binocular fixation disparity with alternating than with normal case (Heller & Radach, 1999 Heller, D. and Radach, R. 1999. “Eye movements in reading: Are two eyes better than one?”. In Current oculomotor research. Physiological and psychological aspects, Edited by: Becker, W., Deubel, H. and Mergner, T. 341–348. New York: Kluwer Academic, Plenum.  [Google Scholar]). While both word frequency and alternating case produced large effects on fixation durations on the target word, neither manipulation affected the magnitude of fixation disparity. It is concluded that linguistic and visual properties of the text being read do not influence binocular coordination of the eyes during reading. Additional analyses also showed no difference in fixation disparity between reading and a nonlinguistic task. Implications of these results for split-fovea models of reading are discussed.     

不同掩蔽材料对阅读知觉广度的影响

采用移动窗口技术,探讨了不同掩蔽材料对中文阅读知觉广度的影响,结果表明：（1）相对于“※”掩蔽,文字掩蔽条件下的阅读效率更低、平均注视时间更长、眼跳幅度更小。（2）“※”掩蔽下被试的知觉广度为注视字左侧1个字,右侧2－3个字;文字掩蔽下被试的知觉广度为注视字左侧1个字,右侧3－4个字。综合上述结果,文字掩蔽材料可以比“※”掩蔽材料获得更大的知觉广度,但阅读效率更低。在中文阅读中,文字掩蔽材料更适合探讨阅读知觉广度     

Parafoveal processing in reading

The present review summarizes research investigating how words are identified parafoveally (and foveally) in reading. Parafoveal and foveal processing are compared when no other concurrent task is required (e.g., in single-word recognition tasks) and when both are required simultaneously (e.g., during reading). We first review methodologies used to study parafoveal processing (e.g., corpus analyses and experimental manipulations, including gaze-contingent display change experiments such as the boundary, moving window, moving mask, and fast priming paradigms). We then turn to a discussion of the levels of representation at which words are processed (e.g., orthographic, phonological, morphological, lexical, syntactic, and semantic). Next, we review relevant research regarding parafoveal processing, summarizing the extent to which words are processed at each of those levels of representation. We then review some of the most controversial aspects of parafoveal processing, as they relate to reading: (1) word skipping, (2) parafoveal-on-foveal effects, and (3) n + 1 and n + 2 preview benefit effects. Finally, we summarize two of the most advanced models of eye movements during reading and how they address foveal and parafoveal processing.     

Is emotional content obtained from parafoveal words during reading? An eye movement analysis

An eye-movement-contingent display change technique was employed to study whether adult readers extract semantic information from parafoveal words during reading. Three types of parafoveal preview conditions were contrasted: an emotional word, a neutral word, and an identical word condition. To have a maximally effective parafoveal manipulation, high-arousal emotional words (sex- and threat-related and curse words) were used as parafoveal previews. Readers' eye fixation patterns around the target word revealed no evidence for parafoveal semantic processing. Furthermore, the pupil size showed no signs for an emotional response triggered by an emotional word previewed parafoveally. These results are consistent with the view that, as a rule, only the fixated word is processed to a semantic level during reading.