On nystagmus,saccades, and fixations

Investigations of the ways in which the eyes move came to prominence in the 19th century, but techniques for measuring them more precisely emerged in the 20th century. When scanning a scene or text the eyes engage in periods of relative stability (fixations) interspersed with ballistic rotations (saccades). The saccade-and-fixate strategy, associated with voluntary eye movements, was first uncovered in the context of involuntary eye movements following body rotation. This pattern of eye movements is now referred to as nystagmus, and involves periods of slow eye movements, during which objects are visible, and rapid returns, when they are not; it is based on a vestibular reflex which attempts to achieve image stabilisation. Post-rotational nystagmus was reported in the late 18th century (by Wells), with afterimages used as a means of retinal stabilisation to distinguish between movement of the eyes and of the environment. Nystagmus was linked to vestibular stimulation in the 19th century, and Mach, Breuer, and Crum Brown all described its fast and slow phases. Wells and Breuer proposed that there was no visual awareness during the ballistic phase (saccadic suppression). The saccade-and-fixate strategy highlighted by studies of nystagmus was shown to apply to tasks like reading by Dodge, who used more sophisticated photographic techniques to examine oculomotor kinematics. The relationship between eye movements and perception, following earlier intuitions by Wells and Breuer, was explored by Dodge, and has been of fundamental importance in the direction of vision research over the last century.     

The time course of plausibility effects on eye movements in reading: evidence from noun-noun compounds

Readers' eye movements were monitored as they read sentences containing noun-noun compounds that varied in frequency (e.g., elevator mechanic, mountain lion). The left constituent of the compound was either plausible or implausible as a head noun at the point at which it appeared, whereas the compound as a whole was always plausible. When the head noun analysis of the left constituent was implausible, reading times on this word were inflated, beginning with the first fixation. This finding is consistent with previous demonstrations of very rapid effects of plausibility on eye movements. Compound frequency did not modulate the plausibility effect, and all disruption was resolved by the time readers' eyes moved to the next word. These findings suggest (contra Kennison, 2005) that the parser initially analyzes a singular noun as a head instead of a modifier. In addition, the findings confirm that the very rapid effect of plausibility on eye movements is not due to strategic factors, because in the present experiment, unlike in previous demonstrations, this effect appeared in sentences that were globally plausible.     

Asymmetries in the perceptual span for Israeli readers

Native Israeli readers read Hebrew and English text as their eye movements were monitored. A window of text moved in synchrony with their eye movements and the window was either symmetrical about the fixation point or offset to the left or right. When subjects were reading Hebrew, the perceptual span was asymmetric to the left and when they were reading English it was asymmetric to the right. The results point out the importance of attentional factors in reading.     

Attention and eye movements in reading: inhibition of return predicts the size of regressive saccades

A spatial cuing task was used to identify two types of readers, those with a relatively fast and those with a relatively slow buildup of inhibition of return (IOR). Backward-directed eye movements (regressions) during sentence reading were then examined as a function of the two IOR types. The results revealed that readers with fast IOR executed larger regressions than readers with slow IOR, as they directed the eyes away from the most recently attended area of text. Forward-directed eye movements (saccades), by contrast, were not a function of IOR type. Ease of sentence comprehension influenced the size of regressions, but this effect was also independent of IOR type. Multiple mechanisms of spatial attention, including IOR, bias eye movements toward upcoming words in the text during reading.     

Long-range regressions to previously read words are guided by spatial and verbal memory

To examine the nature of the information that guides eye movements to previously read text during reading (regressions), we used a relatively novel technique to request a regression to a particular target word when the eyes reached a predefined location during sentence reading. A regression was to be directed to a close or a distant target when either the first or the second line of a complex two-line sentence was read. In addition, conditions were created that pitted effects of spatial and linguistic distance against each other. Initial regressions were more accurate when the target was spatially near, and effects of spatial distance dominated effects of verbal distance. Initial regressions rarely moved the eyes onto the target, however, and subsequent "corrective" regressions that homed in on the target were subject to general linguistic processing demands, being more accurate during first-line reading than during second-line reading. The results suggest that spatial and verbal memory guide regressions in reading. Initial regressions are primarily guided by fixation-centered spatial memory, and corrective regressions are primarily guided by linguistic knowledge.     

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.     

阅读障碍儿童与其年龄和能力匹配儿童阅读空格文本的注视位置效应

采用EyeLink II眼动仪, 选取阅读障碍儿童及与其年龄相同、阅读能力水平相同的儿童为被试, 要求他们阅读正常无空格和词间空格句子。结果发现, 在阅读正常无空格和词间空格句子时, 阅读障碍儿童与年龄匹配组和能力匹配组儿童一样, 单次注视时往往将首次注视定位于词的中心, 多次注视时首次注视往往落在词的开头; 当首次注视落在词的开头时再注视该词的概率增加, 而且再注视往往落在词的结尾部分。我们认为, 中国儿童在阅读过程中采用的是“战略-战术”策略。     

信息加工效率与阅读的关系研究

对23名大学生进行知觉广度、记忆广度和阅读理解的多项测验,探求知觉、记忆加工效率与不同语言阅读成绩和阅读眼动特性之间的关系。结果发现：低水平的视觉符号方向信号知觉广度与阅读不存在明显的关系,从眼跳幅度指标上反映出右侧知觉广度大的被试对第二语言加工难度更为敏感。短时记忆和工作记忆能力对阅读的影响主要反映在眼跳幅度方面,与单个注视点获取的信息量有关,但与课文理解水平的关系不明显。短时记忆能力强的被试在眼跳幅度上以及第二语言言语工作记忆弱的被试在注视时间上均出现语言差异效应。     

Working memory,reading ability and the effects of distance and typicality on anaphor resolution in children

We investigated the time course of anaphor resolution in children and whether this is modulated by individual differences in working memory and reading skill. The eye movements of 30 children (10–11 years) were monitored as they read short paragraphs in which (1) the semantic typicality of an antecedent and (2) its distance in relation to an anaphor were orthogonally manipulated. Children showed effects of distance and typicality on the anaphor itself and also on the word to the right of the anaphor, suggesting that anaphoric processing begins immediately but continues after the eyes have left the anaphor. Furthermore, children showed no evidence of resolving anaphors in the most difficult condition (distant atypical antecedent), suggesting that anaphoric processing that is demanding may not occur online in children of this age. Finally, working memory capacity and reading comprehension skill affect the magnitude and time course of typicality and distance effects during anaphoric processing.     

Evaluation of eye movement variables of Chinese and American readers

Eye movements were recorded while competent readers of English and Chinese read in their respective languages. There were no important differences in oculometric patterns of fixation pause durations for Chinese and American readers, suggesting that cognitive aspects of reading are more important than perceptual ones in determining eye movement patterns and fixation pauses of competent readers. An analysis of undershoot saccades associated with return of the eyes from the end of one line to the beginning of the next line suggests that these occur more frequently during reading than during the performance of similar eye movements that are more perceptually determined, however, the amount of undershoot does not discriminate between readers of alphabetic and logographic texts.     

Temporal dynamics of the eye–voice span and eye movement control during oral reading

The distance between eye movements and articulation during oral reading, commonly referred to as the eye–voice span, has been a classic issue of experimental reading research since Buswell (1921). To examine the influence of the span on eye movement control, synchronised recordings of eye position and speech production were obtained during fluent oral reading. The viewing of a word almost always preceded its articulation, and the interval between the onset of a word's fixation and the onset of its articulation was approximately 500 ms. The identification and articulation of a word were closely coupled, and the fixation–speech interval was regulated through immediate adjustments of word viewing duration, unless the interval was relatively long. In this case, the lag between identification and articulation was often reduced through a regression that moved the eyes back in the text. These results indicate that models of eye movement control during oral reading need to include a mechanism that maintains a close linkage between the identification and articulation of words through continuous oculomotor adjustments.     

Reading Text Under Normal and Disappearing Presentation Conditions

InthispaperIwillsummariseaseriesofex鄄perimentsinwhichwe[1,2]investigatedwhetheritwaspossibletoinducea"gapeffect"duringreadingandtoexaminehowwellpeoplecanreadwhenthetextliterallydisappearsfrominfrontoftheireyes.Tocarryouttheworkwerecordedreaders'eyemovementsandemployedanovelsac鄄cadecontingentchangetechniqueinwhichwemadethewordthatthereaderwasfixatingdisap鄄pear60msafterfixationonset.Inadditiontoin鄄vestigatingwhetheragapeffectmightoccurduringreading,thisworkalsoinvestigatedwhethertheprimaryde…     

词边界信息对读者阅读歧义短语时眼跳策略的影响

采用Eye Link 2000眼动仪,选取60个歧义短语,要求大学生被试阅读包含有歧义短语的句子。句子的呈现设置了四种条件:正常无阴影、词间阴影、歧义阴影和字间阴影,以探讨词边界信息是否影响读者阅读歧义短语时的注视位置效应。结果发现:读者对歧义短语的首次注视位置在四种条件下基本一致;词边界信息影响读者对歧义短语的再注视概率。结果表明,词边界信息对歧义短语的影响主要体现在眼跳行动(即"where")的晚期阶段。     

Don’t look! don’t touch! inhibitory control of eye and hand movements

Inhibitory control of eye and hand movements was compared in the stop-signal task. Subjects moved their eyes to the right or left or pressed keys on the right or left in response to visual stimuli. The stimuli were either central (angle brackets pointing left or right) or peripheral (plus signs turning into Xs left or right of fixation), and the task was either pro (respond on the same side as the stimulus) or anti (respond on the opposite side). Occasionally, a stop signal was presented, which instructed subjects to inhibit their responses to the go stimulus. Stop-signal reaction times (SSRTs) were faster overall for eye movements than for hand movements, and they were affected differently by stimulus conditions (central vs. peripheral) and task (pro vs. anti), suggesting that the eyes and hands are inhibited by different processes operating under similar principles (i.e., a race between stop and go processes).     

The effect of factivity on lexical retrieval and postlexical processes during eye fixations in reading

Subjects were required to read short passages of text while their eye movements were monitored. Each experimental passage contained a critical factive or nonfactive verb that was followed by a false complement. In half of the trials, subjects' reading was unimpaired; in the remainder of the trial, a central visual pattern mask, which moved in synchrony with the eyes, was applied. The results showed that (1) factive and nonfactive verbs did not receive different amounts of fixation time during the reading text. However, (2) false complements that followed nonfactive verbs. On the basis of this, it is concluded that individual word characteristics, such as factivity, are encoded automatically while sentence interpretation requires effort to be completed.     

Interdependence of Saccadic and Fixational Fluctuations

Recent research suggests that the different components of eye movements (fixations, saccades) are not strictly separate but are interdependent processes. This argument rests on observations that gaze-step sizes yield unimodal distributions and exhibit power-law scaling, indicative of interdependent processes coordinated across timescales. The studies that produced these findings, however, employed complex tasks (visual search, scene perception). Thus, the question is whether the observed interdependence is a fundamental property of eye movements or emerges in the interplay between cognitive processes and complex visual stimuli. In this study, we used a simple eye movement task where participants moved their eyes in a prescribed sequence at several different paces. We outlined diverging predictions for this task for independence versus interdependence of fixational and saccadic fluctuations and tested these predictions by assessing the spectral properties of eye movements. We found no clear peak in the power spectrum attributable exclusively to saccadic fluctuations. Furthermore, changing the pace of the eye movement sequence yielded a global shift in scaling relations evident in the power spectrum, not just a localized shift for saccadic fluctuations. These results support the conclusion that fixations and saccades are interdependent processes.     

Moving eyes and moving thought: On the spatial compatibility between eye movements and cognition

Grant and Spivey (2003) proposed that eye movement trajectories can influence spatial reasoning by way of an implicit eye-movement-to-cognition link. We tested this proposal and investigated the nature of this link by continuously monitoring eye movements and asking participants to perform a problem-solving task under free-viewing conditions while occasionally guiding their eye movements (via an unrelated tracking task), either in a pattern related to the problem’s solution or in unrelated patterns. Although participants reported that they were not aware of any relationship between the tracking task and the problem, those who moved their eyes in a pattern related to the problem’s solution were the most successful problem solvers. Our results support the existence of an implicit compatibility between spatial cognition and the eye movement patterns that people use to examine a scene.     

Eye Movements Reveal the Influence of Event Structure on Reading Behavior

When we read narrative texts such as novels and newspaper articles, we segment information presented in such texts into discrete events, with distinct boundaries between those events. But do our eyes reflect this event structure while reading? This study examines whether eye movements during the reading of discourse reveal how readers respond online to event structure. Participants read narrative passages as we monitored their eye movements. Several measures revealed that event structure predicted eye movements. In two experiments, we found that both early and overall reading times were longer for event boundaries. We also found that regressive saccades were more likely to land on event boundaries, but that readers were less likely to regress out of an event boundary. Experiment 2 also demonstrated that tracking event structure carries a working memory load. Eye movements provide a rich set of online data to test the cognitive reality of event segmentation during reading.     

眼睛运动如何与记忆相关？

很久以来,人们一直在致力于研究人的眼动与心理活动之间的关系,从而揭示其间的奥妙。众多研究表明,睡眠时的快速眼动（RapidEyeMovements,REM）及其周期对记忆的形成与巩固有重要作用。在清醒状态下,人的眼动就是为了获得视觉信息,如果涉及记忆任务,这就是编码阶段的具体行动。另外,问题解决过程也有眼动参与。总体看来,眼动和记忆之间是一种双向的关系,适当的眼动训练或许能够提高记忆成绩。     

Eye movement control in reading and visual search: Effects of word frequency

Eye movements were recorded as subjects either read text or searched through texts for a target word. In the reading task, there was a robust word frequency effect wherein readers looked longer at low-frequency words than at high-frequency words. However, there was no frequency effect in the search task. The results suggest that decisions to move the eyes during reading are made on a different basis than they are during visual search. Implications for current models of eye movement control in reading are discussed.