How configurations of binocular disparity determine whether stereoscopic slant or stereoscopic occlusion is seen

A partially occluded contour and a slanted contour may generate identical binocular horizontal disparities. We investigated conditions promoting an occlusion resolution indicated by an illusory contour in depth along the aligned ends of horizontally disparate line sets. For a set of identical oblique lines with a constant width added to one eye's view, strength, depth, and stability of the illusory contour were poor, whereas for oblique lines of alternating orientations the illusory contours were strong, indicating a reliance on vertical size disparities rather than vertical positional disparities in generating perceived occlusion. For horizontal lines, occlusion was seen when the lines were of different lengths and absolute width disparity was invariant across the set. In all line configurations, when the additional length was on the wrong eye to be attributed to differential occlusion, lines appeared slanted consistent with their individual horizontal disparities. This rules out monocular illusory contours as the determining factor.     

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.     

Optimal landing position in reading isolated words and continuous text

During isolated-word reading, within-word eye-movement tactics (i.e., whether the eye makes one or more fixations on the word) depend strongly on the eye's first fixation position in the word; there exists an optimal landing position where the probability of having to refixate the word is much smaller than when the eye first fixates other parts of the word. The present experiment was designed to test whether the optimal landing position effect still exists during text reading, and to compare the nature and strength of the effect with the effect found for isolated words. The results confirmed the existence of an optimal landing position in both reading conditions, but the effect for words in texts was weaker than it was for isolated words, probably because of the presence of factors such as reading rhythm and linguistic context. However, the effect still existed in text reading; within-word tactics during text reading are dependent on the eye's initial landing position in words. Moreover, individual fixation durations were dependent on within-word tactics. Thus, the initial landing position in words must be taken into account if one wishes to understand eye-movement behavior during text reading. Further results concerned the effects of word length and word frequency in both reading conditions.     

不同水平五年级维吾尔族学生母语阅读知觉广度

本研究以眼动仪为工具,借助移动窗口技术,比较了16名高阅读水平和14名低阅读水平的五年级维吾尔族小学生维吾尔语阅读知觉广度的大小及其对称性。结果发现:高阅读水平学生的知觉广度为注视点左侧8~11个字符到右侧2~3个字符,而低阅读水平学生的知觉广度为注视点左侧8~11个字符到右侧2个字符。在本研究条件下,可得出以下结论:(1)五年级不同阅读水平的学生维吾尔语阅读知觉广度都具有不对称性,左侧范围大于右侧;(2)阅读水平高的学生其阅读知觉广度略大于低阅读水平的学生,差异主要体现在右侧知觉广度。     

小学五年级语文学优生与学困生阅读知觉广度的眼动研究

本研究以眼动仪为工具,采用移动窗口范式来考察小学五年级语文学优生和学困生的阅读知觉广度。实验结果发现,小学五年级语文学优生的阅读知觉广度范围为注视字左侧一个汉字到注视字右侧三个汉字,小学五年级语文学困生的阅读知觉广度范围为注视字左侧一个汉字到注视字右侧两个汉字。小学五年级语文学优生的阅读知觉广度比学困生更大。     

汉字、数字和符号的身份信息和位置信息加工比较——中文阅读的特别机制

汉字、数字和符号的身份信息和位置信息加工存在怎样的差异,以及在不同呈现方式下是否表现不同,现在仍不清楚。本研究采用9选1部分报告范式,通过字符串水平呈现和竖直呈现两个实验来对这一问题进行探究。结果发现,水平呈现对于不同类型字符的身份信息和位置信息加工都更有优势。数字在不同呈现方式下都表现出绝对优势,且水平呈现时存在首位置优势,表明“改变的接受域”理论对于汉语语系地区数字系列位置效应解释的可能性。同时,汉字与符号更为相似,但水平呈现时汉字位置信息加工更好,且表现出更为明显的注视点左侧(包括注视点)优势,这可能是中文阅读的特别机制。     

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     

Lexical quality and eye movements: Individual differences in the perceptual span of skilled adult readers

Two experiments used the gaze-contingent moving-window paradigm to investigate whether reading comprehension and spelling ability modulate the perceptual span of skilled adult readers during sentence reading. Highly proficient reading and spelling were both associated with increased use information to the right of fixation, but did not systematically modulate the extraction of information to the left of fixation. Individuals who were high in both reading and spelling ability showed the greatest benefit from window sizes larger than 11 characters, primarily because of increases in forward saccade length. They were also significantly more disrupted by being denied close parafoveal information than those poor in reading and/or spelling. These results suggest that, in addition to supporting rapid lexical retrieval of fixated words, the high quality lexical representations indexed by the combination of high reading and spelling ability support efficient processing of parafoveal information and effective saccadic targeting.     

A binocular moving window technique to study the roles of the two eyes in reading

Readers utilize parafoveal information about upcoming words and read less well when this information is denied. McConkie and Rayner (1975) enabled this issue to be explored by developing the moving window paradigm in which the experimenter varies the amount or the quality of the parafoveal information available around the current fixation point. We present a novel binocular version of the moving window technique to study the roles of the two eyes in reading, and we describe a basic experiment allowed by this technique. In the binocular moving window paradigm, each eye contributes its own window to a composite binocular window onto the text. We studied the reading of single lines of text in three conditions: no windows, a symmetrical 8-letters-left and 8-letters-right window for each eye, and a leftward-skewed 14-letters-left and 2-letters-right window for each eye. Note that both eyes saw the composite window onto the text. We tested the hypothesis that readers could be encouraged to generate a greater binocular disparity to augment their window onto the text and to provide a greater preview for one eye. The data offered limited support for this prediction. We observed considerable individual differences in both baseline fixation disparity and in readers' response to the critical asymmetric [14,2] window.     

中文阅读中副中央凹区域文本信息加工时程的眼动研究

副中央凹文本对阅读有非常重要的作用,考察读者在注视何时起对其加工有助于解决阅读中词汇加工方式的理论问题,当前研究结果存在很大争论。本研究采用消失文本范式,操纵词n-1和n+1的呈现时间(0m/40ms),考察读者加工两侧副中央凹信息的时程。结果发现,相比0ms,在注视早期40ms内,词n+1的呈现能够显著促进阅读加工,而词n-1未对阅读产生影响,表明右侧副中央凹信息的加工发生在注视早期,而左侧则未发生在该早期阶段。结果支持阅读眼动控制的并列加工模型。     

Right visual field advantage in parafoveal processing: Evidence from eye-fixation-related potentials

Readers acquire information outside the current eye fixation. Previous research indicates that having only the fixated word available slows reading, but when the next word is visible, reading is almost as fast as when the whole line is seen. Parafoveal-on-foveal effects are interpreted to reflect that the characteristics of a parafoveal word can influence fixation on a current word. Prior studies also show that words presented to the right visual field (RVF) are processed faster and more accurately than words in the left visual field (LVF). This asymmetry results either from an attentional bias, reading direction, or the cerebral asymmetry of language processing. We used eye-fixation-related potentials (EFRP), a technique that combines eye-tracking and electroencephalography, to investigate visual field differences in parafoveal-on-foveal effects. After a central fixation, a prime word appeared in the middle of the screen together with a parafoveal target that was presented either to the LVF or to the RVF. Both hemifield presentations included three semantic conditions: the words were either semantically associated, non-associated, or the target was a non-word. The participants began reading from the prime and then made a saccade towards the target, subsequently they judged the semantic association. Between 200 and 280 ms from the fixation onset, an occipital P2 EFRP-component differentiated between parafoveal word and non-word stimuli when the parafoveal word appeared in the RVF. The results suggest that the extraction of parafoveal information is affected by attention, which is oriented as a function of reading direction.     

Some temporal characteristics of processing during reading

College students read passages displayed on a cathode-ray tube as their eye movements were being monitored. During occasional fixations, all letters to the left of the directly fixated letter or all letters more than four to the right of the fixated letter were replaced by other letters. This replacement occurred either for only the first 100 ms of the fixation or only after the first 100 ms of the fixation. The eye movement data indicated that the eyes can respond to change in the visual stimulus within less than 100 ms and to orthographic irregularity in the text within less than 160 ms. No evidence was found for a left-to-right attentional scan during a fixation. The results were interpreted within the framework of a chronology of processing events occurring during a fixation in reading.     

Panum's fusional area estimated with a criterion-free technique

It has been reported that criterion-free estimates of the upper disparity limits for fusion of line targets are small enough to be accounted for by monocular vernier sensitivity. However, targets such as lines, which contain high spatial frequencies, may ensure small fusion limits, since fusion limits obtained with criterion-dependent methods for narrow-band targets, such as sinusoids or difference-of-Gaussian luminance profiles, are proportional to target spatial periods. Experiment 1 therefore explored whether criterion-free methods give fusion limits for narrow-band targets that can be accounted for by vernier sensitivity. Vertical fusion limits were estimated by a method that forced observers to discriminate a disparate sinusoidal grating from an immediately adjacent zero-disparity grating. Fusion limits were too large to be explained by monocular vernier thresholds obtained for the same targets. In addition, fusion limits were not affected by large changes in target contrast, whereas vernier thresholds increased as contrast was decreased. The results of Experiment 1 also argued against interocular suppression as the cause of single vision, since vernier offsets that were visible when viewed monocularly were invisible under binocular viewing conditions. In Experiment 2, manual adjustment of disparities yielded fusion limits little different from those obtained with the forced-choice method of Experiment 1, demonstrating that it is possible to design adjustment methods for assessing fusion limits that are as sensitive as forced-choice methods. In Experiment 3, large reductions in target contrast, which have the effect of decreasing disparity sensitivity, did not alter fusion limits, disconfirming the idea that fusion limits estimated with discriminative procedures represent disparity-detection thresholds. In Experiment 4, disparities were adjusted until a just noticeable difference in grating contrast appeared. These disparities were larger than fusion limits, indicating that fusion limits did not represent a change in apparent contrast arising from disparity limitations of binocular summation. Together, the four experiments support the existence of binocular fusion as a unique category of sensory performance, disconfirm several nonfusional explanations of single vision, and support the use of criterion-free as well as adjustment methods in measuring fusion limits.     

Panum’s fusional area estimated with a criterion-free technique

It has been reported that criterion-free estimates of the upper disparity limits for fusion of line targets are small enough to be accounted for by monocular vernier sensitivity. However, targets such as lines, which contain high spatial frequencies, may ensure small fusion limits, since fusion limits obtained with criterion-dependent methods for narrow-band targets, such as sinusoids or difference-of-Gaussian luminance profiles, are proportional to target spatial periods. Experiment 1 therefore explored whether criterion-free methods give fusion limits for narrow-band targets that can be accounted for by vernier sensitivity. Vertical fusion limits were estimated by a method that forced observers to discriminate a disparate sinusoidal grating from an immediately adjacent zero-disparity grating. Fusion limits were too large to be explained by monocular vernier thresholds obtained for the same targets. In addition, fusion limits were not affected by large changes in target contrast, whereas vernier thresholds increased as contrast was decreased. The results of Experiment 1 also argued against interocular suppression as the cause of single vision, since vernier offsets that were visible when viewed monocularly were invisible under binocular viewing conditions. In Experiment 2, manual adjustment of disparities yielded fusion limits little different from those obtained with the forced-choice method of Experiment 1, demonstrating that it is possible to design adjustment methods for assessing fusion limits that are as sensitive as forced-choice methods. In Experiment 3, large reductions in target contrast, which have the effect of decreasing disparity sensitivity, did not alter fusion limits, disconfirming the idea that fusion limits estimated with discriminative procedures represent disparity-detection thresholds. In Experiment 4, disparities were adjusted until a just noticeable difference in grating contrast appeared. These disparities were larger than fusion limits, indicating that fusion limits did not represent a change in apparent contrast arising from disparity limitations of binocular summation. Together, the four experiments support the existence of binocular fusion as a unique category of sensory performance, disconfirm several nonfusional explanations of single vision, and support the use of criterion-free as well as adjustment methods in measuring fusion limits.     

词间空格促进从右向左呈现汉语文本的阅读

摘要：为探讨在无阅读经验时,词切分线索是否促进读者的阅读与词汇识别,本研究操纵了阅读方向、词切分线索与目标词的词频。采用眼动仪记录读者的阅读过程。结果发现：阅读方向与词切分线索的交互作用显著,词切分显著地促进了从右向左呈现文本的阅读,但并不影响阅读从左向右呈现的文本;词切分条件下目标词的注视时间显著地短于无词切分条件。表明词切分线索促进了无阅读经验时的阅读,支持词切分线索的促进与文本不熟悉干扰之间权衡作用的假设。     

Targeting regressions: Do readers pay attention to the left?

The perceptual span during normal reading extends approximately 14 to 15 characters to the right and three to four characters to the left of a current fixation. In the present study, we investigated whether the perceptual span extends farther than three to four characters to the left immediately before readers execute a regression. We used a display-change paradigm in which we masked words beyond the three-to-four-character range to the left of a fixation. We hypothesized that if reading behavior was affected by this manipulation before regressions but not before progressions, we would have evidence that the perceptual span extends farther left before leftward eye movements. We observed significantly shorter regressive saccades and longer fixation and gaze durations in the masked condition when a regression was executed. Forward saccades were entirely unaffected by the manipulations. We concluded that the perceptual span during reading changes, depending on the direction of a following saccade.     

The Modulation of Visual and Task Characteristics of a Writing System on Hemispheric Lateralization in Visual Word Recognition—A Computational Exploration

Through computational modeling, here we examine whether visual and task characteristics of writing systems alone can account for lateralization differences in visual word recognition between different languages without assuming influence from left hemisphere (LH) lateralized language processes. We apply a hemispheric processing model of face recognition to visual word recognition; the model implements a theory of hemispheric asymmetry in perception that posits low spatial frequency biases in the right hemisphere and high spatial frequency (HSF) biases in the LH. We show two factors that can influence lateralization: (a) Visual similarity among words: The more similar the words in the lexicon look visually, the more HSF/LH processing is required to distinguish them, and (b) Requirement to decompose words into graphemes for grapheme‐phoneme mapping: Alphabetic reading (involving grapheme‐phoneme conversion) requires more HSF/LH processing than logographic reading (no grapheme‐phoneme mapping). These factors may explain the difference in lateralization between English and Chinese orthographic processing.     

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。     

Evidence for an addition to the reading scan hypothesis

Letters were tachistoscopically presented in pairs to the left or right of fixation for 40 msec. The pair consisted of a target letter (B, D, P, or T) and a noise letter (all other letters of the alphabet except I), with the noise letter appearing either to the inside or the outside of the stimulus letter. S’s task was to report verbally the target letter as fast as possible. Reaction times and number of errors indicated that there was more interference when the noise letter occurred further from the fixation point than the target letter for both the left and right visual field. Since a reading scan cannot account for the results in the right visual field, an outside-toward-fixation scan is proposed. An analysis of the different kinds of errors indicated that the outside to fixation scan is more primitive than the reading scan in that it produces less detailed information about the letters than does the reading scan.     

How does reading direction modulate perceptual asymmetry effects?

Left-side bias effects refer to a bias towards the left side of the stimulus/space in perceptual/visuospatial judgments, and are argued to reflect dominance of right hemisphere processing. It remains unclear whether reading direction can also account for the bias effect. Previous studies comparing readers of languages read from left to right with those read from right to left (e.g., French vs. Hebrew) have obtained inconsistent results. As a language that can be read from left to right or from right to left, Chinese provides a unique opportunity for a within-culture examination of reading direction effects. Chinese participants performed a perceptual judgment task (with both face and Chinese character stimuli; Experiment 1) and two visuospatial attention tasks (the greyscales and line bisection tasks; Experiment 2) once before and once after a reading task, in which they read Chinese passages either from left to right or from right to left for about 20 min. After reading from right to left, participants showed significantly reduced left-side bias in Chinese character perceptual judgments but not in the other three tasks. This effect suggests that the role of reading direction on different forms of left-side bias may differ, and its modulation may be stimulus-specific.