Sublexical and syntactic processing during reading: evidence from eye movements of typically developing and dyslexic readers*

Skilled, typically developing readers and children with dyslexia read correct sentences and sentences that contained verb errors that were pseudo-homophones, morphological over-regularisations or syntactic errors. All errors increased looking time but the nature of the error and participant group influenced the time course of the effects. The pseudo-homophone effect was significant in all eye-movement measures for adults (N?=?26), intermediate (N?=?37) and novice typically developing readers (N?=?38). This effect was larger for intermediate readers than other groups in total duration. In contrast, morphological over-regularisations increased gaze and total duration (but not first fixation) for intermediate and novice readers, and only total duration for adult readers. Syntactic errors only increased total duration. Children with dyslexia (N?=?19) demonstrated smaller effects of pseudo-homophones and over-regularisations than controls, but their processing of syntactic errors was similar. We conclude that dyslexic children's difficulties with reading are linked to overreliance on phonological decoding and underspecified morphological processing, which impacts on word level reading. We highlight that the findings fit well within the grain-size model of word reading [Grainger, J., &; Ziegler, J. C. (2011). A dual-route approach to orthographic processing. Frontiers in Psychology, 2, 54. doi:10.3389/fpsyg.2011.00054].     

Smooth pursuit eye movements in normal and dyslexic children

This paper describes a detailed study of horizontal eye movements associated with visual tracking of a smoothly moving target. Essentially all children, even at target velocities as low as 5 degrees/sec., show some saccadic eye movements superimposed on smooth tracking movements. Detailed analysis of pursuit eye-movements from a group of 26 poor readers and 34 normal controls (8 to 13 yr.) showed that about 25% of poor readers have an abnormally raised saccadic component in smooth pursuit. This suggests that studies of eye movements during tracking of smoothly moving targets at low velocity, combined with a quantitative approach to data analysis, may be useful for early detection of a significant proportion of poor-reading children.     

Latencies of stimulus-driven eye movements are shorter in dyslexic subjects

Eye movements latencies toward peripherally presented stimuli were measured in 10-year-old dyslexic and control children. Dyslexic subjects, previously found to be oversensitive to stimulation of the magnocellular channel, showed reduced latencies as compared to normally reading controls. An attention shifting task was also used which showed no group differences in latencies of eye movements. The data are discussed in terms of the hypothesis of magnocellular system alteration and attention dysfunction in dyslexia. Additionally, sex differences in eye movement latencies were found and are discussed.     

A goal-based perspective on eye movements in visual world studies

There is an emerging literature on visual search in natural tasks suggesting that task-relevant goals account for a remarkably high proportion of saccades, including anticipatory eye movements. Moreover, factors such as “visual saliency” that otherwise affect fixations become less important when they are bound to objects that are not relevant to the task at hand. We briefly review this literature and discuss the implications for task-based variants of the visual world paradigm. We argue that the results and their likely interpretation may profoundly affect the “linking hypothesis” between language processing and the location and timing of fixations in task-based visual world studies. We outline a goal-based linking hypothesis and discuss some of the implications for how we conduct visual world studies, including how we interpret and analyze the data. Finally, we outline some avenues of research, including examples of some classes of experiments that might prove fruitful for evaluating the effects of goals in visual world experiments and the viability of a goal-based linking hypothesis.     

The effect of word predictability on the eye movements of Chinese readers

Eye movements of Chinese readers were monitored as they read sentences containing target words whose predictability from the preceding context was high, medium, or low. Readers fixated for less time on high- and medium-predictable target words than on low-predictable target words. They were also more likely to fixate on low-predictable target words than on high- or medium-predictable target words. The results were highly similar to those of a study by Rayner and Well (1996) with English readers and demonstrate that Chinese readers, like readers of English, exploit target word predictability during reading.     

The effect of word and character frequency on the eye movements of Chinese readers

Eye movements of native Chinese readers were monitored as they read sentences containing target words that varied in terms of word frequency and character frequency. There was an effect of word frequency on fixation times on a target word and it was comparable in size to that typically found with readers of English. Furthermore, character frequency also influenced fixation time on the target word. The effect of the initial character in two character words was more pronounced than that of the second character. However, word frequency modulated the effect of character frequency. The effect of character frequency was attenuated with high frequency target words while it was quite apparent with low frequency target words.     

The effects of interword spacing on the eye movements of young and older readers

Recent evidence indicates that older adults (aged 65+) are more disrupted by removing interword spaces than young adults (aged 18–30). However, it is not known whether older readers also show greater sensitivity to the more subtle changes to this spacing that frequently occur during normal reading. In the present study the eye movements of young and older adults were examined when reading texts for which interword spacing was normal, condensed to half its normal size or expanded to 1.5 times its normal size. Although these changes in interword spacing affected eye movement behaviour, this influence did not differ between young and older adults. Furthermore, a word frequency manipulation showed that these changes did not affect word identification for either group. The results indicate that older adults can adapt their eye moment behaviour to accommodate subtle changes in the spatial layout of text equally effectively as young adults.     

Effects of word frequency and visual complexity on eye movements of young and older Chinese readers

Research using alphabetic languages shows that, compared to young adults, older adults employ a risky reading strategy in which they are more likely to guess word identities and skip words to compensate for their slower processing of text. However, little is known about how ageing affects reading behaviour for naturally unspaced, logographic languages like Chinese. Accordingly, to assess the generality of age-related changes in reading strategy across different writing systems we undertook an eye movement investigation of adult age differences in Chinese reading. Participants read sentences containing a target word (a single Chinese character) that had a high or low frequency of usage and was constructed from either few or many character strokes, and so either visually simple or complex. Frequency and complexity produced similar patterns of influence for both age groups on skipping rates and fixation times for target words. Both groups therefore demonstrated sensitivity to these manipulations. But compared to the young adults, the older adults made more and longer fixations and more forward and backward eye movements overall. They also fixated the target words for longer, especially when these were visually complex. Crucially, the older adults skipped words less and made shorter progressive saccades. Therefore, in contrast with findings for alphabetic languages, older Chinese readers appear to use a careful reading strategy according to which they move their eyes cautiously along lines of text and skip words infrequently. We propose they use this more careful reading strategy to compensate for increased difficulty processing word boundaries in Chinese.     

Auditory word identification in dyslexic and normally achieving readers

The integrity of phonological representation/processing in dyslexic children was explored with a gating task in which children listened to successively longer segments (gates) of a word. At each gate, the task was to decide what the entire word was. Responses were scored for overall accuracy as well as the children's sensitivity to coarticulation from the final consonant. As a group, dyslexic children were less able than normally achieving readers to detect coarticulation present in the vowel portion of the word, particularly on the most difficult items, namely those ending in a nasal sound. Hierarchical regression and path analyses indicated that phonological awareness mediated the relation of gating and general language ability to word and pseudoword reading ability.     

The development of grapheme-phoneme correspondence in normal and dyslexic readers

The present experiment was concerned with the development of grapheme-phoneme conversion ability in normal and reading-age matched dyslexic readers. The use of grapheme-phoneme correspondences was observed in a recognition memory task for pronounceable nonwords. The nonwords were presented in either the visual or auditory modality and had to be recognized immediately from the converse modality, thus necessitating decoding of stimuli across modalities. The use of grapheme-phoneme correspondences increased with reading age in the normal readers but not in the dyslexics. It was postulated that dyslexics have a specific difficulty in grapheme-phoneme conversion. For them an increase in reading age is attributable mainly to an increase in size of sight vocabulary.     

Electrocortical measures during a lexical decision task: a comparison between elementary school-aged normal and dyslexic readers and adult normal and dyslexic readers

The authors examined the differences in performance between 30 dyslexic readers in 4th grade, 30 dyslexic readers attending university, and age-matched normal readers for both groups on a lexical decision task to evaluate the underlying factors of dyslexia that persist into adulthood. In both age groups, the dyslexic readers were significantly less accurate and slower than were the normal readers when reading word lists and in connected text. Electrophysiological data showed 2 main distinguishing components. Results supported the hypothesis that the dyslexia phenomenon is characterized by inaccurate and slow word-recognition skills. In addition, the authors found slow performance speed among all dyslexic readers in all stages of processing.     

Attentional blink differences between adolescent dyslexic and normal readers

The goal of this study was to evaluate the possibility that dyslexic individuals require more working memory resources than normal readers to shift attention from stimulus to stimulus. To test this hypothesis, normal and dyslexic adolescents participated in a Rapid Serial Visual Presentation experiment (Raymond, Shapiro, & Arnell, 1992). Surprisingly, the result showed that the participants with dyslexia produced a shallower attentional blink than normal controls. This result may be interpreted as showing differences in the way the two groups encode information in episodic memory. They also fit in a cascade-effect perspective of developmental dyslexia.     

Letter identification and lateral masking in dyslexic and average readers

Lateral masking and letter identification in dyslexic and average readers were investigated with a methodology that corrected for some of the weaknesses of the Geiger and Lettvin studies (1986, 1987). Target letters were presented alone or embedded within three-letter arrays at retinal locations from 0 degrees to 15 degrees to the right or left of a fixation point. A foveal letter, which was the same as or different from a target letter, appeared as a distractor, and comparisons were made between scaled and unscaled stimuli. Dyslexic readers were found to be better than average readers at detecting scaled letters embedded in an array in some of the peripheral locations tested. Unlike the results of Geiger and Lettvin, however, this finding of better letter detection in the periphery by dyslexics was limited to selected conditions of the study. Reading groups were also found to differ in responding to the foveal distractor in the letter task. Detection of letters by average readers was affected by the type of distractor, but this variable was not found to influence the dyslexic readers. These findings suggest some differences between dyslexic and average readers in attention to stimuli presented at multiple locations in the visual field.     

Processing syntactic functions of words in normal and dyslexic readers

Readers with dyslexia were compared with normal readers for the ability to identify the grammatical function of words in the course of sentence processing by means of electrophysiological measures along with behavior measures. Participants were 18 dyslexic and 18 normally reading, native Hebrew-speaking male university students, aged 18 to 27 years. Obtained results confirmed the hypothesis (Leikin & Breznitz, 1999) that Hebrew readers used lexical-morphological properties of words to identify their grammatical roles. However, the morphologically based strategy acquired full expression only in the presence of the verb, which in the Hebrew sentence fulfills the central role. Seemingly, readers use a few different procedures to identify the grammatical roles of words. Selection of a particular strategy seems to be influenced by diverse factors, including syntactic and lexical-morphological characteristics of the stimuli and level of reading skills. In addition, the results showed significant differences in sentence processing between normal and dyslexic readers, as reflected by ERP measures. These results are in line with the hypothesis, suggesting the existence of a syntactic processing weakness in readers with dyslexia.     

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.     

词汇预测性对中文高、低阅读技能儿童眼动行为的影响

操纵目标词的预测性、词频和阅读技能水平,考察句子阅读中词汇预测性对高、低阅读技能儿童眼动行为的影响,揭示其在儿童阅读发展中的作用。结果显示：儿童对高预测词的跳读率更高、注视时间更短,且预测性与词频交互影响跳读率和注视时间;预测性对高阅读技能儿童早期的跳读率影响更大,而对低阅读技能儿童晚期的再阅读时间具有更大影响。结果表明：词汇预测性影响儿童阅读的眼动行为和词汇加工,且作用大小和发生时程受阅读技能调节。     

A comparison of word recognition processes in dyslexic and normal readers at two reading-age levels

This study addressed the question of whether dyslexic children use qualitatively different word identification processes as compared to normal readers at the same stage of reading acquisition. Fifty-two dyslexic children and reading-age matched normal readers were required to pronounce words and pseudowords designed to tap several word recognition and decoding processes. Performance profiles were compared for the two reading groups at two reading ages. Although an invariant acquisition sequence was observed across reading groups, differences in level of performance between dyslexics and reading-age controls varied as a function of reading age. The performance of the more advanced dyslexics was virtually indistinguishable from normal readers on all measures. In contrast, the younger reading age dyslexics differed from normal readers on several measures of spelling-sound correspondences. However, no reading group differences were observed on measures of word recognition. The results indicated that dyslexics and normal readers at the same reading age use essentially the same processes to recognize words, but may differ in knowledge of correspondence rules.     

Morpheme-based reading aloud: evidence from dyslexic and skilled Italian readers

The role of morphology in reading aloud was examined measuring naming latencies to pseudowords and words composed of morphemes (roots and derivational suffixes) and corresponding simple pseudowords and words. Three groups of Italian children of different ages and reading abilities, including dyslexic children, as well as one group of adult readers participated in the study. All four groups read faster and more accurately pseudowords composed of root and suffix than simple pseudowords (Experiment 1). Unlike skilled young and adult readers, both dyslexics and younger children benefited from morphological structure also in reading aloud words (Experiment 2). It is proposed that the morpheme is a unit of intermediate grain size that proves useful in processing all linguistic stimuli, including words, in individuals with limited reading ability (dyslexics and younger readers) who did not fully develop mastering of whole-word processing. For skilled readers, morphemic parsing is useful for reading those stimuli (i.e., pseudowords made up of morphemes), for which a whole-word lexical unit does not exist; where such whole-word lexical units do exist, skilled readers do not need to rely on morphological parsing because they can rely on a lexical (whole-word) reading unit that is larger than the morpheme.     

On the use of metacontrast to assess magnocellular function in dyslexic readers

It has been proposed that dyslexia is the result of a deficit in the magnocellular system. Reduced metacontrast masking in dyslexic readers has been taken as support for this view. In metacontrast, a masking stimulus reduces the visibility of a spatially adjacent target stimulus when the target stimulus precedes the masking stimulus by about 30–100 msec. Recent evidence indicates that the latency difference between the magnocellular and parvocellular subcortical pathways is at most 20 msec and may be as small as only 5 msec, or even less. This makes it difficult to attribute the latency in metacontrast to the latency differences between the magnocellular and parvocellular systems. It is therefore problematic to attribute reduced metacontrast masking to a deficit in the magnocellular system.