Letter encoding in visual word identification: more evidence for a word-integration explanation for parafoveal preview effects in reading.

A letter string presented briefly in the parafovea facilitates naming a foveally presented word provided that the two stimuli are orthographically similar. The facilitation (called priming) is asymmetrical in that to obtain it, both letter strings must have the first letters in common. One possible explanation, a letter-integration hypothesis, proposes that readers only identify the letters at the beginning of the parafoveal stimulus, an action that facilitates processing the target. Another explanation, a word-integration hypothesis, postulates that all the letters of the parafoveal stimulus are identified and that the asymmetry occurs because the first letters of the parafoveal stimulus are weighted more heavily than the later ones. The two accounts differ in the way the position of the first letter is determined: The first postulates that readers know the side to identify first without reference to the stimulus; the second postulates that readers establish an order on the stimuli postcategorically. To distinguish the views, we presented English and Hebrew stimuli to bilingual readers. Readers could not anticipate the position of the first letters; hence, if the letter-integration explanation is correct, the asymmetry in the priming should be attenuated. Consistent with the word-integration explanation, however, priming occurred when the target shared the beginning letters with the prime in both languages.     

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.     

Integrating information across eye fixations in reading: the role of letter and word units

Eye movements and eye fixations were recorded to study the integration of letter/word information across interword fixations in reading. Two hypotheses were examined. One hypothesis posits that readers obtain effective information from the beginning two or three letters of a parafoveal word. This information facilitates the recognition of the word when it is being fixated. The alternative posits that effective information is obtained from the complete parafoveal word. The results of the present study showed faster reading rates when parafoveal previews comprised complete words than when they comprised beginning letters alone. Furthermore, the usability of parafoveally available partial word information from beginning and ending letters was not affected by small variations in retinal eccentricity. Both findings were taken as evidence that readers gain useful information from all letters of the parafoveally available word and that whole word information, rather than specific letter information, is integrated across interword fixations in reading.     

Effects of parafoveal word length and orthographic features on initial fixation landing positions in reading

Previous research has demonstrated that readers use word length and word boundary information in targeting saccades into upcoming words while reading. Previous studies have also revealed that the initial landing positions for fixations on words are affected by parafoveal processing. In the present study, we examined the effects of word length and orthographic legality on targeting saccades into parafoveal words. Long (8?C9 letters) and short (4?C5 letters) target words, which were matched on lexical frequency and initial letter trigram, were paired and embedded into identical sentence frames. The gaze-contingent boundary paradigm (Rayner, 1975) was used to manipulate the parafoveal information available to the reader before direct fixation on the target word. The parafoveal preview was either identical to the target word or was a visually similar nonword. The nonword previews contained orthographically legal or orthographically illegal initial letters. The results showed that orthographic preprocessing of the word to the right of fixation affected eye movement targeting, regardless of word length. Additionally, the lexical status of an upcoming saccade target in the parafovea generally did not influence preprocessing.     

A developmental, interactive activation model of the word superiority effect

Parallel distributed processing (PDP) models of reading developed out of an appreciation of the role that context plays in letter and word perception. Adult readers can more accurately identify letters in a word than alone or in other random display contexts, a phenomenon known as the Word Superiority Effect (WSE). We examined the effects of orthographic context on the letter recognition skills of dyslexic children, comparing their performance to adults, and chronological- and reading-age matched groups. Consistent with previous studies, results showed adults better able to identify letters in the context of words and pseudowords than in random letter strings. Young normal readers demonstrated the WSE, but their pseudoword advantage was less than adults. The dyslexic children showed no WSE at all. PDP computer simulations for the experimental data using the Interactive Activation model (IA) suggested that the orthographic components of the lexical system of normal children are interactive and distributed as they are in adults but provide less bottom-up activation. In addition, top-down processing increases with age and reading skill, but may be absent for dyslexic readers.     

语境预测性对中文高低阅读技能儿童预视加工的影响

采用呈现随注视变化的边界范式(boundary paradigm),操作目标词的语境预测性和预视类型,考察高、低阅读技能儿童在词汇预视加工中语境预测效应的差异。结果发现,高、低阅读技能儿童对语境预测性的使用在发生时程上存在差异,高阅读技能儿童从词汇副中央凹预视加工阶段开始利用语境预测性信息,而低阅读技能儿童则在加工晚期更加依赖语境预测性信息,符合预测编码框架理论对儿童语境预测性效应差异的解释。     

Rapid processing of letters,digits and symbols: what purely visual‐attentional deficit in developmental dyslexia?

Visual‐attentional theories of dyslexia predict deficits for dyslexic children not only for the perception of letter strings but also for non‐alphanumeric symbol strings. This prediction was tested in a two‐alternative forced‐choice paradigm with letters, digits, and symbols. Children with dyslexia showed significant deficits for letter and digit strings but not for symbol strings. This finding is difficult to explain for visual‐attentional theories of dyslexia which postulate identical deficits for letters, digits and symbols. Moreover, dyslexics showed normal W‐shaped serial position functions for letter and digit strings, which suggests that their deficit is not due to an abnormally small attentional window. Finally, the size of the deficit was identical for letters and digits, which suggests that poor letter perception is not just a consequence of the lack of reading. Together then, our results show that symbols that map onto phonological codes are impaired (i.e. letters and digits), whereas symbols that do not map onto phonological codes are not impaired. This dissociation suggests that impaired symbol‐sound mapping rather than impaired visual‐attentional processing is the key to understanding dyslexia.     

Naming fluency in dyslexic and nondyslexic readers: Differential effects of visual crowding in foveal,parafoveal, and peripheral vision

Reading fluency is often indexed by performance on rapid automatized naming (RAN) tasks, which are known to reflect speed of access to lexical codes. We used eye tracking to investigate visual influences on naming fluency. Specifically, we examined how visual crowding affects fluency in a RAN-letters task on an item-by-item basis, by systematically manipulating the interletter spacing of items, such that upcoming letters in the array were viewed in the fovea, parafovea, or periphery relative to a given fixated letter. All lexical information was kept constant. Nondyslexic readers’ gaze durations were longer in foveal than in parafoveal and peripheral trials, indicating that visual crowding slows processing even for fluent readers. Dyslexics’ gaze durations were longer in foveal and parafoveal trials than in peripheral trials. Our results suggest that for dyslexic readers, influences of crowding on naming speed extend to a broader visual span (to parafoveal vision) than that for nondyslexic readers, but do not extend as far as peripheral vision. The findings extend previous research by elucidating the different visual spans within which crowding operates for dyslexic and nondyslexic readers in an online fluency task.     

Children’s memory for sentences and word strings in relation to reading ability

A previous study of recall of letter strings by good and poor beginning readers IShankweiler, Liberman, Mark, Fowler, & Fischer, 1979 revealed that the performance of good readers was more severely penalized than that of poor readers when the letter names rhymed. To determine whether the differences in susceptibility to phonetic interference extend to materials that more closely resemble actual text, we designed an experiment to test recall of phonetically controlled sentences and word strings. As in the case of letter recall, we found that, although good readers made fewer errors than poor readers when sentences or word strings contained no rhyming words, they did not excel when the materials contained many rhyming words. In contrast to manipulations of phonetic content, systematic manipulations of meaningfulness and variations in syntactic structure did not differentially affect the two reading groups. We conclude that the poor readers’ inferior recall of phonetically nonconfusable sentences, word strings, and letter strings reflects failure to make full use of phonetic coding in working memory.     

Eye movements when reading transposed text: the importance of word-beginning letters

Participants' eye movements were recorded as they read sentences with words containing transposed adjacent letters. Transpositions were either external (e.g., problme, rpoblem) or internal (e.g., porblem, probelm) and at either the beginning (e.g., rpoblem, porblem) or end (e.g., problme, probelm) of words. The results showed disruption for words with transposed letters compared to the normal baseline condition, and the greatest disruption was observed for word-initial transpositions. In Experiment 1, transpositions within low frequency words led to longer reading times than when letters were transposed within high frequency words. Experiment 2 demonstrated that the position of word-initial letters is most critical even when parafoveal preview of words to the right of fixation is unavailable. The findings have important implications for the roles of different letter positions in word recognition and the effects of parafoveal preview on word recognition processes.     

A developmental evaluation of the role of word shape in word recognition

Fourth- and seventh-grade children and college-age adults proofread passages typed either in lowercase or in all capital letters. Words were misspelled by deleting one of four letters, s, c, k, or p, that have similar features in lowercase and uppercase. Proofreading errors decreased with age and increasing reading ability, but all of the subjects were sensitive to changes in word shape--they missed more words with deletions of s or c than k or p in the lowercase passage but not in the all-capitals passage. These findings indicate that word shape is an important variable in recognizing familiar words, even for young readers.     

The influence of parafoveal typographical errors on eye movements in reading

Three experiments are reported, examining the effects of a typographical error in parafoveal vision on aspects of foveal inspection time and saccade targeting. All the experiments involved reading for comprehension. A contingent presentation procedure ensured that typographical errors were restored to their correct form before they were viewed in foveal vision: They were never available for foveal processing. In Experiment 1, the error was formed by replacing the first letter of the target word with a second occurrence of its second letter, producing an illegal nonword. This manipulation had no significant effect on foveal inspection time, but lowered the probability that a short word (“de” or “du”) prior to the target would be skipped. In Experiment 2 the familiarity of the target's initial letters was maintained constant across conditions. This manipulation removed the target 1 skipping effect, suggesting that the outcome of Experiment 1 was due to orthographic rather than lexical illegality, but revealed shorter foveal inspection times as a function of the presence of the error. Experiment 3 manipulated lexical and sublexical properties of the parafoveal typing error. Properties of the parafoveal error again influenced prior foveal inspection times. The pattern of results suggested that the determining properties were sublexical rather than lexical. The results as a whole are incompatible with a view of information processing in reading in which foveal processing remains immune from concurrent parafoveal influences.     

Orthographic and phonological preview benefits: Parafoveal processing in skilled and less-skilled deaf readers

Many deaf individuals do not develop the high-level reading skills that will allow them to fully take part into society. To attempt to explain this widespread difficulty in the deaf population, much research has honed in on the use of phonological codes during reading. The hypothesis that the use of phonological codes is associated with good reading skills in deaf readers, though not well supported, still lingers in the literature. We investigated skilled and less-skilled adult deaf readers' processing of orthographic and phonological codes in parafoveal vision during reading by monitoring their eye movements and using the boundary paradigm. Orthographic preview benefits were found in early measures of reading for skilled hearing, skilled deaf, and less-skilled deaf readers, but only skilled hearing readers processed phonological codes in parafoveal vision. Crucially, skilled and less-skilled deaf readers showed a very similar pattern of preview benefits during reading. These results support the notion that reading difficulties in deaf adults are not linked to their failure to activate phonological codes during reading.     

The role of configuration in the identification of visually degraded words

Two experiments were carried out in which reaction time for identification of words in sets of four was measured. The words were of three letters, with dichotomous variation of the first and third letters, in either upper- or lowercase, with letters chosen to give maximum variation in word configuration in lowercase. Four types of display were used, differing in size and masking. In Experiment 1, the words were easy to identify in uppercase as well as in lowercase, because the letters were easily discriminable in either case, and the results showed no advantage to lowercase words at any level of degradation. In Experiment 2, the letters were more difficult to discriminate in uppercase, and with the most severe degradation, the words in lowercase were identified more rapidly than those in uppercase. Thus the reaction time results showed an advantage of the configural properties available in lowercase only with words difficult to identify in uppercase and with extreme amounts of degradation. Error analyses of both experiments showed that errors were made to individual letters, not on the basis of the configuration, for words in both cases. It is concluded that letter processing occurs even when there is evidence for the use of configural information, thus implying a predominant role of letter perception in word identification. Some reservation is expressed whether whole-word configuration is the only pertinent configural property and whether the results from such simple identification tasks are appropriate to an understanding of natural reading.     

Letter detection in very familiar texts

In the present study, we investigated whether patterns of letter detection for function and content words in texts are affected by the familiarity of the material being read. In Experiment 1, subjects searched for target letters in sentences that had been rehearsed prior to performing the letter detection on them as well as on unfamiliar sentences. In Experiment 2, subjects searched for target letters in highly familiar verses (e.g., nursery rhymes) and in unfamiliar sentences that were matched to the familiar verses. A disadvantage in letter detection for function as compared with content words consistently found with unfamiliar passages was reduced significantly with the familiar material in both experiments. Specifically, letter detection for content words grew worse in familiar text, but letter detection for function words showed a contrasting modest, though nonsignificant, improvement. The results are consistent with the proposition that in very familiar texts, parafoveal analysis permits the identification of generally less familiar content words. Simultaneously, the normal pattern of weighing the structure and content elements of text changes so that more fixations on function words occur than when one is reading unfamiliar texts.     

Parafoveal processing of words and saccade computation during eye fixations in reading

Studied parafoveal word processing during eye fixations in reading to answer two questions: (a) Is the processing of parafoveally available words limited to the identification of beginning letters? (b) Does the parafoveal processing of words affect the following interword saccade? Reading afforded either no parafoveal preview, preview of beginning trigrams, preview of ending trigrams, or preview of the whole parafoveal word. Previews were controlled by replacing original letters either with X's or dissimilar letters. Preview benefits were larger for the whole word previews than for beginning or ending trigram previews. X-masks yielded preview benefits from intact beginning and ending trigrams but dissimilar letter masks yielded benefits from beginning trigrams only. Saccades were larger for whole word previews than for no previews. These results support Logogen-type models of word recognition and a model of saccade computation that posits a time-locked functional relation between the acquisition of parafoveal word information and the positioning of each fixation.     

The use of probabilistic lexicality cues for word segmentation in Chinese reading

In an eye-tracking experiment we examined whether Chinese readers were sensitive to information concerning how often a Chinese character appears as a single-character word versus the first character in a two-character word, and whether readers use this information to segment words and adjust the amount of parafoveal processing of subsequent characters during reading. Participants read sentences containing a two-character target word with its first character more or less likely to be a single-character word. The boundary paradigm was used. The boundary appeared between the first character and the second character of the target word, and we manipulated whether readers saw an identity or a pseudocharacter preview of the second character of the target. Linear mixed-effects models revealed reduced preview benefit from the second character when the first character was more likely to be a single-character word. This suggests that Chinese readers use probabilistic combinatorial information about the likelihood of a Chinese character being single-character word or a two-character word online to modulate the extent of parafoveal processing.     

Phonetic recoding and reading difficulty in beginning readers

The results of a recent study (Liberman, Shankweiler, Liberman, Fowler, & Fischer, 1977) suggest that good beginning readers are more affected than poor readers by the phonetic characteristics of visually presented items in a recall task. The good readers made significantly more recall errors on strings of letters with rhyming letter names than on nonrhyming sequences; in contrast, the poor readers made roughly equal numbers of errors on the rhyming and nonrhyming letter strings. The purpose of the present study was to determine whether the interaction between reading ability and phonetic similarity is solely determined by different rehearsal strategies of the two groups. Accordingly, good and poor readers were tested on rhyming and nonrhyming words using a recognition memory paradigm that minimized the opportunity for rehearsal. Performance of the good readers was more affected by phonetic similarity than that of the poor readers, in agreement with the earlier study. The present findings support the hypothesis that good and poor readers do differ in their ability to access a phonetic representation.     

Transposed-letter effects in reading: evidence from eye movements and parafoveal preview

Three eye movement experiments were conducted to examine the role of letter identity and letter position during reading. Before fixating on a target word within each sentence, readers were provided with a parafoveal preview that differed in the amount of useful letter identity and letter position information it provided. In Experiments 1 and 2, previews fell into 1 of 5 conditions: (a) identical to the target word, (b) a transposition of 2 internal letters, (c) a substitution of 2 internal letters, (d) a transposition of the 2 final letters, or (e) a substitution of the 2 final letters. In Experiment 3, the authors used a further set of conditions to explore the importance of external letter positions. The findings extend previous work and demonstrate that transposed-letter effects exist in silent reading. These experiments also indicate that letter identity information can be extracted from the parafovea outside of absolute letter position from the first 5 letters of the word to the right of fixation. Finally, the results support the notion that exterior letters play important roles in visual word recognition.     

聋人句子阅读中的视觉功能补偿现象：副中央凹−中央凹效应的证据

聋人阅读过程中的视觉功能补偿现象是由于听觉信息的缺失,聋人的视觉功能会发生补偿性改变,表现为对副中央凹视野内文本信息的加工效率更高。本研究采用边界范式,测量聋人的副中央凹-中央凹重复效应,以探究聋人的副中央凹视觉功能补偿现象能否促进其中央凹的词汇识别过程。结果发现,聋人的副中央凹-中央凹重复效应出现在早期阅读指标凝视时间,而阅读能力匹配组只出现在晚期阅读指标总注视时间。因此,相比阅读能力匹配的健听读者,聋人的副中央凹-中央凹重复效应出现得更早,表现出副中央凹视觉功能补偿现象。