Two experiments were conducted to investigate the flexibility of letter-position encoding in word identification during reading. In both experiments, two tasks were used. First, participants鈥 eye movements were measured as they read sentences containing transposed letter (TL) strings. Second, participants were presented with the TL strings in isolation and were asked to discriminate them from nonwords. In Experiment 1, we manipulated the distance between transposed letters ( ligament vs. liagment vs. limagent vs. lieamgnt ). Reading/response times increased with the distance between TLs. In Experiment 2 , we manipulated whether the TLs were consonants, vowels, or one of each ( ssytem vs. faeture vs. fromat ). Reading/response times showed that CV transpositions were the most disruptive. In both experiments, response accuracy was particularly poor for words presented in isolation when there was an intervening letter between TLs. These data show that processing across multiple fixations, and the presence of a meaningful sentence context, are important for flexible letter position encoding in lexical identification.

Prospective memory (PM) represents the ability to successfully realize intentions when the appropriate moment or cue occurs. In this study, we used event-related potentials (ERPs) to explore the impact of cue predictability on the cognitive and neural mechanisms supporting PM. Participants performed an ongoing task and, simultaneously, had to remember to execute a pre-specified action when they encountered the PM cues. The occurrence of the PM cues was predictable (being signaled by a warning cue) for some participants and was completely unpredictable for others. In the predictable cue condition, the behavioral and ERP correlates of strategic monitoring were observed mainly in the ongoing trials wherein the PM cue was expected. In the unpredictable cue condition they were instead shown throughout the whole PM block. This pattern of results suggests that, in the predictable cue condition, participants engaged monitoring only when subjected to a context wherein the PM cue was expected, and disengaged monitoring when the PM cue was not expected. Conversely, participants in the unpredictable cue condition distributed their resources for strategic monitoring in more continuous manner. The findings of this study support the most recent views-the "Dynamic Multiprocess Framework" and the "Attention to Delayed Intention" (AtoDI) model-confirming that strategic monitoring is a flexible mechanism that is recruited mainly when a PM cue is expected and that may interact with bottom-up spontaneous processes.

Abstract The ability to read is supported by the existence of codes that represent the orthographic, phonological, and semantic properties of words. This thesis addresses the issue of how orthographic codes are self-organised. This question is explored using a combination of theoretical and computational approaches, leading to the introduction of a new computational model of Visual word recognition. The thesis begins with a review and critique of existing models of visual word recognition, with particular reference to their inability to satisfy adaptive constraints. This analysis highlights the inability of current models to explain self-organisation processes or to operate in real-world input environments. Subsequent chapters review neural networks for pattern recognition, learning and working memory, focussing on the work of Grossberg and colleagues. Two specific networks-the masking field network and its extension, the SONNET network-exhibit adaptive properties that are lacking in current models of visual word recognition. The SOLAR (Self-Organising Lexical Acquisition and Recognition) model is a new neural network model of visual word recognition that embodies self-organisation and masking principles. The model differs from previous models in its capacity for stable self-organisation, its spatial coding scheme, its combination of serial and parallel processes, and its chunking mechanism. The model also introduces a novel mechanism to explain word frequency effects. Another distinctive feature of the model is its incorporation of a novel opponent processing mechanism for performing lexical decision. The SOLAR model explains a broad range of empirical data, including frequency effects, the lexical status effect, length effects, facilitatory and inhibitory effects of orthographic Similarity, the pseudohomophone effect, masked and unmasked repetition priming effects, the frequency attenuation effect, and left-to-right processing effects. Simulations have also demonstrated the model's ability to recognise complex stimuli (e.g., polysyllabic words) via a chunking mechanism that implements segmentation-through-recognition. This poses a critical challenge to alternative computational models, which are restricted to processing monosyllabic words. The SOLAR model also generates a number of novel empirical predictions. The final chapter discusses how the model might be extended to incorporate phonological codes, and the implications for explaining reading performance in skilled and dyslexic readers. (PsycINFO Database Record (c) 2012 APA, all rights reserved)

Visual word identification requires readers to code the identity and order of the letters in a word and match this code against previously learned codes. Current models of this lexical matching process posit context-specific letter codes in which letter representations are tied to either specific serial positions or specific local contexts (e.g., letter clusters). The spatial coding model described here adopts a different approach to letter position coding and lexical matching based on context-independent letter representations. In this model, letter position is coded dynamically, with a scheme called spatial coding. Lexical matching is achieved via a method called superposition matching, in which input codes and learned codes are matched on the basis of the relative positions of their common letters. Simulations of the model illustrate its ability to explain a broad range of results from the masked form priming literature, as well as to capture benchmark findings from the unprimed lexical decision task.

Recent research has shown that letter identity and letter position are not integral perceptual dimensions (e.g., jugde primes judge in word-recognition experiments). Most comprehensive computational models of visual word recognition (e.g., the interactive activation model, J. L. McClelland & D. E. Rumelhart, 1981, and its successors) assume that the position of each letter within a word is perfectly encoded. Thus, these models are unable to explain the presence of effects of letter transposition (trial-trail), letter migration (beard-bread), repeated letters (moose-mouse), or subset/superset effects (faulty-faculty). The authors extend R. Ratcliff's (1981) theory of order relations for encoding of letter positions and show that the model can successfully deal with these effects. The basic assumption is that letters in the visual stimulus have distributions over positions so that the representation of one letter will extend into adjacent letter positions. To test the model, the authors conducted a series of forced-choice perceptual identification experiments. The overlap model produced very good fits to the empirical data, and even a simplified 2-parameter model was capable of producing fits for 104 observed data points with a correlation coefficient of .91.

Given the lack of spaces between words in Chinese text, Chinese readers must parse these characters into words using their word knowledge. In this situation, are the characters belonging to a single...

We explored how character order information is encoded in isolated word processing or Chinese sentence reading in 2 experiments using a masked priming paradigm and a gaze-contingent display-change paradigm. The results showed that response latencies in the lexical decision task and reading times on the target word region were longer in the unrelated condition (the prime or the preview was unrelated with the target word) than the transposed-character condition (the prime or the preview was a transposition of the 2 characters of the target word), which were respectively longer than in the identity condition (the prime or preview was identical to the target word). These results show that character order is encoded at an early stage of processing in Chinese reading, but character position encoding was not strict. We also found that character order encoding was similar for single-morpheme and multiple-morpheme words, suggesting that morphemic status does not affect character order encoding. The current results represent an early contribution to our understanding of character order encoding during Chinese reading

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.

Readers of Chinese must generally determine word units in the absence of visually distinct inter-word spaces. In the present study, we examined how a sequence of Chinese characters is parsed into words under these conditions. Eye movements were monitored while participants read sentences with a critical four-character (C1234) sequence. Three partially overlapping character groupings formed legal words in the ambiguous condition (C12, C23, and C34), two of which corresponded to context-consistent words (C12 and C34). Two nonoverlapping groupings corresponded to legal words in the control conditions (C12 and C34). In two experiments, readers spent more time viewing the critical character sequence and its two center characters (C23) in the ambiguous condition. These results argue against the strictly serial assignment of characters to words during the reading of Chinese text.

Abstract 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.

Masked transposed-letter (TL) priming effects have been used to index letter position processing over the course of reading development. Whereas some studies have reported an increase in TL priming over development, others have reported a decrease. These findings have led to the development of 2 somewhat contradictory accounts of letter position development: the lexical tuning hypothesis and the multiple-route model. One factor that may be contributing to these discrepancies is the use of baseline primes that substitute letters in the target word, which may confound the effect of changes in letter position processing over development with those of letter identity. The present study included an identity prime (e.g., listen—LISTEN), in addition to the standard two-substituted-letter (2SL; e.g., lidfen—LISTEN) and all-letter-different (ALD; e.g., rodfup—LISTEN) baselines, to remove the potential confound between letter position and letter identity information in determining the effect of the TL prime. Priming effects were measured in a lexical decision task administered to children aged 7–12 and a group of university students. Using inverse transformed response times, targets preceded by a TL prime were responded to significantly faster than those preceded by 2SL and ALD primes, and priming remained stable across development. In contrast, targets preceded by a TL prime were responded to significantly slower than those preceded by an ID prime, and this reaction-time cost increased significantly over development, with adults showing the largest cost. These findings are consistent with a lexical tuning account of letter position development, and are inconsistent with the multiple-route model.

采用眼动仪考察词素位置是否是影响词间空格在新词学习中起作用的重要因素。通过以下方式进行操纵:构造两类假词作为新词,第一类新词由低频首字、高频尾字构成;第二类新词由高频首字、低频尾字构成。采用"学习-测试"范式将新词放在句子中要求被试阅读。结果发现,相比由高频首字和低频尾字构成的新词,词间空格在由低频首字和高频尾字构成的新词学习中促进作用更大。表明在汉语阅读中词素位置可能作为一种线索参与词切分。

Abstract There are currently 2 theoretical accounts of how readers of Chinese select their saccade targets: (a) by moving their eyes to specific saccade targets (i.e., the default-targeting hypothesis) and (b) by adjusting their saccade lengths to accommodate lexical processing (i.e., the dynamic-adjustment hypothesis). In this article, we first report the results of an eye-movement experiment using a gaze-contingent boundary paradigm. This experiment demonstrates that both target-word frequency and its preview validity modulate the lengths of the saccades entering and exiting the target words, with longer saccades to/from high-frequency words when their preview was available. We then report the results of 2 simulations using computational models that instantiate the core theoretical assumptions of the default-targeting and dynamic-adjustment hypotheses. Comparisons of these simulations indicate that the dynamic-adjustment hypothesis provides a better quantitative account of the data from our experiment using fewer free parameters. We conclude by discussing evidence for dynamic saccade adjustment during the reading of alphabetic languages, and why such a heuristic may be necessary to fully explain eye-movement control during the reading of both alphabetic and nonalphabetic languages. PsycINFO Database Record (c) 2016 APA, all rights reserved.

Efficient language processing may involve generating expectations about upcoming input. To investigate the extent to which prediction might facilitate reading, a large-scale survey provided cloze scores for all 2689 words in 55 different text passages. Highly predictable words were quite rare (5% of content words), and most words had a more-expected competitor. An eye-tracking study showed sensitivity to cloze probability but no mis-prediction cost. Instead, the presence of a more-expected competitor was found to be facilitative in several measures. Further, semantic and morphosyntactic information was highly predictable even when word identity was not, and this information facilitated reading above and beyond the predictability of the full word form. The results are consistent with graded prediction but inconsistent with full lexical prediction. Implications for theories of prediction in language comprehension are discussed.

CiteSeerX - Scientific documents that cite the following paper: An interactive activation model of context effects in letter perception: Part 1. An account of basic findings

A computer-based eye-movement controlled, display system was developed for the study of perceptual processes in reading. A study was conducted to identify the region from which skilled readers pick up various types of visual information during a fixation while reading. This study involved making display changes, based on eye position, in the text pattern as the subject was in the act of reading from it, and then examining the effects these changes produced on eye behavior. The results indicated that the subjects acquired word-length pattern information at least 12 to 15 character positions to the right of the fixation point, and that this information primarily influenced saccade lengths. Specific letter- and word-shape information were acquired no further than 10 character positions to the right of the fixation point.

This article presents a theory of visual word recognition that assumes that, in the tasks of word identification, lexical decision, and semantic categorization, human readers behave as optimal Bayesian decision makers. This leads to the development of a computational model of word recognition, the Bayesian reader. The Bayesian reader successfully simulates some of the most significant data on human reading. The model accounts for the nature of the function relating word frequency to reaction time and identification threshold, the effects of neighborhood density and its interaction with frequency, and the variation in the pattern of neighborhood density effects seen in different experimental tasks. Both the general behavior of the model and the way the model predicts different patterns of results in different tasks follow entirely from the assumption that human readers approximate optimal Bayesian decision makers.

Early on during word recognition, letter positions are not accurately coded. Evidence for this comes from transposed-letter (TL) priming effects, in which letter strings generated by transposing two adjacent letters (e.g., ) and the SOLAR model (Davis & Bowers, 2006) explain this effect by proposing a higher level of representation than individual letter identities in which letter position is not coded accurately. An alternative to this is to assume that position coding is noisy (e.g., Gomez, Ratcliff, & Perea, 2008). We propose an extension to the Bayesian Reader (Norris, 2006) that incorporates letter position noise during sampling from perceptual input. This model predicts “leakage” of letter identity to nearby positions, which is not expected from models incorporating alternative position coding schemes. We report three masked priming experiments testing predictions from this model.

Abstract One key issue for any computational model of visual word recognition is the choice of an input coding scheme for assigning letter position. Recent research has shown that transposed-letter similarity effects occur even when the transposed letters are not adjacent (caniso-casino; Perea & Lupker, 2004, JML). In the present study we conducted two single-presentation lexical decision experiments to examine whether transposed-letter effects occur at a syllable level. We tested two types of nonwords: (1) nonwords created by transposing two internal CV syllables (PRIVEMARA; the base word is primavera, the Spanish for spring) and (2) nonwords created by transposing two adjacent bigrams that do not form a syllable (PRIMERAVA). We also created the appropriate orthographic control conditions, in which the critical letters were replaced instead of being switched. Results showed that the transposition of two syllables or two adjacent bigrams produced a quite robust (and similar) transposed-letter effect. Thus, transposed-letter effects seem to occur at an early orthographic, graphemic level, rather than at a syllable level. We examine the implications of the observed results for the input coding schemes in visual word recognition.

Previous research has shown that prior exposure to a word’s substitution neighbor earlier in the same sentence can disrupt processing of that word, indicating that interword lexical priming occurs naturally during reading, due to the competition between lexical candidates during word identification. Through the present research, we extended these findings by investigating the effects of prior exposure to a word’s transposed-letter neighbor (TLN) earlier in a sentence. TLNs are constituted from the same letters, but in different orders. The findings revealed an inhibitory TLN effect, with longer total reading times for target words, and increased regressions to prime and target words, when the target followed a TLN rather than a control word. These findings indicate that prior exposure to a TLN can disrupt word identification during reading. We suggest that this is caused by a failure of word identification, due to the initial misidentification of the target word (potentially as its TLN) triggering postlexical checking.

Associative priming effects can be obtained with masked nonword primes or with masked pseudohomophone primes (e.g., judpe –COURT, tode –FROG), but not with visible primes. The usual explanation is that when the prime is visible, these stimuli no longer activate the semantic representations of their base words. Given the important role of transposed-letter stimuli (e.g., jugde ) in visual word recognition, here we examined whether or not an associative priming effect could be obtained with visible transposed-letter nonword primes (e.g., jugde –COURT) in a series of lexical decision experiments. Results showed a sizable associative priming effect with visible transposed-letter nonword primes (i.e., jugde –COURT faster than neevr –COURT) in Experiments 1–3 that was close to that with word primes. In contrast, we failed to find a parallel effect with replacement-letter nonword primes ( Experiment 2 ). These findings pose some constraints to models of visual word recognition.

正 逆序词是汉语构词的一种特殊形式,其结果为AB-BA(如“工人”-“人工”),逆序词的特点是,构成双字词的两个字其字形和音节是完全相同的,只是它们的位置不同构成一对逆序词的两个词在意义上有的相同或相近(如“相互”-“互相”),有的则完全不同(如“结巴”-“巴结”),本实验采用词义不同的汉语逆序词为材料,探讨了词素在汉语合成词加工中作用。

In an extension of a study by Vitu, O’Regan, Inhoff, and Topolski (1995), we compared global and local characteristics of eye movements during (1) reading, (2) the scanning of transformed text (in which each letter was replaced with a z), and (3) visual search. Additionally, we examined eye behavior with respect to specific target words of high or low frequency. Globally, the reading condition led to shorter fixations, longer saccades, and less frequent skipping of target strings than did scanning transformed text. Locally, the manipulation of word frequency affected fixation durations on the target word during reading, but not during visual search or z-string scanning. There were also more refixations on target words in reading than in scanning. Contrary to Vitu et al.’s (1995) findings, our results show that eye movements are not guided by a global strategy and local tactics, but by immediate processing demands.

Research on the impact of letter transpositions that arise across morpheme boundaries has yielded conflicting results. These results have led to the suggestion that a cross-linguistic difference may exist in the recognition of Spanish and English words. In two masked-priming experiments run on separate groups of Spanish and English speakers, we tested this hypothesis by comparing the impacts of primes with letter transpositions that arose within morphemes or across morpheme boundaries on the recognition of identical or near-identical Spanish鈥揈nglish cognate targets. The results showed transposed-letter benefits in both Spanish and English that were not modulated by the position of the transposed letter in the prime stimulus. Our findings therefore add to the growing body of literature suggesting that the transposed-letter benefit is not affected by the position of the transposed letters relative to the morpheme boundary, and they dispel previous suggestions that there might be a genuine difference in orthographic coding across the Spanish and English writing systems.

It is well known that real-time human language processing is highly incremental and context-driven, and that the strength of a comprehender's expectation for each word encountered is a key determinant of the difficulty of integrating that word into the preceding context. In reading, this differential difficulty is largely manifested in the amount of time taken to read each word. While numerous studies over the past thirty years have shown expectation-based effects on reading times driven by lexical, syntactic, semantic, pragmatic, and other information sources, there has been little progress in establishing the quantitative relationship between expectation (or prediction) and reading times. Here, by combining a state-of-the-art computational language model, two large behavioral data-sets, and non-parametric statistical techniques, we establish for the first time the quantitative form of this relationship, finding that it is logarithmic over six orders of magnitude in estimated predictability. This result is problematic for a number of established models of eye movement control in reading, but lends partial support to an optimal perceptual discrimination account of word recognition. We also present a novel model in which language processing is highly incremental well below the level of the individual word, and show that it predicts both the shape and time-course of this effect. At a more general level, this result provides challenges for both anticipatory processing and semantic integration accounts of lexical predictability effects. And finally, this result provides evidence that comprehenders are highly sensitive to relative differences in predictability - even for differences between highly unpredictable words - and thus helps bring theoretical unity to our understanding of the role of prediction at multiple levels of linguistic structure in real-time language comprehension. (c) 2013 The Authors. Published by Elsevier B.V. All rights reserved.

研究采用眼动随动显示技术考察中文阅读预视加工中的词汇加工问题.前三项实验发现,剥夺预视加工的掩蔽条件、正确提示词n+1右侧边界的掩蔽条件以及不能提示词n+1右侧边界的掩蔽条件都不影响词频效应,说明中文读者对词n+1处文字的预视加工达不到词汇水平.实验4考察剥夺预视加工的掩蔽条件、提示词n+1右侧边界的掩蔽条件对预测性效应的影响,结果发现,剥夺预视加工完全消除预测性效应,提示词n+1右侧边界则减少预测性效应,说明对词汇的预期加工是中文读者切分词n+1的参考线索.综合4项实验结果可知,中文读者较难通过自下而上的文字识别切分词n+1,自上而下的词汇预期则是切分词n+1的加工形式.

The encoding of letter position is a key aspect in all recently proposed models of visual-word recognition. We analyzed the impact of lexical frequency on letter position assignment by examining the temporal dynamics of lexical activation induced by pseudowords extracted from words of different frequencies. For each word (e.g., BRIDGE), we created two pseudowords: A transposed-letter (TL: BRIGDE) and a replaced-letter pseudoword (RL: BRITGE). ERPs were recorded while participants read words and pseudowords in two tasks: Semantic categorization (Experiment 1) and lexical decision (Experiment 2). For high-frequency stimuli, similar ERPs were obtained for words and TL-pseudowords, but the N400 component to words was reduced relative to RL-pseudowords, indicating less lexical/semantic activation. In contrast, TL- and RL-pseudowords created from low-frequency stimuli elicited similar ERPs. Behavioral responses in the lexical decision task paralleled this asymmetry. The present findings impose constraints on computational and neural models of visual-word recognition.

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.

We used eye movement measures of paragraph reading to examine whether word frequency and predictability interact during the earliest stages of lexical processing, with a specific focus on whether these effects are modulated by individual differences in reading comprehension or launch site (i.e., saccade length between the prior and currently fixated word--a proxy for the amount of parafoveal word processing). The joint impact of frequency and predictability on reading will elucidate whether these variables additively or multiplicatively affect the earliest stages of lexical access, which, in turn, has implications for computational models of eye movements during reading. Linear mixed effects models revealed additive effects during both early- and late-stage reading, where predictability effects were comparable for low- and high-frequency words. Moreover, less cautious readers (e.g., readers who engaged in skimming, scanning, mindless reading) demonstrated smaller frequency effects than more cautious readers. Taken together, our findings suggest that during extended reading, frequency and predictability exert additive influences on lexical and postlexical processing, and that individual differences in reading comprehension modulate sensitivity to the effects of word frequency.

This paper describes a novel theoretical framework of how the position of a letter within a string is encoded, the SERIOL model (sequential encoding regulated by inputs to oscillations within letter units). Letter order is represented by a temporal activation pattern across letter units, as is consistent with current theories of information coding based on the precise timing of neural spikes. The framework specifies how this pattern is invoked via an activation gradient that interacts with subthreshold oscillations and how it is decoded via contextual units that activate word units. Using mathematical modeling, this theoretical framework is shown to account for the experimental data from a wide variety of string-processing studies, including hemispheric asymmetries, the optimal viewing position, and positional priming effects.

Open-bigram and spatial-coding schemes provide different accounts of how position is encoded by the brain during visual word recognition. Open-bigram coding involves an explicit representation of order based on pairs, while spatial coding involves a comparison function operating over representations of individual . We identify a set of priming conditions (subset primes and reversed interior primes) for which the two types of coding schemes give opposing predictions, hence providing the opportunity for strong scientific inference. Experimental results are consistent with the open-bigram account, and inconsistent with the spatial-coding scheme.

We examined how letter position coding is achieved in a script (Arabic) in which the different letter forms (i.e., allographs) may vary depending on their position within the letter string (e.g., compare the same-ligation pair and vs. the different-ligation pair and . To that end, we conducted an experiment in Uyghur, an agglutinative language from the Turkic family that employs an Arabic-based script in which both consonants and vowels are explicitly written. Participants had to reproduce the correct word forms in rapid serial visual presentation sentences that either contained jumbled words (with the same ligation or different ligation) or were intact. The results revealed that readers had more difficulty correctly reporting the target words in the jumbled sentences when the letter transposition involved changes in the ligation pattern, thus demonstrating that position-dependent allography affects letter position coding. This finding poses constraints to a universal model of letter position encoding.