Cracking the orthographic code: An introduction

Constraining current neuroanatomical models of reading: the view from Arabic

There is a growing interest in imaging understudied orthographies to unravel their neuronal correlates and their implications for existing computational and neuroanatomical models. Here, we review current brain mapping literature about Arabic words. We first offer a succinct description of some unique linguistic features of Arabic that challenge current cognitive models of reading. We then appraise the existing functional neuroimaging studies that investigated written Arabic word processing. Our review revealed that (1) Arabic is still understudied, (2) the most investigated features concerned the effects of vowelling and diglossia in Arabic reading, (3) findings were not always discussed in the light of existing reading models such as the dual route cascaded, the triangle, and the connectionist dual process models, and (4) current evidence is unreliable when it comes to the exact neuronal pathways that sustain Arabic word processing. Overall, despite the fact that Arabic has some unique linguistic features that challenge and ultimately enrich current reading models, the existing functional neuroimaging literature falls short of offering a reliable evidence about brain networks of Arabic reading. We conclude by highlighting the need for more systematic studies of the linguistic features of Arabic to build theoretical and neuroanatomical models that are concurrently specific and general.

Lateralized displays reveal the perceptual locus of the syllable transposition effect in Korean

Studies of letter transposition effects in alphabetic scripts provide compelling evidence that letter position is encoded flexibly during reading, potentially during an early, perceptual stage of visual word recognition. Recent studies additionally suggest similar flexibility in the spatial encoding of syllabic information in the Korean Hangul script. With the present research, we conducted two experiments to investigate the locus of this syllabic transposition effect. In Experiment 1, lexical decisions for foveal stimulus presentations were less accurate and slower for four-syllable nonwords created by transposing two syllables in a base word as compared to control nonwords, replicating prior evidence for a transposed syllable effect in Korean word recognition. In Experiment 2, the same stimuli were presented to the right and left visual hemifields (i.e., RVF and LVF), which project both unilaterally and contralaterally to each participant's left and right cerebral hemisphere (i.e., LH and RH) respectively, using lateralized stimulus displays. Lexical decisions revealed a syllable transposition effect in the accuracy and latency of lexical decisions for both RVF and LVF presentations. However, response times for correct responses were longer in the LVF, and therefore the RH, as compared to the RVF/LH. As the LVF/RH appears to be selectively sensitive to the visual-perceptual attributes of words, the findings suggest that this syllable transposition effect partly finds its locus within a perceptual stage of processing. We discuss these findings in relation to current models of the spatial encoding of orthographic information during visual word recognition and accounts of visual word recognition in Korean.

Learned Attentional Strategies in Word Holistic Processing

Previous research has shown that, like faces, words are processed either holistically or through the automatic representation of their parts combined. The automaticity assumed to underlie the holistic processing of words presupposes that individuals have a relatively low level of control over these processes. However, they may also be capable of learning from their environments whether processing words as a whole is the most efficient processing strategy-which would require at least some control over the corresponding processes. In fact, previous research supports this latter account in the context of the holistic processing of faces: when provided a task in which participants should ignore half of a stimuli (the irrelevant part) and pay selective attention to the other half (the target part), the participants become better at ignoring the irrelevant part when it is commonly misleading (i.e., this suggests a response that is different from that of the relevant part in the context of the task). In the present work, we extend these considerations to holistic word processing. Our results support a learned attentional account in the context of holistic word processing. When an irrelevant word part is systematically helpful for the judgment of a target word half, participants engage more in holistic processing (vs. when the irrelevant word half is misleading). This reflects an incidental statistical learning process in which individuals identify the irrelevant word half as either providing helpful or misleading information about the target half.

New insights into bilingual visual word recognition: State of the art on the role of orthographic markedness, its theoretical implications, and future research directions

In the past decade, research on bilingual visual word recognition has given rise to a new line of study focusing on a sublexical orthographic variable referred to as orthographic markedness, derived from the comparison of the two orthotactic distributions known by a bilingual reader. Orthographic markers have been shown to speed up language decisions but also, to some extent, to modulate language nonselectivity during lexical access (i.e., the degree of co-activation of lexical representations of the two languages). In this review, we (1) describe the results available in the literature about orthographic markedness on language membership detection and lexical access and discuss the locus of these effects, which leads us to (2) present theoretical extensions to the bilingual interactive activation models and discuss their respective adequacy to the data, finally leading us to (3) propose future research directions in the study of orthographic markedness, such as extension to different reading tasks and contexts as well as considering developmental and learning dynamics.

Phonological decoding and morpho-orthographic decomposition: Complementary routes during learning to read

We examined the reliance on phonological decoding and morpho-orthographic decomposition strategies in developing and skilled readers of French. A lexical decision experiment was conducted where the critical stimuli were four types of nonwords, all derived from the same base word, such as the French word visage (face) in the following examples: (a) pseudo-homophone (PsH) nonwords (e.g., visaje), (b) orthographic controls for PsH nonwords (e.g., visape), (c) pseudo-morphemic (PsM) nonwords (e.g., visageable), and (d) orthographic controls for PsM nonwords (e.g., visagealle, where alle is not a suffix in French). Responses to PsH and PsM nonwords and their controls were studied in three groups of school children (Grades 1, 2, and 5) and one group of skilled adult readers. PsH interference effects (i.e., more errors to PsH nonwords than to the corresponding controls) decreased during reading acquisition to become nonsignificant in skilled readers. Interestingly, the opposite pattern was seen in PsM interference effects (also measured in terms of accuracy), which were already significant in Grade 1 and increased during reading development to reach their maximum in skilled readers. These results point toward opposing learning trajectories in the use of phonological and morphological information when learning to silently read for meaning.

The word superiority effect overcomes crowding

Crowding and the word superiority effect are two perceptual phenomena that influence reading. The identification of the inner letters of a word can be hindered by crowding from adjacent letters, but it can be facilitated by the word context itself (the word superiority effect). In the present study, strings of four-letters (words and non-words) with different inter-letter spacings (ranging from an optimal spacing to produce crowding to a spacing too large to produce crowding) were presented briefly in the periphery and participants were asked to identify the third letter of the string. Each word had a partner word that was identical except for its third letter (e.g., COLD, CORD) so that guessing as the source of the improved performance for words could be ruled out. Unsurprisingly, letter identification accuracy for words was better than non-words. For non-words, it was lowest at closer spacings, confirming crowding. However, for words, accuracy remained high at all inter-letter spacings showing that crowding did not prevent identification of the inner letters. This result supports models of "holistic" word recognition where partial cues can lead to recognition without first identifying individual letters. Once the word is recognized, its inner letters can be recovered, despite their feature loss produced by crowding.

Transposition and substitution-letter effects in a flanker task: Evidence from children and adults

Several studies have shown that parafoveal processing is essential in reading development. In this study, we explore the effect of transposing and substituting inner and outer letters in a flanker lexical decision task administered to 78 children and 65 adults. The results show a significant interaction between the Group factor and the Flanker factor, suggesting differences in the effects of flankers for children and adults. In the case of adults, transposed and substituted letters generated benefit of the same magnitude in comparison with the unrelated condition, but of lesser magnitude than the Identity condition. In the case of children, the results show facilitation for the transposed conditions of the same magnitude as the Identity condition. However, the substitution conditions failed to generate any benefit in comparison with the unrelated condition. The results for the adults are in line with the predictions of the open bigram model, whereas the results for the children are explained through a developmental perspective of the dual-route architecture and open bigram framework.

A predictive coding model of the N400

The N400 event-related component has been widely used to investigate the neural mechanisms underlying real-time language comprehension. However, despite decades of research, there is still no unifying theory that can explain both its temporal dynamics and functional properties. In this work, we show that predictive coding - a biologically plausible algorithm for approximating Bayesian inference - offers a promising framework for characterizing the N400. Using an implemented predictive coding computational model, we demonstrate how the N400 can be formalized as the lexico-semantic prediction error produced as the brain infers meaning from the linguistic form of incoming words. We show that the magnitude of lexico-semantic prediction error mirrors the functional sensitivity of the N400 to various lexical variables, priming, contextual effects, as well as their higher-order interactions. We further show that the dynamics of the predictive coding algorithm provides a natural explanation for the temporal dynamics of the N400, and a biologically plausible link to neural activity. Together, these findings directly situate the N400 within the broader context of predictive coding research. More generally, they raise the possibility that the brain may use the same computational mechanism for inference across linguistic and non-linguistic domains.

On the distinction between position and order information when processing strings of characters

To probe the processing of gaze-dependent positional information and gaze-independent order information when matching strings of characters, we compared effects of visual similarity (hypothesized to affect gaze-centered position coding) with the effects of character transpositions (hypothesized to affect the processing of gaze-independent order information). In Experiment 1, we obtained empirical measures of visual similarity for pairs of characters, separately for uppercase consonants and keyboard symbols. These similarity values were then used in Experiment 2 to create pairs of four-character stimuli (four letters or four symbols) that could differ by substituting one character with a different character from the same category that was visually similar (e.g., FJDK-FJBK) or dissimilar (e.g., FJVK-FJBK). We also compared the effects of transposing two characters (e.g., FBJK-FJBK) with substituting two characters (e.g., FHSK-FJBK). "Different" responses were harder to make in the single substitution condition when the substituted character was visually similar, and this effect was not conditioned by character type. On the other hand, transposition costs (i.e., greater difficulty in detecting a difference with transpositions compared with double substitutions) were greater for letters compared with symbols. We conclude that visual similarity mainly affects the generic gaze-dependent processing of complex visual features, and that the encoding of letter order involves a mechanism that is specific to reading.

Effects of lexical skills and orthographic neighborhood size in word memory

Two experiments were designed to investigate the relationship between individual lexical skills in young adults and memory performance on words varying by their orthographic neighborhood size. In Experiment 1, a sample of 100 university students were administrated a set of spelling, reading, and vocabulary tests to assess their lexical skills. Then, they had to learn mixed lists of words from high and low neighborhood size and perform free recall and memory recognition tasks. Importantly, high lexical skills were found to enhance free recall and, to a lesser extent, recognition. In addition, a typical mirror effect of neighborhood size was found in recognition as words were better recognized and also produced less false alarms when they had a low neighborhood size. In Experiment 2, pure lists of words were designed and a new sample of 90 university students was assessed. We replicated the effect of lexical skills in free recall and the effect of neighborhood size for hits in recognition. Spelling skills were found to interact with neighborhood size in free recall in that low spelling skills were associated with a facilitatory effect of neighborhood size. In recognition, a relation between reading skills and neighborhood size was found such that the higher the reading skills, the higher was the inhibitory effect of neighborhood size. These results provide new evidence of an influence of lexical skills in word memory performance and underline the role of orthographic neighborhood size in episodic memory tasks.

Modelling orthographic similarity effects in recognition memory reveals support for open bigram representations of letter coding

A variety of letter string representations has been proposed in the reading literature to account for empirically established orthographic similarity effects from masked priming studies. However, these similarity effects have not been explored in episodic memory paradigms and very few memory models have employed orthographic representation of words. In the current work, through two recognition memory experiments employing word and pseudoword stimuli respectively, we empirically established a set of key orthographic similarity effects for the first time in recognition memory - namely the substitution effect, transposition effect and reverse effect in recognition memory of words and pseudowords, and a start-letter importance in recognition memory of words. Subsequently, we compared orthographic representations from the reading literature including slot coding, closed-bigram, open-bigram and the overlap model. Each of these representations was situated in a global matching model and fitted to recognition performance via Luce's choice rule in a hierarchical Bayesian framework. Model selection results showed support for the open-bigram representation in both experiments.

Rime Priming Effects in Spoken Word Recognition

In this study, we re-examined the facilitation that occurs when auditorily presented monosyllabic primes and targets share their final phonemes, and in particular the rime (e.g., /vɔʀd/-/kɔʀd/). More specifically, we asked whether this rime facilitation effect is also observed when the two last consonants of the rime are transposed (e.g., /vɔʀd/-/kɔʀd/). In comparison to a control condition in which the primes and the targets were unrelated (e.g., /pylt/-/kɔʀd/), we found significant priming effects in both the rime (/vɔdʀ/-/kɔʀd/) and the transposed-phoneme "rime" /vɔdʀ/-/kɔʀd/ conditions. We also observed a significantly greater priming effect in the former condition than in the latter condition. We use the theoretical framework of the TISK model (Hannagan et al., 2013) to propose a novel account of final overlap phonological priming in terms of activation of both position-independent phoneme representations and bi-phone representations.

An Evidence Accumulation Account of Masked Translation Priming in Two Bilingual Populations

This manuscript addresses the phenomenon of masked priming and the cognitive process of switching from Spanish to English while reading in sequential bilingual texts compared to heritage speakers. A lexical decision task was employed in the present study with masked translation priming, which serves as a valuable tool for elucidating the orthographic and lexical processes involved in the initial stages of reading. This study builds upon previous research conducted on monolingual masked priming, which consistently demonstrates shifts in the response time (RT) distributions when comparing related and unrelated primes. Within the framework of a diffusion model, we implemented two theoretical positions. First, we posited that translation priming operates at the orthographic level, resulting in enhanced efficiency during the encoding process. Second, we explored the possibility that translation priming operates at the semantic level, influencing the accumulation of evidence during the lexical decision task. The findings of the present study indicate that translation priming elicits outcomes similar to those observed in monolingual priming paradigms. Specifically, we observed that translation priming facilitation is manifested as shifts in the RT distributions. These findings are interpreted to suggest that the benefits derived from the encoding process are not specific to the accessed lexicon following a brief stimulus presentation.

Investigating the Role of Response Codes in Masked Priming Lexical Decision Tasks: The Case of Repeated Presentations

The masked priming technique is considered a gold standard among experimental psychologists who specialize in the field of visual word recognition. Typically, this method entails a comparison between two or more critical conditions (e.g., the target word MOUSE being preceded by either the identity prime mouse or the unrelated prime fence). It is noteworthy that, unlike other masked priming tasks, prior experiments examining the properties of unrelated primes (e.g., their frequency as words [high or low] or their legality as nonwords [orthographically legal or illegal]) do not have an impact on the processing of the target item. However, two lexical decision studies reported faster responses to target words when the unrelated prime is a word rather than a nonword (i.e., a response congruency effect). One possible explanation for this discrepancy is a difference in methodology, as these two studies are the only ones to have used repeated presentation of stimuli, which could lead to the creation of an episodic memory trace that amplifies response congruency effects. To examine this hypothesis, we used a set of materials that did not show any congruency effect in a previous experiment with unique presentations, except that here we included repeated presentations. Results showed a response congruency effect, with participants responding faster to word targets when they were preceded by an unrelated word prime as opposed to an unrelated nonword prime. These findings suggest that the activation of response codes in masked priming is contingent upon the nature of cognitive resources required for processing the target stimuli.

Does online masked priming pass the test? The effects of prime exposure duration on masked identity priming

Masked priming is one of the most important paradigms in the study of visual word recognition, but it is usually thought to require a laboratory setup with a known monitor and keyboard. To test if this technique can be safely used in an online setting, we conducted two online masked priming lexical decision task experiments using PsychoPy/PsychoJS (Peirce et al., 2019). Importantly, we also tested the role of prime exposure duration (33.3 vs. 50 ms in Experiment 1 and 16.7 vs. 33.3 ms in Experiment 2), thus allowing us to examine both across conditions and within-conditions effects. We found that our online data are indeed very similar to the masked priming data previously reported in the masked priming literature. Additionally, we found a clear effect of prime duration, with the priming effect (measured in terms of response time and accuracy) being stronger at 50 ms than 33.3 ms and no priming effect at 16.7 ms prime duration. From these results, we can conclude that modern online browser-based experimental psychophysics packages (e.g., PsychoPy) can present stimuli and collect responses on standard end user devices with enough precision. These findings provide us with confidence that masked priming can be used online, thus allowing us not only to run less time-consuming experiments, but also to reach populations that are difficult to test in a laboratory.

Sensitivity to orthographic vs. phonological constraints on word recognition: An ERP study with deaf and hearing readers

The role of phonology in word recognition has previously been investigated using a masked lexical decision task and transposed letter (TL) nonwords that were either pronounceable (barve) or unpronounceable (brvae). We used event-related potentials (ERPs) to investigate these effects in skilled deaf readers, who may be more sensitive to orthotactic than phonotactic constraints, which are conflated in English. Twenty deaf and twenty hearing adults completed a masked lexical decision task while ERPs were recorded. The groups were matched in reading skill and IQ, but deaf readers had poorer phonological ability. Deaf readers were faster and more accurate at rejecting TL nonwords than hearing readers. Neither group exhibited an effect of nonword pronounceability in RTs or accuracy. For both groups, the N250 and N400 components were modulated by lexicality (more negative for nonwords). The N250 was not modulated by nonword pronounceability, but pronounceable nonwords elicited a larger amplitude N400 than unpronounceable nonwords. Because pronounceable nonwords are more word-like, they may incite activation that is unresolved when no lexical entry is found, leading to a larger N400 amplitude. Similar N400 pronounceability effects for deaf and hearing readers, despite differences in phonological sensitivity, suggest these TL effects arise from sensitivity to lexical-level orthotactic constraints. Deaf readers may have an advantage in processing TL nonwords because of enhanced early visual attention and/or tight orthographic-to-semantic connections, bypassing the phonologically mediated route to word recognition.

The mechanisms supporting holistic perception of words and faces are not independent

The question of whether word and face recognition rely on overlapping or dissociable neural and cognitive mechanisms received considerable attention in the literature. In the present work, we presented words (aligned or misaligned) superimposed on faces (aligned or misaligned) and tested the interference from the unattended stimulus category on holistic processing of the attended category. In Experiment 1, we found that holistic face processing is reduced when a face was overlaid with an unattended, aligned word (processed holistically). In Experiment 2, we found a similar reduction of holistic processing for words when a word was superimposed on an unattended, aligned face (processed holistically). This reciprocal interference effect indicates a trade-off in holistic processing of the two stimuli, consistent with the idea that word and face recognition may rely on non-independent, overlapping mechanisms.

Effects of horizontal displacement and inter-character spacing on transposed-character effects in same-different matching

In two same-different matching experiments we investigated whether transposed-character effects can be modulated by the horizontal displacement or inter-character spacing of target stimuli (strings of 6 consonants, digits, or symbols). Reference and target stimuli could be identical or differed either by transposing or substituting two characters. Transposition costs (greater difficulty in detecting a difference with transpositions compared with substitutions) were greater for letter stimuli compared to both digit and symbol stimuli in both experiments. In Experiment 1, half of the targets were displayed at the center of the screen and the other half were shifted by two character-positions to the left or to the right, whereas the reference was always presented at the center of the screen. Target displacement made the task harder and caused an increase in transposition costs whatever the type of stimulus. In Experiment 2, all stimuli were presented at the center of the screen and the inter-character spacing of target stimuli was increased by one character space on half of the trials. Increased spacing made the task harder and paradoxically caused an increase in transposition costs, but only significantly so for letter stimuli, and only in the discriminability (d') measure. These results suggest that target location and inter-character spacing manipulations caused an increase in positional uncertainty during the processing of location-specific complex features prior to activation of a location-invariant representation of character-in-string order. The hypothesized existence of a letter-specific order encoding mechanism accounts for the greater transposition costs seen with letter stimuli, as well as the greater modulation of these effects by an increase in inter-character spacing seen in discriminability (d').

Searching beyond the looking glass with sandwich priming

Duñabeitia et al. (NeuroImage 54(4), 3004-3009, 2011) demonstrated that mirror letters induce the same electrophysiological response as canonical letters during the orthographic stage of visual word recognition. However, behavioral evidence in support of such an effect has remained scarce. We hypothesize that the poor reliability of the behavioral data could be due to the lack of sensitivity of the paradigms used in the literature. In Experiment 1 and Experiment 2, we compared conventional and sandwich-masked priming paradigms. Results showed that mirror primes (mirror) produced a significant priming effect on high-frequency words in the case of sandwich priming only. In Experiment 3, we used sandwich priming with a new material set to address a number of concerns regarding prime-target visual overlap. We obtained a graded facilitatory mirror-letter priming effect that acted additively with lexical frequency, thus supporting the idea that it originates in the fast automatic orthographic stage. Given that the graded priming effect provides little support for the idea of the complete preservation of mirror invariance for non-reversal letters, complementary explanations are explored.

Relative letter-position coding revisited

The notion that the brain achieves visual word recognition by encoding the relative positions of letters with open-bigram representations (e.g., ‘h-e’, ‘h-r’ and ‘e-r’ driving recognition of ‘her’) has been successful in accounting for many behaviors and phenomena. However, one characteristic of open-bigrams has remained unexplored: How is the activation of a bigram modulated by the distance between its constituents in the visual field? On the one hand, contiguous letters (e.g., ‘at’ in ‘father’) may allow for a clearer percept of the bigram. On the other hand, an increasing distance between letters (e.g., ‘ae’ in ‘father’) should create more certainty about their relative positions, which is precisely what the bigram is meant to convey. This matter was investigated with two experiments in which participants indicated whether target pairs of letters occurred in random letter strings. They were instructed that letter order mattered (i.e., ‘a-b’ does not occur in ‘kbac’), while letter contiguity did not (i.e., ‘a-b’ occurs in ‘akcb’). Controlling for crowding and eccentricity, bigrams were recognized faster upon decreasing the letter distance. However, when switching the target letter order (meaning the string should be met by a ‘no’ response), shorter letter distances yielded slower responses and more false positives. Neither relative position-coding models nor absolute position-coding models accommodate both these patterns at once. We discuss how a complete account of our effects may instead combine elements from both model types.

Fast priming of grammatical decisions: repetition and transposed-word priming effects

We used the grammatical decision task to investigate fast priming of written sentence processing. Targets were sequences of 5 words that either formed a grammatically correct sentence or were ungrammatical. Primes were sequences of 5 words and could be the same word sequence as targets, a different sequence of words with a similar syntactic structure, the same sequence with two inner words transposed or the same sequence with two inner words substituted by different words. Prime-word sequences were presented in a larger font size than targets for 200 ms and followed by the target sequence after a 100 ms delay. We found robust repetition priming in grammatical decisions, with same sequence primes leading to faster responses compared with prime sequences containing different words. We also found transposed-word priming effects, with faster responses following a transposed-word prime compared with substituted-word primes. We conclude that fast primed grammatical decisions might offer investigations of written sentence processing what fast primed lexical decisions have offered studies of visual word recognition.

The profile of real-time competition in spoken and written word recognition: More similar than different

Word recognition occurs across two sensory modalities: auditory (spoken words) and visual (written words). While each faces different challenges, they are often described in similar terms as a competition process by which multiple lexical candidates are activated and compete for recognition. While there is a general consensus regarding the types of words that compete during spoken word recognition, there is less consensus for written word recognition. The present study develops a novel version of the Visual World Paradigm (VWP) to examine written word recognition and uses this to assess the nature of the competitor set during word recognition in both modalities using the same experimental design. For both spoken and written words, we found evidence for activation of onset competitors (cohorts, e.g., cat, cap) and words that contain the same phonemes or letters in reverse order (anadromes, e.g., cat, tack). We found no evidence of activation for rhymes (e.g., cat, hat). The results across modalities were quite similar, with the exception that for spoken words, cohorts were more active than anadromes, whereas for written words activation was similar. These results suggest a common characterisation of lexical similarity across spoken and written words: temporal or spatial order is coarsely coded, and onsets may receive more weight in both systems. However, for spoken words, temporary ambiguity during the moment of processing gives cohorts an additional boost during real-time recognition.

ERP Correlates of Altered Orthographic-Phonological Processing in Dyslexia

Automatic visual word recognition requires not only well-established phonological and orthographic representations but also efficient audio-visual integration of these representations. One possibility is that in developmental dyslexia, inefficient orthographic processing might underlie poor reading. Alternatively, reading deficit could be due to inefficient phonological processing or inefficient integration of orthographic and phonological information. In this event-related potential study, participants with dyslexia (N = 25) and control readers (N = 27) were presented with pairs of words and pseudowords in an implicit same-different task. The reference-target pairs could be identical, or different in the identity or the position of the letters. To test the orthographic-phonological processing, target stimuli were presented in visual-only and audiovisual conditions. Participants with and without dyslexia processed the reference stimuli similarly; however, group differences emerged in the processing of target stimuli, especially in the audiovisual condition where control readers showed greater N1 responses for words than for pseudowords, but readers with dyslexia did not show such difference. Moreover, after 300 ms lexicality effect exhibited a more focused frontal topographic distribution in readers with dyslexia. Our results suggest that in developmental dyslexia, phonological processing and audiovisual processing deficits are more pronounced than orthographic processing deficits.

Unveiling the boost in the sandwich priming technique

The masked priming technique (which compares #####-house-HOUSE vs. #####-fight-HOUSE) is the gold-standard tool to examine the initial moments of word processing. Lupker and Davis showed that adding a pre-prime identical to the target produced greater priming effects in the sandwich technique (which compares #####-HOUSE-house-HOUSE vs #####-HOUSE-fight-HOUSE). While there is consensus that the sandwich technique magnifies the size of priming effects relative to the standard procedure, the mechanisms underlying this boost are not well understood (i.e., does it reflect quantitative or qualitative changes?). To fully characterise the sandwich technique, we compared the sandwich and standard techniques by examining the response times (RTs) and their distributional features (delta plots; conditional-accuracy functions), comparing identity versus unrelated primes. The results showed that the locus of the boost in the sandwich technique was two-fold: faster responses in the identity condition (via a shift in the RT distributions) and slower responses in the unrelated condition. We discuss the theoretical and methodological implications of these findings.

Electrophysiological Correlates of Character Transposition in the Left and Right Visual Fields

This study examined the brain activity elicited by the hemispheric asymmetries and morpheme transposition of two-character Chinese words (canonical and transposed word) and pseudowords using event-related potentials (ERPs) with a dual-target rapid serial visual presentation (RSVP) task. Electrophysiological results showed facilitation effects for canonical words with centrally presented visual field (CVF) and right visual field (RVF) presentations but not with left visual field (LVF) presentations, as reflected by less negative N400 amplitudes. Moreover, more positive late positive component (LPC) amplitudes were observed for both canonical words and transposed words irrespective of the visual fields. More importantly, transposed words elicited a more negative N400 amplitude and a less positive LPC amplitude compared with the amplitudes elicited by canonical words for CVF and RVF presentations. For LVF presentations, transposed words elicited a less negative N250 amplitude compared with canonical words, and there was no significant difference between canonical words and transposed words in the N400 effect. Taken together, we concluded that character transposition facilitated the mapping of whole-word orthographic representation to semantic information in the LVF, as reflected by the N250 component, and such morpheme transposition influenced whole-word semantic processing in CVF and RVF presentations, as reflected by N400 and LPC components.

Hands Down: Cognate Effects Persist During Written Word Production

Words that share form and meaning across two or more languages (i.e., cognates) are generally processed faster than control words (non-cognates) by bilinguals speaking these languages. This so-called cognate effect is considered to be a demonstration of language non-selectivity during bilingual lexical access. Still, research up till now has focused mainly on visual and auditory comprehension. For production, research is almost exclusively limited to speech, leaving written production out of the equation. Hence, the goal of the current study was to examine whether bilinguals activate representations from both languages during typewriting. Dutch-English bilinguals completed second-language written sentences with names of displayed pictures. Low-constraint sentences yielded a cognate facilitation effect, whereas high-constraint sentences did not. These findings suggest that co-activation of similar words across languages also occurs during written production, just as in reading and speaking. Also, the interaction effect with sentence constraint shows that grammatical and semantic sentence restrictions may overrule interlingual facilitation effects.

Single Word Reading in the Real World: Effects of Transposed-Letters

We investigated single word reading in a context where isolated word presentation is not unusual reading road signs in a simulated car driving situation. Participants had to indicate if the inscription on the road sign was a real word or not (lexical decision). The critical nonwords were created in two ways: by transposing two letters in a real word (e.g., the word Highway becomes Hihgway) or by substituting the same two letters with different letters (Hifpway). The baseword used to create the critical nonword stimuli were either congruent with a driving context (e.g., highway) or incongruent (e.g., garden). Nonwords created by a letter transposition were harder to reject as such compared with letter substitution nonwords a transposed-letter effect. The effect of baseword congruency was not significant and did not interact with the transposed-letter effect.

Orthographic neighborhood density modulates the size of transposed-letter priming effects

We used transposed-letter (TL) priming to test the lexical tuning hypothesis, which states that words from high-density orthographic neighborhoods have more precise orthographic codes than words from low-density neighborhoods. Replicating standard TL priming effects, target words elicited faster lexical decision responses and smaller amplitude N250s and N400s when preceded by TL primes (e.g., leomn-LEMON) compared with substitution primes (e.g., leuzn-LEMON) overall. We expected that if high-density words have more precise orthographic representations (i.e., with each letter assigned to a specific position), then they should be relatively less activated by TL primes and should give rise to smaller TL priming effects. In line with our prediction, N250 (but not N400 or behavioral) TL priming was significantly smaller for high-density words compared with low-density words over posterior sites. Such an interaction was not observed for pseudoword targets. Consistent with the lexical tuning hypothesis then, this pattern suggests that the nature of the orthographic code used to access lexical representations differs depending on the number of neighboring words in the lexicon. We conclude by discussing how lexical tuning could be implemented in current models of orthographic processing.

Face and word composite effects are similarly affected by priming of local and global processing

Holistic processing has been shown with both faces and words, but it is unclear how similar their underlying mechanisms are. In this study attention to global and local features was manipulated and the consequences for holistic word and face processing were examined. On each trial participants were presented two Navon figures and told to focus on either the global or the local level. Then they performed a composite task in which they indicated whether the target halves of two sequentially presented faces or words were the same or different, ignoring the irrelevant halves. Similar stronger global priming effects were found for faces and words, indicating that holistic processing for the two types of stimuli were susceptible to attention manipulations to similar degrees, which was confirmed with Bayesian analyses. The findings add to the investigation of the similarity and differences between holistic processing and help reveal those aspects of holistic processing that are domain general and those specific to individual categories.

An ERP investigation of transposed-word effects in same-different matching

Can several words be read in parallel, and if so, how is information about word order encoded under such circumstances? Here we focused on the bottom-up mechanisms involved in word-order encoding under the hypothesis of parallel word processing. We recorded EEG while participants performed a visual same-different matching task with sequences of five words (reference sequence followed by a target sequence each presented for 400 ms). The reference sequence could be grammatically correct or an ungrammatical scrambling of the same words (e.g., he wants these green apples/green wants these he apples). Target sequences for 'different' responses were created by either transposing two words in the reference (e.g., he these wants green apples/green these wants he apples), or by changing two words (e.g., he talks their green apples/green talks their he apples). Different responses were harder to make in the transposition condition, and this transposed-word effect started to emerge around 250 ms post-target onset. The transposed-word effect was first seen on an early onsetting N400 component, with reduced amplitudes (i.e., less negative ERPs) in the transposed condition relative to a two-word replacement condition. A later transposed-word effect was seen on a more temporally widespread positive-going component. Converging behavioral and EEG results showed no effects of reference grammaticality on 'different' responses nor an interaction with transposed-word effects. Our results point to the noisy, bottom-up association of word identities to spatiotopic locations as one means of encoding word order information, and one key source of transposed-word effects.

Perceptual expertise with Chinese characters predicts Chinese reading performance among Hong Kong Chinese children with developmental dyslexia

This study explores the theoretical proposal that developmental dyslexia involves a failure to develop perceptual expertise with words despite adequate education. Among a group of Hong Kong Chinese children diagnosed with developmental dyslexia, we investigated the relationship between Chinese word reading and perceptual expertise with Chinese characters. In a perceptual fluency task, the time of visual exposure to Chinese characters was manipulated and limited such that the speed of discrimination of a short sequence of Chinese characters at an accuracy level of 80% was estimated. Pair-wise correlations showed that perceptual fluency for characters predicted speeded and non-speeded word reading performance. Exploratory hierarchical regressions showed that perceptual fluency for characters accounted for 5.3% and 9.6% variance in speeded and non-speeded reading respectively, in addition to age, non-verbal IQ, phonological awareness, morphological awareness, rapid automatized naming (RAN) and perceptual fluency for digits. The findings suggest that perceptual expertise with words plays an important role in Chinese reading performance in developmental dyslexia, and that perceptual training is a potential remediation direction.

Matrices of the frequency and similarity of Arabic letters and allographs

Indicators of letter frequency and similarity have long been available for Indo-European languages. They have not only been pivotal in controlling the design of experimental psycholinguistic studies seeking to determine the factors that underlie reading ability and literacy acquisition, but have also been useful for studies examining the more general aspects of human cognition. Despite their importance, however, such indicators are still not available for Modern Standard Arabic (MSA), a language that, by virtue of its orthographic system, presents an invaluable environment for the experimental investigation of visual word processing. This paper presents for the first time the frequencies of Arabic letters and their allographs based on a 40-million-word corpus, along with their similarity/confusability indicators in three domains: (1) the visual domain, based on human ratings; (2) the auditory domain, based on an analysis of the phonetic features of letter sounds; and (3) the motoric domain, based on an analysis of the stroke features used to write letters and their allographs. Taken together, the frequency and similarity of Arabic letters and their allographs in the visual and motoric domains, as well as the similarities among the letter sounds, will be useful for researchers interested in the processes underpinning orthographic processing, visual word recognition, reading, and literacy acquisition.

Orthographic and phonological contributions to flanker effects

Does phonology contribute to effects of orthographically related flankers in the flankers task? In order to answer this question, we implemented the flanker equivalent of a pseudohomophone priming manipulation that has been widely used to demonstrate automatic phonological processing during visual word recognition. In Experiment 1, central target words were flanked on each side by either a pseudohomophone of the target (e.g., roze rose roze), an orthographic control pseudoword (rone rose rone), or an unrelated pseudoword (mirt rose mirt). Both the pseudohomophone and the orthographic control conditions produced faster and more accurate responses to central targets, but performance in these two conditions did not differ significantly. Experiment 2 tested the same stimuli in a masked priming paradigm and replicated the standard finding in French that pseudohomophone primes produce significantly faster responses to target words than orthographic control primes. Therefore, contrary to its impact on masked priming, phonology does not contribute to effects of flanker relatedness, which would appear to be driven primarily by orthographic overlap.

An ERP investigation of orthographic precision in deaf and hearing readers

Phonology is often assumed to play a role in the tuning of orthographic representations, but it is unknown whether deaf readers' reduced access to spoken phonology reduces orthographic precision. To index how precisely deaf and hearing readers encode orthographic information, we used a masked transposed-letter (TL) priming paradigm. Word targets were preceded by TL primes formed by reversing two letters in the word and substitution primes in which the same two letters were replaced. The two letters that were manipulated were either in adjacent or non-adjacent positions, yielding four prime conditions: adjacent TL (e.g., chikcen-CHICKEN), adjacent substitution (e.g., chidven- CHICKEN), non-adjacent TL (e.g., ckichen-CHICKEN), and non-adjacent substitution (e.g., cticfen-CHICKEN). Replicating the standard TL priming effects, targets preceded by TL primes elicited smaller amplitude negativities and faster responses than those preceded by substitution primes overall. This indicates some degree of flexibility in the associations between letters and their positions within words. More flexible (i.e., less precise) representations are thought to be more susceptible to activation by TL primes, resulting in larger TL priming effects. However, the size of the TL priming effects was virtually identical between groups. Moreover, the ERP effects were shifted in time such that the adjacent TL priming effect arose earlier than the non-adjacent TL priming effect in both groups. These results suggest that phonological tuning is not required to represent orthographic information in a precise manner.

The role of phonology during visual word learning in adults: An integrative review

Throughout their lifetime, adults learn new words in their native lannguage, and potentially also in a second language. However, they do so with variable levels of success. In the auditory word learning literature, some of this variability has been attributed to phonological skills, including decoding and phonological short-term memory. Here I examine how the relationship between phonological skills and word learning applies to the visual modality. I define the availability of phonology in terms of (1) the extent to which it is biased by the learning environment, (2) the characteristics of the words to be learned, and (3) individual differences in phonological skills. Across these three areas of research, visual word learning improves when phonology is made more available to adult learners, suggesting that phonology can facilitate learning across modalities. However, the facilitation is largely specific to alphabetic languages, which have predictable sublexical correspondences between orthography and phonology. Therefore, I propose that phonology bootstraps visual word learning by providing a secondary code that constrains and refines developing orthographic representations.

Does orthographic processing emerge rapidly after learning a new script?

Orthographic processing is characterized by location-invariant and location-specific processing (Grainger, 2018): (1) strings of letters are more vulnerable to transposition effects than the strings of symbols in same-different tasks (location-invariant processing); and (2) strings of letters, but not strings of symbols, show an initial position advantage in target-in-string identification tasks (location-specific processing). To examine the emergence of these two markers of orthographic processing, we conducted a same-different task and a target-in-string identification task with two unfamiliar scripts (pre-training experiments). Across six training sessions, participants learned to fluently read and write one of these scripts. The post-training experiments were parallel to the pre-training experiments. Results showed that the magnitude of the transposed-letter effect in the same-different task and the serial function in the target-in-string identification tasks were remarkably similar for the trained and untrained scripts. Thus, location-invariant and location-specific processing does not emerge rapidly after learning a new script; instead, they may require thorough experience with specific orthographic structures.

Masked identity priming reflects an encoding advantage in developing readers

The masked priming technique is widely used to explore the early moments of letter and word identification. Although this technique is increasingly used in experiments with young readers, the mechanism in play during masked priming with early readers has not yet been fully explored. We investigated the masked priming effects from a modeling perspective; we instantiated competing theories as data models (using Bayes factors) and as a computational model (diffusion model). We carried out a masked priming experiment using identity primes with second- and fourth-grade participants, and we analyzed the data through an evidence accumulation model lens. The priming effect manifests as a shift in the response time distribution, which in evidence accumulation models is accounted for by changes in the encoding process. We describe such changes as savings that have three features of theoretical importance. First, they are numerically very close to the stimulus onset asynchrony between primes and targets. Second, they remain relatively constant from second grade to fourth grade. Third, they seem to operate at the level of abstract orthographic representation because the priming effect occurs in both case-matched and case-mismatched pairs. These findings also have consequences for the practice of data transformation in developmental research; some patterns of data, when transformed, would produce spurious effects.

Measuring Lexical Quality: The Role of Spelling Ability

The construct of 'lexical quality' (Perfetti Scientific Studies of Reading 11, 357-383, 2007) is widely invoked in literature on word recognition and reading to refer to a systematic dimension of individual differences that predicts performance in a range of word identification and reading tasks in both developing readers and skilled adult populations. Many different approaches have been used to assess lexical quality, but few have captured the orthographic precision that is central to the construct. This paper describes, evaluates, and disseminates spelling dictation and spelling recognition tests that were developed to provide sensitive measures of the precision component of lexical quality in skilled college student readers - the population that has provided most of the benchmark data for models of word recognition and reading. Analyses are reported for 785 students who completed the spelling tests in conjunction with standardized measures of reading comprehension, vocabulary, and reading speed, of whom 107 also completed author recognition and phonemic decoding tests. Internal consistency analyses showed that both spelling tests were relatively unidimensional and displayed good internal consistency, although the recognition test contained too many easy items. Item-level analyses are included to provide the basis for further refinement of these instruments. The spelling tests were moderately correlated with the other measures of written language proficiency, but factor analyses revealed that they consistently defined a separate component, demonstrating that they tap a dimension of variability that is partially independent of variance in reading comprehension, speed, and vocabulary. These components appear to align with the precision and coherence dimensions of lexical quality.

Case mixing impedes early lexical access: converging evidence from the masked priming paradigm

When letters are presented in mixed case (e.g., "PlAnE), word recognition is slowed. This case-mixing effect has been used to argue that early stages of word recognition operate holistically (on the entire visual word form) rather than merely letter-by-letter. Contrary to this holistic view, however, a masked priming study (Perea, Vergara-Martínez, & Gomez, Cognition 142:39-43, 2015) with Spanish words argued that case mixing has no effect on early stages of visual word recognition. Their participants made lexical decisions on an uppercase target (e.g., "PLANE") preceded by an identical prime (e.g., "plane") or an unrelated prime (e.g., "music"), presented in lowercase or mixed case. Because priming effects (unrelated-identical) were unaffected by case mixing, they concluded that case mixing does not impede early lexical access. We examined whether this finding applies to English words, while also including lowercase targets to prevent a strong bias against holistic word recognition. We found larger priming effects from lowercase primes than mixed-case primes regardless of target case (lowercase vs. uppercase) and whether target case was varied within blocks (Experiment 1) or between blocks (Experiment 2). Contrary to Perea et al.'s findings for Spanish, our results suggest an early locus for the case-mixing effect, consistent with the holistic view of word recognition.

When does rotation disrupt letter encoding? Testing the resilience of letter detectors in the initial moments of processing

Previous research has reported that both letter and word identification are slower when the stimuli are presented at rotations above 45° than when presented in their canonical horizontal view. Indeed, influential models of word recognition posit that letter detectors in the visual word recognition system are disrupted by rotation angles above 40° or 45° (e.g., Local Combinations Detector model; Dehaene, Cohen, Sigman, & Vinckier, 2005, Trends in Cognitive Sciences). However, recent experiments have shown robust masked identity/form priming effects for 90° rotated words, thus calling into question this assumption. Here we aimed to isolate the degree to which letter detectors are disrupted when manipulating letter rotation in three masked identity priming letter match experiments. Probes and targets were always presented in the canonical upright position, whereas forwardly masked primes were rotated in different angles. The rotation angles were 0° versus 45° (Experiment 1), 22.5° versus 67.5° (Experiment 2), and 45° versus 90° (Experiment 3). Results showed a sizeable masked identity priming effect regardless of the rotation angle, hence demonstrating that letter detectors are not disrupted by rotations smaller than 90° in the early moments of letter processing. This pattern suggests that letter detectors are more resilient to changes in visual form than predicted by the LCD model.

Deaf readers benefit from lexical feedback during orthographic processing

It has been proposed that poor reading abilities in deaf readers might be related to weak connections between the orthographic and lexical-semantic levels of processing. Here we used event related potentials (ERPs), known for their excellent time resolution, to examine whether lexical feedback modulates early orthographic processing. Twenty congenitally deaf readers made lexical decisions to target words and pseudowords. Each of those target stimuli could be preceded by a briefly presented matched-case or mismatched-case identity prime (e.g., ALTAR-ALTAR vs. altar- ALTAR). Results showed an early effect of case overlap at the N/P150 for all targets. Critically, this effect disappeared for words but not for pseudowords, at the N250—an ERP component sensitive to orthographic processing. This dissociation in the effect of case for word and pseudowords targets provides strong evidence of early automatic lexical-semantic feedback modulating orthographic processing in deaf readers. Interestingly, despite the dissociation found in the ERP data, behavioural responses to words still benefited from the physical overlap between prime and target, particularly in less skilled readers and those with less experience with words. Overall, our results support the idea that skilled deaf readers have a stronger connection between the orthographic and the lexical-semantic levels of processing.

Letter migration errors reflect spatial pooling of orthographic information

Prior research has shown that readers may misread words by switching letters across words (e.g., the word sand in sand lane being recognized as land). These so-called letter migration errors have been observed using a divided attention paradigm whereby two words are briefly presented simultaneously, and one is postcued for identification. Letter migrations might therefore be due to a task-induced division of attention across the two words. Here, we show that a similar rate of migration errors is obtained in a flanker paradigm in which a central target word is flanked to the left and to the right by task-irrelevant flanking words. Three words were simultaneously presented for the same brief duration. Asked to type the target word postoffset, participants produced more migration errors when the migrating letter occupied the same position in the flanker and target words, with significantly fewer migrations occurring across adjacent positions, and the effect disappearing across nonadjacent positions. Our results provide further support for the hypothesis that orthographic information spanning multiple words is processed in parallel and spatially integrated (pooled) within a single channel. It is the spatial pooling of sublexical orthographic information that is thought to drive letter migration errors.

Word position coding in reading is noisy

In the present article, we investigate a largely unstudied cognitive process: word position coding. The question of how readers perceive word order is not trivial: Recent research has suggested that readers associate activated word representations with plausible locations in a sentence-level representation. Rather than simply being dictated by the order in which words are recognized, word position coding may be influenced by bottom-up visual cues (e.g., word length information), as well as by top-down expectations. Here we assessed how flexible word position coding is. We let readers make grammaticality judgments about four-word sentences. The incorrect sentences were constructed by transposing two words in a correct sentence (e.g., “the man can run” became “the can man run”). The critical comparison was between two types of incorrect sentence: one with a transposition of the inner two words, and one with a transposition of the outer two words (“run man can the”). We reasoned that under limited (local) flexibility, it should be easier to classify the outer-transposed sentences as incorrect, because the words were farther away from their plausible locations in this condition. If words were recognized irrespective of location, on the other hand, there should be no difference between these two conditions. As it turned out, we observed longer response times and higher error rates for inner- than for outer-transposed sentences, indicating that local flexibility and top-down expectations can jointly lead the reader to confuse the locations of words, with a probability that increases as the distance between the plausible and actual locations of a word decreases. We conclude that word position coding is subject to a moderate amount of noise.