Do young readers have fast access to abstract lexical representations? Evidence from masked priming

Letters away from the looking glass: Developmental trajectory of mirrored and rotated letter processing within words

Discrimination of reversible mirrored letters (e.g., d and b) poses a challenge when learning to read as it requires overcoming mirror invariance, an evolutionary-old perceptual tendency of processing mirror images as equivalent. The present study investigated when, in reading development, mirror-image discrimination becomes automatic during visual word recognition. The developmental trajectory of masked priming effects was investigated from 2nd to 6th grade and in adults, by manipulating letter type (nonreversible; reversible) and prime condition (control; identity; mirrored; rotated). Standardized identity priming increased along reading development. Beginning readers showed mirror invariance during reversible and nonreversible letter processing. A mirror cost (slower word recognition in mirrored-letter than identity prime condition) was found by 5th-grade but only for reversible letters. By 6th grade, orthographic processing was no longer captive of mirror invariance. A multiple linear regression showed that letter representations, but not phonological processes or age, were a reliable predictor of the rise of mirror-image discrimination in 2nd-4th-graders. The present results suggest a protracted development of automatic mirror-image discrimination during orthographic processing, contingent upon the quality of abstract letter representations. RESEARCH HIGHLIGHTS: We traced the developmental trajectory of mirrored-letter and rotated-letter priming effects (e.g., ibea and ipea as primes of IDEA) in visual word recognition. Beginning readers (2nd-4th-graders) showed mirror invariance and plane-rotation sensitivity in orthographic processing, thus still being susceptible to the perceptual biases in charge in object recognition. A mirror cost was found in 5th-graders but only for reversible letters; orthographic processing was no longer captive of mirror invariance by 6th-grade. The automation of mirror-image discrimination during orthographic processing depends on the quality of letter representations but not on phonological processes or age.

The impact of visual cues during visual word recognition in deaf readers: An ERP study

Although evidence is still scarce, recent research suggests key differences in how deaf and hearing readers use visual information during visual word recognition. Here we compared the time course of lexical access in deaf and hearing readers of similar reading ability. We also investigated whether one visual property of words, the outline-shape, modulates visual word recognition differently in both groups. We recorded the EEG signal of twenty deaf and twenty hearing readers while they performed a lexical decision task. In addition to the effect of lexicality, we assessed the impact of outline-shape by contrasting responses to pseudowords with an outline-shape that was consistent (e.g., mofor) or inconsistent (e.g., mosor) with their baseword (motor). Despite hearing readers having higher phonological abilities, results showed a remarkably similar time course of the lexicality effect in deaf and hearing readers. We also found that only for deaf readers, inconsistent-shape pseudowords (e.g., mosor) elicited larger amplitude ERPs than consistent-shape pseudowords (e.g., mofor) from 150 ms after stimulus onset and extending into the N400 time window. This latter finding supports the view that deaf readers rely more on visual characteristics than typical hearing readers during visual word recognition. Altogether, our results suggest different mechanisms underlying effective word recognition in deaf and hearing readers.

The impact of capitalized German words on lexical access

Leading models of visual word recognition assume that the process of word identification is driven by abstract, case-invariant units (e.g., table and TABLE activate the same abstract representation). But do these models need to be modified to meet nuances of orthography as in German, where the first letter of common nouns is capitalized (e.g., Buch [book] and Hund [dog], but blau [blue])? To examine the role of initial capitalization of German words in lexical access, we chose a semantic categorization task ("is the word an animal name?"). In Experiment 1, we compared German words in all-lowercase vs. initial capitalization (hund, buch, blau vs. Hund, Buch, Blau). Results showed faster responses for animal nouns with initial capitalization (Hund < hund) and faster responses for lowercase non-nouns (blau < Blau). Surprisingly, we found faster responses for lowercase non-animal nouns (buch < Buch). As the latter difference could derive from task demands (i.e., buch does not follow German orthographic rules and requires a "no" response), we replaced the all-lowercase format with an orthographically legal all-uppercase format in Experiment 2. Results showed an advantage for all nouns with initial capitalization (Hund < HUND and Buch < BUCH). These findings clearly show that initial capitalization in German words constitutes an essential part of the words' representations and is used during lexical access. Thus, models of visual word recognition, primarily focused on English orthography, should be expanded to the idiosyncrasies of other Latin-based orthographies.

What masked priming effects with abbreviations can tell us about abstract letter identities

Models of visual word recognition share the assumption that lexical access is based on abstract letter identities. The present study re-examined the assumption that this is because information about the visual form of the letter is lost early in the course of activating the abstract letter identities. The main support for this assumption has come from the case-independent masked priming effects. Experiment 1 used common English words presented in lowercase as targets in lexical decision, and replicated the oft-reported case-independent identity priming effect (e.g., edge-edge = EDGE-edge). In contrast, Experiment 2 using abbreviations (e.g., DNA, CIA) produced a robust case-dependent identity priming effect (e.g., DNA-DNA < dna-DNA). Experiment 3 used the same abbreviation stimuli as primes in a semantic priming lexical decision experiment. Here the prime case effect was absent, but so was the semantic priming effect (e.g., dna-GENETICS = DNA-GENETICS = LSD-GENETICS). The results question the view that information about the visual form of the letter is lost early. We offer an alternative perspective that the abstract nature of priming for common words stems from how these words are represented in the reader's lexicon. The implication of these findings for letter and word recognition is discussed. (197 words).

Neural Representation in Visual Word Form Area during Word Reading

The visual word form area (VWFA) has been consistently identified as a crucial structure in visual word processing. Nevertheless, it is controversial whether the VWFA represents external visual information (e.g., case information) of visual words. To address that question, we functionally localized VWFA at the group level (gVWFA) and at the individual level (iVWFA), and used multivariate pattern analysis (MVPA) to explore the information representation in the VWFA during an implicit reading task (i.e., a passive viewing task). Univariate activation analysis revealed that participants showed stronger activations for uppercase English words compared to lowercase ones in the VWFA. MVPA further revealed that the classifier trained based on lowercase words versus letter strings significantly distinguished uppercase words versus letter strings in the iVWFA, while that trained based on lowercase words versus uppercase words distinguished lowercase letter strings versus uppercase letter strings neither in the gVWFA nor in the iVWFA. These results suggest that the VWFA does not represent case information, but represents case-independent linguistic information. Our findings elaborate the function in the VWFA and support the VWFA hypothesis.

The role of letter features on the consonant-bias effect: Evidence from masked priming

Recent research has shown an advantage of consonants at early stages of visual word recognition (C-bias), although the locus of this effect remains elusive. Here we examine whether the C-bias is affected by the consonant letters' features. Skilled readers performed a masked priming lexical decision task in which target words containing only either consonants without any ascending/descending features (flat words, canino[canine]) or consonants with ascending/descending features (non-flat words, palito[toothpick]) were preceded by briefly (50 ms) presented primes that could preserve the same consonants of the targets (cenune-CANINO, pelute-PALITO), the same vowels of the targets (raxizo-CANINO, fajibo-PALITO), or, as controls, unrelated (ruxuze-CANINO, fejube-PALITO) and identity primes (canino-CANINO, palito-PALITO). The case in which prime-target pairs were presented was also manipulated (lower-upper vs. upper-lower). Results showed that in both case conditions flat words were recognized faster than non-flat words. Evidence for the C-bias was observed both for flat and non-flat words in the lower-upper condition, in which a vowel inhibitory priming effect was also observed for non-flat words. In the upper-lower condition, however, the C-bias was restricted to flat words. These findings suggest that letter features play a role in the C-bias and ask for amendments in current models of visual word recognition.

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.

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.

Advantage of the go/no-go task over the yes/no lexical decision task: ERP indexes of parameters in the diffusion model

Previous research findings supporting the advantages of the go/no-go choice over the yes/no choice in lexical decision task (LDT) have suggested that the go/no-go choice might require less cognitive resources in the non-decisional processes. This study aims to test such an idea using the event-related potential method. In this study, the tasks (yes/no LDT and go/no-go LDT) and word frequency (high and low) were manipulated, and the difference between the go/no-go choice and yes/no choice were examined with BP, pN, pN1, P200, N400, and P3 components that were assumed to be closely related with the various parameters in the diffusion model. The results showed that BP, pN and pN1 amplitudes reflecting the preparation stage were not differently affected by word frequency and the task type. However, ERPs after stimulus onset showed differences. The P200 amplitudes were smaller in the go/no-go task than in the yes/no task only for low-frequency words. N400 and P3 amplitudes were only affected by word frequency. The results suggest that the go/no-go task and the yes/no task differ in sub-lexical processes, which is indicated in the T_encoding parameter in the diffusion model. This study is important as it offers the first electrophysiological evidence supporting the assumption in the diffusion model that explains the advantage of the go/no-go choice over the yes/no choice.

Time course analyses of orthographic and phonological priming effects in developing readers

It has been assumed that fluent reading requires efficient integration of orthographic and phonological codes. However, it is thus far unclear how this integration process develops when children learn to become fluent readers. Therefore, we used masked priming to investigate time courses of orthographic and phonological code activation in children at incremental levels of reading development (second, fourth and sixth grade). The first study used targets with small phonological differences between phonological and orthographic primes, which are typical in transparent orthographies. The second study manipulated the strength of the phonological difference between prime and target to clarify whether phonological difference influences phonological priming effects. Results in both studies showed that orthographic priming effects became facilitative at increasingly short durations during reading development, but phonological priming was absent. These results are taken to suggest that development of reading fluency is accompanied by increased automatization of orthographic representations. The absence of phonological priming suggests that developing readers cannot yet activate phonological codes automatically.

Evidence for cross-script abstract identities in learners of Japanese kana

The presence of abstract letter identity representations in the Roman alphabet has been well documented. These representations are invariant to letter case (upper vs. lower) and visual appearance. For example, "a" and "A" are represented by the same abstract identity. Recent research has begun to consider whether the processing of non-Roman orthographies also involves abstract orthographic representations. In the present study, we sought evidence for abstract identities in Japanese kana, which consist of two scripts, hiragana and katakana. Abstract identities would be invariant to the script used as well as to the degree of visual similarity. We adapted the cross-case masked-priming letter match task used in previous research on Roman letters, by presenting cross-script kana pairs and testing adult beginning -to- intermediate Japanese second-language (L2) learners (first-language English readers). We found robust cross-script priming effects, which were equal in magnitude for visually similar (e.g., り/リ) and dissimilar (e.g., あ/ア) kana pairs. This pattern was found despite participants' imperfect explicit knowledge of the kana names, particularly for katakana. We also replicated prior findings from Roman abstract letter identities in the same participants. Ours is the first study reporting abstract kana identity priming (in adult L2 learners). Furthermore, these representations were acquired relatively early in our adult L2 learners.

Does visual letter similarity modulate masked form priming in young readers of Arabic?

We carried out a masked priming lexical decision experiment to study whether visual letter similarity plays a role during the initial phases of word processing in young readers of Arabic (fifth graders). Arabic is ideally suited to test these effects because most Arabic letters share their basic shape with at least one other letter and differ only in the number/position of diacritical points (e.g., ض - ص ;ظ - ط ;غ - ع ;ث - ت - ن ب ;ذ - د ;خ - ح - ج ;ق - ف ;ش - س ;ز - ر). We created two one-letter-different priming conditions for each target word, in which a letter from the consonantal root was substituted by another letter that did or did not keep the same shape (e.g., خدمة - حدمة vs. خدمة - فدمة). Another goal of the current experiment was to test the presence of masked orthographic priming effects, which are thought to be unreliable in Semitic languages. To that end, we included an unrelated priming condition. We found a sizable masked orthographic priming effect relative to the unrelated condition regardless of visual letter similarity, thereby revealing that young readers are able to quickly process the diacritical points of Arabic letters. Furthermore, the presence of masked orthographic priming effects in Arabic suggests that the word identification stream in Indo-European and Semitic languages is more similar than previously thought.

Orthographic learning, fast and slow: Lexical competition effects reveal the time course of word learning in developing readers

Children learn new words via their everyday reading experience but little is known about how this learning happens. We addressed this by focusing on the conditions needed for new words to become familiar to children, drawing a distinction between lexical configuration (the acquisition of word knowledge) and lexical engagement (the emergence of interactive processes between newly learned words and existing words). In Experiment 1, 9-11-year-olds saw unfamiliar words in one of two storybook conditions, differing in degree of focus on the new words but matched for frequency of exposure. Children showed good learning of the novel words in terms of both configuration (form and meaning) and engagement (lexical competition). A frequency manipulation under incidental learning conditions in Experiment 2 revealed different time-courses of learning: a fast lexical configuration process, indexed by explicit knowledge, and a slower lexicalization process, indexed by lexical competition.

Does Top-Down Feedback Modulate the Encoding of Orthographic Representations During Visual-Word Recognition?

In masked priming lexical decision experiments, there is a matched-case identity advantage for nonwords, but not for words (e.g., ERTAR-ERTAR <  ertar-ERTAR; ALTAR-ALTAR = altar-ALTAR). This dissociation has been interpreted in terms of feedback from higher levels of processing during orthographic encoding. Here, we examined whether a matched-case identity advantage also occurs for words when top-down feedback is minimized. We employed a task that taps prelexical orthographic processes: the masked prime same-different task. For "same" trials, results showed faster response times for targets when preceded by a briefly presented matched-case identity prime than when preceded by a mismatched-case identity prime. Importantly, this advantage was similar in magnitude for nonwords and words. This finding constrains the interplay of bottom-up versus top-down mechanisms in models of visual-word identification.

Are There Lower Repetition Priming Effects in Children with Developmental Dyslexia? Priming Effects in Spanish with the Masked Lexical Decision Task

The aim of this study was to compare the reaction times and errors of Spanish children with developmental dyslexia to the reaction times and errors of readers without dyslexia on a masked lexical decision task with identity or repetition priming. A priming paradigm was used to study the role of the lexical deficit in dyslexic children, manipulating the frequency and length of the words, with a short Stimulus Onset Asynchrony (SOA = 150 ms) and degraded stimuli. The sample consisted of 80 participants from 9 to 14 years old, divided equally into a group with a developmental dyslexia diagnosis and a control group without dyslexia. Results show that identity priming is higher in control children (133 ms) than in dyslexic children (55 ms). Thus, the "frequency" and "word length" variables are not the source or origin of this reduction in identity priming reaction times in children with developmental dyslexia compared to control children.

Lexical enhancement during prime-target integration: ERP evidence from matched-case identity priming

A number of experiments have revealed that matched-case identity PRIME-TARGET pairs are responded to faster than mismatched-case identity prime-TARGET pairs for pseudowords (e.g., JUDPE-JUDPE < judpe-JUDPE), but not for words (JUDGE-JUDGE = judge-JUDGE). These findings suggest that prime-target integration processes are enhanced when the stimuli tap onto lexical representations, overriding physical differences between the stimuli (e.g., case). To track the time course of this phenomenon, we conducted an event-related potential (ERP) masked-priming lexical decision experiment that manipulated matched versus mismatched case identity in words and pseudowords. The behavioral results replicated previous research. The ERP waves revealed that matched-case identity-priming effects were found at a very early time epoch (N/P150 effects) for words and pseudowords. Importantly, around 200 ms after target onset (N250), these differences disappeared for words but not for pseudowords. These findings suggest that different-case word forms (lower- and uppercase) tap into the same abstract representation, leading to prime-target integration very early in processing. In contrast, different-case pseudoword forms are processed as two different representations. This word-pseudoword dissociation has important implications for neural accounts of visual-word recognition.

On the nature of consonant/vowel differences in letter position coding: Evidence from developing and adult readers

In skilled adult readers, transposed-letter effects (jugde-JUDGE) are greater for consonant than for vowel transpositions. These differences are often attributed to phonological rather than orthographic processing. To examine this issue, we employed a scenario in which phonological involvement varies as a function of reading experience: A masked priming lexical decision task with 50-ms primes in adult and developing readers. Indeed, masked phonological priming at this prime duration has been consistently reported in adults, but not in developing readers (Davis, Castles, & Iakovidis, 1998). Thus, if consonant/vowel asymmetries in letter position coding with adults are due to phonological influences, transposed-letter priming should occur for both consonant and vowel transpositions in developing readers. Results with adults (Experiment 1) replicated the usual consonant/vowel asymmetry in transposed-letter priming. In contrast, no signs of an asymmetry were found with developing readers (Experiments 2-3). However, Experiments 1-3 did not directly test the existence of phonological involvement. To study this question, Experiment 4 manipulated the phonological prime-target relationship in developing readers. As expected, we found no signs of masked phonological priming. Thus, the present data favour an interpretation of the consonant/vowel dissociation in letter position coding as due to phonological rather than orthographic processing.

Phonological-Lexical Feedback during Early Abstract Encoding: The Case of Deaf Readers

In the masked priming technique, physical identity between prime and target enjoys an advantage over nominal identity in nonwords (GEDA-GEDA faster than geda-GEDA). However, nominal identity overrides physical identity in words (e.g., REAL-REAL similar to real-REAL). Here we tested whether the lack of an advantage of the physical identity condition for words was due to top-down feedback from phonological-lexical information. We examined this issue with deaf readers, as their phonological representations are not as fully developed as in hearing readers. Results revealed that physical identity enjoyed a processing advantage over nominal identity not only in nonwords but also in words (GEDA-GEDA faster than geda-GEDA; REAL-REAL faster than real-REAL). This suggests the existence of fundamental differences in the early stages of visual word recognition of hearing and deaf readers, possibly related to the amount of feedback from higher levels of information.