Substituted-letter and transposed-letter effects in a masked priming paradigm with French developing readers and dyslexics

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.

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.

Flexible letter-position coding in Chinese-English L2 bilinguals: Evidence from eye movements

Theories suggest that efficient recognition of English words depends on flexible letter-position coding, demonstrated by the fact that transposed-letter primes (e.g., JUGDE-judge) facilitate written word recognition more than substituted-letter primes (e.g., JUFBE-judge). The multiple route model predicts that reading experience should drive more flexible letter-position coding as readers transition from decoding words letter-by-letter to recognising words as wholes. This study therefore examined whether letter-position is coded flexibly in second-language English sentence reading for native Chinese speakers, and if this is influenced by English proficiency. Eye movements were measured while 54 adult native Chinese speakers read English sentences including either a real word (e.g., cheaply), a transposed-letter nonword (e.g., "chepaly"), or a substituted-letter nonword (e.g., "chegely"). Flexible letter-position coding was observed in initial and later processing stages-reading times were longer for substituted-letter than transposed-letter nonwords. In addition, reading times were longer in both initial and later processing stages for transposed-letter nonwords than real words, indicating that, despite encoding letter-position flexibly, readers processed letter-position. Although pre-registered frequentist analyses suggested that English proficiency did not predict overall reading times, Bayes Factors indicated that there was evidence for such a relationship. It is therefore likely that this proficiency analysis suffered from low power. Finally, neither frequentist nor Bayes Factor analyses suggested that English proficiency influenced the difference in reading times between different target word types, i.e., the nature of letter-position coding. Overall, these results suggest that highly proficient L2 learners code letter-position flexibly.

Dyslexics Exhibit an Orthographic, Not a Phonological Deficit in Lexical Decision

Dyslexia is theorized to be caused by phonological deficits, visuo-attentional deficits, or some combination of the two. The present study contrasted phonological and visuo-attentional theories of dyslexia using a lexical decision task administered to adult participants with and without dyslexia. Homophone and pseudo-homophone stimuli were included to explore whether the two groups differed in their reliance on phonological encoding. Transposed-letter stimuli, including both TL neighbors and TL non-words, measured potential orthographic impairment predicted by visuo-attentional deficit theories. The findings revealed no significant difference in response time or accuracy between the groups for the homophone and pseudo-homophone stimuli. However, dyslexics were significantly slower and less accurate in their responses to the TL stimuli than controls. Thus, dyslexics presented deficits consistent with visuo-attentional theories, but not with the phonological deficit theory.

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.

A developmental perspective on morphological processing in the flankers task

Recent research with adult participants using the flankers task has shown that the recognition of central target words is facilitated by the presence of morphologically related flanker words. Here we explored the development of such morphological flanker effects in two groups of primary school children (average ages = 8 years 6 months and 10 years 3 months) and a group of adult participants. We examined effects of a transparent morphological relation in two conditions: one where the target was the stem and flankers were derivations (e.g., farmer farm farmer) and the other where the flankers were stems and the target was the derived form (e.g., farm farmer farm). Morphological flanker effects were compared with repetition flanker effects with the same set of stimuli (e.g., farm farm farm; farmer farmer farmer), and effects of related flankers were contrasted with the appropriate unrelated flankers. Results revealed no significant effect of morphological relatedness in the two groups of children and a significant effect in the adult group, but only for suffixed targets and stem flankers. Repetition effects for stem targets were found across all groups, whereas repetition effects for suffixed targets were found only in the older children and adults. These results show that morphological processing, in a context involving multiple words presented simultaneously, takes several years to develop and that morphological complexity (stem vs. derived) is a limiting factor for repetition effects in the flankers task with young children.

Language Dominance Modulates Transposed-Letter N400 Priming Effects in Bilinguals

Models of visual word recognition differ as to how print exposure modulates orthographic precision. In some models, precision is the optimal end state of a lexical representation; the associations between letters and positions are initially approximate and become more precise as readers gain exposure to the word. In others, flexible orthographic coding that allows for rapid access to semantics (i.e., ‘good enough’ orthographic processing) is the optimal end state. To adjudicate between these trajectories, we compared the size of transposed-letter ERP priming effects on two ERP components thought to reflect orthographic and lexico-semantic processing across languages in late English-Spanish bilinguals. Words that are represented precisely should be less susceptible to activation by transposed-letter primes (e.g., shpae-SHAPE) than words that are not, and should therefore yield smaller priming effects. Overall, targets elicited smaller N250s and N400s and faster responses when preceded by transposed-letter primes compared to substitution primes (e.g., shgue-SHAPE). The only effect that significantly differed between languages was N400 priming, which was larger in English, the dominant language. We suggest that these results favor models of learning to read according to which ‘good enough’ orthographic processing increases with print exposure.

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.

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.

Stroop interference is a composite phenomenon: Evidence from distinct developmental trajectories of its components

Only one previous developmental study of Stroop task performance (Schiller, 1966) has controlled for differences in processing speed that exist both within and between age groups. Therefore, the question of whether the early developmental change in the magnitude of Stroop interference actually persists after controlling for processing speed needs further investigation; work that is further motivated by the possibility that any remaining differences would be caused by process(es) other than processing speed. Analysis of data from two experiments revealed that, even after controlling for processing speed using z-transformed reaction times, early developmental change persists such that the magnitude of overall Stroop interference is larger in 3rd- and 5th graders as compared to 1st graders. This pattern indicates that the magnitude of overall Stroop interference peaks after 2 or 3 years of reading practice (Schadler & Thissen, 1981). Furthermore, this peak is shown to be due to distinct components of Stroop interference (resulting from specific conflicts) progressively falling into place. Experiment 2 revealed that the change in the magnitude of Stroop interference specifically results from joint contributions of task, semantic and response conflicts in 3rd- and 5th graders as compared to a sole contribution of task conflict in 1st graders. The specific developmental trajectories of different conflicts presented in the present work provide unique evidence for multiple loci of Stroop interference in the processing stream (respectively task, semantic and response conflict) as opposed to a single (i.e. response) locus predicted by historically - favored response competition accounts.

The developmental trend of transposed letters effects in masked priming

In the current study, we investigated the development of transposed letter (TL) priming effects with masked priming. Recent studies have reported different and contrasting results concerning the age at which TL priming effects first appear and whether they tend to decline or increase with age. One of the aims of this study was to investigate the developmental trend of orthographic mechanisms underlying the TL effects in Italian. We tested three groups of children (second, third, and fifth graders) and a group of adults with a sandwich masked priming procedure, presenting lists of target words preceded by TL or replaced letter (RL) primes. TLs and RLs were either at the beginning (second-third letters) or the end (fourth-sixth letters) of primes in order to see whether the TL priming effect varied according to position in the letter string. We found that TL priming effects increased with age in both accuracy and latency. No effect of position was found. The results are discussed in light of a possible difference in the development of orthographic mechanisms depending on the transparency of the language.

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.

Development of children's identity and position processing for letter, digit, and symbol strings: A cross-sectional study of the primary school years

Letter recognition and digit recognition are critical skills for literate adults, yet few studies have considered the development of these skills in children. We conducted a nine-alternative forced-choice (9AFC) partial report task with strings of letters and digits, with typographical symbols (e.g., $, @) as a control, to investigate the development of identity and position processing in children. This task allows for the delineation of identity processing (as overall accuracy) and position coding (as the proportion of position errors). Our participants were students in Grade 1 to Grade 6, allowing us to track the development of these abilities across the primary school years. Our data suggest that although digit processing and letter processing end up with many similarities in adult readers, the developmental trajectories for identity and position processing for the two character types differ. Symbol processing showed little developmental change in terms of identity or position accuracy. We discuss the implications of our results for theories of identity and position coding: modified receptive field, multiple-route model, and lexical tuning. Despite moderate success for some theories, considerable theoretical work is required to explain the developmental trajectories of letter processing and digit processing, which might not be as closely tied in child readers as they are in adult readers.

Serial mechanism in transposed letters effects: A developmental study

The study describes the developmental trend of transposed letters (TL) effects in a lexical decision task. The TL effect refers to the fact that nonwords derived from words by transposing two middle letters (e.g., talbe from table) are responded to more slowly than control nonwords in which two letters are replaced (RL [replaced letters]; e.g., tafde). We measured this effect in three groups of children (second, third, and fifth graders) and a group of adults. Length was manipulated with short letter strings (four or five letters) and long letter strings (seven or eight letters). In long letter strings, position of letter transposition/replacement was also manipulated; half of the stimuli contained the TL/RL toward the beginning of the string and half toward the end of the string. The results showed that the size of the TL effect increased with age and that this developmental pattern was more marked for transpositions involving the final part of the word. The results suggest that with the increase in reading ability, the reading system relies more strongly on a coarse orthographic representation in which letter position is not precisely coded. Furthermore, the effect of position suggests that a serial mechanism is used to scan the letter string. This determines the extent to which nonwords activate the base words, modulating the influence of lexical effects in nonword decisions. The nature of this effect is discussed.

Individual differences in orthographic priming relate to phonological decoding skill in adults

We examined relationships between individual differences in orthographic priming and a battery of measures assessing orthographic processing ability, reading history, current reading ability, and verbal intelligence in university students. Pronounceable and unpronounceable nonword primes preceded word and nonword targets. Individual differences in nonword reading skill and other measures of reading and spelling ability were associated with the degree of orthographic priming. Individuals with less phonological decoding skill benefited more from anagram primes for word targets preceded by unpronounceable primes and nonword targets preceded by pronounceable primes. Analyses of extreme groups revealed that the group with the lowest phonemic decoding efficiency scores showed a general benefit of orthographic relatedness, while the group with the highest phonemic decoding efficiency scores showed a benefit only under certain conditions. Thus, individuals with worse nonword reading skills may have less precise orthographic representations and therefore benefit more from overlapping coarse-grained orthographic information, regardless of the pronounceability of the prime or the lexical status of the target. These findings demonstrate that university students vary in their orthographic processing skill and the degree to which orthographic information is used during word recognition.

Relationships of French and English Morphophonemic Orthographies to Word Reading, Spelling, and Reading Comprehension during Early and Middle Childhood

Two longitudinal studies of word reading, spelling, and reading comprehension identified commonalities and differences in morphophonemic orthographies-French (Study 1, n=1313) or English (Study 2, n=114) in early childhood (grade 2) and middle childhood (grade 5). For French and English, statistically significant concurrent relationships among these literacy skills occurred in grades 2 and 5, and longitudinal relationships for each skill with itself from grade 2 to 5; but concurrent relationships were more sizable and longitudinal relationships more variable for English than French especially for word reading to reading comprehension. Results show that, for both morphophonemic orthographies, assessment and instructional practices should be tailored to early or middle childhood, and early childhood reading comprehension may not be related to middle childhood spelling. Also discussed are findings applying only to English, for which word origin is primarily Anglo-Saxon in early childhood, but increasingly French in middle childhood.

Automatic phonological activation during visual word recognition in bilingual children: A cross-language masked priming study in grades 3 and 5

Previous masked priming research has shown automatic phonological activation during visual word recognition in monolingual skilled adult readers. Activation also occurs across languages in bilingual adult readers, suggesting that the activation of phonological representations is not language specific. Less is known about developing readers. First, it is unclear whether there is automatic phonological activation during visual word recognition among children in general. Second, no empirical data exist on whether the activation of phonological representations is language specific or not in bilingual children. The current study investigated these issues in bilingual third and fifth graders using cross-language phonological masked priming in a lexical decision task. Targets were French words, and primes were English pseudowords of three types: (a) phonological primes, which share phonological information with the target beginning (e.g., dee-DIMANCHE [Sunday], pronounced /di:/-/dimãʃ/); (b) orthographic control primes, which control for letters shared by the phonological prime and target (e.g., d) and their position (e.g., doo-DIMANCHE, pronounced /du:/-/dimãʃ/); and (c) unrelated primes, which share no phonological or orthographic information with the target beginning (e.g., pow-DIMANCHE, pronounced /paʊ/-/dimãʃ/). Significant phonological priming was observed, suggesting that (a) phonological representations are rapidly and automatically activated by print during visual word recognition from Grade 3 onward and that (b) the activation of phonological representations is not language specific in bilingual children.

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.

Tracking the emergence of the consonant bias in visual-word recognition: evidence with developing readers

Recent research with skilled adult readers has consistently revealed an advantage of consonants over vowels in visual-word recognition (i.e., the so-called "consonant bias"). Nevertheless, little is known about how early in development the consonant bias emerges. This work aims to address this issue by studying the relative contribution of consonants and vowels at the early stages of visual-word recognition in developing readers (2(nd) and 4(th) Grade children) and skilled adult readers (college students) using a masked priming lexical decision task. Target words starting either with a consonant or a vowel were preceded by a briefly presented masked prime (50 ms) that could be the same as the target (e.g., pirata-PIRATA [pirate-PIRATE]), a consonant-preserving prime (e.g., pureto-PIRATA), a vowel-preserving prime (e.g., gicala-PIRATA), or an unrelated prime (e.g., bocelo -PIRATA). Results revealed significant priming effects for the identity and consonant-preserving conditions in adult readers and 4(th) Grade children, whereas 2(nd) graders only showed priming for the identity condition. In adult readers, the advantage of consonants was observed both for words starting with a consonant or a vowel, while in 4(th) graders this advantage was restricted to words with an initial consonant. Thus, the present findings suggest that a Consonant/Vowel skeleton should be included in future (developmental) models of visual-word recognition and reading.

Visual and linguistic determinants of the eyes' initial fixation position in reading development

Two eye-movement experiments with one hundred and seven first- through fifth-grade children were conducted to examine the effects of visuomotor and linguistic factors on the recognition of words and pseudowords presented in central vision (using a variable-viewing-position technique) and in parafoveal vision (shifted to the left or right of a central fixation point). For all groups of children, we found a strong effect of stimulus location, in both central and parafoveal vision. This effect corresponds to the children's apparent tendency, for peripherally located targets, to reach a position located halfway between the middle and the left edge of the stimulus (preferred viewing location, PVL), whether saccading to the right or left. For centrally presented targets, refixation probability and lexical-decision time were the lowest near the word's center, suggesting an optimal viewing position (OVP). The viewing-position effects found here were modulated (1) by print exposure, both in central and parafoveal vision; and (2) by the intrinsic qualities of the stimulus (lexicality and word frequency) for targets in central vision but not for parafoveally presented targets.