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.

Are goats chèvres, chévres, chevres, and chevres? Unveiling the orthographic code of diacritical vowels.

An often overlooked but fundamental issue for any comprehensive model of visual-word recognition is the representation of diacritical vowels: Do diacritical and nondiacritical vowels share their abstract letter representations? Recent research suggests that the answer is "yes" in languages where diacritics indicate suprasegmental information (e.g., lexical stress, as in cámara ['ka.ma.ɾa] camera; Spanish), but "no" in languages where diacritics indicate segmental information such as a different phoneme (e.g., the German vowels ä /ɛ/ and a /a/). Here we examined this issue in French, a language that contains a complex set of diacritical vowels (e.g., for the letter e: é, è, ê, and ë). In Experiment 1, using a semantic categorization task, we compared the word identification times to intact diacritical words (e.g., chèvre, goat in English) with a condition with omitted diacritics (chevre). Results showed that the two conditions behaved similarly. In Experiments 2-4, we compared the intact diacritical words with a condition containing a mismatching diacritic, either existing in French (e.g., chévre, chêvre) or not (the macron sign, as in chevre). We only found a reading cost when replacing the diacritic with an existing one. In Experiments 5-6, we compared the semantic categorization times to intact nondiacritical words (e.g., cheval, horse in English) versus a condition with an added diacritic, either existing (chèval) or not (cheval). We found a reading cost for the words with the added diacritical mark in both cases. We discuss how models of visual-word recognition can be modified to represent diacritical vowels. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

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.

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').

The contribution of semantics to the sentence superiority effect.

When a sequence of written words is presented briefly and participants are asked to report the identity of one of the words, identification accuracy is higher when the words form a correct sentence. Here we examined the extent to which this sentence superiority effect can be modulated by semantic content. The central hypothesis guiding this study is that the sentence superiority effect is primarily a syntactic effect. We therefore predicted little or no modulation of the effect by semantics. The influence of semantic content was measured by comparing the sentence superiority effect obtained with semantically regular sentences (e.g., son amie danse bien [her friend dances well]) and semantically anomalous but syntactically correct sentences (e.g., votre sac boit gros [your bag drinks big]), with effects being measured against ungrammatical scrambled versions of the same words in both cases. We found sentence superiority effects with both types of sentences, and a significant interaction, such that the effects were greater with semantically regular sentences compared with semantically anomalous sentences. We conclude that sentence-level semantic information can constrain word identities under parallel word processing, albeit with less impact than that exerted by syntax.

The sentence superiority effect in young readers.

The sentence superiority effect observed with skilled adult readers has been taken to reflect parallel processing of word identities and the rapid construction of a preliminary syntactic structure. Here we examined if such processing is already present in primary school children in Grade 3 (average age 8.9 years). Children saw sequences of four horizontally aligned words presented simultaneously for 500 ms and followed by a post-mask and post-cue indicating the position for report of one of the four words. Word identification was more accurate in grammatically correct sequences compared with ungrammatical scrambled sequences of the same words, and this sentence superiority effect did not interact with position. This replicates the pattern found in prior research with adults and suggests that parallel word processing and the associated efficiency in syntactic processing arealready in place in Grade 3. We also found that accuracy in identifying words, independently of the surrounding context, correlated with reading age. This points to efficient word-in-sequence identification as one key ingredient of the process of becoming a skilled reader.

Behavioural and ERP Effects of Cognitive and Combined Cognitive and Physical Training on Working Memory and Executive Function in Healthy Older Adults.

Cognitive and physical training have been shown to be effective in improving older adults' cognition. However, it is not yet clear whether combined cognitive and physical training offers an advantage compared to cognitive training alone. Twenty-two older adults performed cognitive or combined cognitive and physical training in order to compare their effects on working memory event-related potentials (ERPs) and on working memory and executive function performance. Before and after eight weeks of training, performance in Plus Minus, Flanker, Updated Span, and Complex Span tasks was measured, and ERPs were registered during performance of an n-back task (0-back, 2-back, and 3-back). Post-training behavioural improvement was observed in Updated Span, Complex Span, and n-back tasks. During the n-back task, the N2/P3 complex was modulated by training, with a decrease in N2 amplitude and an increase in P3 amplitude in the posttraining session compared to the pretraining session. These changes in ERP components suggest that both types of training potentially reduce the need for attentional control to perform the tasks correctly and increase working memory capacity. Thus, based on our data, no conclusion can be reached on the direct advantage of combined training, either at behavioural or at neural level. However, the present study might suggest an indirect advantage of such a combined training, because the cognitive benefit was found to be highly similar in both types of training. Using combined cognitive and physical training may produce a potential improvement in general fitness and an increased appeal of training.

Agreement and illusion of disagreement: An ERP study on Basque.

Agreement is a syntactic relation involving a controller (e.g., a noun) and a target with matching inflectional morphology (e.g., a verb). Across languages, electrophysiological studies consistently report that the presence of a mismatch yields late positive effects (P600), often preceded by early negativities. The current study focuses on person agreement in Basque to investigate whether online processing routines are modulated by the relative semantic prominence of nominal and verbal person features. In an event-related potentials experiment in Basque, we manipulated the semantic markedness of nominal and verbal person features, creating 1st (marked) and 3rd (unmarked) person correct and incorrect sentences [Japoniarrok1pleuskara ikasi dugu1pl/*dute3plgustora (We Japanese have1pl/*3pl learn Basque with pleasure); Japoniarrek3pleuskara ikasi dute3pl/*dugu1pl gustora (The Japanese have3pl/*1pl learnt Basque with pleasure)]. Both mismatches elicited an N400 effect, but only marked 1st person mismatches (Japoniarrok1pl … *dute3.pl) generated a P600, suggesting that (i) mismatches with unmarked 3rd person subjects (Japoniarrek3.pl… *dugu1.pl) are not treated as outright violations; (ii) the emergence of late positive effects is sensitive to fine-grained discourse information. Overall, these results call for a revision in the analysis of agreement relations from a theoretical and a processing perspective.

On the locus of talker-specificity effects in spoken word recognition: an ERP study with dichotic priming.

We used event-related potentials to examine the precise moment at which talker-specific information comes into play during spoken word recognition. Dichotic repetition priming was examined with primes presented in the left unattended ear and targets presented in the right attended ear, and we manipulated both word frequency and talker identity. A clear repetition priming effect was observed in an early time-window spanning 100-200 ms post-target onset, and the effect continued after target word offset in a time-window between 650 and 800 ms. Crucially, we observed that talker change caused a diminution in repetition priming only in the N400 time-window, and only for low frequency words but not for high frequency words. Together, our findings suggest that spoken word recognition relies primarily on abstract representations, and that talker-specific information mainly affects later stages of this process, namely lexical selection.

Consonantal overlap effects in a perceptual matching task.

This study investigates the processing of letter position coding by exploring whether or not two explicitly presented words that share the same consonants, but that differ in their vowels, exert mutual interference more than two words that do not share their consonants. In an explicit perceptual matching task, word targets were preceded by a word reference that could share all the consonants either at the same position or in a different absolute position (while keeping their relative position intact) or preceded by an unrelated reference. Experiment 1 showed larger discrimination costs for pairs sharing the consonants at the same position than for pairs sharing their consonants in a different position. Experiment 2 investigated when and how the types of overlap influence word target processing by using event-related potential recordings. The ERP results showed a Relatedness effect only for targets that share the consonants at the same position from 120 to 600 ms post-target onset, whereas targets that share their consonants in different positions in the string produced null effects. Altogether, these data suggest that targets containing the same consonants included in the references in the same positions are processed as being highly similar to them, thus distorting target processing. Furthermore, these data suggest possible mechanisms of competition between lexical representations of the reference and target stimuli.

Lexical inhibition of neighbors during visual word recognition: an unmasked priming investigation.

Two experiments investigated the lexical inhibitory effect of orthographic neighbors relative to identity priming effects in an unmasked priming paradigm combined with a lexical decision task on word targets. Targets were preceded either by the same word, by a lower frequency orthographic word neighbor, by an orthographic pseudoword neighbor or by an unrelated prime. Experiment 1 showed a standard facilitatory effect from identity primes, whereas inhibitory priming effects were observed for both types of neighbor primes. Experiment 2 examined the time-course of these effects by using event-related potential recordings. A generalized relatedness effect was found in the 200-400 ms time-window, with smaller negativities generated by related primes than unrelated primes regardless of prime type. In contrast, at 400 ms, while identity primes were associated with smaller negativities than unrelated primes, word neighbor primes were associated with greater negativities than unrelated primes. Additionally, pseudoword neighbor primes produce null effects as compared to unrelated primes. These results are discussed in terms of competition between activated lexical representations and revealed that such a mechanism is modulated by the lexical status of the prime.

Evidence for letter-specific position coding mechanisms.

The perceptual matching (same-different judgment) paradigm was used to investigate precision in position coding for strings of letters, digits, and symbols. Reference and target stimuli were 6 characters long and could be identical or differ either by transposing two characters or substituting two characters. The distance separating the two characters was manipulated such that they could either be contiguous, separated by one intervening character, or separated by two intervening characters. Effects of type of character and distance were measured in terms of the difference between the transposition and substitution conditions (transposition cost). Error rates revealed that transposition costs were greater for letters than for digits, which in turn were greater than for symbols. Furthermore, letter stimuli showed a gradual decrease in transposition cost as the distance between the letters increased, whereas the only significant difference for digit and symbol stimuli arose between contiguous and non-contiguous changes, with no effect of distance on the non-contiguous changes. The results are taken as further evidence for letter-specific position coding mechanisms.

Masked repetition priming of letter-in-string identification: an ERP investigation.

In a post-cued letter identification task, participants were presented with 7-letter nonword target stimuli that were formed of a random string of consonants (DCMFPLR) or a pronounceable sequence of consonants and vowels (DAMOPUR). Targets were preceded by briefly presented pattern-masked primes that could be the same sequence of letters as the target, composed of seven different letters, or sharing either the first or last five letters of the target. There was some evidence for repetition priming effects that were independent of target type in an early component, the N/P150, thought to reflect the mapping of visual features onto letter representations, and that is insensitive to orthographic structure. Following this, pronounceable nonwords showed significantly greater repetition priming effects than consonant strings, in line with the behavioral results. Initial versus final overlap only started to influence target processing at around 200-250ms post-target onset, at about the same time as the effects of target type emerged. The results are in line with a model where the initial parallel mapping of visual features onto a location-specific orthographic code is followed by the subsequent activation of location-invariant orthographic and phonological codes.

When less is more: feedback, priming, and the pseudoword superiority effect.

The present study combined masked priming with electrophysiological recordings to investigate orthographic priming effects with nonword targets. Targets were pronounceable nonwords (e.g., STRENG) or consonant strings (e.g., STRBNG), that both differed from a real word by a single letter substitution (STRONG). Targets were preceded by related primes that could be the same as the target (e.g., streng-STRENG, strbng-STRBNG) or the real word neighbor of the target (e.g., strong-STRENG, strong-STRBNG). Independently of priming, pronounceable nonwords were associated with larger negativities than consonant strings, starting at 290ms post-target onset. Overall, priming effects were stronger and longer-lasting with pronounceable nonwords than consonant strings. However, consonant string targets showed an early effect of word neighbor priming in the absence of an effect of repetition priming, whereas pronounceable nonwords showed both repetition and word neighbor priming effects in the same time window. This pattern of priming effects is taken as evidence for feedback from whole-word orthographic representations activated by the prime stimulus that influences bottom-up processing of prelexical representations during target processing.

Masked priming from orthographic neighbors: an ERP investigation.

Two experiments combined masked priming with event-related potential (ERP) recordings to examine effects of primes that are orthographic neighbors of target words. Experiment 1 compared effects of repetition primes with effects of primes that were high-frequency orthographic neighbors of low-frequency targets (e.g., faute-faune [error-wildlife]), and Experiment 2 compared the same word neighbor primes with nonword neighbor primes (e.g., aujel-autel [altar]). Word neighbor primes showed the standard inhibitory priming effect in lexical decision latencies that sharply contrasted with the facilitatory effects of nonword neighbor primes. This contrast was most evident in the ERP signal starting at around 300 ms posttarget onset and continuing through the bulk of the N400 component. In this time window, repetition primes and nonword neighbor primes generated more positive-going waveforms than unrelated primes, whereas word neighbor primes produced null effects. The results are discussed with respect to possible mechanisms of lexical competition during visual word recognition.

Testing computational models of letter perception with item-level event-related potentials.

In the present study, online measures of letter identification were used to test computational models of letter perception. Event-related potentials (ERPs) were recorded to letters and pseudoletters revealing a transition from feature analysis to letter identification in the 100-200-ms time window. Measures indexing this transition were then computed at the level of individual letters. Simulations with several versions of an interactive-activation model of letter perception were fitted with these item-level ERP measures. The results are in favour of a model of letter perception with feedforward excitatory connections from the feature to the letter levels, lateral inhibition at the letter level, and excitatory feedback from the letter to the feature levels.