Chotiga Pattamadilok

The locus of the orthographic consistency effect in auditory word recognition

In Experiments 1–2, we replicated with two different Portuguese materials the consistency effect observed for French by Ziegler and Ferrand (1998). Words with rimes that can be spelled in two different ways (inconsistent) produced longer auditory lexical decision latencies and more errors than did consistent words. In Experiment 3, which used shadowing, no effect of orthographic consistency was found. This task difference could reflect the confinement of orthographic influences to either decisional or lexical processes. In Experiment 4, we tried to untangle these two interpretations by comparing two situations in which a shadowing response was made contingent upon either a lexical or a phonemic criterion. A significant effect of orthographic consistency was observed only in lexically contingent shadowing. We thus argue that lexical but not sublexical processes are affected by orthographic consistency.

Consistency and variability in functional localisers

A critical assumption underlying the use of functional localiser scans is that the voxels identified as the functional region-of-interest (fROI) are essentially the same as those activated by the main experimental manipulation. Intra-subject variability in the location of the fROI violates this assumption, reducing the sensitivity of the analysis and biasing the results. Here we investigated consistency and variability in fROIs in a set of 45 volunteers. They performed two functional localiser scans to identify word- and object-sensitive regions of ventral and lateral occipito-temporal cortex, respectively. In the main analyses, fROIs were defined as the category-selective voxels in each region and consistency was measured as the spatial overlap between scans. Consistency was greatest when minimally selective thresholds were used to define “active” voxels (p < 0.05 uncorrected), revealing that approximately 65% of the voxels were commonly activated by both scans. In contrast, highly selective thresholds (p < 10− 4 to 10− 6) yielded the lowest consistency values with less than 25% overlap of the voxels active in both scans. In other words, intra-subject variability was surprisingly high, with between one third and three quarters of the voxels in a given fROI not corresponding to those activated in the main task. This level of variability stands in striking contrast to the consistency seen in retinotopically-defined areas and has important implications for designing robust but efficient functional localiser scans.

Orthographic effects in spoken language: On-line activation or phonological restructuring?

Previous research has shown that literacy (i.e., learning to read and spell) affects spoken language processing. However, there is an on-going debate about the nature of this influence. Some argued that orthography is co-activated on-line whenever we hear a spoken word. Others suggested that orthography is not activated on-line but has changed the nature of the phonological representations. Finally, both effects might occur simultaneously, that is, orthography might be activated on-line in addition to having changed the nature of the phonological representations. Previous studies have not been able to tease apart these hypotheses. The present study started by replicating the finding of an orthographic consistency effect in spoken word recognition using event-related brain potentials (ERPs): words with multiple spellings (i.e., inconsistent words) differed from words with unique spellings (i.e., consistent words) as early as 330 ms after the onset of the target. We then employed standardized low resolution electromagnetic tomography (sLORETA) to determine the possible underlying cortical generators of this effect. The results showed that the orthographic consistency effect was clearly localized in a classic phonological area (left BA40). No evidence was found for activation in the posterior cortical areas coding orthographic information, such as the visual word form area in the left fusiform gyrus (BA37). This finding is consistent with the restructuring hypothesis according to which phonological representations are contaminated by orthographic knowledge.

How does learning to read affect speech perception

Behavioral studies have demonstrated that learning to read and write affects the processing of spoken language. The present study investigates the neural mechanism underlying the emergence of such orthographic effects during speech processing. Transcranial magnetic stimulation (TMS) was used to tease apart two competing hypotheses that consider this orthographic influence to be either a consequence of a change in the nature of the phonological representations during literacy acquisition or a consequence of online coactivation of the orthographic and phonological representations during speech processing. Participants performed an auditory lexical decision task in which the orthographic consistency of spoken words was manipulated and repetitive TMS was used to interfere with either phonological or orthographic processing by stimulating left supramarginal gyrus (SMG) or left ventral occipitotemporal cortex (vOTC), respectively. The advantage for consistently spelled words was removed only when the stimulation was delivered to SMG and not to vOTC, providing strong evidence that this effect arises at a phonological, rather than an orthographic, level. We propose a possible mechanistic explanation for the role of SMG in phonological processing and how this is affected by learning to read.

The locus of the orthographic consistency effect in auditory word recognition: Further evidence from French

Ventura, Morais, Pattamadilok, and Kolinsky (2004) found, for spoken Portuguese words, an orthographic consistency effect in lexical decision but not in standard shadowing (on-line repetition): words ending with phonological rimes that have several spellings led to longer decision times than words ending with phonological rimes that have only one spelling. This pattern of results was replicated in this study, using French, a language presenting a much higher degree of orthographic inconsistency than Portuguese. The observation of systematic associations between the effects of word orthographic consistency, word frequency and lexicality supports the hypothesis that lexical processing is critical to the occurrence of the consistency effect. Finally, the comparison of the word consistency effects obtained in French and in Portuguese suggests that their size depends on the overall consistency of the languages orthographic code.

Schooling in western culture promotes context-free processing

Culture has been shown to influence the way people apprehend their physical environment. Cognitive orientation is more holistic in East Asian cultures, which emphasize relationships and connectedness among objects in the field, than in Western cultures, which are more prone to focus exclusively on the object and its attributes. We investigated whether, beyond, or in conjunction with culture, literacy and/or schooling may also have an influence on this cognitive orientation. Using the Framed-Line Test both in Portugal and in Thailand, we compared literate schooled adults with two groups of unschooled adults: one of illiterates and one of ex-illiterates. As in former studies on Western people, Portuguese-schooled literates were more accurate in the absolute task than in the relative task. In contrast, Portuguese illiterates and ex-illiterates were more accurate in the relative task than in the absolute task. Such an effect of schooling was not observed in the Thai groups, all of whom performed better on the relative task. Thus, the capacity to abstract from contextual information does not stem only from passive exposure to the culture or the physical environment of Western countries. Western schooling, as part of or in addition to culture, is a crucial factor.

Beyond rhyme or reason: ERPs reveal task-specific activation of orthography on spoken language

Metaphonological tasks, such as rhyme judgment, have been the primary tool for the investigation of the effects of orthographic knowledge on spoken language. However, it has been recently argued that the orthography effect in rhyme judgment does not reflect the automatic activation of orthographic codes but rather stems from sophisticated response strategies. Such a claim stands in sharp contrast with recent findings using event-related brain potentials (ERPs) in lexical and semantic tasks, which were taken to suggest that orthographic information occurs early enough to affect the core process of lexical access. Here, we show that the electrophysiological signature of the orthography effect in rhyme judgment is indeed different from the one obtained in online lexical or semantic tasks. That is, we did not find the orthography effect in the 300-350 ms time window which has previously been shown to process lexical information in the lexico-semantic tasks, but the effect appeared within the 175-250 ms and the 375-750 ms time-windows which we interpreted to reflect segmentation and decisional process, respectively. We conclude that the interactions between phonology and orthography are task-specific. Metaphonological tasks appear of limited use for studying the core processes and interactions that underlie lexical access.

The developmental turnpoint of orthographic consistency effects in speech recognition.

The influence of orthography on childrens online auditory word recognition was studied from the end of Grade 4 to the end of Grade 9 by examining the orthographic consistency effect in auditory lexical decision. Fourth-graders showed evidence of a widespread influence of orthography in their spoken word recognition system; words with rimes that can be spelled in two different ways (inconsistent) produced longer auditory lexical decision times and more errors than did consistent words. A similar consistency effect was also observed on pseudowords. With adult listeners, on exactly the same material, we replicated the usual pattern of an orthographic consistency effect restricted to words in lexical decision. From Grade 6 onward, this adult pattern of orthographic effect on spoken recognition is already observable.

The Orthographic Consistency Effect in the Recognition of French Spoken Words: An Early Developmental Shift from Sublexical to Lexical Orthographic Activation.

The generality of the orthographic consistency effect in speech recognition tasks previously reported for Portuguese beginning readers was assessed in French-speaking children, as the French orthographic code presents a higher degree of inconsistency than the Portuguese one. Although the findings obtained with the French second graders replicated the generalized consistency effect (both for words and pseudowords, in both lexical decision and shadowing) displayed by the Portuguese second to fourth graders, the data obtained with the French third and fourth graders resembled the adult pattern, with the orthographic effect restricted to lexical decision. This suggests that, in the course of literacy acquisition, the overall orthographic inconsistency of the languages orthographic code influences the rate at which orthographic representations will impact on spoken word recognition.

Orthographic representations in spoken word priming: no early automatic activation.

The current study investigated the modulation by orthographic knowledge of the final overlap phonological priming effect, contrasting spoken prime-target pairs with congruent spellings (e.g., `carreau-bourreau, /karo/-/buro/) to pairs with incongruent spellings (e.g., `zéro-bourreau, /zero/-/buro/). Using materials and designs aimed at reducing the impact of response biases or strategies, no orthographic congruency effect was found in shadowing, a speech recognition task that can be performed prelexically. In lexical decision, an orthographic effect occurred only when the processing environment reduced the prominence of phonological overlap and thus induced participants to rely on word spelling. Overall, the data do not support the assumption of early, automatic activation of orthographic representations during spoken word recognition.