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  • Electrophysiological evidence for colour effects on the naming of colour diagnostic and noncolour diagnostic objects
    Publication . Bramão, Inês; Francisco, Ana; Inácio, Filomena; Faísca, Luís; Reis, Alexandra; Petersson, Karl Magnus
    In this study, we investigated the level of visual processing at which surface colour information improves the naming of colour diagnostic and noncolour diagnostic objects. Continuous electroencephalograms were recorded while participants performed a visual object naming task in which coloured and black-and-white versions of both types of objects were presented. The black-and-white and the colour presentations were compared in two groups of event-related potentials (ERPs): (1) The P1 and N1 components, indexing early visual processing; and (2) the N300 and N400 components, which index late visual processing. A colour effect was observed in the P1 and N1 components, for both colour and noncolour diagnostic objects. In addition, for colour diagnostic objects, a colour effect was observed in the N400 component. These results suggest that colour information is important for the naming of colour and noncolour diagnostic objects at different levels of visual processing. It thus appears that the visual system uses colour information, during naming of both object types, at early visual stages; however, for the colour diagnostic objects naming, colour information is also recruited during the late visual processing stages.
  • Component processes subserving rapid automatized naming in dyslexic and non-dyslexic readers
    Publication . Araújo, Susana; Inácio, Filomena; Francisco, Ana; Faísca, Luís; Petersson, Karl Magnus; Reis, Alexandra
    The current study investigated which time components of rapid automatized naming (RAN) predict group differences between dyslexic and non-dyslexic readers (matched for age and reading level), and how these components relate to different reading measures. Subjects performed two RAN tasks (letters and objects), and data were analyzed through a response time analysis. Our results demonstrated that impaired RAN performance in dyslexic readers mainly stem from enhanced inter-item pause times and not from difficulties at the level of post-access motor production (expressed as articulation rates). Moreover, inter-item pause times account for a significant proportion of variance in reading ability in addition to the effect of phonological awareness in the dyslexic group. This suggests that non-phonological factors may lie at the root of the association between RAN inter-item pauses and reading ability. In normal readers, RAN performance was associated with reading ability only at early ages (i.e. in the reading-matched controls), and again it was the RAN inter-item pause times that explain the association.
  • A influência das competências de leitura nas estratégias de dupla codificação
    Publication . Inácio, Filomena; Bramão, Inês; Faísca, Luís; Reis, Alexandra
    Recentemente, alguns autores demonstraram que o desempenho em provas de memória não verbal pode envolver o recurso simultâneo a estratégias verbais e visuo-espaciais para codificar a informação. A leitura tem sido apontada como um factor que pode contribuir para o desenvolvimento destas estratégias de dupla codificação. Neste estudo, fomos investigar se a capacidade de leitura interfere de algum modo na utilização de mecanismos de dupla codificação. Comparámos o desempenho de dois grupos de crianças com diferentes competências de leitura, mas equivalentes na idade e em anos de escolaridade, numa prova de memória não verbal. Foram definidas três condições experimentais, manipulando o grau em que os itens a memorizar eram verbalizáveis. Os resultados mostraram que o grupo com melhores competências de leitura apresenta um desempenho superior na condição pictórica mais difícil de verbalizar quando comparado com o grupo com piores competências de leitura. Estes resultados são discutidos à luz do contributo das competências de leitura na facilitação em utilizar estratégias de dupla codificação para codificar a informação visuo-espacial em memória de trabalho.
  • Implicit learning mechanisms and their application to dyslexia
    Publication . Inácio, Filomena; Petersson, Karl Magnus; Faísca, Luís
    mechanisms and their association with reading and writing processes, both in typical readers and in readers with dyslexia. In the first study, we explored whether the outcomes of implicit structural sequence learning could be captured in eye movement responses. We tested for sensitivity effects (increased eye movements on a printed violation in an implicit artificial grammar learning task) in two experiments that manipulated the presence of a concurrent behavioural classification test. Results show different eye movement patterns when participants discriminate grammatical and non-grammatical sequences in passive viewing of sequences and that this effect is boosted when participants perform a concomitant classification task. This study shows that implicit acquired knowledge can be detected through the analysis of eye-movement patterns, enabling the study of implicit learning without explicit processing interference. In study two, we investigated the influence of implicit learning in the literacy skills of adult typical readers. Three main results prompt us to conclude that implicit learning contributes to reading and writing proficiency: 1) in implicit orthographic knowledge tasks where the frequency of orthographic patterns is manipulated, participants tend to choose the most frequent pattern; 2) reading proficiency and the implicit orthographic knowledge decision task were related to an implicit learning task; and 3) implicit learning increases the impact of exposure to print on reading fluency. Altogether, these results suggest a role of implicit learning capacity in the extraction the written language regularities and in the improvement of literacy skills. In study three, we tested whether dyslexic children present an implicit learning deficit that could contribute to their reading disability. An implicit artificial grammar learning task designed to optimize exposure to regularities was presented to dyslexic children and to two control groups matched by age and reading level. Results showed that dyslexics’ implicit learning abilities are at same level as both control groups, suggesting that the characteristic reading difficulties presented by dyslexics cannot be explained by implicit learning deficits. In conclusion, the studies presented in this thesis provide evidence that: 1) implicit learning can be tested with minimal interference of explicit processes by measuring eye movement sensitivity patterns; 2) implicit learning intervenes in the extraction of written regularities, contributing to literacy proficiency; and 3) dyslexic children do not present an implicit learning deficit and thus can benefit from this preserved ability to improve their reading skills.
  • Implicit sequence learning is preserved in dyslexic children
    Publication . Inácio, Filomena; Faísca, Luís; Forkstam, Christian; Araújo, Susana; Bramão, Inês; Reis, Alexandra; Petersson, Karl Magnus
    This study investigates the implicit sequence learning abilities of dyslexic children using an artificial grammar learning task with an extended exposure period. Twenty children with developmental dyslexia participated in the study and were matched with two control groups-one matched for age and other for reading skills. During 3 days, all participants performed an acquisition task, where they were exposed to colored geometrical forms sequences with an underlying grammatical structure. On the last day, after the acquisition task, participants were tested in a grammaticality classification task. Implicit sequence learning was present in dyslexic children, as well as in both control groups, and no differences between groups were observed. These results suggest that implicit learning deficits per se cannot explain the characteristic reading difficulties of the dyslexics.
  • A aprendizagem implícita em crianças disléxicas
    Publication . Inácio, Filomena; Faísca, Luís; Forkstam, Christian; Araújo, Susana; Bramão, Inês; Reis, Alexandra; Petersson, Karl Magnus
    This study investigates the implicit sequence learning abilities of dyslexic children using an artificial grammar learning task and an extended exposure period. Twenty children with developmental dyslexia participated in the study and were matched with two control groups—one matched for age and the second for reading skills. During 3 days, all participants performed an acquisition task in which they were exposed to sequences of colored geometrical forms with an underlying grammatical structure. On the last day, after the acquisition task, participants were tested in a grammaticality classification task. Sequence learning was present in dyslexic children, as well as in both control groups, and no differences between groups were observed. These results suggest that implicit learning deficits cannot explain the characteristic reading difficulties of the dyslexics.
  • Reading comprehension predictors in European Portuguese adults
    Publication . Gonçalves, Fábio; Reis, Alexandra; Inácio, Filomena; Morais, Inês Salomé; Faisca, Luis
    Research on the predictors of reading comprehension has been largely focused on school-aged children and mainly in opaque orthographies, hindering the generalization of the results to adult populations and more transparent orthographies. In the present study, we aim to test two versions of the Simple View of Reading (SVR): the original model and an extended version, including reading fluency and vocabulary. Additional mediation models were analyzed to verify if other reading comprehension predictors (rapid automatized naming, phonological decoding, phonological awareness, morphological awareness, and working memory) have direct effects or if they are mediated through word reading and reading fluency. A sample of 67 typical adult Portuguese readers participated in this study. The SVR model accounted for 27% of the variance in reading comprehension, with oral language comprehension displaying a larger contribution than word reading. In the extended SVR model, reading fluency and vocabulary provided an additional and significant contribution of 7% to the explained variance. Moreover, vocabulary influenced reading comprehension directly and indirectly, via oral language comprehension. In the final mediation model, the total mediation hypothesis was rejected, and only morphological awareness showed a direct effect on reading comprehension. These results provide preliminary evidence that the SVR (with the possible addition of vocabulary) might be a reliable model to explain reading comprehension in adult typical readers in a semitransparent orthography. Furthermore, oral language comprehension and vocabulary were the best predictors in the study, suggesting that remediation programs addressing reading comprehension in adults should promote these abilities.
  • Modality effects in implicit artificial grammar learning: An EEG study
    Publication . Silva, Susana; Folia, Vasiliki; Inácio, Filomena; Castro, Sao Luis; Petersson, Karl Magnus
    Recently, it has been proposed that sequence learning engages a combination of modality-specific operating networks and modality-independent computational principles. In the present study, we compared the behavioural and EEG outcomes of implicit artificial grammar learning in the visual vs. auditory modality. We controlled for the influence of surface characteristics of sequences (Associative Chunk Strength), thus focusing on the strictly structural aspects of sequence learning, and we adapted the paradigms to compensate for known frailties of the visual modality compared to audition (temporal presentation, fast presentation rate). The behavioural outcomes were similar across modalities. Favouring the idea of modality-specificity, ERPs in response to grammar violations differed in topography and latency (earlier and more anterior component in the visual modality), and ERPs in response to surface features emerged only in the auditory modality. In favour of modality-independence, we observed three common functional properties in the late ERPs of the two grammars: both were free of interactions between structural and surface influences, both were more extended in a grammaticality classification test than in a preference classification test, and both correlated positively and strongly with theta event-related-synchronization during baseline testing. Our findings support the idea of modality-specificity combined with modality-independence, and suggest that memory for visual vs. auditory sequences may largely contribute to cross-modal differences. (C) 2018 Elsevier B.V. All rights reserved.
  • Eye-movements in implicit artificial grammar learning
    Publication . Silva, Susana; Inácio, Filomena; Folia, Vasiliki; Petersson, Karl Magnus
    Artificial grammar learning (AGL) has been probed with forced-choice behavioral tests (active tests). Recent attempts to probe the outcomes of learning (implicitly acquired knowledge) with eye-movement responses (passive tests) have shown null results. However, these latter studies have not tested for sensitivity effects, for example, increased eye movements on a printed violation. In this study, we tested for sensitivity effects in AGL tests with (Experiment 1) and without (Experiment 2) concurrent active tests (preference- and grammaticality classification) in an eye-tracking experiment. Eye movements discriminated between sequence types in passive tests and more so in active tests. The eye-movement profile did not differ between preference and grammaticality classification, and it resembled sensitivity effects commonly observed in natural syntax processing. Our findings show that the outcomes of implicit structured sequence learning can be characterized in eye tracking. More specifically, whole trial measures (dwell time, number of fixations) showed robust AGL effects, whereas first-pass measures (first-fixation duration) did not. Furthermore, our findings strengthen the link between artificial and natural syntax processing, and they shed light on the factors that determine performance differences in preference and grammaticality classification tests.
  • Object naming in dyslexic children: more than a phonological deficit
    Publication . Araújo, Susana; Faísca, Luís; Bramão, Inês; Inácio, Filomena; Petersson, Karl Magnus; Reis, Alexandra
    In the present study, the authors investigate how some visual factors related to early stages of visual-object naming modulate naming performance in dyslexia. The performance of dyslexic children was compared with 2 control groups—normal readers matched for age and normal readersmatched for reading level—while performing a discrete naming task in which color and dimensionality of the visually presented objects were manipulated. The results showed that 2-dimensional naming performance improved for color representations in control readers but not in dyslexics. In contrast to control readers, dyslexics were also insensitive to the stimulus’s dimensionality. These findings are unlikely to be explained by a phonological processing problem related to phonological access or retrieval but suggest that dyslexics have a lower capacity for coding and decoding visual surface features of 2-dimensional representations or problems with the integration of visual information stored in long-term memory.