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- When the eyes no longer lead: familiarity and length effects on eye-voice spanPublication . Silva, Susana; Reis, Alexandra; Casaca, Luís; Petersson, Karl Magnus; Faísca, LuísDuring oral reading, the eyes tend to be ahead of the voice (eye-voice span, EVS). It has been hypothesized that the extent to which this happens depends on the automaticity of reading processes, namely on the speed of print-to-sound conversion. We tested whether EVS is affected by another automaticity component - immunity from interference. To that end, we manipulated word familiarity (high-frequency, low-frequency, and pseudowords, PW) and word length as proxies of immunity from interference, and we used linear mixed effects models to measure the effects of both variables on the time interval at which readers do parallel processing by gazing at word N + 1 while not having articulated word N yet (offset EVS). Parallel processing was enhanced by automaticity, as shown by familiarity x length interactions on offset EVS, and it was impeded by lack of automaticity, as shown by the transformation of offset EVS into voice eye span (voice ahead of the offset of the eyes) in PWs. The relation between parallel processing and automaticity was strengthened by the fact that offset EVS predicted reading velocity. Our findings contribute to understand how the offset EVS, an index that is obtained in oral reading, may tap into different components of automaticity that underlie reading ability, oral or silent. In addition, we compared the duration of the offset EVS with the average reference duration of stages in word production, and we saw that the offset EVS may accommodate for more than the articulatory programming stage of word N.
- The P600 in Implicit Artificial Grammar LearningPublication . Silva, Susana; Folia, Vasiliki; Hagoort, Peter; Petersson, Karl MagnusThe suitability of the artificial grammar learning (AGL) paradigm to capture relevant aspects of the acquisition of linguistic structures has been empirically tested in a number of EEG studies. Some have shown a syntax-related P600 component, but it has not been ruled out that the AGL P600 effect is a response to surface features (e. g., subsequence familiarity) rather than the underlying syntax structure. Therefore, in this study, we controlled for the surface characteristics of the test sequences (associative chunk strength) and recorded the EEG before (baseline preference classification) and after (preference and grammaticality classification) exposure to a grammar. After exposure, a typical, centroparietal P600 effect was elicited by grammatical violations and not by unfamiliar subsequences, suggesting that the AGL P600 effect signals a response to structural irregularities. Moreover, preference and grammaticality classification showed a qualitatively similar ERP profile, strengthening the idea that the implicit structural mere-exposure paradigm in combination with preference classification is a suitable alternative to the traditional grammaticality classification test.
- Modality effects in implicit artificial grammar learning: An EEG studyPublication . Silva, Susana; Folia, Vasiliki; Inácio, Filomena; Castro, Sao Luis; Petersson, Karl MagnusRecently, 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.
- Too little or too much? Parafoveal preview benefits and parafoveal load costs in dyslexic adultsPublication . Silva, Susana; Faísca, Luís; Araújo, Susana; Casaca, Luis; Carvalho, Loide; Petersson, Karl Magnus; Reis, AlexandraTwo different forms of parafoveal dysfunction have been hypothesized as core deficits of dyslexic individuals: reduced parafoveal preview benefits ("too little parafovea") and increased costs of parafoveal load ("too much parafovea"). We tested both hypotheses in a single eye-tracking experiment using a modified serial rapid automatized naming (RAN) task. Comparisons between dyslexic and non-dyslexic adults showed reduced parafoveal preview benefits in dyslexics, without increased costs of parafoveal load. Reduced parafoveal preview benefits were observed in a naming task, but not in a silent letter-finding task, indicating that the parafoveal dysfunction may be consequent to the overload with extracting phonological information from orthographic input. Our results suggest that dyslexics' parafoveal dysfunction is not based on strict visuo-attentional factors, but nevertheless they stress the importance of extra-phonological processing. Furthermore, evidence of reduced parafoveal preview benefits in dyslexia may help understand why serial RAN is an important reading predictor in adulthood.
- Viés de manutenção da atenção na ansiedade socialPublication . Fernandes, Catarina; Silva, Susana; Pires, Joana; Reis, Alexandra; Jiménez-Ros, Antonia María; Janeiro, Luís; Faisca, Luis; Martins, A.The role of attentional bias in social anxiety is not yet fully understood. Social anxiety individuals can show deliberate avoidance of socially threatening stimuli or, on the contrary, be hypervigilant, persistently allocating attention to those stimuli. Our main purpose was to test whether social anxiety is preferably associated with mechanisms of hypervigilance, avoidance, vigilance-avoidance or maintenance of attention towards socially relevant stimuli. Our secondary goal was to explore the modulating role of personality traits in these attention bias mechanisms. Participants with high vs low social anxiety and different personality structures were exposed to pairs of faces representing different emotions (anger, happiness and neutrality) while their eye movements were continuously recorded. Comparisons between participants with high and low levels of social anxiety showed that participants with high social anxiety were slower in disengaging their attention from happy faces, suggesting that positive emotions can be perceived as a threatening stimuli for social anxious individuals. Preliminary results indicated that depressive personality structure may favour manifestations of hypervigilance bias toward threat faces.
- Eye-movements in implicit artificial grammar learningPublication . Silva, Susana; Inácio, Filomena; Folia, Vasiliki; Petersson, Karl MagnusArtificial 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.