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Too little or too much? Parafoveal preview benefits and parafoveal load costs in dyslexic adults

Publication . Silva, Susana; Faísca, Luís; Araújo, Susana; Casaca, Luis; Carvalho, Loide; Petersson, Karl Magnus; Reis, Alexandra

Two 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.

2016-07Journal article

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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.

2017-09Journal article

Open Access

“There are things I want to say but you do not ask”: a comparison between standardised and individualised evaluations in substance use treatment

Publication . Alves, Paula Cristina Gomes; Sales, Célia Maria Dias; Ashworth, Mark; Faisca, Luis

There has been an increasing call for service users to be more actively involved with the evaluation of treatment outcomes. One strategy to impove such involvement is to ask service users to contribute with their own criteria for evaluation by sharing their personal story and perspective about their clinical situation. In this cross-sectional study, we contrasted the contents elicited by service users completing two individualised measures against the contents of three widely used standardised measures. We also compared two methods to generate individualised data using self-report and interview-based instruments (PSYCHLOPS and PQ). Following a thematic comparison approach, we found that one quarter of the problems reported by patients in individualised measures were not covered by any of our standardised comparators. Also, half of our sample generated at least one problem whose theme was not covered by any of the three standardised measures. We also found that patients in this population have many other concerns beyond drug use. These included psychological (e.g. interpersonal relationships) and socio-economic (e.g. money) problems, which were frequently reported. Our study suggests that listening to service users’ stories allows us to capture issues of importance to service users in substance use treatment, which may be underestimated by standardised measures.

2018Journal article

Open Access

The P600 in Implicit Artificial Grammar Learning

Publication . Silva, Susana; Folia, Vasiliki; Hagoort, Peter; Petersson, Karl Magnus

The 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.

2017-01Journal article

Open Access