Transposition and substitution-letter effects in a flanker task: Evidence from children and adults.

Several studies have shown that parafoveal processing is essential in reading development. In this study, we explore the effect of transposing and substituting inner and outer letters in a flanker lexical decision task administered to 78 children and 65 adults. The results show a significant interaction between the Group factor and the Flanker factor, suggesting differences in the effects of flankers for children and adults. In the case of adults, transposed and substituted letters generated benefit of the same magnitude in comparison with the unrelated condition, but of lesser magnitude than the Identity condition. In the case of children, the results show facilitation for the transposed conditions of the same magnitude as the Identity condition. However, the substitution conditions failed to generate any benefit in comparison with the unrelated condition. The results for the adults are in line with the predictions of the open bigram model, whereas the results for the children are explained through a developmental perspective of the dual-route architecture and open bigram framework.

Differences on morphological and phonological processing between typically developing children and children with Down syndrome.

It is widely acknowledged that people with Down syndrome (Ds) have less highly developed morphosyntactic abilities than typically developing (TD) children. However, little is known about the morphological processing of this population. In this paper we carry out two experiments in which the morphological Base Frequency (BF) effect is explored in both groups. The aim of the experiments is to carry out an in-depth exploration of morphological processing in children with Ds and TD children. In the first experiment children performed a definition task; in the second children had to provide a plural form for singular words. The results show a significant BF effect in only the first experiment. In the second experiment this morphological variable does not reach significance, but the variable we called Ending phoneme (a phonological variable that refers to the last phoneme of the bases prior to the addition of plural morphemes) does. The results also show that children with Ds score significantly below the two control groups in both experiments, with no significant differences between control groups. We go on to discuss morphological processing in children with and without Ds, the role of the two tasks carried out (paying special attention to the role played by working memory), and the possible relationship between our results and morphosyntactic deficits described in the literature.