Hatzidaki, A. 1 , Jones, M. 1 & Santesteban, M. 2
1 University of Edinburgh
2 University of the Basque Country
Despite a growing literature demonstrating the benefits of bilingualism for various cognitive processes (e.g., Bialystok et al., 2006; Costa et al., 2008), there are recent studies that show that bilingualism may be disadvantageous as far as language tasks are concerned (e.g., Gollan et al., 2005; Ivanova & Costa, 2008). In the present study we examined the relationship between dyslexia and bilingualism by testing English native speakers in three groups of 14 participants each: a monolingual dyslexic group; a bilingual dyslexic group; and a monolingual (control) group. All participants performed a stroop experiment in English which consisted of 216 items presented across three blocks in each experimental session. Four colours (blue, green, pink, and red) were used across three conditions: congruent, whereby a word was presented in the same colour as its name; incongruent (stroop), with a word presented in a different colour than its name; and control, where a visual stimulus (a string of Xs) was presented in the colour it was intended to be named. Analyses of variance showed that although there was not a significant difference across the three groups in the number of errors they made in their responses, monolingual dyslexics experienced more interference than the monolingual control group, and bilingual dyslexics showed the largest interference of all the groups. These results suggest that (i) accuracy and speed contribute independently to interference; and (ii) the stroop effect in dyslexics seems to originate from a deficit in selectively attending to colour analysis and inhibiting word processing due to fewer available resources of controlling the processes involved in the stroop task (see Protopapas et al., 2007, for a review). This effect was enhanced in bilingual dyslexics, suggesting a larger difficulty in inhibiting word reading processes in bilingual than monolingual dyslexics. These assumptions will be further discussed in our presentation.