Bidirectional Script Bilingualism Delays Performance on Executive Control Tasks

This study explored script direction effects on executive function in bilingual participants in the Simon Task, a word-based task that measures speed and accuracy of spatial response code mapping and conflict resolution. All participants (N=68) were highly fluent bilinguals, with English as a second language. Their first language was either in the same script direction (SS) as English, for example French or Turkish, or their first language was Arabic, a different script direction (DS) compared to English. The SS group outperformed all DS participants on speed (p<.001) and a DS subgroup on accuracy (p=.008), suggesting a bilingual advantage for SS bilinguals over DS bilinguals. These findings contribute to the research on the effects of bilingualism on cognition and suggest that bilingual advantages are moderated by script direction, where DS bilingualism may increase cognitive load in some situations.