Stability of right visual field advantage in an international lateralized lexical decision task irrespective of participants' sex, handedness or bilingualism.

In lateralized lexical decision tasks (LDTs), accuracy is higher and reaction times (RTs) are faster for right visual field (RVF) than left visual field (LVF) presentations. Visual field differences are thought to demonstrate the left hemisphere's (LH) dominance for language. The use of different tasks and words between studies and languages make direct comparisons difficult. We performed a lateralized LDT for which we selected four to six letter words that are used in three languages of Switzerland (French, German, and Italian) and English and Dutch. We accounted for the potential moderating roles of sex, handedness and multilingualism (early acquisition versus late acquisition of at least one second language). One hundred participants were tested at a French-speaking University in Switzerland. All performed a French vocabulary knowledge task [Brysbaert ( 2013 ). Lextale_FR a fast, free, and efficient test to measure language proficiency in French. Psychologica Belgica, 53(1), 23-27. Retrieved from http://hdl.handle.net/1854/LU-4373981]. Results showed a RVF over LVF advantage (accuracy, RTs and signal detection theory measures) for all groups, that is, irrespective of participants' sex, handedness and how many languages they spoke. We observed, however, that enhanced vocabulary knowledge related to a right hemisphere shift in early bilinguals and a LH shift in late bilinguals. We discuss how the current observations can inform future studies suitable for the validation of the current task using an "international" vocabulary.