Current exposure to a second language modulates bilingual visual word recognition: An EEG study

Bilingual word recognition has been the focus of much empirical work, but research on potential modulating factors, such as individual differences in L2 exposure, are limited. This study represents a first attempt to determine the impact of L2-exposure on bilingual word recognition in both languages. To this end, highly fluent bilinguals were split into two groups according to their L2-exposure, and performed a semantic categorisation task while recording their behavioural responses and electro-cortical (EEG) signal. We predicted that lower L2-exposure should produce less efficient L2 word recognition processing at the behavioural level, alongside neurophysiological changes at the early pre-lexical and lexical levels, but not at a post-lexical level. Results confirmed this hypothesis in accuracy and in the N1 component of the EEG signal. Precisely, bilinguals with lower L2-exposure appeared less accurate in determining semantic relatedness when target words were presented in L2, but this condition posed no such problem for bilinguals with higher L2-exposure. Moreover, L2-exposure modulates early processes of word recognition not only in L2 but also in L1 brain activity, thus challenging a fully non-selective access account (cf. BIA + model, Dijkstra and van Heuven, 2002). We interpret our findings with reference to the frequency-lag hypothesis (Gollan et al., 2011).