Lexical Representations of the Native and Second Languages During L2 Word Reading in Chinese-English Bilinguals

The non-selective processing hypothesis for bilinguals posits that during the processing of the target language, the lexical information of the non-target language is concurrently activated. Nonetheless, the lexical representation of bilinguals in both languages and the temporal dynamics of lexical information representation remain unclear. Here, we utilized fMRI in Experiment 1 and EEG in Experiment 2, combined with representational similarity analysis (RSA), to explore the neural representation of lexical access in both the target and non-target languages during L2 word reading and the modulatory effects of processing demands. Results of two Experiments jointly revealed that the lexical information of L2 was represented widely and earlier during L2 lexical processing, whereas the lexical information of L1 was represented widely and earlier during L2 semantic processing. These findings provide spatiotemporally integrated evidence for the bilingual non-selective access hypothesis, indicating that non-selective processing occurs only under conditions of high semantic processing demands.