Abstract
Bilingualism has been shown to modulate neural mechanisms of auditory selective attention, due to the constant need to select the target language and inhibit the unwanted ones. To investigate the impact of typological similarity between bilinguals’ languages on attentional modulation, this study investigated the neural adaptation of selective attention in early bilinguals speaking very dissimilar languages (Chinese-English), and compared their results to existing data for English monolinguals, and bilinguals speaking more similar languages (early Spanish-English and Dutch-English bilinguals, Olguin et al., 2018; 2019). Using the same dichotic listening design, Chinese-English bilinguals (proficient in L2 English) attended to a narrative in Mandarin Chinese (native language) in one ear, while simultaneously ignoring a competing distractor in the other ear. The type / intelligibility of unattended distractors (Chinese narratives, Serbian narratives （unknown language）, non-linguistic stream or no interference) were manipulated to generate four conditions. EEG activities were cross-correlated with speech envelopes of corresponding attended and unattended streams. Results from Chinese-English bilinguals showed stronger neural encoding of attended than unattended streams in all conditions, and attentional encoding varied as the distractor changed from non-linguistic to linguistic (narratives) but did not differ between conditions of linguistic interference - a pattern half-way between monolinguals and typologically-similar bilinguals. Results of Representational Similarity Analysis indicated that of all bilingual groups, the overall patterns of neural encoding in Chinese-English bilinguals were the closest to those of monolinguals over time, suggesting higher L1-L2 dissimilarity leads to less modulation of selective attention mechanisms and a more monolingual-like pattern of neural encoding.
