The modification of high-level attentional processing in bilingualism
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The modification of high-level attentional processing in bilingualism
Bilingualism has been shown to modify the neural mechanisms of selective attention, even in the absence of behavioural differences between monolinguals and bilinguals (Olguin et al, 2019; Phelps et al, 2022). However, the evidence is so far limited to the adaptation of perceptual, lower-level attentional processing (e.g., neural encoding of speech envelope), and it is not known whether the same applies to the processing of higher-level semantic information.
To investigate whether bilingualism modifies attentional mechanisms beyond low-level perceptual processing, we used EEG to track the neural encoding of attended continuous speech in monolingual and bilingual listeners. Twenty-four English monolinguals and twenty-seven Spanish-English early bilinguals attended to narratives in their native language (English or Spanish) while ignoring different types of interference in the other ear (another narrative in their native language, a narrative in a language unknown to them, non-linguistic interference, or no interference). We used word vector representations to quantify the meaning of each word and assessed how well this semantic information can be reconstructed from the responses of the underlying neuronal populations. Results show the neural encoding of semantic information varies as a function of the type of interference in monolingual listeners, with strong interference (native language) leading to the weakest reconstruction of the attended stream. In contrast, variation in the type of interference did not modulate the encoding of semantic information across conditions in bilinguals. This replicates the pattern of results seen for the encoding of perceptual information in previous studies, suggesting that the demands of learning and using multiple languages lead to modification of attentional processing across different levels of information in bilinguals.