Bilingual infants control their languages as they listen

Abstract

Infants growing up in bilingual homes learn two languages simultaneously without apparent confusion or delay. However, the mechanisms that support this remarkable achievement remain unclear. Here, we demonstrate that infants use language-control mechanisms to preferentially activate the currently heard language during listening. In a naturalistic eye-tracking procedure, bilingual infants were more accurate at recognizing objects labeled in same-language sentences ("Find the dog!") than in switched-language sentences ("Find the !"). Measurements of infants' pupil size over time indicated that this resulted from increased cognitive load during language switches. However, language switches did not always engender processing difficulties: the switch cost was reduced or eliminated when the switch was from the nondominant to the dominant language, and when it crossed a sentence boundary. Adults showed the same patterns of performance as infants, even though target words were simple and highly familiar. Our results provide striking evidence from infancy to adulthood that bilinguals monitor their languages for efficient comprehension. Everyday practice controlling two languages during listening is likely to explain previously observed bilingual cognitive advantages across the lifespan.

Bilingual toddlers’ comprehension of mixed sentences is asymmetrical across their two languages

“…Prior accounts have stressed the role of broad cognitive control processes in language switching, as listeners may struggle to retrieve lexical items in the less active language (e.g., Byers-Heinlein et al, 2017;Green, 1998;Thomas & Allport, 2000). Prior accounts have stressed the role of broad cognitive control processes in language switching, as listeners may struggle to retrieve lexical items in the less active language (e.g., Byers-Heinlein et al, 2017;Green, 1998;Thomas & Allport, 2000).…”

“…We selected this age range because this paradigm has been used successfully with toddlers between 18 and 30 months (e.g., Byers-Heinlein et al, 2017;Marchman et al, 2010) and because previous research on bilingual development does not yield empirical or theoretical reasons to expect differences between 18-and 30-month-olds. We selected this age range because this paradigm has been used successfully with toddlers between 18 and 30 months (e.g., Byers-Heinlein et al, 2017;Marchman et al, 2010) and because previous research on bilingual development does not yield empirical or theoretical reasons to expect differences between 18-and 30-month-olds.…”

“…Byers-Heinlein et al (2017) provided evidence that infants learning French and English experience processing costs mainly when listening to switches from their dominant to non-dominant language. Byers-Heinlein et al (2017) provided evidence that infants learning French and English experience processing costs mainly when listening to switches from their dominant to non-dominant language.…”

Does Exposure to Code‐Switching Influence Language Performance in Bilingual Children?

“…Daneman and Carpenter (1980) argued that weaknesses in WM would lead to deficits in comprehension, particularly for the more demanding comprehension tasks that require integration of words, phrases, and sentences into a coherent whole. Processing of code-switched input may constitute just such a task, with a language switch posing processing and integration costs (Altarriba et al, 1996;Bultena et al, 2015aBultena et al, , 2015bProverbio et al, 2004), and inducing an increased cognitive load (Byers-Heinlein et al, 2017). In fact, neuroimaging literature has revealed that codeswitches encountered during comprehension tasks elicit responses that suggest an increased effort in memory updating processes (e.g., Moreno, Federmeier, & Kutas, 2002;van Der Meij, Cuetos, Carreiras, & Barber, 2011).…”

“…Code-switching (alternation between languages) is a common practice among bilinguals. Yet, a robust psycholinguistic literature indicates that codeswitching carries processing costs, both in production (Bobb & Wodniecka, 2013;Fricke, Kroll, & Dussias, 2016;Meuter & Allport, 1999) and in comprehension (Altarriba, Kroll, Sholl, & Rayner, 1996;Bultena, Dijkstra, & Van Hell, 2015a, 2015bByers-Heinlein, Morin-Lessard, & Lew-Williams, 2017;Proverbio, Leoni, & Zani, 2004). Why then do bilinguals code-switch?…”