The 鈥淧erceptual Wedge Hypothesis鈥?as the basis for bilingual babies鈥?phonetic processing advantage: New insights from fNIRS brain imaging

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• 作者：L.A. Petitto^a ; ^{lauraann.petitto@gmail.com} ; M.S. Berens^a ; ^b ; I. Kovelman^c ; M.H. Dubins^a ; K. Jasinska^a ; M. Shalinsky^c
• 关键词：fNIRS ; Bilingualism ; Infant phonetic processing ; Perceptual Wedge Hypothesis ; Brain development ; Language acquisition ; Broca&rsquo ; s area ; STG ; LIFC
• 刊名：Brain and Language
• 出版年：2012
• 期刊代码：121_0093934x
• 类别：cp
• 出版时间：May, 2012
• 卷：121
• 期：2
• 页码：130-143
• 文件大小：584 K

摘要

In a neuroimaging study focusing on young bilinguals, we explored the brains of bilingual and monolingual babies across two age groups (younger 4-6 months, older 10-12 months), using fNIRS in a new event-related design, as babies processed linguistic phonetic (Native English, Non-Native Hindi) and nonlinguistic Tone stimuli. We found that phonetic processing in bilingual and monolingual babies is accomplished with the same language-specific brain areas classically observed in adults, including the left superior temporal gyrus (associated with phonetic processing) and the left inferior frontal cortex (associated with the search and retrieval of information about meanings, and syntactic and phonological patterning), with intriguing developmental timing differences: left superior temporal gyrus activation was observed early and remained stably active over time, while left inferior frontal cortex showed greater increase in neural activation in older babies notably at the precise age when babies鈥?enter the universal first-word milestone, thus revealing a first-time focal brain correlate that may mediate a universal behavioral milestone in early human language acquisition. A difference was observed in the older bilingual babies鈥?resilient neural and behavioral sensitivity to Non-Native phonetic contrasts at a time when monolingual babies can no longer make such discriminations. We advance the 鈥淧erceptual Wedge Hypothesis鈥?/em> as one possible explanation for how exposure to greater than one language may alter neural and language processing in ways that we suggest are advantageous to language users. The brains of bilinguals and multilinguals may provide the most powerful window into the full neural 鈥渆xtent and variability鈥?that our human species鈥?language processing brain areas could potentially achieve.