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标题：Electrophysiological Evidence of Dissociation Between Explicit Encoding and Fast Mapping of Novel Spoken Words
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作者：Shtyrov, Yury ; Filippova, Margarita ; Blagovechtchenski, Evgeni 等
期刊名称：Frontiers in Psychology
电子版ISSN：1664-1078
出版年度：2021
卷号：12
页码：143
DOI：10.3389/fpsyg.2021.571673
出版社：Frontiers Media
摘要：Existing behavioural, neuropsychological and functional neuroimaging data suggest at least two major cognitive strategies used for new word learning: fast mapping (FM) via context-dependent inference and explicit encoding (EE) via direct instruction. However, these distinctions remain debated at both behavioural and neurophysiological levels, not least due to confounds related to diverging experimental settings. Furthermore, the neural dynamics underpinning these two putative processes remain poorly understood. To tackle this, we designed a paradigm presenting twenty new spoken words in association with pictures in either FM or EE settings, closely matched for auditory and visual features and overall task demands. We tested word acquisition using a range of behavioural measures as well as passive ERP responses, an established measure of word memory trace activation, and compared brain activity elicited by novel FM and EE words before and after the learning session. Behavioural data obtained in free recall, recognition and semantic word-picture matching tasks indicated successful acquisition of new words after just ten exposures. Crucially, we found no behavioural evidence of different acquisition outcomes between FM and EE learning. ERP data, which exhibited the main response peaks at ~170, 250 and 520 ms, also indicated a successful learning, with statistically different responses between novel and familiar words present only before, but not after the training, suggesting rapid formation of new neural memory circuits matching in activation those for previously known words. Furthermore, already at the earliest peak we found different topographic distributions for the two learning types, with left-lateralised FM dynamics, suggestive of core language system involvement, and more diffuse activity for EE items, possibly suggesting the role of attention/executive control network. A similar effect was also manifested later, at ~520 ms. Our data suggest that while both EE and FM learning can be equally successful for rapid word acquisition at the behavioural level, the diverging electrophysiological patterns suggest a dissociation between the neural systems underpinning these learning strategies.
关键词：word learning; language acquisition; fast mapping; explicit encoding; Electroencephalography (EEG); Event- related potential (ERP)