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Electrophysiological Evidence of Dissociation Between Explicit Encoding and Fast Mapping of Novel Spoken Words

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  • Yury Shtyrov
  • Margarita Filippova, St. Petersburg State University
  • ,
  • Evgeni Blagovechtchenski, St. Petersburg State University
  • ,
  • Alexander Kirsanov, St. Petersburg State University
  • ,
  • Elizaveta Nikiforova, St. Petersburg State University
  • ,
  • Olga Shcherbakova, St. Petersburg State University

Existing behavioral, neuropsychological and functional neuroimaging data suggest that at least two major cognitive strategies are 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 behavioral 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 20 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 behavioral measures as well as passive event-related potential (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. Behavioral data obtained in free recall, recognition and semantic word-picture matching tasks indicated successful acquisition of new words after just 10 exposures. Crucially, we found no behavioral 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 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-lateralized 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 also manifested later, at ~520 ms. Our data suggest that while both EE and FM learning can be successful for rapid word acquisition at the behavioral level, the diverging electrophysiological patterns suggest a dissociation between the neural systems underpinning these learning strategies.

Original languageEnglish
Article number571673
JournalFrontiers in Psychology
Volume12
Number of pages15
ISSN1664-1078
DOIs
Publication statusPublished - Mar 2021

Bibliographical note

Funding Information:
We are grateful to Anna Shestakova, Beatriz Martin-Luengo, and Elena Grigorenko for their help at different stages of this research. Funding. This work was supported by RF Government (grant contract no. 14.W03.31.0010), Lundbeck Foundation (grants R140-2013-12951 and R164-2013-15801), and Danish Council for Independent Research (DFF 6110-00486 and project 23776).

Funding Information:
This work was supported by RF Government (grant contract no. 14.W03.31.0010), Lundbeck Foundation (grants R140-2013-12951

Publisher Copyright:
© Copyright © 2021 Shtyrov, Filippova, Blagovechtchenski, Kirsanov, Nikiforova and Shcherbakova.

Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.

    Research areas

  • electroencephalography, event-related potential, explicit encoding, fast mapping, language acquisition, word learning

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