A complementary systems account of word learning: neural and behavioural evidence

Matthew H. Davis, M. Gareth Gaskell

Research output: Contribution to journalLiterature reviewpeer-review

Abstract

In this paper we present a novel theory of the cognitive and neural processes by which adults learn new spoken words. This proposal builds on neurocomputational accounts of lexical processing and spoken word recognition and complementary learning systems (CLS) models of memory. We review evidence from behavioural studies of word learning that, consistent with the CLS account, show two stages of lexical acquisition: rapid initial familiarization followed by slow lexical consolidation. These stages map broadly onto two systems involved in different aspects of word learning: (i) rapid, initial acquisition supported by medial temporal and hippocampal learning, (ii) slower neocortical learning achieved by offline consolidation of previously acquired information. We review behavioural and neuroscientific evidence consistent with this account, including a meta-analysis of PET and functional Magnetic Resonance Imaging (fMRI) studies that contrast responses to spoken words and pseudowords. From this meta-analysis we derive predictions for the location and direction of cortical response changes following familiarization with pseudowords. This allows us to assess evidence for learning-induced changes that convert pseudoword responses into real word responses. Results provide unique support for the CLS account since hippocampal responses change during initial learning, whereas cortical responses to pseudowords only become word-like if overnight consolidation follows initial learning.

Original languageEnglish
Pages (from-to)3773-3800
Number of pages28
JournalPhilosophical Transactions Of The Royal Society Of London Series B - Biological Sciences
Volume364
Issue number1536
DOIs
Publication statusPublished - 27 Dec 2009

Keywords

  • pseudoword
  • meta-analysis
  • hippocampus
  • speech
  • sleep
  • memory
  • MEDIAL TEMPORAL-LOBE
  • SPOKEN LANGUAGE COMPREHENSION
  • VOXEL-BASED MORPHOMETRY
  • EVENT-RELATED FMRI
  • SPEECH-PERCEPTION
  • SEMANTIC KNOWLEDGE
  • TIME-COURSE
  • MEMORY CONSOLIDATION
  • LEXICAL COMPETITION
  • HUMAN HIPPOCAMPUS

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