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

摘要

In this paper we present a novel theory of the cognitive and neural processes by which adults learnnew spoken words. This proposal builds on neurocomputational accounts of lexical processing andspoken word recognition and complementary learning systems (CLS) models of memory. We reviewevidence from behavioural studies of word learning that, consistent with the CLS account, show twostages 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) slowerneocortical learning achieved by offline consolidation of previously acquired information. Wereview behavioural and neuroscientific evidence consistent with this account, including ameta-analysis of PET and functional Magnetic Resonance Imaging (fMRT) studies that contrastresponses to spoken words and pseudowords. From this meta-analysis we derive predictions forthe location and direction of cortical response changes following familiarization with pseudowords.This allows us to assess evidence for learning-induced changes that convert pseudoword responsesinto real word responses. Results provide unique support for the CLS account since hippocampalresponses change during initial learning, whereas cortical responses to pseudowords only becomeword-like if overnight consolidation follows initial learning.