The influence of meaning and memory consolidation on novel word learning

The cognitive mechanisms underpinning adult word learning have become of great interest in recent years. Whilst knowledge about novel word forms and meanings can be acquired quickly, the integration of newly-learnt with existing words often requires offline consolidation after initial encoding. However, it remains relatively underexplored what factors contribute to the time-course and success of this process. A particularly interesting question concerns the role of semantics in word learning: whilst the provision of semantic information during the encoding of new words can benefit declarative memory, it may delay the lexicalization time-course. This thesis therefore investigated the dual influence of meaning and memory consolidation across different levels of spoken word learning in adults. The first question addressed was whether semantic information influenced phonological form learning, and the consequences of offline consolidation for this semantic effect. Study 1 and Study 2 investigated this using event-related potentials, in a learning paradigm in which novel words were learnt with and without consistent semantic associations. The results of these studies suggested that consistent semantic exposure could support the encoding of new phonological form representations, and that this learning benefit was stable following overnight consolidation. The second question was whether this semantic benefit transferred to the lexical integration of new with existing words. Study 3 tested the behavioural impact of semantic learning on lexical competition and observed no lexicalization following overnight consolidation, or at a long term follow-up, despite a semantic and consolidation benefit across other learning measures. The final study sought to address whether phonological attention during learning influenced the lexicalization timecourse. Novel words acquired via phonological training engaged in lexical competition, with a time-course which was unaffected by semantic exposure. These data were interpreted in light of memory consolidation theories to discuss the extent to which encoding influences the offline consolidation process new words undergo.