When Adults Learn Novel Word With Meanings: The Role Of Consolidation In Word Learning And Memory Retention
Open Access
- Author:
- Liu, Yushuang
- Graduate Program:
- Psychology
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- December 15, 2018
- Committee Members:
- Adriana Van Hell, Thesis Advisor/Co-Advisor
Ping Li, Committee Member
Rick Owen Gilmore, Committee Member - Keywords:
- word learning
ERP
semantic integration - Abstract:
- The Complementary Learning Systems Theory (CLS; Davis & Gaskell, 2009) proposes that word learning entails two memory networks. Novel words are initially encoded as episodic memory traces by the hippocampal learning system. After a subsequent period of consolidation, a shift towards more systematic, lexicalized coding of the memory representation in a distributed neocortical network occurs. Previous research examining the CLS and the encoding and consolidation of newly learned words in memory mostly focused on learning new word forms, without explicitly taking semantics into account. Recently researchers have started investigating the role of word meanings. In an ERP study (Bakker, Takashima, van Hell, Janzen, & McQueen, 2015a), participants learned novel printed words paired with novel meanings. Indexed by N400 and Late Positive Components (LPC), Bakker et al. (2015) found that novel word forms had been lexicalized after a 24-hour consolidation period, whereas the semantic integration process has started but was not yet completed. Based on the previous literature, two research questions arise. First, after a longer period of offline consolidation (i.e., one week, in addition to 24 hours), can novel word forms elicit more word-like responses in both the N400 and the LPC windows? When preceded by related prime words, can a longer period of offline consolidation enable the automatic retrieval of semantic meanings for novel words? Second, when learning novel words paired with meanings, would similar behavioral and neurophysiological patterns as in Bakker et al. (2015), who tested multilingual highly experienced foreign language learners, emerge in monolinguals who have very little prior experience in learning foreign languages? For my Master's thesis research, I investigated novel word learning and semantic integration, and examined consolidation both shortly after learning (Day 2) and after a longer period of time (Day 8). Furthermore, I examined novel word learning and the offline consolidation effect in monolingual English speakers in the United States, who have limited prior experiences with learning foreign languages, in order to examine to what extent their findings are similar or different to the multilingual experienced foreign language learners tested by Bakker et al. (2015). Regarding the first research question, ERP results on Day 2 showed a semantic priming effect for novel words learned on Day 1 (after 24-hours of consolidation) only in the LPC time window, but not for recently learned words (on Day 2). This indicates that, after 24-hours of consolidation, evidence for more controlled (non-automatic) retrieval was observed for novel words (indexed by the LPC), but no evidence for automatic semantic retrieval (indexed by N400) was observed. When tested on Day 8, both novel words learned on Day 1 and Day 2 demonstrated LPC and N400 semantic priming effects, indicating that one week after learning semantic retrieval has become automatic. Regarding the second research question, behavioral performance of the semantic priming task indicated that the monolingual inexperienced language learners in the current study remembered fewer novel word meanings than the experienced multilingual language learners in Bakker et al. (2015), which is consistent with previous studies on the effect of prior language learning experience on acquiring vocabulary. However, neural responses in the current monolingual sample were comparable to those in the Dutch participants of Bakker et al. (2015). The results are discussed in light of lexical consolidation and semantic integration of novel words, and similarities and differences in encoding and consolidation strategies in inexperienced versus experienced novel word learners.