Contributions of episodic memory to novel word learning

Abstract

Multiple theories predict that word learning is intimately linked to episodic memory, at least in the early phases of learning. However, it is unclear to what degree this link reflects more domain-specific (i.e., those dedicated to language or the lexicon) or more domain-general episodic memory processes that operate outside of language. One way to address this possibility is by using a behavioral individual differences design. This study examined whether behavioral individual differences in episodic memory abilities predicted adult word learning abilities. If behavioral performance in a nonlinguistic episodic memory task is predictive of behavioral performance in word learning, then it is likely that they share a common underlying nonlinguistic, memory-based mechanism. The results revealed that individual differences in episodic memory abilities predicted word learning abilities shortly after learning but not two days later. These behavioral results are consistent with prior neuropsychological observations (e.g., in amnesia: Kensinger, Ullman, & Corkin, 2001) as well as with theories positing a shift in reliance in lexical development from episodic memory to a distributed neocortical memory system after a period of sleep (e.g., Davis & Gaskell, 2009).

Episodic memory contributions to second language lexical development persist at higher proficiencies

“…They also found that individual differences in nonlinguistic episodic memory abilities predicted vocabulary knowledge immediately after exposure. Unlike Hamrick et al (2019), though, Murphy et al (2021) found that episodic memory was a significant predictor of lexical abilities 2 days later. It is not clear whether the differences in outcomes between these studies are due to differences in study design or an unclear episodic memory effect, or both.…”

“…Participants' episodic memory abilities were assessed with the continuous visual memory task (CVMT; Trahan & Larrabee, 1988), which has been employed in several studies looking at individual differences in episodic memory and language (e.g., Hamrick et al, 2019; Morgan‐Short et al, 2014; Murphy et al, 2021). The CVMT examines continuous recognition memory for abstract shapes.…”

“…Taken together, the bulk of the evidence implicates episodic memory in early stages of L2 word learning for late bilinguals; however, some psycholinguistic data support a continuing role for episodic memory in the L2 lexicon (e.g., Jiang & Forster, 2001; Murphy et al, 2021; Qiao & Forster, 2017; Witzel & Forster, 2012), while other studies have not reported evidence for a decreasing influence of episodic memory on the L2 lexicon over time (e.g., Hamrick et al, 2019; Takashima et al, 2017). Importantly, though, many of these studies only looked at relatively short‐term learning intervals of a few days or weeks (e.g., Hamrick et al, 2019; Murphy et al, 2021; Takashima et al, 2017), and data from more proficient L2 learners has been limited to the psycholinguistic studies on lexical processing by Forster and colleagues. Thus, more evidence is needed to determine whether nonlinguistic episodic memory plays any substantial role in L2 learners' lexical abilities at higher levels of proficiency than have typically been studied.…”

“…Since being identified as important gaps in the field (Hamrick et al, 2018), several studies have aimed to investigate the role of episodic memory in the L2 lexicon (Hamrick et al, 2019; Murphy et al, 2021; Ruiz et al, 2019; Walker et al, 2020). These studies investigated these gaps by examining relationships between behavioral individual differences in nonlinguistic episodic memory abilities and lexical abilities.…”

“…If there were systematic relationships between the two, then it would increase the likelihood that the shared mechanism between the two was genuinely episodic in nature and domain‐general (at least in the sense that it was not purely linguistic). In an incidental word learning study, Hamrick et al (2019) found that participants' abilities to match an auditorily presented word to its correct referent (i.e., a black and white line drawing of a real object) was predicted by participants' episodic memory for abstract designs, but only when their word knowledge was tested immediately after learning. However, 2 days later, when participants were tested on their retention of their newly learned knowledge, their episodic memory abilities no longer predicted their lexical abilities.…”