Learning new meanings for known words: Perturbation of original meanings and retention of new meanings

New in, old out: Does learning a new language make you forget previously learned foreign languages?

Anecdotal evidence suggests that learning a new foreign language (FL) makes you forget previously learned FLs. To seek empirical evidence for this claim, we tested whether learning words in a previously unknown L3 hampers subsequent retrieval of their L2 translation equivalents. In two experiments, Dutch native speakers with knowledge of English (L2), but not Spanish (L3), first completed an English vocabulary test, based on which 46 participant-specific, known English words were chosen. Half of those were then learned in Spanish. Finally, participants' memory for all 46 English words was probed again in a picture naming task. In Experiment 1, all tests took place within one session. In Experiment 2, we separated the English pre-test from Spanish learning by a day and manipulated the timing of the English post-test (immediately after learning vs. 1 day later). By separating the post-test from Spanish learning, we asked whether consolidation of the new Spanish words would increase their interference strength. We found significant main effects of interference in naming latencies and accuracy: Participants speeded up less and were less accurate to recall words in English for which they had learned Spanish translations, compared with words for which they had not. Consolidation time did not significantly affect these interference effects. Thus, learning a new language indeed comes at the cost of subsequent retrieval ability in other FLs. Such interference effects set in immediately after learning and do not need time to emerge, even when the other FL has been known for a long time.

Consolidation improves the learning of new meanings for known words but not necessarily their integration into semantic memory

Consolidation is essential to the integration of novel words into the mental lexicon; however, its role in learning new meanings for known words remains unclear. This old-form-new-meaning learning is very common, as when one learns that "skate" is also a type of fish in addition to its familiar roller- or ice-skating meaning. To address consolidation effects for new meanings, we compared the behavioral and ERP measures on new and original meanings tested 24 hours after learning with words tested immediately after learning. Semantic judgments of both new and original meanings benefitted from the study-test interval. However, N400 amplitudes on studied words-indicators of meaning access from semantic memory-were unaffected by learning or consolidation. These results suggest that while sleep benefits memory for new meanings, the new meanings do not become integrated into the mental lexicon within that period. Instead, episodic retrieval remains functional in accessing new meanings even after 24 hours.

Diversity of narrative context disrupts the early stage of learning the meanings of novel words

High quality lexical representations develop through repeated exposures to words in different contexts. This preregistered experiment investigated how diversity of narrative context affects the earliest stages of word learning via reading. Adults (N = 100) learned invented meanings for eight pseudowords, which each occurred in five written paragraphs either within a single coherent narrative context or five different narrative contexts. The words' semantic features were controlled across conditions to avoid influences from polysemy (lexical ambiguity). Posttests included graded measures of word-form recall (spelling accuracy) and recognition (multiple choice), and word-meaning recall (number of semantic features). Diversity of narrative context did not affect word-form learning, but more semantic features were correctly recalled for words trained in a single context. These findings indicate that learning the meanings of novel words is initially boosted by anchoring them to a single coherent narrative discourse.

The impact of learning new meaning on the previously learned meaning of L2 ambiguous words: The role of semantic similarity

Previous study has found that previously learned meaning affects the learning of new meaning for known second language (L2) words. However, it is not clear whether learning a new meaning also affects the previously learned meaning and whether this effect is modulated by the semantic similarity between them. The current study aimed to explore this issue using event-related potential technique. A word learning task was used, in which Chinese-English bilinguals were required to learn a new meaning that was semantically related or unrelated to the previously learned meaning of familiar L2 words and judge the semantic relatedness between the trained word and a probe word in the same trial. The results showed that both the N400 and late-positive component (LPC) amplitudes for probe words in the unrelated new meaning condition were significantly different from the unlearned condition, which suggests learning new meaning interferes with accessing the previously learned meaning. Moreover, significantly less positive LPC was found in the unrelated new meaning condition relative to the related new meaning condition, showing a mediation of semantic similarity in the perturbation effect. We conclude that learning L2 new meaning has a backward interference effect on accessing the previously learned meaning and this effect is modulated by semantic similarity. These findings provide supporting evidence for the interaction mechanism of learning the multiple meanings of L2 ambiguous words.

Learning new words: Memory reactivation as a mechanism for strengthening and updating a novel word's meaning

In the present study we explored the postlearning changes in a novel word's definition using a cue-induced memory reactivation. Native speakers of Spanish (N = 373) learned low-frequency words with their corresponding definitions. The following day, reactivated groups were exposed to a reminder and provided a subjective assessment of reactivation for each word, while control groups did not receive a reactivation. Study A demonstrated that memory reactivation enhances both explicit recall and semantic integration of new meanings. Study B investigated the effect of memory reactivation in the modification of the new meanings, through three different experiments. Results show an improvement of the updated definitions according to each word's reactivation strength. In addition, congruence with previous knowledge was suggested to be a boundary condition, while consolidation time had a positive modulatory effect. Our findings call attention to reactivation as a factor allowing for malleability as well as persistence of long-term memories for words.