From specific examples to general knowledge in language learning

AbstractThe extraction of general knowledge from individual episodes is critical if we are to learn new knowledge or abilities. Here we uncover some of the key cognitive mechanisms that characterise this process in the domain of language learning. In five experiments adult participants learned new morphological units embedded in fictitious words created by attaching new affixes (e.g., -afe) to familiar word stems (e.g., “sleepafe is a participant in a study about the effects of sleep”). Participants’ ability to generalise semantic knowledge about the affixes was tested using tasks requiring the comprehension and production of novel words containing a trained affix (e.g., sailafe). We manipulated the delay between training and test (Experiment 1), the number of unique exemplars provided for each affix during training (Experiment 2), and the consistency of the form-to-meaning mapping of the affixes (Experiments 3–5). In a task where speeded online language processing is required (semantic priming), generalisation was achieved only after a memory consolidation opportunity following training, and only if the training included a sufficient number of unique exemplars. Semantic inconsistency disrupted speeded generalisation unless consolidation was allowed to operate on one of the two affix-meanings before introducing inconsistencies. In contrast, in tasks that required slow, deliberate reasoning, generalisation could be achieved largely irrespective of the above constraints. These findings point to two different mechanisms of generalisation that have different cognitive demands and rely on different types of memory representations

Targeted memory reactivation of newly learned words during sleep triggers REM-mediated integration of new memories and existing knowledge

Recent memories are spontaneously reactivated during sleep, leading to their gradual strengthening. Whether reactivation also mediates the integration of new memories with existing knowledge is unknown. We used targeted memory reactivation (TMR) during slow-wave sleep (SWS) to selectively cue reactivation of newly learned spoken words. While integration of new words into their phonological neighbourhood was observed in both cued and uncued words after sleep, TMR-triggered integration was predicted by the time spent in rapid eye movement (REM) sleep. These data support complementary roles for SWS and REM in memory consolidation

Higher sleep spindle activity is associated with fewer false memories in adolescent girls

Background: Sleep facilitates the extraction of semantic regularities amongst newly encoded memories, which may also lead to increased false memories. We investigated sleep stage proportions and sleep spindles in the recollection of adolescents' false memories, and their potential sex-specific differences. Methods: 196 adolescents (mean age 16.9 y; SD = 0.1, 61% girls) underwent the Deese, Roediger & McDermott (DRM) false memory procedure and overnight polysomnography, with free recall the following morning. Sleep was scored manually into stages 1, 2, 3 and REM. Stage 2 sleep spindle frequency, density, and peak amplitude were used as measures of spindle activity for slow (10-13 Hz) and fast (13-16 Hz) ranges. Results: In girls, a lower number of critical lures was associated with higher spindle frequency (p Conclusions: In adolescent girls, higher spindle activity was associated with fewer critical lures being falsely recalled in the DRM paradigm. Unlike studies using adult participants, we did not observe any association between slow-wave sleep and false memory recollection.Peer reviewe

The impact of music on learning and consolidation of novel words

Music can be a powerful mnemonic device, as shown by a body of literature demonstrating that listening to text sung to a familiar melody results in better memory for the words compared to conditions where they are spoken. Furthermore, patients with a range of memory impairments appear to be able to form new declarative memories when they are encoded in the form of lyrics in a song, while unable to remember similar materials after hearing them in the spoken modality. Whether music facilitates the acquisition of completely new information, such as new vocabulary, remains unknown. Here we report three experiments in which adult participants learned novel words in the spoken or sung modality. While we found no benefit of musical presentation on free recall or recognition memory of novel words, novel words learned in the sung modality were more strongly integrated in the mental lexicon compared to words learned in the spoken modality. This advantage for the sung words was only present when the training melody was familiar. The impact of musical presentation on learning therefore appears to extend beyond episodic memory and can be reflected in the emergence and properties of new lexical representations

Learning new words: effects of meaning, memory consolidation, and sleep

Although encountering novel words in one's own language in adulthood is not an uncommon event, the relevant cognitive processes have become the target of systematic investigation only in recent years. This thesis addressed three main questions regarding word learning. The first was concerned with the role of meaning: to what degree is meaning necessary in integrating new representations in the lexicon? Experiments 1-3 suggested that meaning is indeed important. In the absence of trained meaning novel words may "inherit" the meaning of neighbouring familiar words, possibly explaining some seemingly incompatible reports in the literature (Experiment 1). Experiment 3 showed that such inherited meaning is sufficient to allow integration of novel words in the lexicon. Having established the importance of meaning in lexical integration, the thesis moved to the second question: does knowledge of novel word meanings benefit from offline memory consolidation? Experiments 4-7 suggested that this is the case. Experiment 4 showed that consolidated novel words elicited faster semantic decisions than words learned just before testing, while Experiment 5 showed that cued recall of word forms is also enhanced over time. Experiments 6-7 refined these conclusions by using semantic priming paradigms, showing that novel word primes facilitate processing of semantically associated familiar words after a period of offline consolidation has been allowed to operate over an extended period of time involving several days and/or nights. The third question focused on the role of sleep in the consolidation of novel words: which aspects of sleep architecture are associated with lexical integration? Experiment 8 looked at sleep during the night after word learning and sought to clarify the roles sleep spindles and different sleep stages play in word learning. Spindle activity was associated with the emergence of lexical competition effects, suggesting that sleep has an active role in word learning, and that spindles in particular are associated with lexical integration. These effects were interpreted in light of complementary learning systems theories