Consolidation of vocabulary is associated with sleep in children

Abstract

Research Highlights We present the first evidence that sleep-associated mechanisms are involved in vocabulary acquisition in childhood and provide the first support for a complementary learning systems account of vocabulary acquisition across development. Using the same paradigm as in adult research, we find that novel words show evidence of engaging in lexical competition with existing items approximately 12 hours after encountering the novel words, but only if sleep has occurred. We also provide the first evidence that sleep is important for the strengthening of new C phonological forms improved approximately 12 hours after training, but only if sleep occurred. In addition, we replicate the key finding that children show sleep-associated consolidation of declarative but not procedural memory in contrast to adults, suggesting that explicit and implicit aspects of word learning (i.e., recall/recognition and changes in lexical activity, respectively) cannot simply be associated with declarative and procedural memory systems. 3 AbstractAlthough the acquisition of a novel word is apparently rapid, adult research suggests that integration of novel and existing knowledge (measured by engagement in lexical competition) requires sleepassociated consolidation. We present the first investigation of whether a similar time-course dissociation characterises word learning across development. Consistent with previous research but counter to adults, 7-12-year-olds showed sleep-associated consolidation effects in declarative but not procedural memory. Nevertheless, the relationship between sleep and word learning was remarkably similar to adults. Following exposure to nonword competitors (e.g., biscal) in the a ability to recognise and recall the nonwords improved only after sleep (after approximately 12-hrs for the p.m. group and 24-hrs for the a.m. group), with performance stable 1-week later. Novel nonwords only induced lexical competition effects after sleep. These findings suggest that children utilize a dualmemory system when acquiring and integrating new vocabulary and highlight sleep as integral to this process.

Bedding down new words: Sleep promotes the emergence of lexical competition in visual word recognition

“…In demonstrating for the first time a sleep effect on visual word learning, the current study extends research on the influence of sleep on oral vocabulary learning (Dumay & Gaskell, 2007;Gaskell et al, 2014;Henderson et al, 2012;but cf. Szmalec et al, 2012).…”

“…Several studies have provided further evidence for the effect of sleep on consolidation of spoken word learning, in both adults (Tamminen, Payne, Stickgold, Wamsley, & Gaskell, 2010) and children (Henderson, Weighall, Brown, & Gaskell, 2012). These effects have been interpreted in the context of Complementary Learning Systems theory (McClelland, McNaughton, & OÕReilly, 1995;OÕReilly & Norman, 2002).…”

When the daffodat flew to the intergalactic zoo: Off-line consolidation is critical for word learning from stories.

“…A similar delayed emergence of lexical integration has been reported when children aged 7-12 years learn spoken novel competitors (Brown, Weighall, Henderson & Gaskell, 2012;Henderson, Weighall, Brown & Gaskell, 2012;Henderson, Weighall, Brown & Gaskell, 2013a (Henderson et al, 2013b). This suggests that the delay in lexical integration is not a consequence of learning meaningless or fictitious words (see also Takashima, Bakker, van Hell, Janzen & McQueen, 2014).…”

“…The pause detection task (Mattys & Clark, 2002) was used to measure lexical integration (following Dumay & Gaskell, 2007;Henderson et al, 2012Henderson et al, , 2013aHenderson et al, , 2013b This study addresses two main hypotheses: (1) …”

When words fail us: insights into language processing from developmental and acquired disorders

“…In this regard, we need more information on basic questions such as when and how often treatment is best applied, and how generalization from treated to untreated material can be enhanced. It may turn out that treatment features such as spacing of training [86] and opportunities for consolidation during sleep [87] could be as important as the specific materials used in intervention. An exciting recent development concerns the use of brain stimulation techniques-transcranial magnetic stimulation or transcranial direct current stimulation-as adjuncts to enhance language therapy [88,89].…”