Lateralised sleep spindles relate to false memory generation

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Sleep is known to enhance false memories: After presenting participants with lists of semantically related words, sleeping before recalling these words results in a greater acceptance of unseen “lure” words related in theme to previously seen words. Furthermore, the right hemisphere (RH) seems to be more prone to false memories than the left hemisphere (LH). In the current study, we investigated the sleep architecture associated with these false memory and lateralisation effects in a nap study. Participants viewed lists of related words, then stayed awake or slept for approximately 90 min, and were then tested for recognition of previously seen-old, unseen-new, or unseen-lure words presented either to the LH or RH. Sleep increased acceptance of unseen-lure words as previously seen compared to the wake group, particularly for RH presentations of word lists. RH lateralised stage 2 sleep spindle density relative to the LH correlated with this increase in false memories, suggesting that RH sleep spindles enhanced false memories in the RH

Age of acquisition predicts rate of lexical evolution

The processes taking place during language acquisition are proposed to influence language evolution. However, evidence demonstrating the link between language learning and language evolution is, at best, indirect, constituting studies of laboratory-based artificial language learning studies or computational simulations of diachronic change. In the current study, a direct link between acquisition and evolution is established, showing that for two hundred fundamental vocabulary items, the age at which words are acquired is a predictor of the rate at which they have changed in studies of language evolution. Early-acquired words are more salient and easier to process than late-acquired words, and these early-acquired words are also more stably represented within the community's language. Analysing the properties of these early-acquired words potentially provides insight into the origins of communication, highlighting features of words that have been ultra-conserved in language. (C) 2014 Elsevier B.V. All rights reserved

Literacy and early language development: Insights from computational modelling

Computational models of reading have tended to focus on the cognitive requirements of mapping among written, spoken, and meaning representations of individual words in adult readers. Consequently, the alignment of these computational models with behavioural studies of reading development has been limited. Computational models of reading have provided us with insights into the architecture of the reading system, and these have recently been extended to investigate literacy development, and the early language skills that influence children’s reading. These models show us: how learning to read builds on early language skills, why various reading interventions might be more or less effective for different children, and how reading develops across different languages and writing systems. Though there is growing alignment between descriptive models of reading behaviour and computational models, there remains a gap, and I lay out the groundwork for how translation may become increasingly effective through future modelling work

Hemispheric processing of memory is affected by sleep

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Sleep is known to affect learning and memory, but the extent to which it influences behavioural processing in the left and right hemispheres of the brain is as yet unknown. We tested two hypotheses about lateralised effects of sleep on recognition memory for words: whether sleep reactivated recent experiences of words promoting access to the long-term store in the left hemisphere (LH), and whether sleep enhanced spreading activation differentially in semantic networks in the hemispheres. In Experiment 1, participants viewed lists of semantically related words, then slept or stayed awake for 12 h before being tested on seen, unseen but related, or unrelated words presented to the left or the right hemisphere. Sleep was found to promote word recognition in the LH, and to spread activation equally within semantic networks in both hemispheres. Experiment 2 ensured that the results were not due to time of day effects influencing cognitive performance

Mutual exclusivity develops as a consequence of abstract rather than particular vocabulary knowledge

Mutual exclusivity (ME) refers to the assumption that there are one-to-one relations between linguistic forms and their meanings. It is used as a word-learning strategy whereby children tend to map novel labels to unfamiliar rather than familiar referents. Previous research has indicated a relation between ME and vocabulary development, which could either be due to children's developing knowledge of the labels for familiar objects, or to enhanced general word-learning skills. In this study, ME was related to receptive vocabulary for 17- to 19-month-old children in a novel paradigm where children's familiarity with the objects and labels was controlled. It was found that infants with larger receptive vocabularies employed ME to a greater extent than infants with a smaller vocabulary size. The results indicate that ME use is more reliable in infants with larger receptive vocabulary size, and, critically, that ME gradually consolidates as an abstract word-learning strategy as infants' linguistic experience increases

Effects of experience in a developmental model of reading

There is considerable evidence showing that age of acquisition (AoA) is an important factor influencing lexical processing. Early-learned words tend to be processed more quickly compared to later-learned words. The effect could be due to the gradual reduction in plasticity as more words are learned. Alternatively, it could originate from differences within semantic representations. We implemented the triangle model of reading including orthographic, phonological and semantic processing layers, and trained it according to experience of a language learner to explore the AoA effects in both naming and lexical decision. Regression analyses on the model’s performance showed that AoA was a reliable predictor of naming and lexical decision performance, and the effect size was larger for lexical decision than for naming. The modelling results demonstrate that AoA operates differentially on concrete and abstract words, indicating that both the mapping and the representation accounts of AoA were contributing to the model’s performance

Cognitive influences in language evolution:Psycholinguistic predictors of loan word borrowing

Languages change due to social, cultural, and cognitive influences. In this paper, we provide an assessment of these cognitive influences on diachronic change in the vocabulary. Previously, tests of stability and change of vocabulary items have been conducted on small sets of words where diachronic change is imputed from cladistics studies. Here, we show for a substantially larger set of words that stability and change in terms of documented borrowings of words into English and into Dutch can be predicted by psycholinguistic properties of words that reflect their representational fidelity. We found that grammatical category, word length, age of acquisition, and frequency predict borrowing rates, but frequency has a non-linear relationship. Frequency correlates negatively with probability of borrowing for high-frequency words, but positively for low-frequency words. This borrowing evidence documents recent, observable diachronic change in the vocabulary enabling us to distinguish between change associated with transmission during language acquisition and change due to innovations by proficient speakers

The role of feedback and instruction on the cross-situational learning of vocabulary and morphosyntax:Mixed effects models reveal local and global effects on acquisition

First language acquisition is implicit, in that explicit information about the language structure to be learned is not provided to children. Instead, they must acquire both vocabulary and grammar incrementally, by generalizing across multiple situations that eventually enable links between words in utterances and referents in the environment to be established. However, this raises a problem of how vocabulary can be acquired without first knowing the role of the word within the syntax of a sentence. It also raises practical issues about the extent to which different instructional conditions – about grammar in advance of learning or feedback about correct decisions during learning – might influence second language acquisition of implicitly experienced information about the language. In an artificial language learning study, we studied participants learning language from inductive exposure, but under different instructional conditions. Language learners were exposed to complex utterances and complex scenes and had to determine the meaning and the grammar of the language from these co-occurrences with environmental scenes. We found that learning was boosted by explicit feedback, but not by explicit instruction about the grammar of the language, compared to an implicit learning condition. However, the effect of feedback was not general across all aspects of the language. Feedback improved vocabulary, but did not affect syntax learning. We further investigated the local, contextual effects on learning, and found that previous knowledge of vocabulary within an utterance improved learning but that this was driven only by certain grammatical categories in the language. The results have implications for theories of second language learning informed by our understanding of first language acquisition as well as practical implications for learning instruction and optimal, contingent adjustment of learners’ environment during their learning

Infants’ attention during cross-situational word learning: Environmental variability promotes novelty preference

Infants as young as 14 months can track cross-situational statistics between sets of words and objects to acquire word–referent mappings. However, in naturalistic word learning situations, words and objects occur with a host of additional information, sometimes noisy, present in the environment. In this study, we tested the effect of this environmental variability on infants’ word learning. Fourteen-month-old infants (N = 32) were given a cross-situational word learning task with additional gestural, prosodic, and distributional cues that occurred reliably or variably. In the reliable cue condition, infants were able to process this additional environmental information to learn the words, attending to the target object during test trials. But when the presence of these cues was variable, infants paid greater attention to the gestural cue during training and subsequently switched preference to attend more to novel word–object mappings rather than familiar ones at test. Environmental variation may be key to enhancing infants’ exploration of new information