Language control in the context of L3 acquisition

This book fills an existing gap in the field of third language acquisition (L3A) by bringing together theoretical, empirical, and practical accounts that contribute to informed teaching practices in multilingual classrooms

Cognitive development and educational attainment across the life span

In this thesis I explore two strands of research: in the first half I explore the effects of language learning on brain structure and cognitive function. In the second half I study to what extent educational attainment alter the rate of cognitive decline in old age. These different strands of research are united through the concept of brain plasticity, which is the brain’s ability to change its structural configuration in response to new experiences. In Study I we charted the neural underpinning of foreign language learning in a sample of younger adults. A total of 56 younger adults were randomized to either a 10-week beginner’s course in Italian or a control condition. For those studying Italian we found that grey-matter change in the right hippocampus was associated with how much time they spent practicing, rather than with how good they became suggesting that effort, rather than achieved proficiency, is what drives neuroplastic change. Study II presents the largest (to date) randomized trial looking into the causal effects of language learning as cognitive engagement in older age, specifically foreign language learning. 160 people between ages 65 and 75 were randomized to either an 11-week beginner’s course in Italian, or an 11-week relaxation training course. While we predicted that language learning would improve cognitive function, specifically associative memory, we found no evidence to support this hypothesis. Study III and IV address the question of whether or not educational attainment affects the rate of cognitive decline in old age. While it is clear that educational attainment is associated with level of cognitive function, we find no evidence that it alters the rate of decline in old age. Study III address this question using a novel statistical approach while Study IV presents a meta-analysis on the subject, arriving at similar conclusions

Primary School Education May Be Sufficient to Moderate a Memory-Hippocampal Relationship

According to the cognitive reserve theory, intellectual stimuli acquired during life can prevent against developing cognitive impairment. The underlying cognitive reserve mechanisms were underexplored in low-educated individuals. Because episodic memory impairment due to hippocampal dysfunction is a key feature of Alzheimer’s dementia (AD), we sought to look at a possible cognitive reserve mechanism by determining whether few years of education moderated the relationship between the hippocampal volumes and the episodic-memory scores. The sample was composed by 183 older adults, 40.1% male, with the median age of 78[76,82] years and the median years of education of 4[2,10] who had undergone an episodic-memory test and a 3-Tesla MRI scan to access the hippocampal volumes. Overall, 112 were cognitively healthy, 26 had cognitive impairment-no dementia (CIND) and 45 had dementia. We used multiple linear regression to assess whether the interaction between years of education and each hippocampal volume significantly predicted the episodic-memory scores’ variance, controlling for cognitive diagnosis and nuisance variables. The interaction term with the left hippocampus (ß = 0.2, p = 0.043, CI = 1.0, 1.4), but not with the right (ß = 0.1, p = 0.218, CI = 0.9, 1.2) significantly predicted the variation on memory scores. The mechanism by which the left hippocampus seems to play a more important role on memory processing in more educated individuals needs to be further investigated and might be associated with a better use of mnemonic strategies or higher hippocampal connectivity. Because the sample’s median years of education was four, which corresponds to primary school, we may infer that this level might be sufficient to contribute for building cognitive reserve

Learning a Foreign Language: A Review on Recent Findings About Its Effect on the Enhancement of Cognitive Functions Among Healthy Older Individuals

Currently, there is an increasing number of older population groups, especially in developed countries. This demographic trend, however, may cause serious problems, such as an increase in aging diseases, one of which is dementia whose main symptom consists in the decline of cognitive functioning. Although there has been ongoing pharmacological research on this neurological disorder, it has not brought satisfying results as far as its treatment is concerned. Therefore, governments all over the world are trying to develop alternative, non-pharmacological strategies/activities, which could help to prevent this cognitive decline while this aging population is still healthy in order to reduce future economic and social burden. One of the non-pharmacological approaches, which may enhance cognitive abilities and protect against the decline in healthy older population, seems to be the learning of a foreign language. The purpose of this mini-review article is to discuss recent findings about the effect of foreign language learning on the enhancement of cognitive functions among healthy older individuals. The findings, divided into three research areas, show that the learning of a foreign language may generate a lot of benefits for older individuals, such as enhancement of cognitive functioning, their self-esteem, increased opportunities of socializing, or reduction of costs. However, as Ware et al. (2017) indicate, any intervention program on foreign language learning should be well thought of and tailored to the needs of older people in order to be effective and avoid accompanying factors, such as older people’s anxiety or low self-confidence. Nevertheless, more empirical studies should be done in this area

Redefining bilingualism as a spectrum of experiences that differentially affect brain structure and function

Learning and using an additional language is shown to have an impact on the structure and function of the brain, including in regions involved in cognitive control and the connections between them. However, the available evidence remains variable in terms of the localization, extent and trajectory of these effects. Variability likely stems from the fact that bilingualism has been routinely operationalized as a categorical variable (bilingual/monolingual), whereas it is a complex and dynamic experience with a number of potentially deterministic factors affecting neural plasticity. Here we present the first study investigating the combined effects of experience-based factors (EBFs) in bilingual language use on brain structure and functional connectivity. EBFs include an array of measures of everyday usage of a second language in different types of immersive settings (e.g., amount of use in social settings). Analyses reveal specific adaptations in the brain, both structural and functional, correlated to individual EBFs and their combined effects. Taken together the data show that the brain adapts to be maximally efficient in the processing and control of two languages, although modulated ultimately by individual language experience

Linguistic immersion and structural effects on the bilingual brain: a longitudinal study

Learning and using additional languages can result in structural changes in the brain. However, the time course of these changes, as well as the factors the predict them, are still not well understood. In this longitudinal study we test the effects of bilingual immersion on brain structure of adult sequential bilinguals not undergoing any language training, who were scanned twice, three years apart. We observed significant increases in grey matter volume in the lower left cerebellum, mean white matter diffusivity in the frontal cortex, and reshaping of the left caudate nucleus and amygdala and bilateral hippocampus. Moreover, both prior length of immersion and L2 age of acquisition were significant predictors of volumetric change in the cerebellum. Taken together, these results indicate that bilingualism-induced neurological changes continue to take place across the lifespan and are strongly related to the quantity and quality of bilingual immersion, even in highly-immersed adult bilingual populations

Understanding structural plasticity in the bilingual brain: The Dynamic Restructuring Model

Research on the effects of bi-/multilingualism on brain structure has so far yielded variable patterns. Although it cannot be disputed that learning and using additional languages restructures grey (cortical, subcortical and cerebellar) and white matter in the brain, both increases and reductions in regional volume and diffusivity have been reported. This paper revisits the available evidence from simultaneous and sequential bilinguals, multilinguals, interpreters, bimodal bilinguals, children, patients and healthy older adults from the perspective of experience-based neuroplasticity. The Dynamic Restructuring Model (DRM) is then presented, a three-stage model accounting for, and reinterpreting, all the available evidence by proposing a time-course for the reported structural adaptations, and by suggesting that these adaptations are dynamic and depend on the quantity and quality of the language learning and switching experience. This is followed by suggestions for future directions for the emerging field of bilingualism-induced neuroplasticit

Neuroimaging the sleeping brain: Insight on memory functioning in infants and toddlers.

Episodic memory, or the ability to remember past events with specific detail, is central to the human experience and is related to learning and adaptive functioning in a variety of domains. In typically developing children, episodic memory emerges during infancy and improves during early childhood and beyond. Developmental processes within the hippocampus are hypothesized to be primarily responsible for both the early emergence and persistence of episodic memory in late infancy and early childhood. However, these hypotheses are based on non-human models. In-vivo investigations in early human development of hippocampal processes have been significantly limited by methodological challenges in acquiring neuroimaging data, particularly task-related functional neuroimaging data, from infants and toddlers. Recent studies in adults have shown neural activity in the brain regions supporting episodic memory during slow-wave sleep using functional magnetic resonance imaging (fMRI), and fMRI has been increasingly utilized in infancy and early childhood to address other research questions. We review initial evidence and present preliminary data showing the promise of this approach for examining hippocampal contribution to how infants and toddlers remember individual events, and their association with information about the context in which the event occurred. Overall, our review, integrated with the presentation of some preliminary data provides insight on leveraging sleep to gain new perspectives on early memory functioning

Eye-tracking the time‐course of novel word learning and lexical competition in adults and children

Lexical competition is a hallmark of proficient, automatic word recognition. Previous research suggests that there is a delay before a new spoken word becomes engaged in this process, with sleep playing an important role. However, data from one method--the visual world paradigm--consistently show competition without a delay. We trained 42 adults and 40 children (aged 7-8) on novel word-object pairings, and employed this paradigm to measure the time-course of lexical competition. Fixations to novel objects upon hearing existing words (e.g., looks to the novel object biscal upon hearing “click on the biscuit”) were compared to fixations on untrained objects. Novel word-object pairings learned immediately before testing and those learned the previous day exhibited significant competition effects, with stronger competition for the previous day pairings for children but not adults. Crucially, this competition effect was significantly smaller for novel than existing competitors (e.g., looks to candy upon hearing “click on the candle”), suggesting that novel items may not compete for recognition like fully-fledged lexical items, even after 24 hours. Explicit memory (cued recall) was superior for words learned the day before testing, particularly for children; this effect (but not the lexical competition effects) correlated with sleep-spindle density. Together, the results suggest that different aspects of new word learning follow different time courses: visual world competition effects can emerge swiftly, but are qualitatively different from those observed with established words, and are less reliant upon sleep. Furthermore, the findings fit with the view that word learning earlier in development is boosted by sleep to a greater degree