The Source of Enhanced Cognitive Control in Bilinguals: Evidence From Bimodal Bilinguals

Bilinguals often outperform monolinguals on nonverbal tasks that require resolving conflict from competing alternatives. The regular need to select a target language is argued to enhance executive control. We investigated whether this enhancement stems from a general effect of bilingualism (the representation of two languages) or from a modality constraint that forces language selection. Bimodal bilinguals can, but do not always, sign and speak at the same time. Their two languages involve distinct motor and perceptual systems, leading to weaker demands on language control. We compared the performance of 15 monolinguals, 15 bimodal bilinguals, and 15 unimodal bilinguals on a set of flanker tasks. There were no group differences in accuracy, but unimodal bilinguals were faster than the other groups; bimodal bilinguals did not differ from monolinguals. These results trace the bilingual advantage in cognitive control to the unimodal bilingual’s experience controlling two languages in the same modality

Does Speaking Two Dialects in Daily Life Affect Executive Functions? An Event-Related Potential Study

Whether using two languages enhances executive functions is a matter of debate. Here, we take a novel perspective to examine the bilingual advantage hypothesis by comparing bidialect with mono-dialect speakers’ performance on a non-linguistic task that requires executive control. Two groups of native Chinese speakers, one speaking only the standard Chinese Mandarin and the other also speaking the Southern-Min dialect, which differs from the standard Chinese Mandarin primarily in phonology, performed a classic Flanker task. Behavioural results showed no difference between the two groups, but event-related potentials recorded simultaneously revealed a number of differences, including an earlier P2 effect in the bi-dialect as compared to the mono-dialect group, suggesting that the two groups engage different underlying neural processes. Despite differences in the early ERP component, no between-group differences in the magnitude of the Flanker effects, which is an index of conflict resolution, were observed in the N2 component. Therefore, these findings suggest that speaking two dialects of one language does not enhance executive functions. Implications of the current findings for the bilingual advantage hypothesis are discussed

Lifelong Bilingualism Maintains White Matter Integrity in Older Adults

Previous research has shown that bilingual speakers have higher levels of cognitive control than comparable monolinguals, especially at older ages. The present study investigates a possible neural correlate of this behavioral effect. Given that white matter (WM) integrity decreases with age in adulthood, we tested the hypothesis that bilingualism is associated with maintenance of WM in older people. Using diffusion tensor imaging, we found higher WM integrity in older people who were lifelong bilinguals than in monolinguals. This maintained integrity was measured by fractional anisotropy (FA) and was found in the corpus callosum extending to the superior and inferior longitudinal fasciculi. We also hypothesized that stronger WM connections would be associated with more widely distributed patterns of functional connectivity in bilinguals. We tested this by assessing the resting-state functional connectivity of frontal lobe regions adjacent to WM areas with group differences in FA. Bilinguals showed stronger anterior to posterior functional connectivity compared to monolinguals. These results are the first evidence that maintained WM integrity is related to lifelong naturally occurring experience; the resulting enhanced structural and functional connectivity may provide a neural basis for “brain reserve.

Language control and parallel recovery of language in individuals with aphasia

Background: The causal basis of the different patterns of language recovery following stroke in bilingual speakers is not well understood. Our approach distinguishes the representation of language from the mechanisms involved in its control. Previous studies have suggested that difficulties in language control can explain selective aphasia in one language as well as pathological switching between languages. Here we test the hypothesis that difficulties in managing and resolving competition will also be observed in those who are equally impaired in both their languages even in the absence of pathological switching. Aims: To examine difficulties in language control in bilingual individuals with parallel recovery in aphasia and to compare their performance on different types of conflict task. Methods & procedures: Two right-handed, non-native English-speaking participants who showed parallel recovery of two languages after stroke and a group of non-native English-speaking, bilingual controls described a scene in English and in their first language and completed three explicit conflict tasks. Two of these were verbal conflict tasks: a lexical decision task in English, in which individuals distinguished English words from non-words, and a Stroop task, in English and in their first language. The third conflict task was a non-verbal flanker task. Outcomes & Results: Both participants with aphasia were impaired in the picture description task in English and in their first language but showed different patterns of impairment on the conflict tasks. For the participant with left subcortical damage, conflict was abnormally high during the verbal tasks (lexical decision and Stroop) but not during the non-verbal flanker task. In contrast, for the participant with extensive left parietal damage, conflict was less abnormal during the Stroop task than the flanker or lexical decision task. Conclusions: Our data reveal two distinct control impairments associated with parallel recovery. We stress the need to explore the precise nature of control problems and how control is implemented in order to develop fuller causal accounts of language recovery patterns in bilingual aphasia

Morphosyntactic processing in late second-language learners

The goal of the present study was to investigate the electro- physiological correlates of second-language (L2) morphosyn- tactic processing in highly proficient late learners of an L2 with long exposure to the L2 environment. ERPs were col- lected from 22 English–Spanish late learners while they read sentences in which morphosyntactic features of the L2 present or not present in the first language (number and gender agree- ment, respectively) were manipulated at two different sentence positions—within and across phrases. The results for a control group of age-matched native-speaker Spanish participants in- cluded an ERP pattern of LAN-type early negativity followed by P600 effect in response to both agreement violations and for both sentence positions. The late L2 learner results included a similar pattern, consisting of early negativity followed by P600, in the first sentence position (within-phrase agreement viola- tions) but only P600 effects in the second sentence position (across-phrase agreement violation), as well as significant am- plitude and onset latency differences between the gender and the number violation effects in both sentence positions. These results reveal that highly proficient learners can show electro- physiological correlates during L2 processing that are qualita- tively similar to those of native speakers, but the results also indicate the contribution of factors such as age of acquisition and transfer processes from first language to L

Neuroscience and education: prime time to build the bridge

As neuroscience gains social traction and entices media attention, the notion that education has much to benefit from brain research becomes increasingly popular. However, it has been argued that the fundamental bridge toward education is cognitive psychology, not neuroscience. We discuss four specific cases in which neuroscience synergizes with other disciplines to serve education, ranging from very general physiological aspects of human learning such as nutrition, exercise and sleep, to brain architectures that shape the way we acquire language and reading, and neuroscience tools that increasingly allow the early detection of cognitive deficits, especially in preverbal infants. Neuroscience methods, tools and theoretical frameworks have broadened our understanding of the mind in a way that is highly relevant to educational practice. Although the bridge’s cement is still fresh, we argue why it is prime time to march over it

On natural metalinguistic abilities in aphasia: a preliminary study

Natural metalinguistic abilities, which are put into play without explicit instructions, constitute the cognitive basis for a 'reflexive' use of language, a particular manifestation of the executive function when applied to language and verbal behaviour. This reflexive use entails a specific attentional activity by speakers and hearers with regard to linguistic outputs, and an intentional experience-based control over the language use. Putting into play natural metalinguistic abilities can be considered a significant factor for explaining different kinds of adaptive processes. Our results permit us to conclude that an impairment of metalinguistic abilities is involved in aphasia to different degrees. Moreover, the examination of preserved metalinguistic abilities provides an alternative way for assessing the degree of severity of impaired communicative behaviour by people with aphasia. Our procedure, presumably, will also be useful for suggesting new factors when designing therapeutic programmes

Towards ‘languages for all’ in England: the state of the debate

Whether the study of languages should be a core element of a balanced and broadly based curriculum for all pupils in England’s 11–16 state-funded secondary schools is also part of a wider debate concerning how to harness England’s rich linguistic and cultural diversity and improve the quality and range of language skills of the country. While learning a second language throughout compulsory schooling is increasingly the norm across the world, fewer than 50% of 14–16 year olds in state-funded schools in England gained a modern language qualification (General Certification of Secondary Education or GCSE) in 2015. From 2015, recent government education policy has required the majority of pupils commencing secondary school to study a language to GCSE level, suggesting that schools who do not comply will be unable to gain the top inspection grade. This paper reviews the state of the debate examining divergent and contradictory perspectives within education policy and in the literature. It concludes by setting out six conditions for achieving this policy goal for enabling secondary schools to successfully implement a coherent and relevant languages curriculum for all young people, such that they can develop the linguistic and intercultural competencies needed to contribute to and thrive in increasingly diverse local and global communities

The threshold hypothesis revisited: bilingual lexical knowledge and non-verbal IQ development

The threshold hypothesis (Cummins 1976 et passim) is one of the most influential theoretical frameworks on the relation between bilingualism and cognition. The aim of our study is to contribute towards an operationalisation of the threshold hypothesis. We analyse data from 100 Turkish-English successive bilingual children and from their parents, and investigate the relation between bilingualism and cognition. When compared with monolingual control groups, the bilinguals in our study have smaller vocabulary sizes in both languages. However, when both vocabularies are taken together and the total conceptual vocabulary is computed no bilingual disadvantage can be identified. Children with parental support for L1 outperform the monolingual control groups in our study in terms of non-verbal intelligence scores. The originality of the present study resides in the fact that, to our knowledge, for the first time parental support for L1 and dominance in L1 is linked to the cognitive development of the children