The Impact of Bilingualism on Working Memory: A Null Effect on the Whole May Not Be So on the Parts

The Effect of Phonetic Similarity on Domain-General Executive Control in Color-Shape Task: Evidence from Cantonese-Mandarin and Beijing-Dialect-Mandarin Bidialectals

The present study was carried out to investigate whether bidialectals have a similar advantage in domain-general executive function as bilinguals and if so whether the phonetic similarity between two different dialects can modulate the executive function performance in the conflicting-switching task. The results showed that the latencies for switching trials in mixed block (SMs) were longest, non-switching trials in mixed block (NMs) were medium, and non-switching trials in pure block (NPs) were the shortest in the conflict-switching task in all three groups of participants. Importantly, the difference between NPs and NMs varied as a function of phonetic similarity between two dialects with Cantonese-Mandarin bidialectal speakers being the minimum, Beijing-dialect-Mandarin bidialectals medium, and Mandarin native speakers maximum. These results provide strong evidence that there is an advantage in balanced bidialectals's executive function which is modulated by the phonetic similarity between two dialects suggesting that phonetic similarity plays an important role in domain-general executive function.

Working Memory Models and Measures in Language and Bilingualism Research: Integrating Cognitive and Affective Perspectives

Although emotional or affective working memory (WM) is quite well established in general psychology, not much research has looked into its potential implications for the language sciences and bilingualism and second language acquisition (SLA) research until recently. To fill this gap, this paper aims to propose that WM has not just cognitive implications, but its affective dimension may also make complementary and unique contributions to language and bilingualism/SLA research. Towards this end, we first briefly synthesize the cognitive views of WM conceptions and assessment procedures in the current language sciences and bilingualism/SLA research. Next, we turn to discuss the theoretical models and assumptions of affective WM and explore their theoretical implications for bilingualism/SLA research based on emerging empirical evidence. Then, we propose a conceptual framework integrating cognitive and affective WM perspectives and further provide guidelines for designing affective WM span tasks that can be used in future affective WM–language research, focusing on the construction procedures of several emotion-based affective WM span tasks (e.g., the emotional reading span task, the emotional operation span task, and the emotional symmetry span task) as examples. Overall, we argue that affective feelings are also an integral part of the mental representations held in WM and future research in the language sciences and bilingualism/SLA should incorporate both cognitive and affective WM dimensions.

School Readiness in Language-Minority Dual Language Learners in Japan: Language, Executive Function, and Theory of Mind

The present study investigated school readiness in Brazilian (Portuguese-Japanese dual language learner or DLL) 5-year-olds in Japan (1) by examining their language skills, executive function (EF), and theory of mind (ToM) in comparison to their monolingual peers and (2) by investigating the developmental relations between these three skills. DLLs scored lower than monolinguals in Japanese language skills, specifically in receptive vocabulary and the understanding of complement clauses in Japanese. DLLs and monolinguals performed similarly in EF, particularly in inhibitory control tasks measuring interference suppression and response inhibition. However, monolinguals outperformed DLLs in ToM tasks assessing false belief understanding. Finally, DLLs' interference suppression and understanding of complement clauses were both positively related to their false belief understanding. In conclusion, DLLs had school readiness difficulties in Japanese language skills and ToM, but not in EF, compared to their Japanese monolingual peers. Furthermore, the positive relationship of language and EF skills with ToM development, which is commonly reported in monolingual children, extended to an understudied population of DLLs in this study.

The role of working memory in children's ability for prosodic discrimination

Previous research established that young children are sensitive to prosodic cues discriminating between syntactic structures of otherwise similarly sounding sentences in a language unknown to them. In this study, we explore the role of working memory that children might deploy for the purpose of the sentence-level prosodic discrimination. Nine-year old Slovenian monolingual and bilingual children (N = 70) were tested on a same-different prosodic discrimination task in a language unknown to them (French) and on the working memory measures in the form of forward and backward digit span and non-word repetition tasks. The results suggest that both the storage and processing components of the working memory are involved in the prosodic discrimination task.

Rethinking the Neural Basis of Prosody and Non-literal Language: Spared Pragmatics and Cognitive Compensation in a Bilingual With Extensive Right-Hemisphere Damage

Above and beyond the critical contributions of left perisylvian regions to language, the neural networks supporting pragmatic aspects of verbal communication in native and non-native languages (L1s and L2, respectively) have often been ascribed to the right hemisphere (RH). However, several reports have shown that left-hemisphere activity associated with pragmatic domains (e.g., prosody, indirect speech, figurative language) is comparable to or even greater than that observed in the RH, challenging the proposed putative role of the latter for relevant domains. Against this background, we report on an adult bilingual patient showing preservation of pragmatic verbal skills in both languages (L1: Spanish, L2: English) despite bilateral damage mainly focused on the RH. After two strokes, the patient sustained lesions in several regions previously implicated in pragmatic functions (vast portions of the right fronto-insulo-temporal cortices, the bilateral amygdalae and insular cortices, and the left putamen). Yet, comparison of linguistic and pragmatic skills with matched controls revealed spared performance on multiple relevant tasks in both her L1 and L2. Despite mild difficulties in some aspects of L2 prosody, she showed no deficits in comprehending metaphors and idioms, or understanding indirect speech acts in either language. Basic verbal skills were also preserved in both languages, including verbal auditory discrimination, repetition of words and pseudo-words, cognate processing, grammaticality judgments, equivalent recognition, and word and sentence translation. Taken together, the evidence shows that multiple functions of verbal communication can be widely spared despite extensive damage to the RH, and that claims for a putative relation between pragmatics and the RH may have been overemphasized in the monolingual and bilingual literature. We further discuss the case in light of previous reports of pragmatic and linguistic deficits following brain lesions and address its relation to cognitive compensation in bilingual patients.

Neural Correlates of Enhanced Audiovisual Processing in the Bilingual Brain

Bilingualism is associated with enhancements in perceptual and cognitive processing necessary for juggling multiple languages. Recent psychophysical studies demonstrate bilinguals also show enhanced multisensory processing and more restricted temporal binding windows for integrating audiovisual information. Here, we probed the neural mechanisms of bilinguals' audiovisual benefits. We recorded neuroelectric responses in mono- and bi-lingual listeners to the double-flash paradigm in which auditory beeps concurrent with a single visual flash induces the perceptual illusion of multiple flashes. Relative to monolinguals, bilinguals showed less susceptibility to the illusion (fewer false perceptual reports) coupled with stronger and faster event-related potentials to audiovisual information. Source analyses of EEG data revealed monolinguals' increased propensity for erroneously perceiving audiovisual stimuli was attributed to increased activity in primary visual (V1) and auditory cortex (PAC), increases in multisensory association areas (BA 37), but reduced frontal activity (BA 10). Regional activations were associated with an opposite pattern of behaviors: whereas stronger V1 and PAC activity predicted slower behavioral responses, stronger frontal BA10 responses elicited faster judgments. Our results suggest bilinguals' higher precision in audiovisual perception reflects more veridical sensory coding of physical cues coupled with superior top-down gating of sensory information to suppress the generation of false percepts. Findings underscore that the plasticity afforded by speaking multiple languages shapes extra-linguistic brain regions and can enhance audiovisual brain processing in a domain-general manner.

Bilingualism and working memory performance: Evidence from a large-scale online study

The bilingual executive advantage (BEA) hypothesis has attracted considerable research interest, but the findings are inconclusive. We addressed this issue in the domain of working memory (WM), as more complex WM tasks have been underrepresented in the previous literature. First, we compared early and late bilingual vs. monolingual WM performance. Second, we examined whether certain aspects of bilingual experience, such as language switching frequency, are related to bilinguals' WM scores. Our online sample included 485 participants. They filled in an extensive questionnaire including background factors such as bilingualism and second language (L2) use, and performed 10 isomorphic verbal and visuospatial WM tasks that yielded three WM composite scores (visuospatial WM, verbal WM, n-back). For verbal and visuospatial WM composites, the group comparisons did not support the BEA hypothesis. N-back analysis showed an advantage of late bilinguals over monolinguals and early bilinguals, while the latter two groups did not differ. This between-groups analysis was followed by a regression analysis relating features of bilingual experience to n-back performance, but the results were non-significant in both bilingual groups. In sum, group differences supporting the BEA hypothesis were limited only to the n-back composite, and this composite was not predicted by bilingualism-related features. Moreover, Bayesian analyses did not give consistent support for the BEA hypothesis. Possible reasons for the failure to find support for the BEA hypothesis are discussed.

Changes in executive function over time in bilingual and monolingual school-aged children

We examined the development of 3 executive function (EF) components-inhibition, updating, and task shifting-over time in monolingual and bilingual school-age children. We tested 41 monolingual and 41 simultaneous bilingual typically developing children (ages 8-12) on nonverbal tasks measuring inhibition (the Flanker task), updating (the Corsi blocks task), and task shifting (the Dimensional Change Card Sort task; DCCS) at 2 time points, 1 year apart. Three indexes of task shifting (shifting, switching, and mixing costs) were derived from the DCCS task. The 2 groups did not differ in their development of updating, but did demonstrate distinct patterns of development for inhibition. Specifically, while the bilingual group demonstrated a steep improvement in inhibition from Year 1 to Year 2, the monolingual group was characterized by stable inhibition performance over this time period. The 2 groups did not differ in their developmental patterns for shifting and switching costs, but for mixing costs, the bilingual children outperformed the monolingual children in both years. Together, the findings indicate that bilingual experience may modulate the developmental rates of some components of EF but not others, resulting in specific EF performance differences between bilinguals and monolinguals only at certain developmental time points. (PsycINFO Database Record

Top-Down Cognitive and Linguistic Influences on the Suppression of Spontaneous Otoacoustic Emissions

Auditory sensation is often thought of as a bottom-up process, yet the brain exerts top-down control to affect how and what we hear. We report the discovery that the magnitude of top-down influence varies across individuals as a result of differences in linguistic background and executive function. Participants were 32 normal-hearing individuals (23 female) varying in language background (11 English monolinguals, 10 Korean-English late bilinguals, and 11 Korean-English early bilinguals), as well as cognitive abilities (working memory, cognitive control). To assess efferent control over inner ear function, participants were presented with speech-sounds (e.g., /ba/, /pa/) in one ear while spontaneous otoacoustic emissions (SOAEs) were measured in the contralateral ear. SOAEs are associated with the amplification of sound in the cochlea, and can be used as an index of top-down efferent activity. Individuals with bilingual experience and those with better cognitive control experienced larger reductions in the amplitude of SOAEs in response to speech stimuli, likely as a result of greater efferent suppression of amplification in the cochlea. This suppression may aid in the critical task of speech perception by minimizing the disruptive effects of noise. In contrast, individuals with better working memory exert less control over the cochlea, possibly due to a greater capacity to process complex stimuli at later stages. These findings demonstrate that even peripheral mechanics of auditory perception are shaped by top-down cognitive and linguistic influences.

A core avenue for transcultural research on dementia: on the cross-linguistic generalization of language-related effects in Alzheimer's disease and Parkinson's disease

OBJECTIVE

Language is a key source of cross-cultural variability, which may have both subtle and major effects on neurocognition. However, this issue has been largely overlooked in two flourishing lines of research assessing the relationship between language-related neural systems and dementia. This paper assesses the limitations of the evidence on (i) the neuroprotective effects of bilingualism in Alzheimer's disease and (ii) specific language deficits as markers of Parkinson's disease.

DESIGN

First, we outline the rationale behind each line of research. Second, we review available evidence and discuss the potential impact of cross-linguistic factors. Third, we outline ideas to foster progress in both fields and, with it, in cross-cultural neuroscience at large.

RESULTS

On the one hand, studies on bilingualism suggest that sustained use of more than one language may protect against Alzheimer's disease symptoms. On the other hand, insights from the embodied cognition framework point to syntactic and action-verb deficits as early (and even preclinical) markers of Parkinson's disease. However, both fields share a key limitation that lies at the heart of cultural neuroscience: the issue of cross-linguistic generalizability.

CONCLUSION

Relevant evidence for both research trends comes from only a handful of (mostly Indo-European) languages, which are far from capturing the full scope of structural and typological diversity of the linguistic landscape worldwide. This raises questions on the external validity of reported findings. Greater collaboration between linguistic typology and cognitive neuroscience seems crucial as a first step to assess the impact of transcultural differences on language-related effects across neurodegenerative diseases. Copyright © 2017 John Wiley & Sons, Ltd.

Developmental dyslexia and specific language impairment: distinct syntactic profiles?

Recent work exploring syntax in developmental dyslexia (DD) has identified morphosyntactic deficits, striking parallelisms between children with DD and specific language impairment (SLI). The question remains open if the underlying causes for such deficits are related to difficulties in phonology, which is affected in DD, or to working memory, as has been previously reported for SLI. We focus on the production of third person accusative clitic pronouns (ACC3) and of homophonous definite determiners in French-speaking children with DD and SLI as well as typically developing (TD) controls. If syntactic complexity modulates performance of DD children, as has already been shown for SLI, we predict children with DD to perform significantly worse on ACC3 compared to definite determiners, which are homophonous but syntactically simpler. In addition, if impairment in ACC3 stems from phonology or working memory difficulties, we expect ACC3 performance in both clinical groups to relate to performance on non-word repetition or forward/backward digit spans. We studied 2 groups of 21 children and adolescents, with DD and SLI (7-15 years) and age-matched TD controls. Results reveal significant weaknesses with ACC3 in DD and SLI groups compared to TD controls, but no difficulty for homophonous definite determiners, confirming a deficit relating specifically to syntactic complexity. As for links to phonology and working memory, a single correlation emerged between ACC3 and the backward digit span in SLI, but not in DD, suggesting different underlying sources for syntactic deficits in these populations. Clinical implications of these results are discussed.

Children's early bilingualism and musical training influence prosodic discrimination of sentences in an unknown language

This study investigated whether early bilingualism and early musical training positively influence the ability to discriminate between prosodic patterns corresponding to different syntactic structures in otherwise phonetically identical sentences in an unknown language. In a same-different discrimination task, participants (N = 108) divided into four groups (monolingual non-musicians, monolingual musicians, bilingual non-musicians, and bilingual musicians) listened to pairs of short sentences in a language unknown to them (French). In discriminating phonetically identical but prosodically different sentences, musicians, bilinguals, and bilingual musicians outperformed the controls. However, there was no interaction between bilingualism and musical training to suggest an additive effect. These results underscore the significant role of both types of experience in enhancing the listeners' sensitivity to prosodic information.

Cognitive Advantages of Bilingual Children in Different Sociolinguistic Contexts

Many studies have shown that bilingual children outperform monolinguals on tasks testing executive functioning, but other studies have not revealed any effect of bilingualism. In this study we compared three groups of bilingual children in the Netherlands, aged 6-7 years, with a monolingual control group. We were specifically interested in testing whether the bilingual cognitive advantage is modulated by the sociolinguistic context of language use. All three bilingual groups were exposed to a minority language besides the nation's dominant language (Dutch). Two bilingual groups were exposed to a regional language (Frisian, Limburgish), and a third bilingual group was exposed to a migrant language (Polish). All children participated in two working memory tasks (verbal, visuospatial) and two attention tasks (selective attention, interference suppression). Bilingual children outperformed monolinguals on selective attention. The cognitive effect of bilingualism was most clearly present in the Frisian-Dutch group and in a subgroup of migrant children who were relatively proficient in Polish. The effect was less robust in the Limburgish-Dutch sample. Investigation of the response patterns of the flanker test, testing interference suppression, suggested that bilingual children more often show an effect of response competition than the monolingual children, demonstrating that bilingual children attend to different aspects of the task than monolingual children. No bilingualism effects emerged for verbal and visuospatial working memory.

The impact of bilingualism on brain reserve and metabolic connectivity in Alzheimer's dementia

Cognitive reserve (CR) prevents cognitive decline and delays neurodegeneration. Recent epidemiological evidence suggests that lifelong bilingualism may act as CR delaying the onset of dementia by ∼4.5 y. Much controversy surrounds the issue of bilingualism and its putative neuroprotective effects. We studied brain metabolism, a direct index of synaptic function and density, and neural connectivity to shed light on the effects of bilingualism in vivo in Alzheimer's dementia (AD). Eighty-five patients with probable AD and matched for disease duration (45 German-Italian bilingual speakers and 40 monolingual speakers) were included. Notably, bilingual individuals were on average 5 y older than their monolingual peers. In agreement with our predictions and with models of CR, cerebral hypometabolism was more severe in the group of bilingual individuals with AD. The metabolic connectivity analyses crucially supported the neuroprotective effect of bilingualism by showing an increased connectivity in the executive control and the default mode networks in the bilingual, compared with the monolingual, AD patients. Furthermore, the degree of lifelong bilingualism (i.e., high, moderate, or low use) was significantly correlated to functional modulations in crucial neural networks, suggesting both neural reserve and compensatory mechanisms. These findings indicate that lifelong bilingualism acts as a powerful CR proxy in dementia and exerts neuroprotective effects against neurodegeneration. Delaying the onset of dementia is a top priority of modern societies, and the present in vivo neurobiological evidence should stimulate social programs and interventions to support bilingual or multilingual education and the maintenance of the second language among senior citizens.