The source of enhanced cognitive control in bilinguals: evidence from bimodal bilinguals

Bilingual Spatial Cognition: Spatial Cue Use in Bilinguals and Monolinguals

Structural plasticity changes and functional differences in executive control tasks have been reported in bilinguals compared to monolinguals, supporting a proposed bilingual 'advantage' in executive control functions (e.g., task switching) due to continual usage of control mechanisms that inhibit one of the coexisting languages. However, it remains unknown whether these differences are also apparent in the spatial domain. The present fMRI study explores the use of spatial cues in 15 bilinguals and 14 monolinguals while navigating in an open-field virtual environment. In each trial, participants had to navigate towards a target object that was visible during encoding but hidden in retrieval. An extensive network was activated in bilinguals compared to monolinguals in the encoding and retrieval phase. During encoding, bilinguals activated the right temporal and left parietal regions (object trials) and left inferior frontal, precentral, and lingual regions more than monolinguals. During retrieval, the same contrasts activated the left caudate nucleus and the right dorsolateral prefrontal cortex (DLPFC), the left parahippocampal gyrus, as well as caudate regions. These results suggest that bilinguals may recruit neural networks known to subserve not only executive control processes but also spatial strategies.

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.

Genetic bases of language control in bilinguals: Evidence from an EEG study

Previous studies have debated whether the ability for bilinguals to mentally control their languages is a consequence of their experiences switching between languages or whether it is a specific, yet highly-adaptive, cognitive ability. The current study investigates how variations in the language-related gene FOXP2 and executive function-related genes COMT, BDNF, and Kibra/WWC1 affect bilingual language control during two phases of speech production, namely the language schema phase (i.e., the selection of one language or another) and lexical response phase (i.e., utterance of the target). Chinese-English bilinguals (N = 119) participated in a picture-naming task involving cued language switches. Statistical analyses showed that both genes significantly influenced language control on neural coding and behavioral performance. Specifically, FOXP2 rs1456031 showed a wide-ranging effect on language control, including RTs, F(2, 113) = 4.00, FDR p = .036, and neural coding across three-time phases (N2a: F(2, 113) = 4.96, FDR p = .014; N2b: F(2, 113) = 4.30, FDR p = .028, LPC: F(2, 113) = 2.82, FDR p = .060), while the COMT rs4818 (ts >2.69, FDR ps < .05), BDNF rs6265 (Fs >5.31, FDR ps < .05), and Kibra/WWC1 rs17070145 (ts > -3.29, FDR ps < .05) polymorphisms influenced two-time phases (N2a and N2b). Time-resolved correlation analyses revealed that the relationship between neural coding and cognitive performance is modulated by genetic variations in all four genes. In all, these findings suggest that bilingual language control is shaped by an individual's experience switching between languages and their inherent genome.

The influence of bilingual experience on executive function under emotional interference: Evidence from the N1 component

The influence of bilingual education and experience on an individual’s information-processing ability has recently been a hot issue in international studies. Previous studies have found that bilingual experience affects executive function, but the results remain controversial. Executive function refers to the conscious control of purposeful behavior. It is responsible for processing high-level action controls, including such sub-functions as inhibitory control, cognitive switching, and working memory updating. Emotion, as an essential factor in daily life, also has a complex interaction with executive function. This paper explores whether the bilingual cognitive advantage effect can continue in the more complex conditions of emotional interference. To investigate the specific electrophysiological characteristics of the participants at different stages of cognitive processing, we used a combination of the behavioral and ERP experiments in which the positive, neutral, and negative emotional stimuli were selected as emotional interference conditions and the emotional Simon paradigm, the cognitive switching of emotion paradigm, and the emotional N-back paradigm was adopted. The results show that the main effect of the N1 component amplitude is significant. Specifically, the amplitude of the N1 component in the proficient bilinguals is significantly smaller than that of the non-proficient bilinguals, while the main effects of other component groups are not significant, indicating that under the condition of emotional interference, the influence of bilingual experience on executive function only exists in the early attention stage and that the bilingual experience can improve the individual’s attentional control and speed up attention processing in the early attention stage.

Bilingualism can cause enhanced monitoring and occasional delayed responses in a flanker task

Complex cognitive tasks require different stages of processing (i.e. conflict monitoring, attentional resource allocation and stimulus categorisation). Performance differences between bilinguals and monolinguals on conflict tasks can be affected by the balance of these sub-processes. The current study investigated the effect of bilingualism on these sub-processes during a conflict task with medium monitoring demand. Behavioural responses and evoked potentials from bilinguals and monolinguals were examined during a flanker task with 25% incongruent trials. Behavioural differences were analysed by means of averaged response times and exponentially modified Gaussian analyses of response time distributions. For evoked potentials, the study focussed on N2 (reflecting conflict monitoring) and P3 responses (reflecting allocation of attentional resources for cognitive control). Bilinguals had significantly longer response distribution tails compared to monolinguals. Bilinguals were shown to have a more pronounced N2 and smaller P3 compared to monolinguals, independent of condition, suggesting a different balance of sub-processes for the two groups. This suggests that bilinguals were engaged more strongly in monitoring processes, leading to the allocation of fewer attentional resources during stimulus categorisation. Additionally, the P3 amplitudes were negatively related with the length of response distribution tails for bilinguals. These results are consistent with enhanced conflict monitoring in bilinguals that led to reduced engagement of attentional resources for stimulus categorisation. This enhanced conflict monitoring could lead to occasional extremely slow responses. Thus, the bilingual experience appears to impact the balance of cognitive control processes during conflict tasks, which might only be reflected in a minority of responses.

Exploring the ventral white matter language network in bimodal and unimodal bilinguals

We used diffusion magnetic resonance imaging tractography to investigate the effect of language modality on the anatomy of the ventral white matter language network by comparing unimodal (Italian/English) and bimodal bilinguals (Italian/Italian Sign Language). We extracted the diffusion tractography measures of the Inferior Longitudinal fasciculus (ILF), Uncinate fasciculus (UF) and Inferior Fronto-Occipital fasciculus (IFOF) and we correlated them with the degree of bilingualism and the individual performance in fluency tasks. For both groups of bilinguals, the microstructural properties of the right ILF were correlated with individual level of proficiency in L2, confirming the involvement of this tract in bilingualism. In addition, we found that the degree of left lateralization of the ILF predicted the performance in semantic fluency in L1. The microstructural properties of the right UF correlated with performance in phonological fluency in L1, only for bimodal bilinguals. Overall, the pattern shows both similarities and differences between the two groups of bilinguals.

The executive function of bilingual and monolingual children: A technical efficiency approach

This paper introduces a novel approach to evaluate performance in the executive functioning skills of bilingual and monolingual children. This approach targets method- and analysis-specific issues in the field, which has reached an impasse (Antoniou et al., 2021). This study moves beyond the traditional approach towards bilingualism by using an array of executive functioning tasks and frontier methodologies, which allow us to jointly consider multiple tasks and metrics in a new measure; technical efficiency (TE). We use a data envelopment analysis technique to estimate TE for a sample of 32 Greek-English bilingual and 38 Greek monolingual children. In a second stage, we compare the TE of the groups using an ANCOVA, a bootstrap regression, and a k-means nearest-neighbour technique, while controlling for a range of background variables. Results show that bilinguals have superior TE compared to their monolingual counterparts, being around 6.5% more efficient. Robustness tests reveal that TE yields similar results to the more complex conventional MANCOVA analyses, while utilising information in a more efficient way. By using the TE approach on a relevant existing dataset, we further highlight TE's advantages compared to conventional analyses; not only does TE use a single measure, instead of two principal components, but it also allows more group observations as it accounts for differences between the groups by construction.

Does Early Exposure to Chinese-English Biliteracy Enhance Cognitive Skills?

Clarifying the effects of biliteracy on cognitive development is important to understanding the role of cognitive development in L2 learning. A substantial body of research has shed light on the cognitive factors contributing to biliteracy development. Yet, not much is known about the effect of the degree of exposure to biliteracy on cognitive functions. To fill this research void, we measured three categories of biliteracy skills (language, reading, and cognitive-linguistic skills in both Chinese and English) jointly and investigated the effects of biliteracy skill performance in these three categories on cognitive skills (working memory and attentional control) in Chinese L1 children who were exposed to English as L2 beginning at age 3 ("early") or in grade 3 ("late"). In this cross-sectional study, 10 parallel Chinese and English language, reading, and cognitive-linguistic measures were administered to emerging Chinese-English bilingual children in grade 3 (n = 178) and grade 6 (n = 176). The results revealed that early exposure to Chinese-English biliteracy enhanced cognitive skills but with a cost of a slight delay in performance on Chinese L1 language skills in grade 3 (but not in grade 6). Importantly, the present findings suggest that, in addition to universal and developmental processes, the cumulative effect of early and sustained bi-scriptal exposure enhances working memory and attention in school children.

How does bilingualism modify cognitive function? Attention to the mechanism

It has been claimed that bilingual experience leads to an enhancement of cognitive control across the lifespan, a claim that has been investigated by comparing monolingual and bilingual groups performing standard executive function (EF) tasks. The results of these studies have been inconsistent, however, leading to controversy over the essential assumptions underlying the research program, namely, whether bilingualism produces cognitive change. We argue that the source of the inconsistency is not in the evidence but rather in the framework that has typically been used to motivate the research and interpret the results. We examine the componential view of EF with its central role for inhibition and argue that it provides a poor fit to both bilingual experience and the results of these studies. As an alternative, we propose a more holistic account based on attentional control that overrides the processes in the componential model of EF and applies to a wider range of tasks. The key element in our account is that behavioral differences between monolingual and bilingual individuals reflect differences in the efficiency and deployment of attentional control between the two language groups. In support of this point we show how attentional control provides a more satisfactory account for a range of findings that cannot reasonably be attributed to inhibition. We also suggest that group differences will emerge only when the attentional demands of a task exceed the control abilities of one of the groups, regardless of the EF components involved. We then review literature from across the lifespan to evaluate the extent to which this account is consistent with existing evidence, and conclude with some suggestions on how the field may be advanced by new lines of empirical enquiry.

Lessons to be Learned from Bimodal Bilingualism

This article presents a selective overview of topics related to the language experience of early bimodal bilinguals - individuals who are raised from an early age using two languages from two different modalities, typically spoken (or written) and signed. We show that deaf and hearing bimodal bilinguals may display patterns of bilingualism that are similar to unimodal bilinguals in some ways, such as the use of both languages in a single situation or even a single utterance. Nevertheless, there are also differences between bimodal and unimodal bilinguals, and differences among different subgroups of bimodal bilinguals, given large variation in relative access to the dominant and minority language(s) in their environment and their differential experiences in schooling and interactions with potential interlocutors. Moreover, we review studies discussing potential advantages of the sign modality and advantages of bilingualism in this population. We hope to highlight the importance of considering children's overall language experience, including the age(s) at which they are exposed to each of their languages, the richness of their experiences with each of the languages, and the ways that the language-learning experience may contribute to the child's linguistic and cognitive development.

Cross-Task Adaptation Effects of Bilingual Language Control on Cognitive Control: A Dual-Brain EEG Examination of Simultaneous Production and Comprehension

For bilinguals, speaking and listening are assisted by complex control processes including conflict monitoring and inhibition. However, the extent to which these processes adapt to linguistic and situational needs has been examined separately for language production and comprehension. In the present study, we use a dual-EEG to record the carry-over effects of language control on general cognitive control in three language contexts (single-first language [L1], single-second language [L2], and mixed). Chinese learners of English were placed in dyads in which one participant was asked to name pictures while the other listened. Interleaved after each naming/listening trial were flanker trials. The results from picture naming and listening revealed higher delta and theta synchronization in the single-L2 and mixed contexts compared with the single-L1 context and higher theta synchronization in the mixed context compared with the single-L2 and single-L1 contexts. The results from the interleaved flanker trials demonstrated that inhibition was adaptively generalized in the single-L2 and mixed contexts. Altogether, the findings support the natural adaptation of language control to cognitive control and underscore the importance of linguistic context. We argue that these adaptive patterns have the potential to affect corresponding control processes across language and cognitive control tasks.

Clear Theories Are Needed to Interpret Differences: Perspectives on the Bilingual Advantage Debate

The heated debate regarding bilingual cognitive advantages remains ongoing. While there are many studies supporting positive cognitive effects of bilingualism, recent meta-analyses have concluded that there is no consistent evidence for a bilingual advantage. In this article we focus on several theoretical concerns. First, we discuss changes in theoretical frameworks, which have led to the development of insufficiently clear theories and hypotheses that are difficult to falsify. Next, we discuss the development of looking at bilingual experiences and the need to better understand language control. Last, we argue that the move from behavioural studies to a focus on brain plasticity is not going to solve the debate on cognitive effects, especially not when brain changes are interpreted in the absence of behavioural differences. Clearer theories on both behavioural and neural effects of bilingualism are needed. However, to achieve this, a solid understanding of both bilingualism and executive functions is needed first.

Moving From Bilingual Traits to States: Understanding Cognition and Language Processing Through Moment-to-Moment Variation

The study of how bilingualism is linked to cognitive processing, including executive functioning, has historically focused on comparing bilinguals to monolinguals across a range of tasks. These group comparisons presume to capture relatively stable cognitive traits and have revealed important insights about the architecture of the language processing system that could not have been gleaned from studying monolinguals alone. However, there are drawbacks to using a group-comparison, or Traits, approach. In this theoretical review, we outline some limitations of treating executive functions as stable traits and of treating bilinguals as a uniform group when compared to monolinguals. To build on what we have learned from group comparisons, we advocate for an emerging complementary approach to the question of cognition and bilingualism. Using an approach that compares bilinguals to themselves under different linguistic or cognitive contexts allows researchers to ask questions about how language and cognitive processes interact based on dynamically fluctuating cognitive and neural states. A States approach, which has already been used by bilingualism researchers, allows for cause-and-effect hypotheses and shifts our focus from questions of group differences to questions of how varied linguistic environments influence cognitive operations in the moment and how fluctuations in cognitive engagement impact language processing.

Does language context impact the neural correlates of executive control in monolingual and multilingual young adults?

Some previous studies have shown that creating a language context in which words from both languages are interspersed into a flanker task improves executive control performance for bilinguals, but these studies have produced inconsistent results. The studies have used different versions of the task and not included monolinguals, limiting generalization. Here, English-Chinese multilinguals and English monolinguals performed a flanker task while EEG was recorded. There were three language context blocks - English, Chinese, or both - and participants were instructed to ignore the interspersed words. Multilinguals displayed faster flanker RTs and earlier P2 and N2 waveforms than monolinguals. There was also a significant correlation between the P2/N2 latency and reaction times, connecting these waveforms to behavior. Finally, P2 amplitude differed between groups in the mixed context, and language context impacted P3 amplitude for monolinguals but not multilinguals. These results are interpreted in terms of language context effects on monolingual executive function processing and possible difference in bilingual experience between current participants and those in previous studies.

Absence of a bilingual cognitive flexibility advantage: A replication study in preschoolers

Some studies have found a bilingual advantage in children's executive function and some failed to find a bilingual advantage. For example, the results of a previous study by Bialystok & Martin (2004) indicated that Chinese-English bilingual preschool children outperformed English monolingual children in solving the dimensional change card sort (DCCS). The goal of our study was to replicate this study using the same dimensional change card sort task. We also tested our participants on vocabulary and digit span. Our participants were 40 English monolingual and 40 Mandarin-English bilingual children and were within the same age range as the children in Bialystok & Martin's (2004) study. Our results showed no difference between bilinguals and monolinguals. Both groups of children in the present study performed better than those in Bialystok and Martin (2004), but the bigger difference was between the two groups of monolinguals. These results suggest that it could be important to attend to monolingual children's performance, in addition to bilinguals', when testing for a bilingual advantage. Our replication study is important because it helps with clarifying the validity of studies finding a bilingual advantage and to help future researchers know whether to build on their findings or not.

Cognitive control in bilinguals: Proficiency and code-switching both matter

We examined the impact of bilingualism as a construct of both language usage and language proficiency on the effectiveness of cognitive control. In particular, we asked whether the frequency of daily dense code-switching - frequent change of language within and between sentences with the same interlocutor- and the level of L2 proficiency separately and or interactively affect cognitive control efficiency in the Simon task. Results from 134 bilinguals showed that frequently code-switching bilinguals had fewer errors and their accuracy rate improved over trials leading to a smaller Simon effect. For response times (RTs), however, L2 proficiency modulated the Simon effect, and interacted with code-switching frequency in intricate ways in modulating overall RTs over trials. Crucially, highly proficient frequently code-switching bilinguals were better at conflict adaptation. These results show that bilinguals differ among themselves, and that researchers need to take both proficiency and language use into account to test the impact of bilingual experience on cognitive control. Bilingualism should be regarded as a continuum, with many different factors contributing to the language experience and affecting cognitive functioning.

Cognitive Flexibility in Schoolchild Through the Graphic Representation of Movement

Neuroconstructivism postulates the progressive complexity of mental representation over the course of cognitive development and the role of the graphic representation of movement in the transformation of mental schemas, cognitive flexibility, and representational complexity. This study aims to: (1) understand children's resources in the drawing of movement (5-8 years); and (2) verify whether there are differences in the graphic representation of movement as an indicator of cognitive flexibility. The participants were N = 240 children aged 5-8 years; 1,440 drawings were collected representing 2,880 characters (both animate and inanimate) from six stories. The analysis consisted: (1) data quality control, using the kappa coefficient, and Generalizability Theory to test the instrument's validity and reliability; (2) Multivariate General Analysis and Mixed Linear Analysis of the factors (age and stories); (3) Multivariate General Analysis of the graphic components: categories and microcategories, as well as the elements that make up the macrocategories: "Static," "Indication," and "Movement"; and (4) calculation of the generalizability coefficient (G-coefficient). The results show that: (a) age best explains variability, with a high effect size (η 2 = 0.732) across all components (F = 153.445; p < 0.001), thus increasing its complexity and (b) at ages 6 and 7, "Indication" appears as a modulator of "Static" (age 5) toward "Movement" (age 8). The generalizability coefficient is optimal (0.995). It is concluded that changes in the initial graphic representation of movement may interactively transform mental representation, thus increasing cognitive flexibility and prompting teaching applications to optimize such changes.

Meta-Analysis Reveals a Bilingual Advantage That Is Dependent on Task and Age

Debate continues on whether a bilingual advantage exists with respect to executive functioning. This report synthesized the results of 170 studies to test whether the bilingual advantage is dependent on the task used to assess executive functioning and the age of the participants. The results of the meta-analyses indicated that the bilingual advantage was both task- and age-specific. Bilinguals were significantly faster than monolinguals (Hedges' g values ranged from 0.23 to 0.34), and significantly more accurate than monolinguals (Hedges' g values ranged between 0.18 and 0.49) on four out of seven tasks. Also, an effect of age was found whereby the bilingual advantage was larger for studies comprising samples aged 50-years and over (Hedges' g = 0.49), compared to those undertaken with participants aged between 18 and 29 years (Hedges' g = 0.12). The extent to which the bilingual advantage might be due to publication bias was assessed using multiple methods. These were Egger's Test of Asymmetry, Duval and Tweedie's Trim and Fill, Classic Fail-Safe N, and PET-PEESE. Publication bias was only found when using Egger's Test of Asymmetry and PET-PEESE method, but not when using the other methods. This review indicates that if bilingualism does enhance executive functioning, the effects are modulated by task and age. This may arise because using multiple languages has a highly specific effect on executive functioning which is only observable in older, relative to younger, adults. The finding that publication bias was not uniformly detected across the different methods raises questions about the impact that unpublished (or undetected) studies have on meta-analyses of this literature.

Bridging ears and eyes when learning spoken words: On the effects of bilingual experience at 30 months

From the very first moments of their lives, infants selectively attend to the visible orofacial movements of their social partners and apply their exquisite speech perception skills to the service of lexical learning. Here we explore how early bilingual experience modulates children's ability to use visible speech as they form new lexical representations. Using a cross-modal word-learning task, bilingual children aged 30 months were tested on their ability to learn new lexical mappings in either the auditory or the visual modality. Lexical recognition was assessed either in the same modality as the one used at learning ('same modality' condition: auditory test after auditory learning, visual test after visual learning) or in the other modality ('cross-modality' condition: visual test after auditory learning, auditory test after visual learning). The results revealed that like their monolingual peers, bilingual children successfully learn new words in either the auditory or the visual modality and show cross-modal recognition of words following auditory learning. Interestingly, as opposed to monolinguals, they also demonstrate cross-modal recognition of words upon visual learning. Collectively, these findings indicate a bilingual edge in visual word learning, expressed in the capacity to form a recoverable cross-modal representation of visually learned words.

A Meta-Analysis of Gray Matter Differences Between Bilinguals and Monolinguals

Bilingualism is of great interest to the neuroscience of language, and understanding the anatomical changes associated with second language learning help inform theories of bilingual advantage across the lifespan. While the literature on structural differences between bilinguals and monolinguals is robust, relatively few studies of gray matter (GM) have directly compared bilinguals with monolinguals in a whole-brain analysis. Overall, this and heterogeneity of study samples and methodology have led to a lack of clear anatomical support for major theories. Here, we engage in an activation likelihood estimate (ALE) meta-analysis of voxel-based morphometry (VBM) studies of GM for cases that directly compare bilingual and monolingual subjects in a whole-brain analysis. The analysis (sixteen foci, from ten contrasts across eight studies) resulted in one cluster located primarily within the anterior lobe of the right cerebellum. However, when the one pediatric study was removed, the analysis revealed no consistent results across the studies included in this meta-analysis. This suggests that for VBM studies of bilingual and monolingual adults there is considerable heterogeneity of results that complicate the understanding of the bilingual brain. Future studies will need to include larger, more well-defined samples and interrogate more fine-grained anatomical features such as cortical thickness and surface area in order to more fully examine the anatomical changes associated with bilingualism across the lifespan.

Turning languages on and off: Switching into and out of code-blends reveals the nature of bilingual language control

When spoken language (unimodal) bilinguals switch between languages, they must simultaneously inhibit 1 language and activate the other language. Because American Sign Language (ASL)-English (bimodal) bilinguals can switch into and out of code-blends (simultaneous production of a sign and a word), we can tease apart the cost of inhibition (turning a language off) and activation (turning a language on). Results from a cued picture-naming task with 43 bimodal bilinguals revealed a significant cost to turn off a language (switching out of a code-blend), but no cost to turn on a language (switching into a code-blend). Switching from single to dual lexical retrieval (adding a language) was also not costly. These patterns held for both languages regardless of default language, that is, whether switching between speaking and code-blending (English default) or between signing and code-blending (ASL default). Overall, the results support models of bilingual language control that assume a primary role for inhibitory control and indicate that disengaging from producing a language is more difficult than engaging a new language. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Bilingualism, Demographics, and Cognitive Control: A Within-Group Approach

Previous studies have suggested a bilingual advantage in cognitive control as a result of the bilinguals’ language experience. However, the results are controversial as there are various factors (language proficiency, SES, culture, and intelligence, etc.) affecting cognitive control. In the current study, after between-group comparisons, we adopted a within-group approach by multiple regressions to investigate whether the performance by 10-to-75-year-old participants (N = 91) of tasks measuring inhibition, monitoring, and mental set shifting could be predicted by bilingualism, or demographic factors, or both. The results of multiple stepwise regression analyses showed that L2 proficiency was a significant predictor for conflict monitoring and inhibition, education and age were significant predictors for mental set shifting, and SES was a minor predictor for inhibition. These findings provide evidence that cognitive control is affected by both bilingualism and demographic factors. Future studies are encouraged to further identify the relationship between bilingualism and cognitive control from specific bilingual experience.

Language Experience Impacts Brain Activation for Spoken and Signed Language in Infancy: Insights From Unimodal and Bimodal Bilinguals

Recent neuroimaging studies suggest that monolingual infants activate a left-lateralized frontotemporal brain network in response to spoken language, which is similar to the network involved in processing spoken and signed language in adulthood. However, it is unclear how brain activation to language is influenced by early experience in infancy. To address this question, we present functional near-infrared spectroscopy (fNIRS) data from 60 hearing infants (4 to 8 months of age): 19 monolingual infants exposed to English, 20 unimodal bilingual infants exposed to two spoken languages, and 21 bimodal bilingual infants exposed to English and British Sign Language (BSL). Across all infants, spoken language elicited activation in a bilateral brain network including the inferior frontal and posterior temporal areas, whereas sign language elicited activation in the right temporoparietal area. A significant difference in brain lateralization was observed between groups. Activation in the posterior temporal region was not lateralized in monolinguals and bimodal bilinguals, but right lateralized in response to both language modalities in unimodal bilinguals. This suggests that the experience of two spoken languages influences brain activation for sign language when experienced for the first time. Multivariate pattern analyses (MVPAs) could classify distributed patterns of activation within the left hemisphere for spoken and signed language in monolinguals (proportion correct = 0.68; p = 0.039) but not in unimodal or bimodal bilinguals. These results suggest that bilingual experience in infancy influences brain activation for language and that unimodal bilingual experience has greater impact on early brain lateralization than bimodal bilingual experience.

Is there a bilingual advantage on interference-control tasks? A multiverse meta-analysis of global reaction time and interference cost

A contentious issue in contemporary psycholinguistics is whether bilingualism enhances executive functions. Here, we report a meta-analysis of 80 studies (253 effect sizes) comparing performance of monolinguals and bilinguals on non-verbal interference-control tasks, while examining potential moderators of effects on two dependent variables (DVs): global reaction time (RT) and interference cost. We used a multiverse approach to determine how robust conclusions were to several dataset construction and analysis decisions. In our "preferred" analysis, using a broad definition of bilinguals and standard versions of interference-control tasks, there was a very small but significant bilingual advantage for global RT (g =.13), which became non-significant once corrected for publication bias. For interference cost, there was a very small but significant bilingual advantage (g =.11). Effects were not significantly moderated by task or participant age, but were moderated by an interaction between age of second language acquisition (AoA) and the DV. Unexpectedly, larger effect sizes for interference cost were observed for studies involving bilinguals with late as opposed to early AoA. The multiverse analysis produced results largely consistent with the preferred analysis, confirming our conclusion that evidence for a bilingual advantage on interference-control tasks is weak.

The impact of bilingualism on executive function in adolescents

AIMS AND OBJECTIVES/PURPOSE/RESEARCH QUESTIONS

In early childhood and older adulthood, bilinguals generally demonstrate better performance on executive function tasks than their monolingual counterparts, but in the young adult population, these differences are infrequently observed. However, few studies have examined these effects in the adolescent population, so the trajectory of these changes is unclear. The objective of the study was to compare performance on a modified flanker task for monolingual and bilingual adolescents, a time when the executive functions are still developing.

DESIGN/METHODOLOGY/APPROACH

The flanker task was adapted by including a rule-switching component and contained three blocks: (1) rule; (2) flanker; and (3) mixed. In the rule block, a single red or blue arrow (indicated by light grey or medium grey in Figure 1) denoted a response rule; for example, a blue arrow signaled pressing the button indicating the direction the arrow was pointing but a red arrow signaled pressing the button indicating the opposite direction. The flanker block was a standard flanker task consisting of congruent and incongruent trials. The mixed block manipulated both congruency and rule conditions.

DATA AND ANALYSIS

Mean reaction times and accuracy from 33 monolingual and 32 bilingual adolescents were analyzed using a repeated-measures analysis of variance with language group as the between-subjects variable and congruency and/or rule-type as the within-subjects variable depending on the block.

FINDINGS/CONCLUSIONS

Bilingual adolescents outperformed monolingual adolescents but only on the block that was most similar to the standard flanker task. The blocks with the rule-switching component yielded equivalent performance.

ORIGINALITY

Unlike previous studies, the current study adapted a simple executive control task to require greater attentional resources by manipulating task demands.

SIGNIFICANCE/IMPLICATIONS

Our findings add to the growing body of literature examining bilingualism and executive control in the adolescent population and fill in the gap in our understanding of the lifespan trajectory of these effects.

Bilingualism as a desirable difficulty: Advantages in word learning depend on regulation of the dominant language

Bilingualism imposes costs to language processing but benefits to word learning. We test a new hypothesis that relates costs in language processing at study to benefits in learning at test as desirable difficulties. While previous studies have taught vocabulary via bilinguals' native language (L1), recent evidence suggests that bilinguals acquire regulatory skill in the L1 to coordinate the use of each language. We hypothesized that L1 regulation underlies the observed costs and benefits, with word learning advantages depending on learning via the L1. Four groups learned novel Dutch words via English translations: English monolinguals, and English-Spanish, Spanish-English, and Chinese-English bilinguals. Only English-Spanish bilinguals demonstrated a word learning advantage, but they adopted a costly study strategy compared to monolinguals. The results suggest that bilingual advantages in vocabulary learning depend on learning via the L1 or dominant language because learning via the L1 allows bilinguals to engage regulatory skills that benefit learning.

A longitudinal investigation of structural brain changes during second language learning

Few studies have examined the time course of second language (L2) induced neuroplasticity or how individual differences may be associated with brain changes. The current longitudinal structural magnetic resonance imaging study examined changes in cortical thickness (CT) and gray matter volume (GMV) across two semesters of L2 Spanish classroom learning. Learners' lexical processing was assessed via a language decision task containing English and Spanish words. Our findings indicated that (1) CT increased in the left anterior cingulate cortex (ACC) and right middle temporal gyrus (MTG) after L2 learning, (2) CT in the right MTG increased in individuals who were better able to discriminate between native language and L2 words, and (3) CT in the left ACC was correlated with functional connectivity between the ACC and MTG. These findings indicate that L2 lexical development is associated with functional and structural changes in brain regions important for cognitive control and semantic processing.

Assessment of executive function in bilingual adults with history of mild traumatic brain injury

Background and objective:

Adults with a history of traumatic brain injury (TBI) often show deficits in executive function (EF), including the ability to inhibit, switch, and attend to task relevant information. Although performances differences between bilinguals and monolinguals have been observed in EF tasks, there is little research on the effect of TBI on EF in bilinguals. In this study, an ecologically valid standardized measure and experimental computerized tasks of EF were administered to Spanish-English bilingual adults with and without history of mild traumatic brain injury (mTBI).

Method:

Twenty-two bilinguals with a history of mTBI [mean age=20.1 years, SD=3.7; education=13.4 years, SD=0.7] and 20 control bilinguals [mean age=20.8 years, SD=3.6; education=13.7 years, SD=1.1], matched for age and education, completed language proficiency questionnaires, the Functional Assessment of Verbal Reasoning and Executive Strategies (FAVRES), English and Spanish language assessments, and a Flanker task (a test of inhibition).

Results:

Performance was analyzed using analyses of covariance. The results revealed that bilinguals with a history of mTBI performed worse on both the standardized assessment (FAVRES) and inhibition task. Interestingly, self-reported EF deficits were consistent with performance on these measures.

Conclusion:

The findings of this study provide useful information regarding assessment of EF deficits in bilinguals with a history mTBI. Computerized experimental tasks of EF may also prove useful in the assessment of EF in individuals with mTBI.

Retracted: The Effect of Bilingualism on Older Adults' Inhibitory Control: A Meta-Analysis

BACKGROUND AND OBJECTIVES

The effect bilingualism has on older adults' inhibitory control has been extensively investigated, yet there is continued controversy regarding whether older adult bilinguals show superior inhibitory control compared with monolinguals. The objective of the current meta-analysis was to examine the reliability and magnitude of the bilingualism effect on older adults' inhibitory control as measured by the Simon and Stroop tasks. In addition, we examined whether individual characteristics moderate the bilingual advantage in inhibition, including age (young-old vs old-old), age of second language acquisition, immigrant status, language proficiency, and frequency of language use.

RESEARCH DESIGN AND METHODS

A total of 22 samples for the Simon task and 14 samples for the Stroop task were derived from 28 published and unpublished articles (32 independent samples, with 4 of these samples using more than 1 task) and were analyzed in 2 separate meta-analyses.

RESULTS

Analyses revealed a reliable effect of bilingualism on older adults' performance on the Simon (g = 0.60) and Stroop (g = 0.27) tasks. Interestingly, individual characteristics did not moderate the association between bilingualism and older adults' inhibitory control.

DISCUSSION AND IMPLICATIONS

The results suggest there is a bilingual advantage in inhibitory control for older bilinguals compared with older monolinguals, regardless of the individual characteristics previously thought to moderate this effect. Based on these findings, bilingualism may protect inhibitory control from normal cognitive decline with age.

Does the Bilingual Advantage in Cognitive Control Exist and If So, What Are Its Modulating Factors? A Systematic Review

Recently, doubts were raised about the existence of the bilingual advantage in cognitive control. The aim of the present review was to investigate the bilingual advantage and its modulating factors. We searched the Medline, ScienceDirect, Scopus, and ERIC databases for all original data and reviewed studies on bilingualism and cognitive control, with a cut-off date of 31 October 2018, thereby following the guidelines of the preferred reporting items for systematic reviews and meta-analysis (PRISMA) protocol. The results of the 46 original studies show that indeed, the majority, 54.3%, reported beneficial effects of bilingualism on cognitive control tasks; however, 28.3% found mixed results and 17.4% found evidence against its existence. Methodological differences seem to explain these mixed results: Particularly, the varying selection of the bilingual participants, the use of nonstandardized tests, and the fact that individual differences were often neglected and that longitudinal designs were rare. Therefore, a serious risk for bias exists in both directions (i.e., in favor of and against the bilingual advantage). To conclude, we found some evidence for a bilingual advantage in cognitive control; however, if significant progress is to be made, better study designs, bigger data, and more longitudinal studies are needed.

Support for parents of deaf children: Common questions and informed, evidence-based answers

To assist medical and hearing-science professionals in supporting parents of deaf children, we have identified common questions that parents may have and provide evidence-based answers. In doing so, a compassionate and positive narrative about deafness and deaf children is offered, one that relies on recent research evidence regarding the critical nature of early exposure to a fully accessible visual language, which in the United States is American Sign Language (ASL). This evidence includes the role of sign language in language acquisition, cognitive development, and literacy. In order for parents to provide a nurturing and anxiety-free environment for early childhood development, signing at home is important even if their child also has the additional nurturing and care of a signing community. It is not just the early years of a child's life that matter for language acquisition; it's the early months, the early weeks, even the early days. Deaf children cannot wait for accessible language input. The whole family must learn simultaneously as the deaf child learns. Even moderate fluency on the part of the family benefits the child enormously. And learning the sign language together can be one of the strongest bonding experiences that the family and deaf child have.

Bilingualism reveals fundamental variation in language processing

Although variation in the ways individuals process language has long been a topic of interest and discussion in the psycholinguistic literature, only recently have studies of bilingualism and its cognitive consequences begun to reveal the fundamental dynamics between language and cognition. We argue that the active use of two languages provides a lens through which the interactions between language use, language processing, and the contexts in which these take place can be fully understood. Far from bilingualism being considered a special case, it may provide the common basis upon which the principles of language learning and use can be modeled.

Does Extreme Language Control Training Improve Cognitive Control? A Comparison of Professional Interpreters, L2 Teachers and Monolinguals

There is currently a lively debate in the literature whether bilingualism leads to enhanced cognitive control or not. Recent evidence suggests that knowledge of more than one language does not always suffice for the manifestation of a bilingual cognitive control advantage. As a result, ongoing research has focused on modalities of bilingual language use that may interact with the bilingual advantage. In this study, we explored the cognitive control performance of simultaneous interpreters. These highly proficient bilinguals comprehend information in one language while producing in the other language, which is a complex skill requiring high levels of language control. In a first experiment, we compared professional interpreters to monolinguals. Data were collected on interference suppression (flanker task), prepotent response inhibition (Simon task), and short-term memory (digit span task). The results showed that the professional interpreters performed similarly to the monolinguals on all measures. In Experiment 2, we compared professional interpreters to monolinguals and second language teachers. Data were collected on interference suppression (advanced flanker task), prepotent response inhibition (advanced flanker task), attention (advanced flanker task), short-term memory (Hebb repetition paradigm), and updating (n-back task). We found converging evidence for our finding that experience in interpreting may not lead to superior interference suppression, prepotent response inhibition, and short-term memory. In fact, our results showed that the professional interpreters performed similarly to both the monolinguals and the second language teachers on all tested cognitive control measures. We did, however, find anecdotal evidence for a (small) advantage in short-term memory for interpreters relative to monolinguals when analyzing composite scores of both experiments together. Taken together, the results of the current study suggest that interpreter experience does not necessarily lead to general cognitive control advantages. However, there may be small interpreter advantages in short-term memory, suggesting that this might be an important cognitive control aspect of simultaneous interpreting. The results are discussed in the light of ongoing debates about bilingual cognitive control advantages.

Functional Neuroanatomy of Second Language Sentence Comprehension: An fMRI Study of Late Learners of American Sign Language

The neurobiology of sentence comprehension is well-studied but the properties and characteristics of sentence processing networks remain unclear and highly debated. Sign languages (i.e., visual-manual languages), like spoken languages, have complex grammatical structures and thus can provide valuable insights into the specificity and function of brain regions supporting sentence comprehension. The present study aims to characterize how these well-studied spoken language networks can adapt in adults to be responsive to sign language sentences, which contain combinatorial semantic and syntactic visual-spatial linguistic information. Twenty native English-speaking undergraduates who had completed introductory American Sign Language (ASL) courses viewed videos of the following conditions during fMRI acquisition: signed sentences, signed word lists, English sentences and English word lists. Overall our results indicate that native language (L1) sentence processing resources are responsive to ASL sentence structures in late L2 learners, but that certain L1 sentence processing regions respond differently to L2 ASL sentences, likely due to the nature of their contribution to language comprehension. For example, L1 sentence regions in Broca's area were significantly more responsive to L2 than L1 sentences, supporting the hypothesis that Broca's area contributes to sentence comprehension as a cognitive resource when increased processing is required. Anterior temporal L1 sentence regions were sensitive to L2 ASL sentence structure, but demonstrated no significant differences in activation to L1 than L2, suggesting its contribution to sentence processing is modality-independent. Posterior superior temporal L1 sentence regions also responded to ASL sentence structure but were more activated by English than ASL sentences. An exploratory analysis of the neural correlates of L2 ASL proficiency indicates that ASL proficiency is positively correlated with increased activations in response to ASL sentences in L1 sentence processing regions. Overall these results suggest that well-established fronto-temporal spoken language networks involved in sentence processing exhibit functional plasticity with late L2 ASL exposure, and thus are adaptable to syntactic structures widely different than those in an individual's native language. Our findings also provide valuable insights into the unique contributions of the inferior frontal and superior temporal regions that are frequently implicated in sentence comprehension but whose exact roles remain highly debated.

Executive Function in Deaf Children: Auditory Access and Language Access

Purpose

Deaf children are frequently reported to be at risk for difficulties in executive function (EF); however, the literature is divided over whether these difficulties are the result of deafness itself or of delays/deficits in language that often co-occur with deafness. The purpose of this study is to discriminate these hypotheses by assessing EF in populations where the 2 accounts make contrasting predictions.

Method

We use a between-groups design involving 116 children, ages 5-12 years, across 3 groups: (a) participants with normal hearing (n = 45), (b) deaf native signers who had access to American Sign Language from birth (n = 45), and (c) oral cochlear implant users who did not have full access to language prior to cochlear implantation (n = 26). Measures include both parent report and performance-based assessments of EF.

Results

Parent report results suggest that early access to language has a stronger impact on EF than early access to sound. Performance-based results trended in a similar direction, but no between-group differences were significant.

Conclusions

These results indicate that healthy EF skills do not require audition and therefore that difficulties in this domain do not result primarily from a lack of auditory experience. Instead, results are consistent with the hypothesis that language proficiency, whether in sign or speech, is crucial for the development of healthy EF. Further research is needed to test whether sign language proficiency also confers benefits to deaf children from hearing families.

Verbal and Nonverbal Anticipatory Mechanisms in Bilinguals

Empirical evidence collected so far has revealed that the bilingual advantage cannot be reduced to a single component of the executive functioning, and point to the need to understand the effects of bilingual experience on cognition as influencing a wider family of mental processes, including, but not limited to, cognitive control. The present study aims to explore a relatively underinvestigated domain of bilingual cognitive processes, namely anticipation, through a series of different paradigms tapping proactive and reactive mechanisms at different levels of cognitive complexity and linguistic components. The sample included 25 adult bilinguals ([Formula: see text] years) and 25 monolinguals ([Formula: see text] years) matched for age, gender, and non-verbal IQ. Participants were administered two experimental tasks: Attentional Network Task (ANT), and auditory picture-word identification task. Compared to monolinguals, bilinguals showed overall faster reaction times and reduced conflict effect on both the ANT and the picture-word identification task. In addition, associations between performances in the nonverbal and the verbal tasks support the role of the nonverbal monitoring component on verbal anticipation. Results are discussed in light of a dynamic interaction between proactive and reactive mechanisms of cognitive control.

Learning across languages: bilingual experience supports dual language statistical word segmentation

Bilingual acquisition presents learning challenges beyond those found in monolingual environments, including the need to segment speech in two languages. Infants may use statistical cues, such as syllable-level transitional probabilities, to segment words from fluent speech. In the present study we assessed monolingual and bilingual 14-month-olds' abilities to segment two artificial languages using transitional probability cues. In Experiment 1, monolingual infants successfully segmented the speech streams when the languages were presented individually. However, monolinguals did not segment the same language stimuli when they were presented together in interleaved segments, mimicking the language switches inherent to bilingual speech. To assess the effect of real-world bilingual experience on dual language speech segmentation, Experiment 2 tested infants with regular exposure to two languages using the same interleaved language stimuli as Experiment 1. The bilingual infants in Experiment 2 successfully segmented the languages, indicating that early exposure to two languages supports infants' abilities to segment dual language speech using transitional probability cues. These findings support the notion that early bilingual exposure prepares infants to navigate challenging aspects of dual language environments as they begin to acquire two languages.

Learning across languages: bilingual experience supports dual language statistical word segmentation

Bilingual acquisition presents learning challenges beyond those found in monolingual environments, including the need to segment speech in two languages. Infants may use statistical cues, such as syllable-level transitional probabilities, to segment words from fluent speech. In the present study we assessed monolingual and bilingual 14-month-olds' abilities to segment two artificial languages using transitional probability cues. In Experiment 1, monolingual infants successfully segmented the speech streams when the languages were presented individually. However, monolinguals did not segment the same language stimuli when they were presented together in interleaved segments, mimicking the language switches inherent to bilingual speech. To assess the effect of real-world bilingual experience on dual language speech segmentation, Experiment 2 tested infants with regular exposure to two languages using the same interleaved language stimuli as Experiment 1. The bilingual infants in Experiment 2 successfully segmented the languages, indicating that early exposure to two languages supports infants' abilities to segment dual language speech using transitional probability cues. These findings support the notion that early bilingual exposure prepares infants to navigate challenging aspects of dual language environments as they begin to acquire two languages.

Data trimming procedure can eliminate bilingual cognitive advantage

Bilingualism and its cognitive impacts have drawn increasing interest. Recently, inconsistencies in the findings have raised discussions on what might have caused such discrepancies and how evidence should be evaluated. This review tries to shed new light onto the reasons for the inconsistencies by taking a novel perspective. Motivated by the finding that bilingualism affects response time distribution profiles, particularly findings that suggest bilinguals have fewer long responses, we investigated the relation between maximum response times allowed/included in the analysis of an experiment and the finding of a bilingual advantage. We reviewed 68 experiments from 33 articles that compared monolingual and bilingual speakers' performance in three commonly used non-verbal interference tasks (Simon, Spatial Stroop and Flanker). We found that studies that included longer responses in their analysis were more likely to report a bilingualism effect. We conclude that seemingly insignificant details such as the data trimming procedure can have a potential impact on whether an effect is observed. We also discuss the implication of our findings and suggest the usefulness of more fine-grid analytical procedures.

Comparing visual search and eye movements in bilinguals and monolinguals

Recent research has suggested that bilinguals show advantages over monolinguals in visual search tasks, although these findings have been derived from global behavioral measures of accuracy and response times. In the present study we sought to explore the bilingual advantage by using more sensitive eyetracking techniques across three visual search experiments. These spatially and temporally fine-grained measures allowed us to carefully investigate any nuanced attentional differences between bilinguals and monolinguals. Bilingual and monolingual participants completed visual search tasks that varied in difficulty. The experiments required participants to make careful discriminations in order to detect target Landolt Cs among similar distractors. In Experiment 1, participants performed both feature and conjunction search. In Experiments 2 and 3, participants performed visual search while making different types of speeded discriminations, after either locating the target or mentally updating a constantly changing target. The results across all experiments revealed that bilinguals and monolinguals were equally efficient at guiding attention and generating responses. These findings suggest that the bilingual advantage does not reflect a general benefit in attentional guidance, but could reflect more efficient guidance only under specific task demands.

Bilinguals' Working Memory (WM) Advantage and Their Dual Language Practices

The present study investigates a possible working memory (WM) difference between monolingual and bilingual groups and explores the relationship between their WM advantage and language practices. A mixed methods design was employed for the study. To measure participants’ WM, auditory and visual digit span tasks were conducted on the different language groups: 20 Korean near-monolinguals, and 40 Korean–English bilinguals with two different levels of second language (L2) proficiency. Bilinguals’ daily language practices were explored through semi-structured interviews with eight bilinguals. The convergence of the findings from both tests and interview data suggests that knowing two languages does not guarantee bilingual WM advantages over monolinguals, but the advantage might be linked to bilinguals’ unique L2 use environment where they need to hold incoming L2 information while decoding it.

Sequential congruency effects reveal differences in disengagement of attention for monolingual and bilingual young adults

Three studies examined the hypothesis that bilinguals can more rapidly disengage attention from irrelevant information than monolinguals by investigating the impact of previous trial congruency on performance in a simple flanker task. In Study 1, monolingual and bilingual young adults completed two versions of a flanker task. There were no differences between language groups on mean reaction time using standard analyses for congruent or incongruent trials or the size of the flanker effect. Sequential congruency effects (SCEs) however, which account for previous trial congruency, were smaller for bilinguals than for monolinguals. This finding was strongest at the shortest response-to-stimulus interval (RSI). Study 2 replicated this effect using a slightly different flanker task and a shorter RSI than study 1. Study 3 showed that at long RSIs, where behavioral SCE differences between groups disappear because of sufficient time to recover from the previous trial, event-related potentials demonstrated a continued influence of previous trial congruency for monolinguals but not bilinguals at both the N2 and the P3, replicating the reaction time effects in Studies 1 and 2. Together, these studies demonstrate that bilinguals experience less influence from previous trial congruency and have greater ability to disengage attention from the previous trial in order to focus attention on the current trial than is found for monolinguals.