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

New insights into bilingual visual word recognition: State of the art on the role of orthographic markedness, its theoretical implications, and future research directions

In the past decade, research on bilingual visual word recognition has given rise to a new line of study focusing on a sublexical orthographic variable referred to as orthographic markedness, derived from the comparison of the two orthotactic distributions known by a bilingual reader. Orthographic markers have been shown to speed up language decisions but also, to some extent, to modulate language nonselectivity during lexical access (i.e., the degree of co-activation of lexical representations of the two languages). In this review, we (1) describe the results available in the literature about orthographic markedness on language membership detection and lexical access and discuss the locus of these effects, which leads us to (2) present theoretical extensions to the bilingual interactive activation models and discuss their respective adequacy to the data, finally leading us to (3) propose future research directions in the study of orthographic markedness, such as extension to different reading tasks and contexts as well as considering developmental and learning dynamics.

How Mandarin-English bilinguals interpret qián/forward: impact of language proficiencies on retrieval of temporal concepts

Mandarin qián and English forward are semantically equivalent in the domain of Space, but could be semantically opposite in the domain of Time. In other words, equivalent spatial lexical items could convey opposite temporal concepts. What temporal concepts conveyed by qián and forward would be retrieved by Mandarin-English (M-E) bilinguals with different language proficiencies? Drawing a sample from college students in Mainland China, this study examines how L1 and L2 proficiencies would affect M-E bilinguals' retrieval of temporal concepts by examining their interpretation of the Mandarin temporal metaphor of qián and the English temporal metaphors of forward. The results show that L1 temporal concepts would be retrieved more frequently than L2 temporal concepts regardless of the testing languages, that L1 and L2 proficiencies were not predictors for the way of interpretation, and that the higher L2 proficiency group could retrieve temporal concepts in line with the testing languages with higher accuracy than the lower L2 proficiency group. The findings suggest that bilinguals with higher L2 proficiency may be able to represent temporal concepts with language tags or may have an attentional and/or inhibitory control advantage.

Examining the relation between bilingualism and age of symptom onset in frontotemporal dementia

Bilingualism is thought to confer advantages in executive functioning, thereby contributing to cognitive reserve and a later age of dementia symptom onset. While the relation between bilingualism and age of onset has been explored in Alzheimer's dementia, there are few studies examining bilingualism as a contributor to cognitive reserve in frontotemporal dementia (FTD). In line with previous findings, we hypothesized that bilinguals with behavioral variant FTD would be older at symptom onset compared to monolinguals, but that no such effect would be found in patients with nonfluent/agrammatic variant primary progressive aphasia (PPA) or semantic variant PPA. Contrary to our hypothesis, we found no significant difference in age at symptom onset between monolingual and bilingual speakers within any of the FTD variants, and there were no notable differences on neuropsychological measures. Overall, our results do not support a protective effect of bilingualism in patients with FTD-spectrum disease in a U.S. based cohort.

Attention networks in multilingual adults who do and who do not stutter

This study investigated whether multilinguals who stutter differ from multilinguals who do not stutter in terms of attention networks. Towards that end, it measured (a) performance differences in attention networks between multilinguals who stutter and those who do not stutter and (b) the correlation between stuttering characteristics and attention networks. Twenty-four multilingual Dutch-English speaking adults (20-46y), half of whom were diagnosed with stuttering, completed the Attentional Network Task (ANT) that evaluates the attention networks of alerting, orienting, and executive control. A language and social background questionnaire and a lexical decision task (LexTALE) assessed the participants' language proficiency. The Stuttering Severity Instrument 4th Ed. and the Brief Version of the Unhelpful Thoughts and Beliefs About Stuttering Scale were used to evaluate stuttering characteristics. The two groups did not differ in the ANT in terms of reaction time and error rate scores. Furthermore, no differences were observed in the three attention networks between the groups. Lastly, no correlation was found between stuttering characteristics and attention networks. The results suggest that the attention abilities of multilinguals who stutter do not differ from multilinguals who do not stutter.

It's our job to bridge the gap: Perspectives of bilingual autism providers on heritage language care

LAY ABSTRACT

In the United States, many people have heritage languages they speak in their homes other than English, such as Chinese or Spanish. Autistic children whose families speak different languages could benefit from support and teaching in their heritage languages. Still, caregivers have reported that it is challenging to do so. Many autism professionals make suggestions that are not based on research. To date, researchers have not examined the perspectives of the small group of bilingual professionals in the United States who provide bilingual support for autistic children. Therefore, this study explored how bilingual autism providers in the United States talked about their work, bilingualism, and the impacts their bilingual work has on autistic children and families. The bilingual providers in this study reported many positive outcomes for autistic children when they can learn and use their heritage languages and some negative outcomes when providers cannot communicate in the same language. Recommendations from this study highlight the need to recruit more bilingual providers in the field of autism.

Bilingual disadvantages are systematically compensated by bilingual advantages across tasks and populations

Bilingualism is linked to both enhanced and hampered performance in various cognitive measures, yet the extent to which these bilingual advantages and disadvantages co-occur is unclear. To address this gap, we perform a systematic review and two quantitative analyses. First, we analyze results from 39 studies, obtained through the PRISMA method. Less than 50% of the studies that show up as results for the term "bilingual disadvantage" report exclusively a disadvantage, that shows bilinguals performing worse than monolinguals in a task. A Bayesian analysis reveals robust evidence for bilingual effects, but no evidence for differences in the proportion of advantages and disadvantages, suggesting that when results from different cognitive domains such as executive functions and verbal fluency are analyzed together, bilingual effects amount to a zero-sum game. This finding was replicated by repeating the analysis, using the datasets of two recent meta-analyses. We propose that the equilibrium we observe between positive and negative outcomes may not be accidental. Contrary to widespread belief, advantageous and disadvantageous effects are not stand-alone outcomes in free variation. We reframe them as the connatural components of a dynamic trade-off, whereby enhanced performance in one cognitive measure is offset by an incurred cost in another domain.

Robustness of the cognitive gains in 7-month-old bilingual infants: A close multi-center replication of Kovács and Mehler (2009)

We present an exact replication of Experiment 2 from Kovács and Mehler's 2009 study, which showed that 7-month-old infants who are raised bilingually exhibit a cognitive advantage. In the experiment, a sound cue, following an AAB or ABB pattern, predicted the appearance of a visual stimulus on the screen. The stimulus appeared on one side of the screen for nine trials and then switched to the other side. In the original experiment, both mono- and bilingual infants anticipated where the visual stimulus would appear during pre-switch trials. However, during post-switch trials, only bilingual children anticipated that the stimulus would appear on the other side of the screen. The authors took this as evidence of a cognitive advantage. Using the exact same materials in combination with novel analysis techniques (Bayesian analyses, mixed effects modeling and cluster based permutation analyses), we assessed the robustness of these findings in four babylabs (N = 98). Our results did not replicate the original findings: although anticipatory looks increased slightly during post-switch trials for both groups, bilingual infants were not better switchers than monolingual infants. After the original experiment, we presented additional trials to examine whether infants associated sound patterns with cued locations, for which we did not find any evidence either. The results highlight the importance of multicenter replications and more fine-grained statistical analyses to better understand child development. HIGHLIGHTS: We carried out an exact replication across four baby labs of the high-impact study by Kovács and Mehler (2009). We did not replicate the findings of the original study, calling into question the robustness of the claim that bilingual infants have enhanced cognitive abilities. After the original experiment, we presented additional trials to examine whether infants correctly associated sound patterns with cued locations, for which we did not find any evidence. The use of novel analysis techniques (Bayesian analyses, mixed effects modeling and cluster based permutation analyses) allowed us to draw better-informed conclusions.

Analyzing Qualitative Changes in Metalinguistic Processing in Typically Developing 5- to 7-Year-Old Children

This study was based on an analysis of some of the qualitative aspects underlying the findings of previous research into the metalinguistic abilities in 160 Italian-speaking, typically developing children aged from 5 to 7 years. This previous research had used six metalinguistic tasks, a nonverbal intelligence test, and two lexical- and grammar-comprehension tests. The outcomes showed a significant improvement in all the dependent variables in the age range considered, measured by a series of ANOVAs, with high correlation between all the variables and a strong homogeneity between the metalinguistic tasks, as revealed by a factor analysis. Using generalized estimating equation (GEE) analysis, the current study analyzed the cognitive levels of response that constituted the total score of each task, at each age (5-6, 6-7, and 7-8 years). Although based on the different distribution of the cognitive levels at each age and in each task, the results of this analysis further confirmed the significance of the developmental changes, and showed different developmental trajectories as a function of the specific task. These results are discussed in light of the different involvement of cognitive processes and literacy skills in the transitional phase between kindergarten and the first two years of primary school.

Multilingualism is associated with small task-specific advantages in cognitive performance of older adults

The protective effects of multiple language knowledge on the maintenance of cognitive functions in older adults have been discussed controversially, among others, because of methodological inconsistencies between studies. In a sample of N = 528 German monolinguals and multilinguals (speaking two or more languages) older than 60 years, this study examined (1) whether speaking multiple languages is positively related to performance on tasks of interference suppression, working memory, concept shifting, and phonemic and semantic fluency, and (2) whether language proficiency and age of second language acquisition (AoA) are associated with cognitive performance of multilinguals. Controlling for education and daily activity, we found small cognitive benefits of speaking multiple languages on interference suppression, working memory, and phonemic fluency, but not on concept shifting and semantic fluency. Furthermore, no substantive correlations were found between language proficiency or AoA and cognitive performance. In conclusion, multilingualism appears to have small incremental effects on cognitive performance beyond education and daily activity in older age that are task-specific and widely independent of proficiency and AoA.

A Classification Bias and an Exclusion Bias Jointly Overinflated the Estimation of Publication Biases in Bilingualism Research

A publication bias has been argued to affect the fate of results in bilingualism research. It was repeatedly suggested that studies presenting evidence for bilingual advantages are more likely to be published compared to studies that do not report results in favor of the bilingual advantage hypothesis. This work goes back to the original claim and re-examines both the dataset and the classification of the studies that were employed. We find that the exclusion of published works such as doctoral dissertations, book chapters, and conference proceedings from the original dataset significantly inflated the presumed publication bias. Moreover, the estimation of the publication bias was affected by a classification bias that uses a mega-category that consists of both null and negative outcomes. Yet finding evidence for a bilingual disadvantage is not synonymous with obtaining a result indistinguishable from zero. Consequently, grouping together null and negative findings in a mega-category has various ramifications, not only for the estimation of the presumed publication bias but also for the field's ability to appreciate the insofar hidden correlations between bilingual advantages and disadvantages. Tracking biases that inflate scientific results is important, but it is not enough. The next step is recognizing the nested Matryoshka doll effect of bias-within-bias, and this entails raising awareness for one's own bias blind spots in science.

Clinical Neuropsychology of Bilingual Mexican American Adults: Effect of Language Proficiency and Dominance

OBJECTIVE

To assess the association between language proficiency and absolute dominance on language versus visual-perceptual formatted and executive versus delayed memory neuropsychological measures in bilingual adults.

METHODS

Data from 55 bilingual, conversationally fluent, neurologically intact, Mexican American, consecutive, adults tested in separate sessions in Spanish and English in a counterbalanced order were analyzed. Age, years of education, self-reported language proficiency, Woodcock-Muñoz Language Survey-Revised (WMLS-R) picture vocabulary measures of language proficiency, and dominance (absolute Spanish-English WMLS-R difference scores) were correlated with 11 measures from La Batería Neuropsicólogica en Español and its original English language tests.

RESULTS

Self-reported and WMLS-R measures of language proficiency were significantly correlated in each language. Absolute language dominance was not significantly associated with any Spanish or English neuropsychological raw score. The WMLS-R language proficiency, but not age or years of education, was significantly correlated with language-formatted neuropsychological measures of California Verbal Learning Test delayed free recall number of words (both languages), letter fluency (both languages), delayed story memory (in English), and Stroop interference (Spanish). Linear regression models using age, years of education, and WMLS-R picture vocabulary scores as predictors were significant for all these measures excepting the last. The WMLS-R language proficiency was not significantly associated with raw scores on any visual-perceptual formatted measure.

CONCLUSIONS

Monolingual neuropsychological test norms for language-formatted tests likely overestimate bilingual Mexican Americans' performance.

Why Should We Study the Foreign Language Effect: Debiasing through Affecting Metacognition?

Debiasing is a method of improving people's decisions by reducing their reliance on salient intuitions causing them to behave suboptimally or biasedly. However, many of the known debiasing techniques have limited effectiveness or can only remedy a one-shot decision, rather than having a lasting impact. In this work, I focus on the role of metacognition in debiasing decision-making and discuss how it can be better understood through the lens of the foreign language effect. The foreign language effect suggests that using a foreign language can sometimes benefit people's decision-making without providing them with additional information or instructions regarding the task. However, we do not fully understand how the foreign language effect works and its limitations. I conclude by urging scientists to research this effect with the hope of having a lasting positive impact on society.

The impact of bilingualism in within-language conflict resolution: an ERP study

We compared Spanish (L1)-English (L2) bilinguals and Spanish monolinguals in a semantic judgment relationship task in L1 that produced within-language conflict due to the coactivation of the two meanings of a Spanish homophone (e.g., "hola" and "ola" meaning "hello" and "a wave" in English). In this task, participants indicated if pairs of words were related or not ("agua-hola," "water-hello"). Conflict arose because a word ("agua," "water") not related to the orthographic form of a homophone ("hola," "hello") was related to the alternative orthographic form ("ola," "wave"). Compared to a control condition with unrelated word pairs ("peluche-hola," "teddy-hello"), the behavioral results revealed greater behavioral interference in monolinguals compared to bilinguals. In addition, electrophysiological results revealed N400 differences between monolinguals and bilinguals. These results are discussed around the impact of bilingualism on conflict resolution.

The impact of multiple language exposure on cognition during childhood: evidence from the UK Millennium Cohort Study

Introduction

Many studies argue that exposure to, and use of, multiple languages in childhood has beneficial effects beyond the linguistic domain, including on executive functions (EFs), although recent evidence remains controversial. EFs encompass abilities necessary for regulating goal-directed behaviours in everyday life and, in children, EFs strongly predict later academic achievement and wellbeing. One theoretical framework distinguishes "hot" EFs, which have a reward or affective component, from "cool" EFs that do not. How exposure to more than one language in early childhood modulates hot and cool EFs in later childhood, alongside other environmental and cognitive factors, remains poorly understood.

Methods

We analysed data from the UK Millennium Cohort Study, a large-scale, nationally representative longitudinal cohort study, which provides information on perinatal and environmental factors (e.g., languages spoken in the home, maternal education) alongside cognitive measures assessed in English. At 3 years, we examined the effect of multiple language exposure on the Bracken school readiness assessment (knowledge of shapes, letters, etc.), and on naming vocabulary. At age 11, we examined the predictors of cool EF, measured with a spatial working memory task; hot EF, measured using a gambling task; and vocabulary, measured using a verbal reasoning task.

Results

Data from 16,134 children were analysed. At age 3, a negative effect of multiple language exposure on school readiness and vocabulary was observed, but the difference was smaller with higher maternal education. At age 11, there was also a negative effect on vocabulary, but smaller than that observed at age 3. There were no direct effects of language exposure on either spatial working memory or gambling scores. For hot EF, the multiple language exposure effects were indirect, mediated by early cognition, and the most significant predictor of gambling strategy was sex. For cool EF, school readiness and vocabulary at age 3 were the strongest predictors.

Discussion

Our findings, based on a UK population sample, highlight the importance of considering socioeconomic status and early-life abilities when interpreting the effects of language environments on hot and cool EFs.

Referential expressions in monolingual and bilingual children with and without Autism Spectrum Disorder (ASD): A study of informativeness and definiteness

The current study evaluated the separate and combined effects of bilingualism and Autism Spectrum Disorder (ASD) on informativeness and definiteness marking of referential expressions. Hebrew-speaking monolingual children (21 with ASD and 28 with typical language development) and Russian-Hebrew-speaking bilingual children (13 with ASD and 30 with typical language development) aged 4-9 years participated. Informativeness, indexed by referential contrasts, was affected by ASD, but not by bilingualism. Definiteness use was non-target-like in children with ASD and in bilingual children, and it was mainly predicted by children's morpho-syntactic abilities in Hebrew. Language-universal and language-specific properties of referential use are discussed.

Effects of language background on executive function: Transfer across task and modality

The relation between linguistic experience and cognitive function has been of great interest, but recent investigations of this question have produced widely disparate results, ranging from proposals for a "bilingual advantage," to a "bilingual disadvantage," to claims of no difference at all as a function of language. There are many possible sources for this lack of consensus, including the heterogeneity of bilingual populations, and the choice of different tasks and implementations across labs. We propose that another reason for this inconsistency is the task demands of transferring from linguistic experience to laboratory tasks can differ greatly as the task is modified. In this study, we show that task modality (visual, audio, and orthographic) can yield different patterns of performance between monolingual and multilingual participants. The very same task can show similarities or differences in performance, as a function of modality. In turn, this may be explained by the distance of transfer - how close (or far) the laboratory task is to the day to day lived experience of language usage. We suggest that embodiment may provide a useful framework for thinking about task transfer by helping to define the processes of linguistic production and comprehension in ways that are easily connected to task manipulations.

Does Language Distance Modulate the Contribution of Bilingualism to Cognitive Reserve in Seniors? A Systematic Review

We report a systematic review and exploratory meta-regression investigating the hypothesis that the effects of bilingualism on cognitive reserve are modulated by the distance between the pair of languages a bilingual uses. An inclusive multiple database search was performed in order to identify all relevant published research conducted in bilingual seniors. A combination of qualitative and quantitative synthesis methods were used in order to investigate our research questions. Results suggest that healthy bilingual seniors speaking more distant language pairs show improved monitoring performance on cognitive tasks. Evidence regarding a modulatory influence of language distance (LD) on the age of dementia diagnosis was inconclusive due to the small number of published studies meeting our inclusion criteria. We recommend more detailed reporting of individual differences in bilingual experience to assess the impact of LD and other variables on typical cognitive aging and the development of dementia. Linguistic differences in samples should also be considered as a constraint on bilingual advantages in future studies. Preregistration: PROSPERO CRD42021238705; OSF DOI 10.17605/OSF.IO/VPRBU.

Comparison of language awareness in Kurdish-Persian bilingual children and Persian monolingual children

The present study examines language awareness between bilinguals and monolingual children. Language awareness is a person's explicit understanding of language and its role in thinking, learning, and social life, which is associated with executive functioning. Delis-Kaplan Executive Function System (D-KEFS) test was designed to evaluate executive functioning. The test includes two parts: verbal and non-verbal. In this study, the verbal part including Twenty Questions, Word context, and proverb of D-KEFS was used. Kurdish-Persian bilinguals and Persian monolinguals attended this study. The results showed that in the Twenty Questions, word context, and proverb, there was a significant difference between bilinguals and monolinguals. Bilinguals outperformed monolinguals in both twenty-question and word context tests, while they performed lower on the proverb test. It can be concluded that bilingualism affects language awareness and also influences different aspects of executive functioning in different manners.

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.

The effects of bilingualism on cognition and behaviour in individuals with attention deficits: A scoping review

Background

Weaknesses in executive function have persistently been found to be associated with Attention Deficit Hyperactivity Disorder (ADHD), while bilinguals have been argued to show advantages in executive functions. While there has been some research into how bilingualism affects cognitive skills and behaviour in individuals with attention deficits, the question is still very much open. The aim of this systematic review is to gather, synthesise and evaluate existing evidence on how bilingual language experience and attention deficits affect executive function performance and ADHD-related symptoms in children and adults.

Methods

Following PRISMA guidelines, a comprehensive literature search in relevant databases (PsycInfo, PubMed, Scopus, ERIC, Web of Science, EMBASE, MEDLINE, LLBA) was performed using search strings related to attention difficulties/ADHD and bilingualism. All quantitative studies were included that presented original empirical data on the combined effects of bilingualism and attention levels, regardless of age group and methodology. The screening procedure revealed nine relevant studies.

Results

Across the nine identified studies, a total of 2071 participants were tested. Of these, seven studies involved children and two adults. The studies varied considerably with respect to their design and methodology, the targeted executive function skills or behavioural symptoms, as well as their measure of bilingualism and attention levels. Most studies assessed aspects of executive function performance such as interference control, response inhibition, working memory or cognitive flexibility. Three studies looked at the effects of bilingualism on ADHD-related symptoms or ADHD diagnosis. Across the studies, no systematic advantage or disadvantage of bilingualism on cognitive performance or behaviour in people with attention deficits was observed.

Conclusion

The limited number of identified studies provide no consistent evidence that bilingualism alleviates or intensifies attention difficulties in adults or children with ADHD. Based on the current state of research, individuals with ADHD and their families should not be concerned that learning additional languages has a negative impact on functioning or cognitive performance.

Systematic review registration

https://doi.org/10.17605/OSF.IO/PK768.

The swerve: How childhood bilingualism changed from liability to benefit

Early research that relied on standardized assessments of intelligence reported negative effects of bilingualism for children, but a study by Peal and Lambert (1962) reported better performance by bilingual than monolingual children on verbal and nonverbal intelligence tests. This outcome led to the view that bilingualism was a positive experience. However, subsequent research abandoned intelligence tests as the assessment tool and evaluated performance on cognitive tasks, making the research after Peal and Lambert qualitatively different from that before their landmark study, creating a disconnect between the new and earlier research. These newer cognitive studies showed both positive effects of bilingualism and no differences between language groups. But why were Peal and Lambert's results so different from previous studies that were also based on intelligence tests? The present study analyzed data from verbal and nonverbal intelligence tests that were collected from 6,077 participants across 79 studies in which intelligence tests were administered as background measures to various cognitive tasks. By including adults, the study extends the results across the life span. On standardized verbal tests, monolinguals outperformed bilinguals, but on nonverbal measures of intelligence, there were no differences between language groups. These results, which are different from those reported by Peal and Lambert, are used to reinterpret their findings in terms of the sociolinguistic, political, and cultural context in which the Peal and Lambert study was conducted and the relevance of those factors for all developmental research. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Developmental behavioral genetics research on school achievement is missing vulnerable children, to our detriment

Gene-environment processes tell us how genetic predispositions and environments work together to influence children in schools. One type of gene-environment process that has been extensively studied using behavioral genetics methods is a gene-by-environment interaction. A gene-by-environment interaction shows us when the effect of your context on a phenotype differs depending on your genetic predispositions, or vice versa, when the effect of your genetic predispositions on a phenotype differs depending on your context. Developmental behavioral geneticists interested in children's school achievement have examined many different contexts within the gene-by-environment interaction model, including contexts measured from within children's home and school environments. However, this work has been overwhelmingly focused on WEIRD samples children, leaving us with non-inclusive scientific evidence. This can lead to detrimental outcomes when we overgeneralize this non-inclusive scientific evidence to racialized groups. We conclude with a call to include racialized children in more research samples.

The Multifaceted Nature of Bilingualism and Attention

Attention has recently been proposed as the mechanism underlying the cognitive effects associated with bilingualism. However, similar to bilingualism, the term attention is complex, dynamic, and can vary from one activity to another. Throughout our daily lives, we use different types of attention that differ in complexity: sustained attention, selective attention, alternating attention, divided attention, and disengagement of attention. The present paper is a focused review summarizing the results from studies that explore the link between bilingualism and attention. For each level of attention, a brief overview of relevant theoretical models will be discussed along with a spotlight on paradigms and tasks used to measure these forms of attention. The findings illustrate that different types and levels of attention are modified by the variety of bilingual experiences. Future studies wishing to examine the effects of bilingualism on attention are encouraged to embrace the complexity and diversity of both constructs rather than making global claims about bilingualism and attention.

Testing the Bilingual Cognitive Advantage in Toddlers Using the Early Executive Functions Questionnaire

The present study aims to assess differences in executive functioning between monolingual and multilingual 23-month-old toddlers, both when dichotomizing multilingualism and assessing it on a continuum. It is hypothesized that multilinguals, individuals with greater non-dominant language exposure, and individuals with more translation equivalents, would perform better in the following domains: response inhibition, attentional flexibility, and regulation. No differences are expected for working memory. The Early Executive Functions Questionnaire, a newly developed parental report, is used to measure the four executive functions of interest. Multilinguals and individuals with greater non-dominant language exposure have significantly higher response inhibition; however, no differences are noted for any other executive function. Additionally, no associations between translation equivalents and executive functioning are found. Post-hoc analyses reveal that non-dominant language production had a positive correlation with working memory. The present findings support the notion of a domain-specific cognitive advantage for multilingual toddlers.

What Is a Language? Who Is Bilingual? Perceptions Underlying Self-Assessment in Studies of Bilingualism

Research on the cognitive consequences of bilingualism typically proceeds by labeling participants as "monolingual" or "bilingual" and comparing performance on some measures across these groups. It is well-known that this approach has led to inconsistent results. However, the approach assumes that there are clear criteria to designate individuals as monolingual or bilingual, and more fundamentally, to determine whether a communication system counts as a unique language. Both of these assumptions may not be correct. The problem is particularly acute when participants are asked to classify themselves or simply report how many languages they speak. Participants' responses to these questions are shaped by their personal perceptions of the criteria for making these judgments. This study investigated the perceptions underlying judgments of bilingualism by asking 528 participants to judge the extent to which a description of a fictional linguistic system constitutes a unique language and the extent to which a description of a fictional individual's linguistic competence qualifies that person as bilingual. The results show a range of responses for both concepts, indicating substantial ambiguity for these terms. Moreover, participants were asked to self-classify as monolingual or bilingual, and these decisions were not related to more objective information regarding the degree of bilingual experience obtained from a detailed questionnaire. These results are consistent with the notion that bilingualism is not categorical and that specific language experiences are important in determining the criteria for being bilingual. The results impact interpretations of research investigating group differences on the cognitive effects of bilingualism.

Nonverbal Switching Ability of Monolingual and Bilingual Children with and without Developmental Language Disorder

Bilingualism is associated with enhanced switching skills, while a developmental language disorder (DLD) may negatively impact switching ability. However, both studies with bilinguals as well as studies including children with DLD have revealed mixed results. Moreover, the interaction of bilingualism and DLD has not been addressed and the origin of the stronger or weaker switching performance is unknown. The current study aimed to fill these gaps. Monolingual and bilingual children with and without DLD (n = 32 in each of the four groups) completed a nonverbal color/shape switching task when they were 7 to 8 years old, and a Continuous Performance Task two years earlier. The latter tapped into their response inhibition and sustained attention skills, which may underlie switching ability. No differences between monolinguals and bilinguals were found on the switching task. Children with DLD had higher mixing costs than peers without DLD, which was driven by differences in sustained attention skills. These results add to the body of research indicating that the cognitive advantages of bilingualism are unstable. Additionally, the results substantiate the hypothesis that attention processes are foundational for complex cognitive skills, such as switching, and suggest cascading effects for children with weaker attention skills, such as children with DLD.

Words Versus Pictures: Bilingual Performance on Verbal and Pictorial Measures of Executive Functions

PURPOSE

This study examined bilinguals' performance on functional executive function map tasks such as the Zoo Map from the Behavioural Assessment of the Dysexecutive Syndrome and the extent to which working memory, set-shifting, and inhibition measures predicted bilinguals' performance on these tasks. Additionally, we explored the utility of pictorial map tasks as a measure of complex executive function in bilinguals. We hypothesized that bilinguals would perform better on the pictorial map tasks due to the reduced language processing demand.

METHOD

The analyses included 131 bilingual young adults who completed a comprehensive language history questionnaire, an English proficiency test, a battery of working memory and executive function tasks, and verbal and pictorial map tasks.

RESULTS

Contrary to predictions, bilinguals' performance on the verbal maps did not differ significantly from that on the pictorial maps. Two multiple regression models significantly predicted performance on the verbal and pictorial maps, accounting for 7%-25% of the variance in the map scores. Working memory and interference control were the most prominent predictors within these models.

CONCLUSIONS

In our study, bilinguals' performance on the verbal maps did not differ significantly from that on the pictorial maps. Additionally, English proficiency did not correlate with the participants' verbal map scores. These results suggest that executive function map tasks (e.g., the Zoo Map) are a useful clinical tool for assessing executive function in bilinguals. The findings of this study are discussed in light of the current literature on executive functions in bilinguals.

Development of inhibition and working memory in school-age Moroccan children

Studies regarding executive functions (EFs) in children rarely focus on populations of North Africa countries. In this context, this research aimed to adapt EFs tests to the Moroccan context and provide preliminary normative data on the development of inhibitory control and working memory (WM). In addition, the executive performance of school-age Moroccan children was examined, as well as the effects of gender, parents' education level and multilingualism. The sample included 115 children at age 7 to 12 from Fes city. Results showed that the translation and adaptation steps were sufficient for the cross-cultural adaptation of the tasks. In addition, an overall effect of age on inhibition and WM performances was found, whereas gender and parents' education level showed non-significant effects. Multilingualism effects had a partial positive influence on EFs, with improved scores on a few executive tasks for multilingual children compared to their bilingual peers. Overall, results suggest that EFs in school-age Moroccan children operate on relatively homogeneous development trajectories, marked by improvements that differ according to tasks. As neuropsychological tools and normative data are still lacking in Morocco, this study helps better understand EFs development of children in this country.

Bilingualism as a Contributor to Cognitive Reserve: What it Can do and What it Cannot do

In the absence of effective pharmacological interventions for the prevention of dementia, attention has turned to lifestyle factors that contribute to cognitive reserve. Although cognitive reserve cannot prevent the occurrence of disease, the trajectory is different for high reserve and low reserve patients, giving more time for independent living to high reserve individuals. We argue that lifelong bilingual experience meets the criteria for an experience that confers cognitive reserve, although neural reserve, a related concept, is more difficult to validate. Bilingual patients show symptoms at a later stage of disease and decline more rapidly than comparable monolingual patients. These patterns are considered in terms of evidence from behavioural, imaging and epidemiological studies. Finally, the role of bilingualism in protecting against symptoms of some forms of dementia are discussed in the context of other protective factors and the limits of this reserve approach in dealing with the consequences of dementia.

Do Bilinguals Outperform Monolinguals in Switching Tasks? Contrary Evidence for Nonlinguistic and Linguistic Switching Tasks

The benefits of bilingualism in executive functions are highly debated. Even so, in switching tasks, these effects seem robust, although smaller than initially thought (Gunnerud et al., 2020; Ware et al., 2020). By handling two languages throughout their lifespan, bilinguals appear to train their executive functions and show benefits in nonlinguistic switching tasks compared to monolinguals. Nevertheless, because bilinguals need to control for the interference of another language, they may show a disadvantage when dealing with task-switching paradigms requiring language control, particularly when those are performed in their less dominant language. The present work explored this issue by studying bilingualism's effects on task switching within the visual and language domains. On the one hand, our results show that bilinguals were overall faster and presented reduced switch costs compared to monolinguals when performing perceptual geometric judgments with no time for task preparation. On the other hand, no bilingual advantage was found when a new sample of comparable bilinguals and monolinguals completed a within-language switching task. Our results provide clear evidence favoring the bilingual advantage, yet only when the task imposes greater executive demands and does not involve language control.

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.

Aphasia in Multilingual Patients

PURPOSE OF REVIEW

We summarize recent published work concerning assessment and treatment of aphasia in bilingual and multilingual people and review current related models of treatment outcomes. As well, we discuss studies that address the recently debated topic of cognitive processes in bilingual individuals with aphasia, with a focus on the effects of bilingualism on aphasia recovery and its potential protective effects.

RECENT FINDINGS

Providing assessment and treatment tools that best serve multilingual individuals with aphasia and unpacking the variables and mechanisms that underlie response to treatment have emerged as goals of several recent studies. Additionally, while findings are still contradictory, some empirical studies reported that aphasia may manifest less severely in multilingual individuals and may improve faster compared to in monolingual counterparts. The findings of recent studies with the focus of aphasia in multilingual individuals are crucial to understanding theoretical and clinical aspects of brain-related language impairment in multilingual people and to the study of language representation and processing in the brain.

Age-related changes of cognitive flexibility and planning skills in school-age Moroccan children

North African countries such as Morocco are scarcely the focus of neuropsychological studies, although the role of culture in cognition processes is widely recognized. Currently, studies on flexibility and planning skills in the Moroccan context are still lacking and there are no adapted tools to assess these functions in the country. In this scenario, this study aimed to adapt the Child Executive Functions Battery (CEF-B) tasks and the playing cards task of the Behavioral Assessment of the Dysexecutive Syndrome for Children (BADS-C) to Morocco and provide preliminary normative data on the development of flexibility and planning. In addition, this study proposed to examine the effects of gender, parents' education level and multilingualism on executive development. To this end, six tasks of the CEF-B were adapted through a translation and back-translation process and administered to 115 children aged 7-12 years. Results showed that the adopted procedure was sufficient for the cross-cultural adaptation of the tasks. Analyses showed a continuous increase with age on executive performance in most of the variables. However, gender and parents' level of education showed mostly non-significant effects. On the other hand, a significant effect of multilingualism was found on the two analyzed functions, with better results for multilingual children if compared to their bilingual peers. In general, results suggest that the identified pattern of development is consistent with international studies. Although normative data on executive functions are still lacking in Morocco, this unprecedented study will help better understand their development in this context.

The Relationship between Overweight/Obesity and Executive Control in College Students: The Mediating Effect of BDNF and 5-HT

The main aim of this study was to explore the association between overweight/obesity and executive control (EC) in young adults, and to further analyze the mediating effect of brain-derived neurotrophic factor (BDNF) and serotonin (5-hydroxytryptamine (5-HT)) on the relationship between overweight/obesity and EC. A total of 449 college students aged between 18 and 20 years were recruited for the study between March and December 2019. Their height and weight were then measured professionally. Subsequently, body mass index (BMI) was calculated as weight (kg) divided by the square of height (m). The EC of the participants was then estimated using the Flanker task, while their serum BDNF levels and 5-HT levels were measured using an enzyme-linked immunosorbent assay (ELISA) kit. Finally, the multiple intermediary models in SPSS were used to analyze the mediating effect of 5-HT and BDNF between overweight/obesity and EC. The result show that the overweight/obesity of college students was positively correlated with the response of EC (p ≤ 0.005). However, it was negatively correlated with BDNF (p ≤ 0.05) and 5-HT (p ≤ 0.05). Moreover, BDNF (p ≤ 0.001) and 5-HT (p ≤ 0.001) were negatively correlated with the response of EC. The BDNF level played a partial mediating role between overweight/obesity and EC that accounted for 7.30% of the total effect value. Similarly, the 5-HT of college students played a partial mediating role between overweight/obesity and EC that accounted for 8.76% of the total effect value. Gender and age had no regulatory effect on the relationship between overweight/obesity, BDNF, 5-HT, and EC. This study provides the evidence that 5-HT and BDNF mediated the association between overweight/obesity and executive control. It is indicated that 5-HT and BDNF might be the biological pathways underpinning the link between overweight/obesity and executive control.

Bilingualism: Pathway to Cognitive Reserve

Cognitive reserve is characterized by a dissociation between cognitive level and brain structure, thereby reducing the impact of deteriorating brain structure on cognitive function. Cognitive reserve is therefore a promising approach to maintaining cognitive function and protecting against symptoms of dementia. The present paper evaluates evidence supporting the claim that bilingualism contributes to cognitive reserve. Four types of evidence are presented: (i) brain and cognitive function in healthy aging, (ii) age of onset of symptoms of dementia, (iii) relation between clinical level and neuropathology for patients, and (iv) rate of cognitive decline in later stages of dementia. In all cases, bilinguals revealed patterns that were consistent with the interpretation of protection from cognitive reserve when compared with monolinguals.

Neural differences in the temporal cascade of reactive and proactive control for bilinguals and monolinguals

This study explored differences in sustained top-down attentional control (i.e., proactive control) and spontaneous types of control (i.e., reactive control) in bilingual and monolingual speakers. We modified a Color-Word Stroop task to varying levels of conflict and included switching trials in addition to more "traditional" inhibition Stroop conditions. The task was administered during scalp electroencephalography (EEG) to evaluate the temporal course of cognitive control during trials. The behavioral Stroop effect was observed across the whole sample; however, there were no differences in accuracy or response time between the bilingual and monolingual groups. Event-related potentials (ERPs) were calculated for the N200, N450, and conflict Sustained Potential (SP). On the pure-blocked incongruent trials, the bilingual group displayed reduced signal during interference suppression (N450) and increased later signal, as indexed by the conflict SP. On the mixed-block incongruent trials, both the bilinguals and monolinguals displayed increased later signal at the conflict SP. This suggests that proactive control may be a default mode for bilinguals on tasks requiring inhibition. In the switching trials, that place high demands on the executive control component of shifting, the language groups did not differ. Overall, these results suggest processing differences between bilinguals and monolinguals extend beyond early response inhibition processes. Greater integration of proactive and reactive control may be needed to sort conflicting language environments for bilinguals, which may be transferring to domain-general mechanisms.

Characterizing Bilingual Effects on Cognition: The Search for Meaningful Individual Differences

A debate over the past decade has focused on the so-called bilingual advantage-the idea that bilingual and multilingual individuals have enhanced domain-general executive functions, relative to monolinguals, due to competition-induced monitoring of both processing and representation from the task-irrelevant language(s). In this commentary, we consider a recent study by Pot, Keijzer, and de Bot (2018), which focused on the relationship between individual differences in language usage and performance on an executive function task among multilingual older adults. We discuss their approach and findings in light of a more general movement towards embracing complexity in this domain of research, including individuals' sociocultural context and position in the lifespan. The field increasingly considers interactions between bilingualism/multilingualism and cognition, employing measures of language use well beyond the early dichotomous perspectives on language background. Moreover, new measures of bilingualism and analytical approaches are helping researchers interrogate the complexities of specific processing issues. Indeed, our review of the bilingualism/multilingualism literature confirms the increased appreciation researchers have for the range of factors-beyond whether someone speaks one, two, or more languages-that impact specific cognitive processes. Here, we highlight some of the most salient of these, and incorporate suggestions for a way forward that likewise encompasses neural perspectives on the topic.

Exploration of Attentional and Executive Abilities in French-Speaking Children Immersed in Dutch Since 1, 2, 3, and 6 Years

Advantages in diverse aspects of cognitive functioning have been reported in early bilinguals (Bialystok, 2011) as well as in children frequenting an early bilingual immersion school program (Nicolay and Poncelet, 2015). However, during the last decade, some studies failed to replicate these advantages. Currently, the presence of cognitive benefits in children frequenting an immersion program remains debated. The lack of consistency between the studies could come from the fact that time spent by children within the immersion program is variable from one study to the other and that studies used different tasks to assess the same cognitive function. The main aim of the present study was to determine how time spent in immersion affects the emergence of cognitive advantages along the primary schooling. We compared 196 immersed Dutch-speaking children since they were 5 years old and 195 non-immersed French-speaking children, from different grades of the primary schooling (i.e., at 6, 7, 8, and 12 years old) by using the same attentional and executive tasks as those used in previous studies having shown a bilingual advantage. Furthermore, these groups were matched on a set of variables known to influence cognitive functioning. After 1, 2, and 3 years of enrolment in this program, performances of immersed compared to non-immersed children did not differ for any task. However, after 6 years, immersed children outperformed non-immersed children on the cognitive flexibility and the working memory tasks. These results show that, in French-speaking children immersed in Dutch, cognitive advantages could depend on the length of time spent in immersion since they are not present at the beginning (after 1, 2, and 3 years) but seem to emerge at the end of it (after 6 years). In contrast, in previous studies conducted in English immersion, advantages appear at the beginning of the primary schooling but are absent at the end of it. Furthermore, these results suggest that the emergence of cognitive advantages may vary depending on the second language learned. The results are discussed in terms of linguistic characteristics and status of the languages at stake.