Mapping individual aspects of bilingual experience to adaptations in brain structure.

Individual differences in using multiple languages are thought to differentially affect brain structure and function. The present study assessed the neuroanatomical predictions of an emerging theory, the Unifying the Bilingual Experience Trajectories framework, which provides the most comprehensive set of predictions of how individual differences in bilingual experiences lead to specific neural and cognitive adaptations. A total of 140 young adults with variable language experiences were scanned using magnetic resonance imaging and completed demographic questionnaires. Brain structure measures implicated in predictions of the Unifying the Bilingual Experience Trajectories model were extracted and regressed against the model's experiential factors. Consistent with the model's predictions, greater intensity and diversity of bilingual language use resulted in changes in gray matter volume in cortical regions involved in executive control (including inferior frontal gyrus, middle temporal gyrus, angular gyrus, and medial frontal gyrus), indicating adaptations toward handling increased executive control demands. Conversely, duration of bilingual engagement resulted in changes within white matter microstructure (bilateral superior longitudinal fasciculus) and increases in subcortical gray matter (left caudate), indicative of adaptations toward increased efficiency of control. Overall, this research enhances our understanding of how bilingual experiences influence brain structure and provides the first direct empirical evidence for the predictions made by the Unifying the Bilingual Experience Trajectories framework.

Functional neural architecture of cognitive control mediates the relationship between individual differences in bilingual experience and behaviour.

Bilinguals have often, but not always, been found to outperform monolinguals on domain-general attentional control. Inconsistent findings have been argued to stem, at least partly, from treating bilingualism as a uniform category and from not considering how neural adaptations to bilingual experiences modulate behavioural outcomes. The present study investigated how patterns of language experience, including language switching behaviour, duration and intensity/diversity of bilingual language use, influence the brain processes underlying cognitive control, and how these in turn translate to cognitive control performance. We examined reaction times and spectral dynamics of the electroencephalograms (EEG) of two-hundred-and-thirty-nine participants (about 70% bilinguals) with diverse language experiences during two cognitive control paradigms testing interference suppression (flanker and Simon task). Using structural equation modelling, we found that different bilingual experience factors were related with neurocognitive measures, which in turn were related with behavioural interference effects, for the flanker but not the Simon task. More specifically, increased frequency of language switching and intensity/diversity of bilingual language usage was negatively related to induced top-down control measures (especially midline-frontal theta), which in turn was beneficial for interference control. In contrast, duration of bilingual engagement correlated negatively with evoked bottom-up control measures (especially P3) and was therefore detrimental to interference control. We demonstrate here for the first time how the different factors of bilingual experience lead to different neural adaptations which impact behavioural outcomes. SIGNIFICANCE STATEMENT: Like other intensive experiences, bilingualism leads to brain adaptations. It results in structural changes in language areas, and, due to demands on language control, in brain areas associated with domain-general cognitive control. Related to this, bilinguals often outperform monolinguals on cognitive control tasks. But what is often ignored is that bilingualism is a multi-dimensional phenomenon, with variations such as diversity of language usage and duration of language use. The present large-scale study of neural functioning in bilingualism revealed for the first time how individual differences in bilingual experience lead to adaptations to brain functioning which in turn affect cognitive control behaviour. It exemplifies how the complexity of individual experiences plays a fundamental role in brain function.

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 challenge of relational referents in early word extensions: Evidence from noun-noun compounds.

Young children struggle more with mapping novel words onto relational referents (e.g., verbs) compared to non-relational referents (e.g., nouns). We present further evidence for this notion by investigating children's extensions of noun-noun compounds, which map onto combinations of non-relational referents, i.e., objects (e.g., baby and bottle for baby bottle), and relations (e.g., a bottle FOR babies). We tested two- to five-year-olds' and adults' generalisations of novel compounds composed of novel (e.g., kig donka) or familiar (e.g., star hat) nouns that were combined by one of two relations (e.g., donka that has a kig attached (=attachment relation) versus donka that stores a kig (=function relation)). Participants chose between a relational (shared relation) and a non-relational (same colour) match. Results showed a developmental shift from encoding non-relational aspects (colour) towards relations of compound referents, supporting the challenge of relational word referents. Also, attachment relations were more frequently encoded than function relations.

What about lexical competition? Exploring the locus of lexical retrieval deficits in adults with developmental dyslexia.

OBJECTIVE: Individuals with dyslexia do not only show deficits with reading but are also less accurate in naming pictures. This has mainly been linked to prevalent phonological deficits. However, deficits in lexical retrieval of picture names could also be due to increased lexical-semantic competition. The present study tested whether adults with dyslexia (AwDs) are more affected by a competitive lexical-semantic context than control participants. METHOD: Twenty-seven AwD and 34 control participants completed the blocked-cyclic picture-naming paradigm and the Hayling sentence completion task. RESULTS: In the blocked-cyclic naming task, AwDs showed a larger semantic interference effect than controls in terms of errors, especially producing competitor errors. In the Hayling sentence completion task, AwDs made more errors than controls when asked to complete sentences with semantically unrelated words, that is, in the competitive condition. They especially produced semantically related words or antonyms to target words. CONCLUSIONS: We found that AwDs experience difficulties with resolving lexical competition that go beyond their phonological deficits. Future studies will need to establish the mechanisms behind the increased lexical competition that AwDs exhibit. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Bilingualism Enhances Reported Perspective Taking in Men, but Not in Women.

Bilingual speakers have often been found to be superior in taking the perspective of another person. Also, females are commonly found to have enhanced perspective taking (PT) abilities compared with males, with male PT being generally more easily affected by external factors. The present study investigated whether bilingualism improves PT in males more strongly than in females. In total, 108 bilingual and 108 matched monolingual adults, with equal numbers of males and females, filled in the PT subscale of the Interpersonal Reactivity index. While monolinguals showed the typical result of females scoring higher on PT than males, scores of male and female bilinguals did not differ, with both bilingual groups scoring as high as female monolinguals. Thus, bilingualism enhanced self-reported PT only in males, suggesting that male PT can be enhanced through socialization.

Beyond the Shape of Things: Infants Can Be Taught to Generalize Nouns by Objects' Functions.

Two-year-olds typically extend labels of novel objects by the objects' shape (shape bias), whereas adults do so by the objects' function. Is this because shape is conceptually easier to comprehend than function? To test whether the conceptual complexity of function prevents infants from developing a function bias, we trained twelve 17-month-olds (function-training group) to focus on objects' functions when labeling the objects over a period of 7 weeks. Our training was similar to previously used methods in which 17-month-olds were successfully taught to focus on the shape of objects, resulting in a precocious shape bias. We exposed another 12 infants (control group) to the same objects over 7 weeks but without labeling the items or demonstrating their functions. Only the infants in the function-training group developed a function bias. Thus, the conceptual complexity of function was not a barrier for developing a function bias, which suggests that the shape bias emerges naturally because shape is perceptually more accessible than function.

A Bilingual Advantage? An Appeal for a Change in Perspective and Recommendations for Future Research.

The debate on possible cognitive advantages bilinguals have over monolinguals continues to occupy the research community. There is an ever-growing research body focusing on adjudicating whether there is, in fact, an effect of using two or more languages regularly on cognition. In this paper, we briefly review some of the more pertinent literature that has attempted to identify attenuating, modulating, and confounding factors in research comparing monolingual and bilingual populations, and we highlight issues that should be taken into account in future research to move forward as a research community. At the same time, we argue for a change in perspective concerning what is deemed an advantage and what is not and argue for more ecologically valid research that investigates real-life advantages.

Early and Late Effects of Semantic Distractors on Electroencephalographic Responses During Overt Picture Naming.

This study investigated the nature of the interference effect of semantically related distractors in the picture-word interference paradigm, which has been claimed to be caused by either competition between lexical representations of target and distractor or by a late response exclusion mechanism that removes the distractor from a response buffer. EEG was recorded while participants overtly named pictures accompanied by categorically related versus unrelated written distractor words. In contrast to previous studies, stimuli were presented for only 250 ms to avoid any re-processing. ERP effects of relatedness were found around 290, 470, 540, and 660 ms post stimulus onset. In addition, related distractors led to an increase in midfrontal theta power, especially from about 440 to 540 ms, as well as to decreased high beta power between 40 and 110 ms and increased high beta power between 275 and 340 ms post stimulus onset. Response-locked analyses showed no differences in ERPs, however increased low and high beta power for related distractors in various time windows, most importantly a high beta power increase between -175 and -155 ms before speech onset. These results suggest that the semantic distractor effect is a combination of various effects and that the lexical competition account and the response exclusion account each capture a part, but not all aspects of the effect.

The benefit of simultaneously encountered exemplars and of exemplar variability to verb learning.

Young children are conservative when extending novel verbs to novel exemplars. We investigated whether multiple, simultaneously presented exemplars would aid young children's verb learning, as well as the importance of exemplar variability. Three-year-olds were taught novel verbs, while viewing either one action-scene featuring a novel action performed on a novel object, or two action-scenes side-by-side in which the action performed was the same but the object varied, or two action-scenes side-by-side in which no aspect of the scenes varied. They were asked to extend the novel verbs to one of two scenes: one that maintained the action and one that maintained the object. Findings indicated that children were only able to extend verbs correctly after viewing two action-scenes in which the content varied. These findings suggest that simultaneously presented exemplars of a verb can support verb learning in younger children, but only when the content of the exemplars varies.

Do Children with Autism Spectrum Disorder Benefit from Structural Alignment When Constructing Categories?

Individuals with ASD seem to construct categories via processes different to typically developing individuals. We examined whether individuals with ASD engage in structural alignment of exemplars when constructing categories. We taught children with ASD and typically developing children novel nouns for either single or multiple exemplars, and then examined their extensions of the learned nouns to objects that were either a perceptual or conceptual match to the original exemplar(s). Results indicated that, unlike typically developing participants, those with ASD gained no benefit from seeing multiple exemplars of the category and, thus, did not appear to engage in structural alignment in their formation of categories. However, they demonstrated superior performance compared to typically developing children when presented with a single exemplar.

I: INTRODUCTION.

The majority of the world's children grow up learning two or more languages. The study of early bilingualism is central to current psycholinguistics, offering insights into issues such as transfer and interference in development. From an applied perspective, it poses a universal challenge to language assessment practices throughout childhood, as typically developing bilingual children usually underperform relative to monolingual norms when assessed in one language only. We measured vocabulary with Communicative Development Inventories for 372 24-month-old toddlers learning British English and one Additional Language out of a diverse set of 13 (Bengali, Cantonese, Dutch, French, German, Greek, Hindi-Urdu, Italian, Mandarin, Polish, Portuguese, Spanish, and Welsh). We furthered theoretical understanding of bilingual development by showing, for the first time, that linguistic distance between the child's two languages predicts vocabulary outcome, with phonological overlap related to expressive vocabulary, and word order typology and morphological complexity related to receptive vocabulary, in the Additional Language. Our study also has crucial clinical implications: we have developed the first bilingual norms for expressive and receptive vocabulary for 24-month-olds learning British English and an Additional Language. These norms were derived from factors identified as uniquely predicting CDI vocabulary measures: the relative amount of English versus the Additional Language in child-directed input and parental overheard speech, and infant gender. The resulting UKBTAT tool was able to accurately predict the English vocabulary of an additional group of 58 bilinguals learning an Additional Language outside our target range. This offers a pragmatic method for the assessment of children in the majority language when no tool exists in the Additional Language. Our findings also suggest that the effect of linguistic distance might extend beyond bilinguals' acquisition of early vocabulary to encompass broader cognitive processes, and could constitute a key factor in the study of the debated bilingual advantage.

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.

Removing speech artifacts from electroencephalographic recordings during overt picture naming.

A number of electroencephalography (EEG) studies have investigated the time course of brain activation during overt word production. The interpretation of their results is complicated by the fact that articulatory movements may mask the cognitive components of interest. The first aim of the present study was to investigate when speech artifacts occur during word production planning and what effects they have on the spatio-temporal neural activation pattern. The second aim was to propose a new method that strongly attenuates speech artifacts during overt picture naming and to compare it with existing methods. EEG and surface electromyograms (EMGs) of the lips were recorded while participants overtly named pictures in a picture-word interference paradigm. The comparison of the raw data with lip EMG and the comparison of source localizations of raw and corrected EEG data showed that speech artifacts occurred mainly from ~400 ms post-stimulus onset, but some earlier artifacts mean that they occur much earlier than hitherto assumed. We compared previously used methods of speech artifacts removal (SAR) with a new method, which is based on Independent Component Analysis (SAR-ICA). Our new method clearly outperformed other methods. In contrast to other methods, there was only a weak correlation between the lip EMG and the corrected data by SAR-ICA. Also, only the data corrected with our method showed activation of cerebral sources consistent with meta-analyses of word production.

How much exposure to English is necessary for a bilingual toddler to perform like a monolingual peer in language tests?

BACKGROUND: Bilingual children are under-referred due to an ostensible expectation that they lag behind their monolingual peers in their English acquisition. The recommendations of the Royal College of Speech and Language Therapists (RCSLT) state that bilingual children should be assessed in both the languages known by the children. However, despite these recommendations, a majority of speech and language professionals report that they assess bilingual children only in English as bilingual children come from a wide array of language backgrounds and standardized language measures are not available for the majority of these. Moreover, even when such measures do exist, they are not tailored for bilingual children. AIMS: It was asked whether a cut-off exists in the proportion of exposure to English at which one should expect a bilingual toddler to perform as well as a monolingual on a test standardized for monolingual English-speaking children. METHODS & PROCEDURES: Thirty-five bilingual 2;6-year-olds exposed to British English plus an additional language and 36 British monolingual toddlers were assessed on the auditory component of the Preschool Language Scale, British Picture Vocabulary Scale and an object-naming measure. All parents completed the Oxford Communicative Development Inventory (Oxford CDI) and an exposure questionnaire that assessed the proportion of English in the language input. Where the CDI existed in the bilingual's additional language, these data were also collected. OUTCOMES & RESULTS: Hierarchical regression analyses found the proportion of exposure to English to be the main predictor of the performance of bilingual toddlers. Bilingual toddlers who received 60% exposure to English or more performed like their monolingual peers on all measures. K-means cluster analyses and Levene variance tests confirmed the estimated English exposure cut-off at 60% for all language measures. Finally, for one additional language for which we had multiple participants, additional language CDI production scores were significantly inversely related to the amount of exposure to English. CONCLUSIONS & IMPLICATIONS: Typically developing 2;6-year-olds who are bilingual in English and an additional language and who hear English 60% of the time or more, perform equivalently to their typically developing monolingual peers.

Agreeing to disagree: deaf and hearing children's awareness of subject-verb number agreement.

This study investigated deaf adolescents' implicit and explicit awareness of subject-verb number agreement. In Experiment 1, a self-paced reading task, the reading times of deaf and hearing children (matched for reading and chronological age, mean=8;3 and 13;10 years) increased when sentences contained disagreeing subject-verb number markers. However, deaf adolescents' slowing occurred later in the sentence than it did in both groups of hearing children. The same deaf adolescents were unable to detect and correct subject-verb agreement errors in Experiment 2, whereas both groups of hearing children performed well on this task. Thus, deaf adolescents demonstrated implicit awareness of agreement in the absence of explicit knowledge. Moreover, this nascent awareness was below that expected on the basis of their (substantially delayed) reading ability. Therefore, grammatical difficulties could be a significant impediment to deaf children's literacy. Future research should examine whether this is a result of late or incomplete learning of English, bilingualism, or another factor.