Differential cerebral involvement in the cognitive functioning of bilinguals

The cognitive processing strategies of two groups of French-English bilinguals were studied by means of an auditory Stroop test designed to evaluate cerebral hemispheric involvement. An “early bilingual” group were bilingual before the age of 5, and a “late bilingual” group were bilingual after the age of 10. Stimuli were words uttered in pitches that were related to word meanings either congruently (as in the word “high” uttered in a high pitch) or incongruently (the word “haute” uttered in a low pitch). In one condition, subjects were to differentiate low from high pitches, disregarding meaning, while in a second condition, they were to disregard pitch and respond to word meanings. Measures of field independence were also taken. Results of data analyses suggest that male early bilinguals—the most field independent subgroup—process meaning efficiently in both cerebral hemispheres, but process pitch better in the right hemisphere. However, male late bilinguals and female bilinguals, both early and late, process meaning more rapidly in the right cerebral hemisphere and pitch equally rapidly in both hemispheres. The findings are interpreted as reflecting hemisphere-based strategy and sex differences in information-processing by the two bilingual groups.     

Attentional control in early and later bilingual children

We examined differences in attentional control among school-age children who were monolingual English speakers, early Spanish-English bilinguals (who began speaking both languages by age 3), and later Spanish-English bilingual children (who began speaking English after age 3). Children's attentional control was tested using the Attention Network Test (ANT). All language groups performed equally on ANT networks; however, when controlling for age and verbal ability, groups differed significantly on reaction time. Early bilingual children responded faster on the ANT compared to both monolingual and later bilingual children, suggesting an attentional monitoring advantage for early bilinguals. These results add to evidence of advantaged cognitive functioning among bilinguals and are consistent with the possibility that children who begin speaking a second language earlier in childhood have greater advantages, due either to effects of acquiring a second language earlier or to longer duration of bilingual experience.     

Shared and separate systems in bilingual language processing: converging evidence from eyetracking and brain imaging

The neurological and cognitive aspects of bilingual language processing were examined in late Russian-English bilinguals using headband-mounted eyetracking and functional neuroimaging. A series of three eyetracking studies suggested that, at early stages of word recognition, bilinguals can activate both languages in parallel, even when direct linguistic input is in one language only. A functional neuroimaging study suggested that, although the same general structures are active for both languages, differences within these general structures are present across languages and across levels of processing. For example, different centers of activation were associated with first versus second language processing within the left Inferior Frontal Gyrus, but not within the Superior Temporal Gyrus. We suggest that parallel activation (as found with eyetracking) and shared cortical structures (as found with fMRI) may be characteristic of early stages of language processing (such as phonetic processing), but the two languages may be using separate structures at later stages of processing (such as lexical processing).     

Language processing in bilinguals

The present study investigated the language processing strategies of three subgroups of adult bilinguals with different histories of language acquisition: infant bilinguals whose bilinguality dated from infancy; childhood bilinguals who became bilingual around 5 years of age; and adolescent bilinguals who had become bilingual at secondary school age only. All were completely balanced bilinguals in French and English at the time of testing. The experimental procedure, a language recognition task, required the subjects to indicate, by pressing a response button, whether each of a series of words, presented monaurally through earphones, was French or English. Concomitantly, left and right hemisphere EEG activity was monitored, with measures taken of latency to N₁, latency to P₂, and N₁-P₂ peak-to-peak amplitudes. Results indicated shorter latencies to N₁ in the left than in the right hemisphere for the infant and childhood bilinguals but shorter latencies in the right hemisphere for the adolescent bilinguals. Overall, the N₁ latency was shorter for the adolescent subgroup than for the two other subgroups. There were no RT differences. The findings appear to reflect strategy differences: The adolescent group seemed to rely more on a right hemisphere-based, possibly more gestalt-like or melodic strategy, while the early bilinguals relied more on a left hemisphere-based, possibly semantic or analytic type of strategy. The results are discussed in terms of previous research on bilingual subtypes and general forms of language processing among bilinguals.     

The Role of Age of Acquisition in Bilingual Word Translation: Evidence from Spanish-English Bilinguals

The present research tested the hypothesis that the age at which one’s first language (L1) words are learned influences language processing in bilinguals. Prior research on bilingual language processing by Kroll and colleagues has suggested that memory links between L1 words and conceptual representations are stronger than memory links between one’s second language (L2) word and conceptual representations. We hypothesized that the strengths of memory links between L1 words and conceptual representations are stronger for words learned early in life than for words learned later in life. Support for the hypothesis was obtained in bilingual translation experiment with 36 Spanish–English bilinguals. Participants translated L1 words into L2 and L2 words into L1. Half of the L1 words were learned early in childhood (early AoA words), and half were learned later in life (late AoA words). The L2 words were translation equivalents of the L1 words tested; the average age at which L2 words were learned was age 7. Target words were presented either in random order or blocked by semantic category. Translation times were longer when trials were blocked by semantic category (i.e., categorical interference) occurred only when early AoA L1 words were translated into L2. Implications for current models of bilingual memory are discussed.     

The emotional Stroop task and emotionality rating of negative and neutral words in late Thai–English bilinguals

The current study investigated how emotions are represented in the lexicon of late Thai–English bilinguals and a comparison group of native English speakers. Two tasks were used. In the emotional Stroop task, which taps into an automatic early lexical level of processing, the bilingual participants did not display the same automatic level of activation in their second language (L2) as in their first language (L1). In the emotionality‐rating task, which involves a later, more in‐depth conscious level of processing than the preceding task, similar results were found in both languages spoken by the bilinguals. These findings are interpreted as indicating that late bilinguals do not automatically respond to the emotional arousal associated with the meanings of L2 words to the same extent as in the L1, and this is likely to be mediated by language proficiency and the context in which the language is learned.     

中英双语者情绪注意偏向中的双语优势效应

采用改进的点–探测范式,考察熟练双语者在情绪注意偏向中对情绪信息加工的优势效应及该效应产生的原因。采用2（熟练双语者和非熟练双语者）×3（靶刺激与消极词汇出现的位置一致、不一致和中性条件）×2（线索呈现时间为100 ms和400 ms）的混合实验设计,记录被试对靶子的按键反应时和错误率。结果发现：线索呈现100 ms和400 ms时,两组被试在注意定向分数上无显著差异;线索呈现100 ms时,两组被试的注意解除分数无显著差异;线索呈现400 ms时,熟练双语者的注意解除分数显著小于非熟练双语者。结果表明,在情绪注意偏向任务中,熟练双语者比非熟练双语者表现出了对情绪词汇信息更好的注意抑制控制能力,体现出对情绪信息加工的双语优势效应,产生这一优势效应的原因是熟练双语者在注意的晚期阶段比非熟练双语者具有更好的情绪信息注意解除能力。     

Are there bilingual advantages on nonlinguistic interference tasks? Implications for the plasticity of executive control processes

It has been proposed that the unique need for early bilinguals to manage multiple languages while their executive control mechanisms are developing might result in long-term cognitive advantages on inhibitory control processes that generalize beyond the language domain. We review the empirical data from the literature on nonlinguistic interference tasks to assess the validity of this proposed bilingual inhibitory control advantage. Our review of these findings reveals that the bilingual advantage on conflict resolution, which by hypothesis is mediated by inhibitory control, is sporadic at best, and in some cases conspicuously absent. A robust finding from this review is that bilinguals typically outperform monolinguals on both compatible and incompatible trials, often by similar magnitudes. Together, these findings suggest that bilinguals do enjoy a more widespread cognitive advantage (a bilingual executive processing advantage) that is likely observable on a variety of cognitive assessment tools but that, somewhat ironically, is most often not apparent on traditional assays of nonlinguistic inhibitory control processes.     

Neuropsychological,Cognitive, and Theoretical Considerations for Evaluation of Bilingual Individuals

As the number of bilinguals in the USA grows rapidly, it is increasingly important for neuropsychologists to be equipped and trained to address the unique challenges inherent in conducting ethical and competent neuropsychological evaluations with this population. Research on bilingualism has focused on two key cognitive mechanisms that introduce differences between bilinguals and monolinguals: (a) reduced frequency of language-specific use (weaker links), and (b) competition for selection within the language system in bilinguals (interference). Both mechanisms are needed to explain how bilingualism affects neuropsychological test performance, including the robust bilingual disadvantages found on verbal tasks, and more subtle bilingual advantages on some measures of cognitive control. These empirical results and theoretical claims can be used to derive a theoretically informed method for assessing cognitive status in bilinguals. We present specific considerations for measuring degree of bilingualism for both clients and examiners to aid in determinations of approaches to testing bilinguals, with practical guidelines for incorporating models of bilingualism and recent experimental data into neuropsychological evaluations. This integrated approach promises to provide improved clinical services for bilingual clients, and will also contribute to a program of research that will ultimately reveal the mechanisms underlying language processing and executive functioning in bilinguals and monolinguals alike.     

Native language influences on word recognition in a second language: a megastudy

Many studies have reported that word recognition in a second language (L2) is affected by the native language (L1). However, little is known about the role of the specific language combination of the bilinguals. To investigate this issue, the authors administered a word identification task (progressive demasking) on 1,025 monosyllabic English (L2) words to native speakers of French, German, and Dutch. A regression approach was adopted, including a large number of within- and between-language variables as predictors. A substantial overlap of reaction time patterns was found across the groups of bilinguals, showing that word recognition results obtained for one group of bilinguals generalize to bilinguals with different mother tongues. Moreover, among the set of significant predictors, only one between-language variable was present (cognate status); all others reflected characteristics of the target language. Thus, although influences across languages exist, word recognition in L2 by proficient bilinguals is primarily determined by within-language factors, whereas cross-language effects appear to be limited. An additional comparison of the bilingual data with a native control group showed that there are subtle but significant differences between L1 and L2 processing.     

Bilinguals in a monolingual and a bilingual speech mode: The effect on lexical access

The time course of lexical access in fluent Portuguese-English bilinguals and in English speaking monolinguals was examined during the on-line processing of spoken sentences using the phoneme-triggered lexical decision task (Blank, 1980). The bilinguals were tested in two distinct speech modes: a monolingual, English or Portuguese, speech mode, and a bilingual, code-switching, speech mode. Although the bilingual’s lexical decision response times to word targets in the monolingual speech modes were identical to those of the monolingual subjects, their response times to code-switched word targets in the bilingual mode were significantly slower. In addition, the bilinguals took longer to detect nonwords in both the monolingual and bilingual modes. These results confirm that bilinguals cannot totally deactivate their other language when in a monolingual speech mode. It is hypothesized that bilinguals search both lexicons when confronted with nonwords, even when in a totally monolingual mode, and that they search the base-language lexicon before the other lexicon when in a bilingual, code-switching, speech mode.     

Imagery skill and preference in bilinguals

A number of studies have reported differences in the performance of bilinguals and monolinguals in verbal tasks. It has been suggested that one source of this difference is a greater tendency among bilinguals to use non-verbal ways of representing events, because of the potential for confusions between their two verbal codes. In the present study, bilingual and monolingual college students were compared on three dimensions of self-reported aspects of imagery—control, vividness and preference—as well as on a performance measure of spatial manipulation skill. When these tasks were preceded by a nominally verbal activity (prose comprehension), there were no group differences on the self-report or objective imagery measures. In contrast, when they were preceded by an imagery rating task, some evidence of a compensatory reliance on spatial codes among bilinguals was obtained. Implications of these task induction effects on both subjective and performance measures of a skill were discussed.     

Better early or late? Examining the influence of age of exposure and language proficiency on executive function in early and late bilinguals

Previous research has shown that early and late bilinguals differ in their language learning experiences and linguistic outcomes. However, evidence of differences between these bilinguals on measures of executive function (EF) has been mixed. As a result, the current study sought to (1) determine whether early and late bilinguals vary from one another and (2) exhibit cognitive advantages in EF relative to monolinguals. One hundred and five participants (42 monolinguals, 40 early bilinguals and 23 late bilinguals) completed the study. Participants' EF skills were assessed using the Auditorily Cued Number Numeral Task. Overall, the results did not reveal clear advantages for the early bilinguals compared to the two other groups. In fact, early bilinguals and monolinguals were equivalent in their performance on the EF task, whereas the late bilinguals were less accurate, relative to the other two groups. The differences in the performance of early and late bilinguals are discussed in terms of the competition model of second-language learning proposed in previous research. Taken together, these findings indicate that individual differences in EF influence the observed differences found in EF across language groups.     

Brain bases of English morphological processing: A comparison between Chinese-English,Spanish-English bilingual,and English monolingual children

How do early bilingual experiences influence children's neural architecture for word processing? Dual language acquisition can yield common influences that may be shared across different bilingual groups, as well as language-specific influences stemming from a given language pairing. To investigate these effects, we examined bilingual English speakers of Chinese or Spanish, and English monolinguals, all raised in the US (N = 152, ages 5–10). Children completed an English morphological word processing task during fNIRS neuroimaging. The findings revealed both language-specific and shared bilingual effects. The language-specific effects were that Chinese and Spanish bilinguals showed principled differences in their neural organization for English lexical morphology. The common bilingual effects shared by the two groups were that in both bilingual groups, increased home language proficiency was associated with stronger left superior temporal gyrus (STG) activation when processing the English word structures that are most dissimilar from the home language. The findings inform theories of language and brain development during the key periods of neural reorganization for learning to read by illuminating experience-based plasticity in linguistically diverse learners.     

Disentangling Context Availability and Concreteness in Lexical Decision and W ord Translation

This study examines contrasting predictions of the dual coding theory and the context availability hypothesis regarding concreteness effects in monolingual and bilingual lexical processing. In three experiments, concreteness was controlled for or confounded with rated context availability. In the first experiment, bilingual subjects performed lexical decision in their native language (Dutch, L1). In the second experiment, lexical decision performance of bilinguals in their second language (English, L2) was examined. In the third experiment, bilinguals translated words 'forwards' (from L1 to L2) or 'backwards' (from L2 to L1). Both monolingual and bilingual tasks showed a concreteness effect when concreteness was confounded with context availability. However, concreteness effects disappeared when abstract and concrete words were matched on context availability, and even occasionally reversed. Implications of these results for theories that account for concreteness effects, particulary in bilingual processing, are discussed.     

The bilingual brain: cerebral representation of languages.

The present article deals with theoretical and experimental aspects of language representation in the multilingual brain. Two general approaches were adopted in the study of the bilingual brain. The study of bilingual aphasics allows us to describe dissociations and double dissociations between the different subcomponents of the various languages. Furthermore, symptoms peculiar to bilingual aphasia were reported (pathological mixing and switching and translations disorders) which allowed the correlation of some abilities specific to bilinguals with particular neurofunctional systems. Another approach to the study of the bilingual brain is of the experimental type, such as electrophysiological investigations (electrocorticostimulation during brain surgery and event-related potentials) and functional neuroanatomy studies (positron emission tomography and functional magnetic resonance imaging). Functional neuroanatomy studies investigated the brain representation of languages when processing lexical and syntactic stimuli and short stories. Neurophysiologic and neuroimaging studies evidenced a similar cerebral representation of L1 and L2 lexicons both in early and late bilinguals. The representation of grammatical aspects of languages seems to be different between the two languages if L2 is acquired after the age of 7, with automatic processes and correctness being lower than those of the native language. These results are in line with a greater representation of the two lexicons in the declarative memory systems, whereas morphosyntactic aspects may be organized in different systems according to the acquisition vs learning modality.     

Executive control in older Welsh monolinguals and bilinguals

Evidence for a bilingual advantage in executive control has led to the suggestion that being bilingual might protect against late-life cognitive decline. We assessed the performance of socially homogeneous groups of older (≥60 years) bilingual Welsh/English (n?=?50) and monolingual English (n?=?49) speakers on a range of executive control tasks yielding 17 indices for comparison. Effect sizes (>.2) favoured monolinguals on 10 indices, with negligible differences observed on the remaining 7 indices. Univariate analyses indicated that monolinguals performed significantly better on 2 of 17 indices. Multivariate analysis indicated no significant overall differences between the two groups in performance on executive tasks. Older Welsh bilinguals do not show a bilingual advantage in executive control, and where differences are observed, these tend to favour monolinguals. A possible explanation may lie in the nature of the socio-linguistic context and its influence on cognitive processing in the bilingual group.     

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.

     

No evidence for reduced Simon cost in elderly bilinguals and bidialectals

We explored whether a bilingual advantage in executive control is associated with differences in cultural and ethnic background associated with the bilinguals' immigrant status, and whether dialect use in monolinguals can also incur such an advantage. Performance on the Simon task in older non-immigrant (Gaelic-English) and immigrant (Bengali, Gujarati, Hindi, Malay, Punjabi, Urdu-English) bilinguals was compared with three groups of older monolingual English speakers, who were either monodialectal users of the same English variety as the bilinguals or were bidialectal users of a local variety of Scots. Results showed no group differences in overall reaction times as well as in the Simon effect thus providing no evidence that an executive control advantage is related to differences in cultural and ethnic background as was found for immigrant compared to non-immigrant bilinguals, nor that executive control may be improved by use of dialect. We suggest the role of interactional contexts and bilingual literacy as potential explanations for inconsistent findings of a bilingual advantage in executive control.     

The "Perceptual Wedge Hypothesis" as the basis for bilingual babies' phonetic processing advantage: new insights from fNIRS brain imaging

In a neuroimaging study focusing on young bilinguals, we explored the brains of bilingual and monolingual babies across two age groups (younger 4-6 months, older 10-12 months), using fNIRS in a new event-related design, as babies processed linguistic phonetic (Native English, Non-Native Hindi) and nonlinguistic Tone stimuli. We found that phonetic processing in bilingual and monolingual babies is accomplished with the same language-specific brain areas classically observed in adults, including the left superior temporal gyrus (associated with phonetic processing) and the left inferior frontal cortex (associated with the search and retrieval of information about meanings, and syntactic and phonological patterning), with intriguing developmental timing differences: left superior temporal gyrus activation was observed early and remained stably active over time, while left inferior frontal cortex showed greater increase in neural activation in older babies notably at the precise age when babies’ enter the universal first-word milestone, thus revealing a first-time focalbrain correlate that may mediate a universal behavioral milestone in early human language acquisition. A difference was observed in the older bilingual babies’ resilient neural and behavioral sensitivity to Non-Native phonetic contrasts at a time when monolingual babies can no longer make such discriminations. We advance the “Perceptual Wedge Hypothesis” as one possible explanation for how exposure to greater than one language may alter neural and language processing in ways that we suggest are advantageous to language users. The brains of bilinguals and multilinguals may provide the most powerful window into the full neural “extent and variability” that our human species’ language processing brain areas could potentially achieve.