Co-learning companionship benefits word learning in a new language: Evidence from a dual-brain EEG examination.

Companionship refers to one's being in the presence of another individual. For adults, acquiring a new language is a highly social activity that often involves learning in the context of companionship. However, the effects of companionship on new language learning have gone relatively underexplored, particularly with respect to word learning. Using a within-subject design, the current study employs electroencephalography to examine how two types of companionship (monitored and co-learning) affect word learning (semantic and lexical) in a new language. Dyads of Chinese speakers of English as a second language participated in a pseudo-word-learning task during which they were placed in monitored and co-learning companionship contexts. The results showed that exposure to co-learning companionship affected the early attention stage of word learning. Moreover, in this early stage, evidence of a higher representation similarity between co-learners showed additional support that co-learning companionship influenced attention. Observed increases in delta and theta interbrain synchronization further revealed that co-learning companionship facilitated semantic access. In all, the similar neural representations and interbrain synchronization between co-learners suggest that co-learning companionship offers important benefits for learning words in a new language.

Sleep-dependent consolidation effects on foreign language word acquisition in a virtual reality environment.

Sleep-dependent consolidation is important for novel word learning, but previous studies have neglected the potential modulating role of learning environments. The present study examines sleep-dependent consolidation effects by comparing learning in a virtual reality (VR) environment and in a traditional picture-word (PW) environment. Two groups of Chinese-English bilinguals were randomly assigned to a VR or PW environment. In both learning environments, they learned novel words in Korean, a language with which they had no prior experience. All participants learned one set of novel words on Day 1 and another set on Day 2. An explicit recognition task and an implicit primed lexical-decision task were employed to measure sleep-dependent consolidation effects from the two environments. Results revealed sleep-dependent consolidation effects in both explicit and implicit measures, but only the primed lexical-decision task showed an influence of learning environment, suggesting that novel words learned via VR had better consolidation. Taken together, our findings suggest that a VR environment that fosters a rich sensory experience facilitates sleep-dependent consolidation effects. We argue that these results provide new evidence and implications for the complementary learning system (CLS) model.

The right superior temporal gyrus plays a role in semantic-rule learning: Evidence supporting a reinforcement learning model.

In real-life communication, individuals use language that carries evident rewarding and punishing elements, such as praise and criticism. A common trend is to seek more praise while avoiding criticism. Furthermore, semantics is crucial for conveying information, but such semantic access to native and foreign languages is subtly distinct. To investigate how rule learning occurs in different languages and to highlight the importance of semantics in this process, we investigated both verbal and non-verbal rule learning in first (L1) and second (L2) languages using a reinforcement learning framework, including a semantic rule and a color rule. Our computational modeling on behavioral and brain imaging data revealed that individuals may be more motivated to learn and adhere to rules in an L1 compared to L2, with greater striatum activation during the outcome phase in the L1. Additionally, results on the learning rates and inverse temperature in the two rule learning tasks showed that individuals tend to be conservative and are reluctant to change their judgments regarding rule learning of semantic information. Moreover, the greater the prediction errors, the greater activation of the right superior temporal gyrus in the semantic-rule learning condition, demonstrating that such learning has differential neural correlates than symbolic rule learning. Overall, the findings provide insight into the neural mechanisms underlying rule learning in different languages, and indicate that rule learning involving verbal semantics is not a general symbolic learning that resembles a conditioned stimulus-response, but rather has its own specific characteristics.

The COMT gene modulates the relationship between bilingual adaptation in executive function and decision-making: an EEG study.

Bilingual adaptive control mechanisms appear to be linked to congenital genetic factors such as dopamine (DA) genes. However, it is unclear as to whether acquired cognitive exercise can vanquish innate influences that allow bilingual executive advantages to be shown in other cognitive areas. In the present study, we examine the relationship between gene-dependent executive control and decision-making by targeting the enzyme catecholamine-O-methyltransferase (COMT) and employing electroencephalography (EEG). Chinese-English bilinguals (N = 101) participated in a language switching task and the Iowa Gambling Task (IGT). The findings showed that COMT Val158Met polymorphism played a complex role in decision-making and bilingual executive control processing: Bilinguals with Valine (Val) homozygotes had poorer performance in the IGT, while Methionine (Met) carriers had larger switch costs in the language switching task. Second, the cross-task relationships varied among bilinguals with different COMT genotypes: Bilinguals with Met allele genotypes showed larger switch costs and better performance on the IGT. These findings suggest that bilinguals who carry Met allele are equipped with more efficient adaptive mechanisms of executive functions that are generalized to other cognitive domains. Supplementary Information: The online version contains supplementary material available at 10.1007/s11571-022-09867-2.

Spatiotemporal evidence uncovers differential neural activity patterns in cognitive and affective conflict control.

Studies have shown that there are overlapping neural bases for cognitive and affective conflict control, but whether the neural activity patterns caused by the two types of conflict are similar remains to be explored. The present study utilizes electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) to temporally and spatially analyze the differences between cognitive and affective conflict control. We employ a semantic conflict task which includes blocks of cognitive and affective judgements primed by conflicting and non-conflicting contexts. The results showed a typical neural conflict effect in the cognitive judgment blocks as reflected by greater amplitudes of P2, N400, and the late positive potential (LPP), as well as greater activation of the left pre-supplementary motor area (pre-SMA) and the right inferior frontal gyrus (IFG) in the conflict condition relative to the non-conflict condition. These patterns did not emerge in the affective judgments, but instead, showed reversed effects of the LPP and in the left SMA. Taken together, these findings suggest that cognitive and affective conflict control result in different neural activity patterns.

fMRI reveals overlapping and non-overlapping neural bases of domain-general and emotional conflict control.

The present study uses functional magnetic resonance image (fMRI) to examine the overlapping and specific neural correlates of contextualized emotional conflict control and domain-general conflict control. During a performance on emotional and domain-general conflict tasks, conjunction analyses showed that neural areas distributed in the frontoparietal network were engaged in both processes, supporting the notion that similar neural mechanisms are implemented in these two types of control. Importantly, disjunction analyses revealed a broader neural recruitment of emotional conflict control compared to domain-general conflict control as shown by the possible lateralization of the lateral prefrontal cortex (lPFC), such that emotional conflict control significantly involved the left lPFC while domain-general conflict control seemly involved the right lPFC. Results of generalized psychophysiological interaction (gPPI) analyses further demonstrated that emotional conflict control, compared to domain-general conflict control, elicited broader synergistic activities in individuals' brain networks. Together, these findings offer novel and compelling neural evidence that furthers our understanding of the complex relationship between domain-general and emotional conflict control.

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

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

An event-related potential study of self-positivity bias in native and foreign language contexts.

Self-positivity bias is a common psychological phenomenon in which individuals often associate positive information with themselves. However, little is known about how self-positivity bias is modulated by different language contexts (e.g., a first vs. second language). To this end, we analyzed behavioral and electrophysiological data to examine whether first or second languages play differential roles in the self-positivity bias effect. We used a modified self-positivity bias task which required Chinese-English bilinguals to judge strings of letters or characters as realwords or not and match associations between identity (self, other) and a geometric shape (circle, triangle). The target words in the experiment consisted of positive, negative, and neutral emotional words. The results showed that in the L2 context, the self-positivity condition elicited a smaller N400 effect relative to the self-negativity condition and a larger late positive component effect relative to the self-negativity and self-neutrality conditions. Furthermore, the other-positivity condition elicited a stronger N400 effect than the other-neutrality condition. These patterns did not emerge in the L1 context. We discuss the implications and contributions of these findings to better understand the interaction between emotion and self-concept in different language contexts.

Neural circuits underlying language control and modality control in bilinguals: An fMRI study.

Human communication not only involves the need to switch between the modalities of speaking and listening, but for bilinguals, it can also involve switching between languages. It is unknown as to whether modality and language switching share underlying control mechanisms or whether one type of switching affects control processes involved in the other. The present study uses behavioral and fMRI measures to examine neural circuits of control during communicative situations that required Chinese-English bilinguals to switch between modalities and their two languages according to associated color cues. The results showed that for both language and modality control, similar brain regions were recruited during speech production and comprehension. For modality control, the specific control processes partly depended on the corresponding modality. Finally, switching between modalities appears to exert more influence on language control in production compared to comprehension. These findings offer a first detailed characterization of the neural bases involved in control mechanisms in bilingual communication.

How processing emotion affects language control in bilinguals.

Research has shown that several variables affect language control among bilingual speakers but the effect of affective processing remains unexplored. Chinese-English bilinguals participated in a novel prime-target language switching experiment in which they first judged the affective valence (i.e., positive or negative) of auditorily presented words and then named pictures with neutral emotional valence in either the same (non-switch trial) or different language (switch trial). Brain activity was monitored using functional magnetic resonance imaging (fMRI). The behavioral performance showed that the typical switch cost (i.e., the calculated difference between switch and non-switch trials) emerged after processing positive words but not after negative words. Brain imaging demonstrated that processing negative words immediately before non-switch picturing naming trials (but not for switch trials) increased activation in brain areas associated with domain-general cognitive control. The opposite patterns were found after processing positive words. These findings suggest that an (emotional) negative priming effect is induced by spontaneous exposure to negative words and that these priming effects may be triggered by reactive emotional processing and that they may interact with higher level cognitive functions.

Control mechanisms in voluntary versus mandatory language switching: Evidence from ERPs.

The present study measured event-related potentials (ERP) and behavioral performance to examine whether inhibitory control is involved in voluntary language switching, and if so, to explore the differences in inhibitory control between voluntary and mandatory language switching. Unbalanced Chinese-English bilinguals completed two picture naming tasks: one involving mandatory language switches and one in which participants could voluntarily switch between the two languages. Behavioral data showed significant switch costs and a reversed language dominance effect in both switching tasks. Critically, both effects were larger in mandatory compared to voluntary switching. ERP results revealed that neural switch costs during mandatory switching was significantly different than voluntary switching in both N2 and LPC amplitudes. In contrast, a significant difference in the reversed language dominance effect between both tasks was only observed in LPC amplitude. Together, these findings suggest the involvement of inhibitory control in both mandatory and voluntary language switching, but the degree of inhibition and the time-course of control processes between both tasks appear to be distinct.

Partially shared neural mechanisms of language control and executive control in bilinguals: Meta-analytic comparisons of language and task switching studies.

The extent to which bilingual language control (BLC) is related to domain-general executive control (EC) remains unclear. The present study applied activation likelihood estimation (ALE) meta-analyses to identify commonalities and distinctions in the brain regions across domains reported in neuroimaging studies. We specifically compare results from two experimental tasks: language switching, a typical measure of BLC, and task switching, an experiment that measures EC. Conjunction analyses showed a domain-general pattern between language switching and task switching, with convergent activity in the left dorsolateral prefrontal cortex (DLPFC), pre-SMA/dACC complex (pre-supplementary motor area/dorsal anterior cingulate cortex), and left precuneus. Regarding domain-specificity, contrast analyses revealed stronger convergence of activation in the left fusiform gyrus and occipital gyrus in language switching compared to task switching, and conversely, stronger convergence of activation in the left DLPFC in task switching. Overall, these findings illustrate the partially overlapping nature of the neural circuits involved in BLC and EC.

Uncovering the effects of bilingual language control on rational decisions: An ERP study.

A growing body of research suggests that the language in which bilinguals make decisions affects the rationality of such decisions. Furthermore, bilinguals constantly confront cross-language interference that requires complex language control processes to resolve this competition. However, the relationship between language control and decision-making is unclear. In the current study, we analyze electrophysiological and behavior data elicited from two groups of Chinese-English bilinguals. One group was trained in intensive language switching and then completed the Iowa Gambling Task (IGT) and the other group completed the two tasks in the reverse order. We found that bilinguals who first received language switching training significantly scored higher on the IGT, with the score positively correlating with L1 and L2 switch costs. More importantly, training with language switching first led to an N2 component for L1 switching costs that negatively correlated with both loss feedback-related negativity and the P3 component. These effects did not emerge among the group of bilinguals who performed the IGT first. Taken together, the findings suggest that bilinguals are assisted in making rational decisions by language control on feedback evaluation.

The influence of peripheral emotions on inhibitory control among children.

In this study, we investigated the cognitive-emotional interplay by measuring the effects of executive competition (Pessoa, 2013), i.e., how inhibitory control is influenced when emotional information is encountered. Sixty-three children (8 to 9 years of age) participated in an inhibition task (central task) accompanied by happy, sad, or neutral emoticons (displayed in the periphery). Typical interference effects were found in the main task for speed and accuracy, but in general, these effects were not additionally modulated by the peripheral emoticons indicating that processing of the main task exhausted the limited capacity such that interference from the task-irrelevant, peripheral information did not show (Pessoa, 2013). Further analyses revealed that the magnitude of interference effects depended on the order of congruency conditions: when incongruent conditions preceded congruent ones, there was greater interference. This effect was smaller in sad conditions, and particularly so at the beginning of the experiment. These findings suggest that the bottom-up perception of task-irrelevant emotional information influenced the top-down process of inhibitory control among children in the sad condition when processing demands were particularly high. We discuss if the salience and valence of the emotional stimuli as well as task demands are the decisive characteristics that modulate the strength of this relation.

First and second languages differentially affect rationality when making decisions: An ERP study.

The present study examined how decision-making is affected by first (L1) and second languages (L2), emotion, and cognitive load. In a cross-task study, 30 Chinese-English bilinguals were asked to implement lexical-semantic judgment and gambling task. The results showed that after lexical decisions under high cognitive load, P3 was more positive for negative words than for neutral words in L1. The reverse was the case in the L2 in which P3 was more positive for neutral words compared to negative words. Critically, under high cognitive load, as the P3 effect increased for negative words relative to neutral words, the rationality of the decisions after these negative words decreased in the L1 but increased in the L2. The results moreover revealed that the increased Granger causal strength predicted more rational choices in the L2 high-load negative condition. Altogether, the findings offer evidence of how L1s and L2s can differentially influence rational decision-making.

Cross-task adaptation effects of bilingual language control on cognitive control: a dual-brain eeg examination of simultaneous production and comprehension.

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

Switching between newly learned languages impacts executive control.

Previous research has explored the relationship between language control and executive control based on performance in bilinguals' skilled languages. However, this relationship between bilingualism and executive control has not been examined at the very initial stage of language learning. In the present study, we trained Chinese speakers to learn words in German and Japanese, two languages with which they had no prior experience. In pre- and post-training, we measured participants' electrophysiological data to investigate how switching between these two newly learned languages affected executive control. We observed that, while lacking the language switching effect in the behavioral data, a flanker task elicited larger N2 and P3 amplitudes in the post-training session when participants were required to switch between German and Japanese compared to when they responded to only German or Japanese. These results provided evidence of language control of newly learned languages on domain-general executive control, specifically at the (very) initial period of language learning. Our findings support the adaptive nature of the relationship between bilingual language control and executive control.

Cognitive and Neurocognitive Effects From the Unique Bilingual Experiences of Interpreters.

For bilinguals, research suggests that both languages are constantly active and competing in the mind, even when only using one. However, this body of work has reported inconclusive results on the long-term effects of the constant parallel activation and use of more than one language on the brain. This has mostly been due to inconsistent comparisons between groups of bilinguals and monolinguals. Not all bilingualisms are the same. The investigation of the use of more than one language over a lifetime offers the opportunity to better understand the consequences of bilingualism on the brain. However, few studies have specifically looked at the long-standing effects of being an interpreter. In this paper, we review theories from the field of Translation and Interpreting Studies and provide a critical review of work that offers insight on the cognitive and neurocognitive effects that seem to arise from the unique, highly-cognitive-demanding practices experienced by interpreters.