Bilingualism Alters the Neural Correlates of Sustained Attention

The present study examined whether monolingual and bilingual language experience -- including first and second language proficiency, exposure, and age of acquisition -- modify the neural mechanisms of attention during nonverbal sound discrimination. English monolinguals and Korean-English bilinguals performed an auditory two-stimulus oddball task while their EEG was recorded. Participants heard a series of two different tones (high pitch tone versus low pitch tone), one of which occurred less frequently (deviant trials) than the other (standard trials), and were asked to mentally count the number of infrequent tones. We found that in the early time window, bilinguals had larger amplitudes than monolinguals in response to both standard and deviant trials, suggesting that bilinguals initially increased attention to identify which of the two tones they heard. In the later time window, however, bilinguals had a smaller ERP effect (deviant minus standard trials) relative to monolinguals, suggesting that bilinguals used fewer cognitive resources for the infrequent stimuli at later stages of processing. Furthermore, across the entire sample, increased exposure to the native language led to larger early, middle, and late ERP effects. These results suggest that native language exposure shapes perceptual processes involved in detection and monitoring. Knowing more than one language may alter sustained attentional processes, with implications for perception and learning.

The effect of training on sensitivity and stability of double fusion in Panum's limiting case

Panum's limiting case is a phenomenon of monocular occlusion in binocular vision. This occurs when one object is occluded by the other object for one eye, but the two objects are both visible for the other eye. Although previous studies have found that vertical gradient of horizontal disparity and cue conflict are two important factors for double fusion, the effect of training on the sensitivity and stability of Panum's limiting case remains unknown. The current study trained 26 participants for 5 days with several of Panum's configurations (Gilliam, Frisby, and Wang series). The latency and duration of double fusion were recorded to examine the effects of training on sensitivity and stability of double fusion in Panum's limiting case. For each level of vertical gradient of horizontal disparity and cue conflict, the latency of double fusion decreased and the duration of double fusion increased with each additional training session. The results showed that vertical gradient of horizontal disparity and cue conflict interacted, and the duration of high cue conflict was significantly shorter than that of medium and low cue conflict for each level of vertical gradient of horizontal disparity. The findings suggest that there is an effect of training for vertical gradient of horizontal disparity and cue conflict in Panum's limiting case, and that the three factors jointly affect the sensitivity and stability of double fusion.

Cultural background and input familiarity influence multisensory emotion perception

OBJECTIVES

During multisensory emotion perception, the attention devoted to the visual versus the auditory modality (i.e., modality dominance) varies depending on the cultural background of the perceiver. In the present study, we examined (a) how cultural familiarity influences multisensory emotion perception in Eastern and Western cultures and (b) the underlying processes accounting for the cultural difference in modality dominance.

METHOD

Native Mandarin speakers from China and native English speakers from the United States were presented with audiovisual emotional stimuli from their own culture (i.e., familiar) and from a different culture (i.e., unfamiliar) and asked to evaluate the emotion from one of the two modalities. Across modalities, the emotions were either the same (i.e., congruent, happy face, and happy voice) or different (i.e., incongruent, happy face, and sad voice).

RESULTS

When the input was in a familiar cultural context, American participants were more influenced by the visual modality, while Chinese participants were more influenced by the auditory modality. While both groups integrated the incongruent emotion from the irrelevant modality, only the American group integrated the congruent emotion from the irrelevant modality. When the input was in a less familiar cultural context, both groups showed increased visual dominance, but only the Chinese group simultaneously showed decreased auditory dominance.

CONCLUSIONS

We conclude that cultural background and input familiarity interact to influence modality dominance during multisensory emotion perception. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Audio-Visual Interactions During Emotion Processing in Bicultural Bilinguals

Despite the growing number of bicultural bilinguals in the world, the way in which multisensory emotions are evaluated by bilinguals who identify with two or more cultures remains unknown. In the present study, Chinese-English bicultural bilinguals from Singapore viewed Asian or Caucasian faces and heard Mandarin or English speech, and evaluated the emotion from one of the two simultaneously-presented modalities. Reliance on the visual modality was greater when bicultural bilinguals processed Western audio-visual emotion information. Although no differences between modalities emerged when processing East-Asian audio-visual emotion information, correlations revealed that bicultural bilinguals increased their reliance on the auditory modality with more daily exposure to East-Asian cultures. Greater interference from the irrelevant modality was observed for Asian faces paired with English speech than for Caucasian faces paired with Mandarin speech. We conclude that processing of emotion in bicultural bilinguals is guided by culture-specific norms, and that familiarity influences how the emotions of those who speak a foreign language are perceived and evaluated.

Predictors of language proficiency and cultural identification in heritage bilinguals

According to the 2020 U.S. Census Bureau, more than 66 million residents over the age of 5 in the United States speak a language other than English at home. Some bilinguals become dominant in the majority language that is spoken in the community as opposed to their native "heritage" language acquired at home. The objective of the current study was to uncover the predictors of language proficiency and cultural identification in different groups of heritage speakers. In our sample, heritage speakers acquired their heritage language first and English second and rated their proficiency in their heritage language lower than in English. We found that English proficiency was most reliably predicted by the duration of heritage language immersion, while heritage language proficiency was most reliably predicted by contexts of acquisition and exposure to both languages. Higher heritage language proficiency was associated with greater heritage language experience through friends and reading, less English experience through family, and later age of English acquisition. The trade-off between heritage language and English language experience was more pronounced for non-Spanish than Spanish heritage speakers. Finally, despite higher proficiency in English, cultural identification was higher with the heritage language, and was predicted by heritage language receptive proficiency and heritage language experience through family and reading. We conclude that self-reported proficiency and cultural identification differ depending on heritage speakers' native languages, as well as how the heritage language and majority language are acquired and used. Our findings highlight the importance of taking individual language history into consideration when combining different groups of heritage speakers.

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).

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.

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

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

Continuous effects of bilingualism and attention on Flanker task performance

Both bilingualism and attention contribute to the development of executive functioning (EF), with higher levels of both leading to better outcomes. The present study treats bilingualism and attention as continuous variables to investigate their impact on EF. Eighty-two 9-year-olds who were attending a French school in an anglophone community completed a flanker task. Children's progress in French represented their level of bilingualism, and attention was assessed through a standard standardized instrument. Degree of bilingualism and degree of attention were both positively related to performance, but exposure to a third language in the home did not further affect outcomes.

The impact of bilingualism on executive function in adolescents

AIMS AND OBJECTIVES/PURPOSE/RESEARCH QUESTIONS

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

DESIGN/METHODOLOGY/APPROACH

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

DATA AND ANALYSIS

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

FINDINGS/CONCLUSIONS

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

ORIGINALITY

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

SIGNIFICANCE/IMPLICATIONS

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

Language and cognitive control networks in bilinguals and monolinguals

Neuroimaging studies have reported overlapping neural circuits for cognitive control when engaging in tasks that involve verbal and nonverbal stimuli in young adult bilinguals. However, no study to date has examined the neural basis of verbal and nonverbal task switching in both monolinguals and bilinguals due to the inherent challenge of testing verbal task switching with monolinguals. Therefore, it is not clear whether the finding for overlapping networks is unique to bilingualism or indicative of general cognitive control. To address this question, the current study compared functional neural activation for young adults who were bilingual speakers of English and French or monolingual English speakers who had limited French learning experience ("functional monolinguals") on verbal and nonverbal task switching. Analyses showed common variance explaining general cognitive control in task switching across verbal and nonverbal domains for both groups, in line with the explanation that task switching involves general cognitive control, as well as unique brain regions recruited by monolinguals and bilinguals. Specifically, beyond the processing common to the tasks, monolinguals also recruited distinct networks for each of verbal and nonverbal switching but bilinguals used a common shared network. Thus, the domain-general aspect of switching is different for monolinguals and bilinguals.

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

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

The neural correlates of vertical disparity gradient and cue conflict in Panum's limiting case

Although Panum's limiting case has been extensively researched, only recently has it been discovered that in addition to horizontal disparity, the final perception of depth is influenced by (i) the vertical disparity gradient and (ii) the degree of cue conflict between 2D and 3D shapes. The present study examines the neural correlates of the two factors, using EEG while observers viewed several versions of stereoscopic stimuli, which depicted Panum's limiting case. In these patterns the vertical disparity gradient was varied from 0.1 to 0.6, while the degree of cue conflict was manipulated from low to high. The ERP data showed that the amplitude of the N170 component (exogenous) was modulated by the vertical disparity gradient and cue conflict. In contrast, the N270 component (endogenous) was modulated by cue conflict only. Such findings demonstrate that both factors affect the perception of depth in Panum's limiting case, but at different stages: the vertical disparity gradient at an early stage of processing (N170) and cue conflict at two stages (N170 and N270). Hence, vertical disparity gradient is related to low-level visual stimulus parameters and can modulate exogenous component, while cue conflict is related to both exogenous and endogenous components.

The relationship between bilingualism and selective attention in young adults: Evidence from an ambiguous figures task

Previous research has shown that bilinguals outperform monolinguals on a variety of tasks that have been described as involving executive functioning, but the precise mechanism for those effects or a clear definition for "executive function" is unknown. This uncertainty has led to a number of studies for which no performance difference between monolingual and bilingual adults has been detected. One approach to clarifying these issues comes from research with children showing that bilinguals were more able than their monolingual peers to perceive both interpretations of an ambiguous figure, an ability that is more tied to a conception of selective attention than to specific components of executive function. The present study extends this notion to adults by assessing their ability to see the alternative image in an ambiguous figure. Bilinguals performed this task more efficiently than monolinguals by requiring fewer cues to identify the second image. This finding has implications for the role of selective attention in performance differences between monolinguals and bilinguals.

Lexical selection differences between monolingual and bilingual listeners

Three studies are reported investigating how monolinguals and bilinguals resolve within-language competition when listening to isolated words. Participants saw two pictures that were semantically-related, phonologically-related, or unrelated and heard a word naming one of them while event-related potentials were recorded. In Studies 1 and 2, the pictures and auditory cue were presented simultaneously and the related conditions produced interference for both groups. Monolinguals showed reduced N400s to the semantically-related pairs but there was no modulation in this component by bilinguals. Study 3 inserted an interval between picture and word onset. For picture onset, both groups exhibited reduced N400s to semantically-related pictures; for word onset, both groups showed larger N400s to phonologically-related pictures. Overall, bilinguals showed less integration of related items in simultaneous (but not sequential) presentation, presumably because of interference from the activated non-English language. Thus, simple lexical selection for bilinguals includes more conflict than it does for monolinguals.

Mapping the "forbidden zone" near and away from the fixation point

Burt and Julesz modified the classical view of Panum's fusional area by incorporating the concept of the disparity gradient. They found that an area of double vision, described as the forbidden zone for single vision, is present when the angular separation between two objects is small. However, Krol and van de Grind argued that Burt and Julesz's finding could be explained by the classical theories (specifically Ogle, 1932 JOSA 22 664-728) in which the probability for fusion is a function of peripheral angle and disparity magnitude. We examined whether a forbidden zone can be specified within Ogle's experimental space. We found forbidden zones (a) when fixation was placed on one of the two objects and (b) when fixation was placed away from both objects. Krol and van de Grind's arguments do not easily explain the results in (b). The size of the forbidden zones was less than the predicted disparity gradient of unity that Burt and Julesz found in their experiment.