Developmental associations between bilingual experience and inhibitory control trajectories in Head Start children

Children from lower socioeconomic (SES) backgrounds tend to be at‐risk for executive function (EF) impairments by the time they are in preschool, placing them at an early disadvantage for academic success. The present study examined the potentially protective role of bilingual experience on the development of inhibitory control (IC) in 1146 Head Start preschoolers who were followed for an 18‐month period during the transition to kindergarten as part of the longitudinal Family and Child Experiences Survey (FACES) 2009 study. Using three waves of data, we predicted individual variation in developmental trajectories of IC for three groups that differed in bilingual experience—English monolinguals, Spanish‐English bilinguals, and a group of children who transitioned from being Spanish monolingual to Spanish‐English bilinguals during the course of the study. Compared to their English monolingual peers, bilingual children from Spanish‐speaking homes showed higher IC performance at Head Start entry, as well as steeper IC growth over time. Children who were Spanish monolingual at the beginning of Head Start showed the lowest IC performance at baseline. However, their rate of IC growth exceeded that of children who remained English monolingual and did not differ from that of their peers who entered Head Start being bilingual. These results suggest that acquiring bilingualism and continued bilingual experience are associated with more rapid IC development during the transition from preschool to kindergarten in children from lower SES backgrounds.     

Effects of past language experience and present language context on the shape bias in Spanish–English bilingual children

English‐monolingual children develop a shape bias early in language acquisition, such that they more often generalize a novel label based on shape than other features. Spanish‐monolingual children, however, do not show this bias to the same extent (Hahn & Cantrell, 2012). Studying children who are simultaneously learning both Spanish and English presents a unique opportunity to further investigate how this word‐learning bias develops. Thus, we asked how Spanish–English bilingual children (M_age = 21.31 months) perform in a novel‐noun generalization (NNG) task, specifically examining how past language experience (i.e. language exposure and vocabulary size) and present language context (i.e. whether the NNG task was conducted in Spanish or English) influence the strength of the shape bias. Participants completed the NNG task either entirely in English (N = 16) or entirely in Spanish (N = 16), as well as language understanding tasks in both English and Spanish to ensure that they understood what the experimenter was asking them to do. Parents completed a language exposure survey and vocabulary checklists in Spanish and English. There was a significant interaction between condition and choice type: Bilingual children in the English condition showed a shape bias in the NNG task, but bilingual children in the Spanish condition showed no reliable biases. No measures of past language experience were related to NNG task performance. These results suggest that when learning new words, bilingual children are attuned to the regularities of the present language context, and prior language experiences may play a more secondary role.     

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.     

语言转换对非熟练双语者不同认知控制成分的即时影响

语言转换情境是否影响非熟练双语者的认知控制存在争议。实验1和实验2分别采用不同的实验范式探讨语言转换对非熟练双语者的认知控制是否会有即时的影响, 以及对不同认知控制成分的影响是否会有不同。结果表明, 语言转换情境能够即时地促进反应抑制, 阻碍干扰抑制, 但对认知灵活性没有影响, 同时说明了反应抑制、干扰抑制和认知灵活性属于3种不同的认知成分, 其内在作用机制不同。此外, 研究结果还进一步说明了双语者的认知控制优势是双语者长期双语使用的结果, 为双语优势的内在机制提供了实验支持。     

Language-experience facilitates discrimination of /d-th/ in monolingual and bilingual acquisition of English

To trace how age and language experience shape the discrimination of native and non-native phonetic contrasts, we compared 4-year-olds learning either English or French or both and simultaneous bilingual adults on their ability to discriminate the English /d-th/ contrast. Findings show that the ability to discriminate the native English contrast improved with age. However, in the absence of experience with this contrast, discrimination of French children and adults remained unchanged during development. Furthermore, although simultaneous bilingual and monolingual English adults were comparable, children exposed to both English and French were poorer at discriminating this contrast when compared to monolingual English-learning 4-year-olds. Thus, language experience facilitates perception of the English /d-th/ contrast and this facilitation occurs later in development when English and French are acquired simultaneously. The difference between bilingual and monolingual acquisition has implications for language organization in children with simultaneous exposure.     

Language proficiency does not modulate executive control in older bilinguals

ABSTRACT

We examined if language proficiency modulates performance in tasks that measure executive control in older Telugu-English bilinguals (n = 50, mean age = 57.15 years). We administered numerical Stroop task, Attention Network Task, Dimensional Change Card Sorting task, and stop-signal task that are known to tap into different aspects of executive functioning on healthy aging Telugu-English bilinguals. Second language (English) proficiency was calculated as a cumulative score that considered both subjective and objective measures of L2 fluency and use. Bilinguals were divided into two groups based on the cumulative score and compared on each task. We did not find any effect of language proficiency on any of the executive control measures. The additional Bayesian analysis also supported these findings. Therefore, the results do not support the claim that bilingual language proficiency modulates executive control, at least in the elderly population. We discuss the results with regard to the issue of bilingual advantage in executive control and the role of age and language use.     

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.     

Reading,syntactic, orthographic,and working memory skills of bilingual Arabic-English speaking Canadian children

This study assessed the reading, language, and memory skills of 56 bilingual Arab-Canadian children age's 9-14. English was their main instructional language, and Arabic was the language spoken at home. All children attended a Heritage Language Program in Toronto where they were taught to read and write Arabic. The children were administered word and pseudo-word reading, language, and working memory tests in English and Arabic. The majority of the children showed at least adequate proficiency in both languages. There was a significant relationship between the acquisition of word and pseudo-word reading working memory, and syntactic awareness skills in the two languages. The poor readers in Arabic had lower scores on all linguistic tasks, except the visual task. There were no significant differences between bilingual English Arabic children and monolingual English-speaking children on the reading, language, and memory tasks. However, bilingual English Arabic children who had reading problems in English had higher scores on English pseudo-word reading and spelling tasks than monolingual English-speaking children with reading disabilities, probably because of positive transfer from the regular nature of Arabic orthography. In this case, bilingualism does not appear to have negative consequences for the development of language reading skills in both languages—Arabic and English—despite the different nature of the two orthographies.     

Spanish-English bilingual toddlers’ vocabulary skills: The role of caregiver language input and warmth

There is a well-documented link between bilingual language development and the relative amounts of exposure to each language. Less is known about the role of quality indicators of caregiver-child interactions in bilingual homes, including caregiver input diversity, warmth and sensitivity. This longitudinal study examines the relation between caregiver input (lexical diversity, amount), warmth and sensitivity and bilingual toddlers’ subsequent vocabulary outcomes. We video-recorded caregiver-child interactions in Spanish-English Latino homes when toddlers (n = 47) were 18 months of age (M = 18.32 months; SD = 1.02 months). At the 24-month follow-up, we measured children's vocabulary as total vocabulary (English, Spanish combined) as well as within language (Spanish, English). Results revealed that Spanish lexical diversity exposure at 18 months from caregivers was positively associated with children's Spanish and total vocabulary scores at 24 months, while English lexical diversity was positively associated with children's English scores; lexical diversity and amount were highly correlated. Additionally, caregivers’ warmth was positively associated with children's Spanish, English and total vocabulary scores. Together, these factors accounted for substantial variance (30–40%) in vocabulary outcomes. Notably, caregiver input accounted for more variance in single language outcomes than did caregiver warmth, whereas caregiver warmth uniquely accounted for more variance in total vocabulary scores. Our findings extend prior research findings by suggesting that children's dual language development may depend on their exposure to a diverse set of words, not only amount of language exposure, as well as warm interactions with caregivers. A video abstract of this article can be viewed at https://youtu.be/q1V_7fz5wog

Highlights

• Video-recorded observations of caregiver-child interactions revealed warmth and high sensitivity from Latino caregivers.
• Linguistically-detailed analyses of caregiver input revealed wide variation in the diversity of Spanish and English directed at 18-month-old bilingual toddlers.
• Bilingual toddlers’ vocabulary (single language, total) was positively associated with caregivers’ diverse input and warmth, thus extending prior findings on bilinguals’ amount of language exposure.
• Findings suggest that caregivers’ lexical diversity explains more variance in bilingual toddlers’ single language outcomes, whereas warmth explains more variance in total vocabulary scores.

     

The effects of bilingualism on toddlers' executive functioning

Bilingual children have been shown to outperform monolingual children on tasks measuring executive functioning skills. This advantage is usually attributed to bilinguals’ extensive practice in exercising selective attention and cognitive flexibility during language use because both languages are active when one of them is being used. We examined whether this advantage is observed in 24-month-olds who have had much less experience in language production. A battery of executive functioning tasks and the cognitive scale of the Bayley test were administered to 63 monolingual and bilingual children. Native bilingual children performed significantly better than monolingual children on the Stroop task, with no difference between groups on the other tasks, confirming the specificity of bilingual effects to conflict tasks reported in older children. These results demonstrate that bilingual advantages in executive control emerge at an age not previously shown.     

Effects of classroom bilingualism on task‐shifting,verbal memory,and word learning in children

We examined the effects of classroom bilingual experience in children on an array of cognitive skills. Monolingual English‐speaking children were compared with children who spoke English as the native language and who had been exposed to Spanish in the context of dual‐immersion schooling for an average of 2 years. The groups were compared on a measure of non‐linguistic task‐shifting; measures of verbal short‐term and working memory; and measures of word learning. The two groups of children did not differ on measures of non‐linguistic task‐shifting and verbal short‐term memory. However, the classroom‐exposure bilingual group outperformed the monolingual group on the measure of verbal working memory and a measure of word learning. Together, these findings indicate that while exposure to a second language in a classroom setting may not be sufficient to engender changes in cognitive control, it can facilitate verbal memory and verbal learning.     

What do bilingual infants actually hear? Evaluating measures of language input to bilingual‐learning 10‐month‐olds

Examining how bilingual infants experience their dual language input is important for understanding bilingual language acquisition. To assess these language experiences, researchers typically conduct language interviews with caregivers. However, little is known about the reliability of these parent reports in describing how bilingual children actually experience dual language input. Here, we explored the quantitative nature of dual language input to bilingual infants. Furthermore, we described some of the heterogeneity of bilingual exposure in a sample of French–English bilingual families. Participants were 21 families with a 10‐month‐old infant residing in Montréal, Canada. First, we conducted language interviews with the caregivers. Then, each family completed three full‐day recordings at home using the Language Environment Analysis recording system. Results showed that children’s proportion exposure to each language was consistent across the two measurement approaches, indicating that parent reports are reliable for assessing a bilingual child’s language experiences. Further exploratory analyses revealed three unique findings: (a) there can be considerable variability in the absolute amount of input among infants hearing the same proportion of input, (b) infants can hear different proportions of language input when considering infant‐directed versus overheard speech, (c) proportion of language input can vary by day, depending on who is caring for the infant. We conclude that collecting naturalistic recordings is complementary to parent‐report measures for assessing infant’s language experiences and for establishing bilingual profiles.     

Coordination of executive functions in monolingual and bilingual children

Two groups of 8-year-old children who were monolingual or bilingual completed a complex classification task in which they made semantic judgments on stimuli that were presented either visually or auditorily. The task requires coordinating a variety of executive control components, specifically working memory, inhibition, and shifting. When each of the visual and auditory tasks was presented alone, performance was comparable for children in the two groups. Combining the two modalities into a dual-task paradigm made the task more difficult, and on this combined task bilingual children maintained better accuracy than monolingual children, especially on the visual task. The results are interpreted in terms of the enhanced ability of bilingual children to coordinate the executive control components required in performing this complex task.     

Bilingual enhancements have no socioeconomic boundaries

To understand how socioeconomic status (SES) and bilingualism simultaneously operate on cognitive and sensory function, we examined executive control, language skills, and neural processing of sound in adolescents who differed in language experience (i.e. English monolingual or Spanish‐English bilingual) and level of maternal education (a proxy for SES). We hypothesized that experience communicating in two languages provides an enriched linguistic environment that can bolster neural precision in subcortical auditory processing which, in turn, enhances cognitive and linguistic function, regardless of the adolescent's socioeconomic standing. Consistent with this, we report that adolescent bilinguals of both low and high SES demonstrate more stable neural responses, stronger phonemic decoding skills, and heightened executive control, relative to their monolingual peers. These results support the argument that bilingualism can bolster cognitive and neural function in low‐SES children and suggest that strengthened neural response consistency provides a biological mechanism through which these enhancements occur.     

The missing explanation of the false‐belief advantage in bilingual children: a longitudinal study

Bilingual preschoolers often perform better than monolingual children on false‐belief understanding. It has been hypothesized that this is due to their enhanced executive function skills, although this relationship has rarely been tested or supported. The current longitudinal study tested whether metalinguistic awareness was responsible for this advantage. Further, we examined the contributions of both executive functioning and language ability to false‐belief understanding by including multiple measures of both. Seventy‐eight children (n = 40 Spanish‐English bilingual; age M = 49.29, SD = 7.38 and, n = 38 English monolingual; age M = 47.75, SD = 6.86) were tested. A year later the children were tested again (n = 22 bilingual, n = 25 monolingual). The results indicated that language and executive function (inhibitory control) at time 1 were related to false belief in monolinguals at time 2. In contrast, bilinguals' metalinguistic performance at time 1 was the sole predictor of false belief at time 2. The different linguistic and cognitive profiles of monolinguals and bilinguals may create different pathways for their development of false‐belief understanding. A video abstract of this article can be viewed at: https://youtu.be/vILn2gKjFxw     

Neuroanatomical profiles of bilingual children

The goal of the present study was to examine differences in cortical thickness, cortical surface area, and subcortical volume between bilingual children who are highly proficient in two languages (i.e., English and Spanish) and bilingual children who are mainly proficient in one of the languages (i.e., Spanish). All children (N = 49) learned Spanish as a native language (L1) at home and English as a second language (L2) at school. Proficiency of both languages was assessed using the standardized Woodcock Language Proficiency Battery. Five‐minute high‐resolution anatomical scans were acquired with a 3‐Tesla scanner. The degree of discrepancy between L1 and L2 proficiency was used to classify the children into two groups: children with balanced proficiency and children with unbalanced proficiency. The groups were comparable on language history, parental education, and other variables except English proficiency. Values of cortical thickness and surface area of the transverse STG, IFG‐pars opercularis, and MFG, as well as subcortical volume of the caudate and putamen, were extracted from FreeSurfer. Results showed that children with balanced bilingualism had thinner cortices of the left STG, left IFG, left MFG and a larger bilateral putamen, whereas unbalanced bilinguals showed thicker cortices of the same regions and a smaller putamen. Additionally, unbalanced bilinguals with stronger foreign accents in the L2 showed reduced surface areas of the MFG and STS bilaterally. The results suggest that balanced/unbalanced bilingualism is reflected in different neuroanatomical characteristics that arise from biological and/or environmental factors.     

Components of executive control with advantages for bilingual children in two cultures

The present study used a behavioral version of an anti-saccade task, called the ‘faces task’, developed by [Bialystok, E., Craik, F. I. M., & Ryan, J. (2006). Executive control in a modified anti-saccade task: Effects of aging and bilingualism. Journal of Experimental Psychology: Learning, Memory, and Cognition, 32, 1341-1354] to isolate the components of executive functioning responsible for previously reported differences between monolingual and bilingual children and to determine the generality of these differences by comparing bilinguals in two cultures. Three components of executive control were investigated: response suppression, inhibitory control, and cognitive flexibility. Ninety children, 8-years old, belonged to one of three groups: monolinguals in Canada, bilinguals in Canada, and bilinguals in India. The bilingual children in both settings were faster than monolinguals in conditions based on inhibitory control and cognitive flexibility but there was no significant difference between groups in response suppression or on a control condition that did not involve executive control. The children in the two bilingual groups performed equivalently to each other and differently from the monolinguals on all measures in which there were group differences, consistent with the interpretation that bilingualism is responsible for the enhanced executive control. These results contribute to understanding the mechanism responsible for the reported bilingual advantages by identifying the processes that are modified by bilingualism and establishing the generality of these findings across bilingual experiences. They also contribute to theoretical conceptions of the components of executive control and their development.     

语言经验对大脑激活的影响：来自第二语言初学者的证据

研究采用功能磁共振成像技术考察语言经验在塑造大脑激活模式中的作用。12名只有很少英语学习经验因而熟练程度很低的小学儿童参与了实验。结果发现,在视觉呈现的押韵判断任务中,英文任务和中文任务共同激活了左侧额下回负责语音加工的脑区。更重要的是,虽然英文任务更难,也更多地激活了双侧的顶叶区域,但是它在额叶诱发的激活强度显著低于中文。这个结果进一步说明第二语言的语音皮层表征是随着学习经验的增加而逐渐发展起来的。     

不同熟练双语儿童注意定向中的抑制控制

研究目的：探讨不同熟练双语儿童“注意定向”成分中抑制控制的差异,及这一差异是否依赖于双语儿童第二语言的熟练程度。方法：采用IOR范式的行为实验。被试为平衡、未平衡双语儿童和单语儿童。结果：SOA600ms时,三组被试均出现了IOR,平衡双语儿童与单语儿童的IOR效应量差异显著,其余被试间差异均不显著。结论：（1）双语学习促进了平衡双语儿童抑制控制能力的发展。（2）双语学习对抑制控制能力的促进作用依赖于双语儿童第二语言的熟练程度。