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On the bilingualism effect in task switching*

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Abstract

In one task-switching experiment, we compared bilinguals and monolinguals to explore the reliability of the bilingualism effect on the n-2 repetition cost. In a second task-switching experiment, we tested another group of bilinguals and monolinguals and measured both the n-1 shift cost and the n-2 repetition cost to test the hypothesis that bilingualism should confer a general greater efficiency of the executive control functioning. According to this hypothesis, we expected a reduced n-1 shift cost and an enhanced n-2 repetition cost for bilinguals compared to monolinguals. However, we did not observe such results. Our findings suggest that previous results cannot be replicated and that the n-2 repetition cost is another index that shows no reliable bilingualism effect. Finally, we observed a negative correlation between the two switch costs among bilinguals only. This finding may suggest that the two groups employ different strategies to cope with interference in task-switching paradigms.

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... In contrast, only one scholar established more studies in one publication with different participants (Branzi, Calabria, Gade, Fuentes, & Costa, 2018). Table A4 in Appendix indicates the general results of the present review. ...
... In contrast, Branzi et al. (2018) conducted two studies by administering the task assessing n-2 repetition cost to different monolingual and bilingual groups to measure interference suppression among them. However, previous study results by Prior (2012) could not be replicated in their study. ...
... This part aims to answer whether a larger sample size influences bilingual inhibitory control advantage's research outcomes. Table A4 in Appendix indicates that the results of the included studies with more than 50 participants per language group, most of them reported no evidence of a bilingual advantage in inhibitory control Antón et al., 2019;Branzi et al., 2018;Duñabeitia et al., 2014;Paap & Sawi, 2014). ...
Thesis
Background: For many years, research has focused on the cognitive consequences of bilingualism. While earlier studies reported that bilinguals were more efficient in executive control, particularly with respect to inhibitory processes (bilingual advantage), more recent studies have often failed to replicate this effect. Moreover, studies have shown the unity and diversity of inhibitory control and distinguished between response inhibition and interference suppression. Aim: This literature review aims to elucidate whether the bilingual inhibitory control advantage, especially in its two components, exists across the life span and to investigate its modulating factors. Method: A literature search was conducted via EBSCO in many databases and reference lists for all original data on bilingualism and inhibitory control, with a cut-off date of April 30, 2020. Following the preferred reporting items for systematic reviews and meta-analysis (PRISMA) protocols, 21 original studies were eligible to be included in this review. Results: The review yielded little evidence of bilingual inhibitory control advantage with different patterns of results for response inhibition and interference suppression. The heterogeneous outcomes might be related to individual differences, such as age and methodological issues, such as the use of different tasks. Conclusion: This literature review found heterogeneous results regarding the bilingual advantage in response inhibition and interference suppression. It stresses the importance of accounting for possible modulating factors when investigating the relationship between bilingualism and inhibition. If significant progress is to be made, accounting for confounding factors and reevaluating the inhibitory control measurement is required. Keywords: bilingual advantage, inhibitory control, interference suppression, response inhibition
... The hypothesis is that bilinguals have long-term practice in BLC which can affect the performance of EC. The results are mixed, while some studies show smaller behavioral switch costs on a non-linguistic task for bilinguals than monolinguals (Prior and Macwhinney, 2010;Prior and Gollan, 2011;Houtzager et al., 2017), many other studies did not (Hernández et al., 2013;Paap and Greenberg, 2013;Paap et al., 2017;Branzi et al., 2018). Four, studies that show a relation between how much people switch between their languages on a daily basis and the switch cost in a non-linguistic task (Hartanto and Yang, 2016). ...
... The experimental design was the same as previous studies investigating the n-1 shift cost and n-2 repetition cost (Philipp and Koch, 2006;Branzi et al., 2016aBranzi et al., , 2018. Depending on the two preceding trials the current n trial was allocated to one of three conditions (CAA, CBA, and ABA). ...
... The sum does not add up to 100% because the first two trials of each block were removed as well as the trial after a repetition trial (CAA). See Branzi et al. (2016aBranzi et al. ( , 2018 for the same procedure and further details. ...
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Bilingual speakers are suggested to use control processes to avoid linguistic interference from the unintended language. It is debated whether these bilingual language control (BLC) processes are an instantiation of the more domain-general executive control (EC) processes. Previous studies inconsistently report correlations between measures of linguistic and non-linguistic control in bilinguals. In the present study, we investigate the extent to which there is cross-talk between these two domains of control for two switch costs, namely the n-1 shift cost and the n-2 repetition cost. Also, we address an important problem, namely the reliability of the measures used to investigate cross-talk. If the reliability of a measure is low, then these measures are ill-suited to test cross-talk between domains through correlations. We asked participants to perform both a linguistic- and non-linguistic switching task at two sessions about a week apart. The results show a dissociation between the two types of switch costs. Regarding test–retest reliability, we found a stronger reliability for the n-1 shift cost compared to the n-2 repetition cost within both domains as measured by correlations across sessions. This suggests the n-1 shift cost is more suitable to explore cross-talk of BLC and EC. Next, we do find cross-talk for the n-1 shift cost as demonstrated by a significant cross-domain correlation. This suggests that there are at least some shared processes in the linguistic and non-linguistic task.
... Our results appear inconsistent with evidence that bilinguals are faster than monolinguals on cognitivecontrol tasks (Bialystok, 2010;Bialystok et al., 2004;Costa et al., 2009;Hernández, Costa, Fuentes, Vivas & Sebastián-Gallés, 2010;Martin-Rhee & Bialystok, 2008) -in fact, we found that bilinguals were overall slower on the Stroop task. From this perspective, our findings align with recent studies failing to find evidence of a bilingual advantage in performance across various executive-function tasks (Branzi, Calabria, Gade, Fuentes & Costa, 2016;Hilchey & Klein, 2011;Paap & Greenberg, 2013;von Bastian, Souza & Gade, 2016). One explanation for such mixed findings is that bilingualism does not actually impact cognitive control, and the positive results are due to study confounds and/or random chance (Paap & Greenberg, 2013;. ...
... One explanation for such mixed findings is that bilingualism does not actually impact cognitive control, and the positive results are due to study confounds and/or random chance (Paap & Greenberg, 2013;. This explanation has received growing support as many studies with large samples and early, highly proficient bilinguals have found no consistent evidence of bilingual/monolingual differences in inhibitory control, task-switching, or conflict monitoring (Antón, Duñabeitia, Estévez, Hernández, Castillo, Fuentes, Davidson & Carreiras, 2014;Branzi, Calabria, et al., 2016;Duñabeitia et al., 2014;Gathercole, Thomas, Kennedy, Prys, Young, Vinas Guasch, Roberts, Hughes & Jones, 2014;von Bastian et al., 2016). Moreover, the DRD2 genetic phenotype varies systematically across certain bilingual and monolingual populations (Hernandez et al., 2015), suggesting that, when observed, cognitive control differences could be explained by genetic rather than linguistic factors. ...
Article
Bilinguals sometimes outperform monolinguals on tasks involving cognitive control – the regulation of mental activity when confronted with information-processing conflict – perhaps stemming from experience monitoring for and resolving conflict between languages. We test the hypothesis that bilingualism affects moment-to-moment cognitive-control recruitment by examining how trial history influences bilinguals’ and monolinguals’ behavioral performance and associated neural activity on a Stroop task. We assessed dynamic effects of preceding trial conflict on current trial performance to separate the ability to proactively detect conflict (performance on new instances of conflict) from the ability to reactively recruit cognitive control (performance on trials following conflict). Across two experiments, monolinguals’ – but not bilinguals’ – accuracy decreased after non-conflict trials, i.e., when detecting initial conflicts. Bilinguals exhibited greater conflict-detection activity in ventrolateral prefrontal cortex (vlPFC/insula; BA 47) within a language-switching network, suggesting that they may monitor for information-conflict more proactively than monolinguals by recruiting brain regions involved in switching languages.
... Furthermore, although we did not observe neither congruence cost nor global switching cost, we did observe reduced mixing cost for Hungarian-Serbian bilinguals. These results are in line with studies most similar to ours in terms of homogeneity of participants: Hernández et al. (2013), and Branzi et al. (2018) also report an absence of global and switch cost effects for their samples of balanced Catalan-Spanish bilinguals. The last measure derived from AST, the Sequential Congruency Effect (SCE) revealed a (nonsignificant) tendency towards a larger SCE in our bilingual participants. ...
Article
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Among the factors argued to contribute to a bilingual advantage in executive function (EF), the combination of languages spoken by the bilingual is often overlooked. In this study, we explored the role of language similarity on memory and EF task by comparing performance of three groups of young adults—Hungarian–Serbian and Slovak–Serbian early balanced bilinguals, and Serbian-speaking monolinguals. Slovak is typologically related to Serbian, which are both Slavic, in contrast to Hungarian, which is Finno–Ugric. On the computerized tasks from the CANTAB battery (CANTAB Cognition, 2016, www.cantab.com), differences between monolinguals and bilinguals emerged on the EF tasks: Stockings of Cambridge (SOC) and Attentional Set Shifting (AST), but not the memory tasks: Delayed Matching to Sample (DMS), Paired Associate Learning (PAL), Spatial Working Memory (SWM). Both Hungarian–Serbian and Slovak–Serbian bilinguals outperformed the monolinguals on the more difficult SOC tasks, solved using more than a minimally required number of moves. This is in line with reports that bilinguals perform better under more complex conditions that require more monitoring and switching. However, bilinguals speaking Hungarian and Serbian spent less time preparing to execute the simpler SOC tasks, which can be solved in a minimum of two or three moves; they also exhibited reduced local switching cost and were faster overall on AST than both the Slovak–Serbian bilinguals and Serbian monolinguals. The advantageous performance of speakers of the typologically unrelated languages in our study suggests that these bilinguals may have more efficient attention switching and inhibition systems than bilinguals who speak typologically similar languages.
... A different line of studies also showed that using an L2 reduces decision-making bias and fosters more utilitarian decisions in moral dilemmas (e.g., Costa et al., 2014;Hayakawa et al., 2017), suggesting that in L2, decision-making is more deliberate and less intuitive than in L1 (for reviews, see Costa et al., 2017;Hayakawa et al., 2016). These differences were further documented in studies showing that, in contrast to L1, information processing in L2 recruits more brain areas related to control processes (Branzi et al., 2016). ...
Article
The linguistic expectancy bias (LEB) reflects the tendency to describe expectancy-consistent behavior more abstractly than expectancy-inconsistent. The current studies replicate the LEB in Portuguese and examine it in a second language (English). Earlier studies found differences in processing a first language (L1) and a second language (L2) shaping affective and cognitive processes. We did not expect these differences to shape the LEB because controlled lexical decisions (e.g., use of verbs and adjectives) are unlikely, even when using L2. Participants wrote stereotypically male or female behavioral descriptions for male and female targets. A new group of participants read those descriptions and was asked about their causes. Expectancy-consistent behavior was described more abstractly and shaped more dispositional inferences in L1 and L2. Aside from replicating the LEB in a different language, these studies indicate that structural features of language preserve a linguistic bias with implications for social perception even when using a second language.
... The variability of the findings seems to have led some researchers to doubt the existence of the disputed advantages (Branzi, Calabria, Gade, Fuentes, & Costa, 2018;Valian, 2015). The inconsistencies in the findings of such studies are mainly attributed to lack of correctly mapping neural activities onto behaviors measured by cognitive tasks, precisely operationalizing concepts, disentangling the effects of correlating factors, the heterogenous nature of the study population, small sample size, and researchers' biases (Antoniou, 2018;Bedore et al., 2012). ...
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The paper examines the roles of cognitive control in multilingual speakers and implications have been drawn for language in education policy.
... However, such an effect of bilingualism on an individual's executive control functioning has been recently challenged. A growing number of studies suggest a lack of robustness and reliability of such a bilingualism effect with some researchers even discrediting the existence of bilingual cognitive advantages per se (see, for instance, Paap and Greenberg, 2013;Paap et al., 2015;Branzi et al., 2016;von Bastian et al., 2016). This, coupled with some particular disadvantages of our participants (a late age of acquisition, restricted L2 context, etc.), leads to the largely target-deviant pattern of RT in L2 learners across proficiencies. ...
Article
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This study tests whether Chinese learners of English can reconstruct their cognitive pattern in the direction of the target system when judging the similarity between spontaneous motion screens in a match–to–sample task. English main verbs encode Manner of motion only, while Chinese verb compounds express Manner and Path simultaneously. Chinese monolinguals are thus predicted to develop a motion cognition pattern highlighting both Manner and Path salience whereas English monolinguals are more likely to be Manner-oriented. Our research findings are twofold. First, when assessed by the explicit measure of selection strategies (i.e., either Manner–match or Path-match), both monolingual and L2 learners show a general preference for the Path–match. However, when gauged by the implicit measure of processing speed (i.e., reaction time), Chinese monolinguals reacted significantly quicker than their English counterparts, particularly in making Path-matched judgments. Further, the L2 English learners across proficiencies responded significantly more slowly than their monolingual counterparts even at an advanced stage of acquisition, suggesting that the process of conceptual reconstructing, as demonstrated in our experiment, can be cognitively demanding and needs a longer period of time to complete. These findings are generally consistent with a weak version of the linguistic relativity hypothesis.
... This fMRI study demonstrates that word retrieval in multilinguals is enacted by different portions of the vlPFC associated with reactive and proactive language control processes and that during language switching multilingual speakers engage proactive control to activate the target language. These findings may have an impact on research into a multilingual advantage in domain-general executive control (Antón et al., 2014;Branzi, Calabria, Gade, Fuentes, & Costa, 2018), as they suggest that the extent to which an advantage in proactive control is observed might depend on the ratio of cognates to noncognates in the languages of a multilingual. ...
Article
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This functional magnetic resonance imaging study established that different portions of the ventrolateral prefrontal cortex (vlPFC) support reactive and proactive language control processes during multilingual word retrieval. The study also examined whether proactive language control consists in the suppression of the nontarget lexicon. Healthy multilingual volunteers participated in a task that required them to name pictures alternately in their dominant and less‐dominant languages. Two crucial variables were manipulated: the cue‐target interval (CTI) to either engage (long CTI) or prevent (short CTI) proactive control processes, and the cognate status of the to‐be‐named pictures (noncognates vs. cognates) to capture selective pre‐activation of the target language. The results of the functional connectivity analysis showed a clear segregation between functional networks related to mid‐vlPFC and anterior vlPFC during multilingual language production. Furthermore, the results revealed that multilinguals engage in proactive control to prepare the target language. This proactive modulation, enacted by anterior vlPFC, is achieved by boosting the activation of lexical representations in the target language. Finally, control processes supported by both mid‐vlPFC and the left inferior parietal lobe, were similarly engaged by reactive and proactive control, possibly exerted on phonological representations to reduce cross‐language interference.
... Moreover, Soveri et al. (2011) found that in young bilinguals, the frequency of switching between languages predicted smaller mixing cost in terms of accuracy. However, several studies have found no evidence of superior task switching in bilinguals compared to monolinguals (Branzi et al., 2017;Hernández et al., 2013;Jylkkä et al., 2017;Mor et al., 2014;Moradzadeh et al., 2014;Paap and Greenberg, 2013;Paap and Sawi, 2014;Shulley and Shake, 2016). ...
Article
The current study investigated behavioral and electrophysiological (event-related potential; ERP) differences associated with task switching in a sample of young and older monolingual and bilingual adults. ERPs associated with task preparation (switch and mixing positivity) and task execution processes (N2 and P3b) were investigated. Participants performed a cued letter-number task switching paradigm that included single task and mixed task blocks, while their electroencephalography was recorded. Behavioral results revealed smaller switch and mixing costs in bilinguals relative to monolinguals, in both young and older participants. There were no ERP differences in the effect size of the cue-locked mixing and switch positivities, nor the target-locked mixing and switch N2 and P3b components. However, overall larger target-locked N2 amplitudes were observed in bilinguals relative to monolinguals. In addition, bilingual older adults exhibited smaller P3b amplitudes than monolingual older adults. The smaller behavioral mixing and switch costs observed in bilinguals suggest that bilinguals exhibit superior sustained attention and faster task-set reconfiguration processes compared to monolinguals. The ERP measures provide evidence for differences in brain processes between monolinguals and bilinguals and a reliance on different processing strategies in bilingual compared to monolingual older adults.
... In fact, numerous studies have addressed the relation between language control and cognitive control, albeit with mixed evidence. Domain-general control mechanisms seem to contribute to language selection (Gollan & Goldrick, 2016), and, conversely, language control in bilinguals seems to be implicated in non-linguistic cognitive tasks (Branzi, Calabria, Gade, Fuentes, & Costa, 2016;Garbin et al., 2010). Various studies posit an overlap between language control and cognitive control: language control may rely, at least in part, on domain-general control abilities, as suggested by correlations between linguistic and non-linguistic switching tasks (Declerck, Grainger, Koch, & Philipp, 2017;Prior & Gollan, 2011) and the overlap of cortical areas engaged in linguistic and non-linguistic control (Abutalebi & Green, 2008;Coderre, Smith, van Heuven, & Horwitz, 2016;De Baene, Duyck, Brass, & Carreiras, 2015;Hernandez, 2009). ...
Article
The ability to selectively access two languages characterises the bilingual everyday experience. Previous studies showed the role of second language (L2) proficiency, as a proxy for dominance, on language control. However, the role of other aspects of the bilingual experience-such as age of acquisition and daily exposure-are relatively unexplored. In this study, we used a cued language switching task to examine language switching and mixing in two groups of highly proficient bilinguals with different linguistic backgrounds, to understand how the ability to control languages is shaped by linguistic experience. Our analysis shows that the ability to switch between languages is not only modulated by L2 proficiency, but also by daily L2 exposure. Daily L2 exposure also affects language mixing. Finally, L2 age of acquisition predicts naming latencies in the L2. Together, these findings show that language dominance is characterised by multiple aspects of the bilingual experience, which modulate language control.
... Studies which investigated whether bilinguals compared to monolinguals show improved EC through reduced switch costs suggest that the origin of improved EC lies in the long-term practice in BLC bilinguals have. Those results are mixed, while some studies show reduced switch costs (Garbin et al., 2010;Houtzager, Lowie, Sprenger, & De Bot, 2017;Prior & Gollan, 2011;Prior & Macwhinney, 2010;Stasenko, Matt, & Gollan, 2017), many other studies did not (Branzi, Calabria, Gade, Fuentes, & Costa, 2018;Hernández et al., 2013;Paap et al., 2017;Paap & Greenberg, 2013;Timmer et al., 2017a). Hernández and colleagues (2013) did not reveal reduced switch costs for bilinguals but did show a reduced restart cost (cue-processing cost) for them. ...
Article
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What is the relationship between bilingual language control (BLC) mechanisms and domain-general executive control (EC) processes? Do these two domains share some of their mechanisms? Here, we take a novel approach to this question, investigating whether short-term language switching training improves non-linguistic task switching performance. Two groups of bilinguals were assigned to two different protocols; one group was trained in language switching (switching-task training group) another group was trained in blocked language picture naming (single-block training group). Both groups performed a non-linguistic and linguistic switching task before (pre-training) and after training (post-training). Non-linguistic and linguistic switch costs decreased to a greater extent for the switching-task training than for the single-block training group from pre- to post-training. In contrast, mixing costs showed similar reductions for both groups. This suggests short-term language switching training can transfer to the non-linguistic domain for certain sub-mechanisms (i.e., switch cost). Thus, there is some overlap of the control mechanisms across domains.
... We report for the first time that this proactive modulation is achieved via activation of target lexical representations. These findings may also have an impact on the research on multilingual advantage in domain-general executive control (Antón et al., 2014;Branzi et al., 2018), as they suggest that the extent to which the advantage in proactive control could be observed might depend on the ratio between cognates and non-cognates in the languages of a multilingual. ...
Preprint
A fundamental cognitive operation involved in speech production is word retrieval from the mental lexicon, which in monolinguals is supported by dissociable ventro-lateral prefrontal cortex (vlPFC) mechanisms associated with proactive and reactive control. This functional magnetic resonance imaging (fMRI) study established whether in multilinguals word retrieval is supported by the same prefrontal mechanisms, and whether proactive modulation consists in suppression of the non-target lexicon. Healthy multilingual volunteers participated in a task that required them to name pictures alternatively in their dominant and less-dominant language. Two crucial variables were manipulated: the cue-target interval (CTI) to either engage (long CTI) or prevent proactive control processes (short CTI), and the cognate status of the pictures to-be-named (non-cognates versus cognates) to capture the presence of selective pre-activation of the target language. Results support the two-process account of vlPFC and indicate that multilinguals engage in proactive control to prepare the target language. This proactive modulation, enacted by anterior vlPFC, is achieved by boosting the activation of lexical representations of the target language. Control processes supported by mid-vlPFC and left inferior parietal lobe together, are similarly engaged in pre-and post-word retrieval, possibly exerted on phonological representations to reduce cross-language interference. Significance Statement Word retrieval in monolingual speech production is enacted by left ventro-lateral prefrontal cortex (vlPFC) supporting controlled access to conceptual representations (proactive control), and left mid-vlPFC supporting post-retrieval lexical selection (reactive control). In this functional magnetic resonance imaging (fMRI) study we demonstrate that multilingual word retrieval is supported by similar prefrontal mechanisms. However, differently from monolinguals, multilingual speakers retrieve words by applying proactive control on lexical representations to reduce cross-language interference. Alternatively to what it has been proposed by one of the most influential models, here we show that this proactive modulation is achieved by boosting the activation of lexical representations of the target language.
... The authors embrace the idea that bilingualism positively affects the ease with which people can switch between different tasks. However, this evidence on the advantage of bilingualism on task switching has been called into question repeatedly (Branzi, Calabria, Gade, Fuentes & Costa, 2016;Hernández, Martin, Barceló & Costa, 2013) -information that the authors conveniently ignore. Still, let us assume that they are correct and that bilingualism helps to switch between task sets. ...
Article
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Ikizer and Ramirez-Esparza (2017) reported a study suggesting that bilingualism may have a positive impact on people's social skills. They found that a) bilinguals scored higher on a scale that is supposed to reveal social flexibility, and that b) they also report having social interactions more frequently than monolinguals. The authors relate this advantage in social flexibility to the need of exercising language switching in bilingual speakers. In this commentary, we argue that their arguments are not theoretically sound and that their observations are not compelling enough to reach this conclusion.
... In fact, numerous studies have addressed the relation between language control and cognitive control, albeit with mixed evidence. Domain-general control mechanisms seem to contribute to language selection (Gollan & Goldrick, 2016), and, conversely, language control in bilinguals seems to be implicated in non-linguistic cognitive tasks (Garbin et al., 2010;Branzi, Calabria, Gade, Fuentes, & Costa, 2016). Various studies posit an overlap between language control and cognitive control: language control may rely, at least in part, on domain-general control abilities, as suggested by correlations between linguistic and non-linguistic switching tasks (Prior & Gollan, 2011;Declerck, Grainger, Koch, & Phillip, 2017) and the overlap of cortical areas engaged in linguistic and non-linguistic control (Abutalebi & Green, 2008;Hernandez, 6 (Li & Grant, 2015). ...
Thesis
One of the main findings of research on bilingualism in the last twenty years is the fact that both languages are always active, to some extent, and interact with each other. This interaction gives rise to a computationally complex feature of the bilingual mind, namely that the two languages compete with each other. Many studies have addressed the linguistic consequences of this competition (e.g. differences in linguistic attainment), while others have instead addressed the cognitive consequences (e.g. training effects on cognitive control). These two strands of research, when brought together, can shed light on the dynamics of language processing and of its relationship with other cognitive abilities; however, they do not often converge. The first aim of this thesis is to seam them together. The second aim of this thesis is to understand the effects of specific aspects of language experience on linguistic and non linguistic abilities. A critical assumption I make is that bilingualism is not a dichotomous variable, but rather a continuum, characterised by several aspects such as linguistic proficiency, age of acquisition, and daily exposure. All of these factors interact with each other to give rise to potentially infinite types of bilingual experiences, and arguably modulate how bilinguals deal with competing languages. However, the effects of these factors on linguistic and non linguistic abilities are poorly understood. Hence, in this thesis I examine if the bilingual experience affects other cognitive abilities (study 1), how the ability to handle this competition is modulated by experience (study 2), and how it affects language processing (study 3). To examine how specific dimensions of the bilingual continuum affect these abilities, I compare four populations of bilinguals, whose linguistic experience ranges from late bilinguals who are immersed in their native language and are passive users of their second language, to early highly proficient bilinguals who use both languages actively. My first study examines cognitive control performance and shows that high active proficiency and early age of acquisition, together, represent beneficial circumstances for the ability to modulate cognitive control; however, their effects are not strong enough to override individual variability. The second study investigates how the bilingual experience modulates the ability to access the two languages separately, overcoming the competition between them at different levels. This could be at a local level, i.e. the level of the individual linguistic representation (e.g. naming time of a specific word), or at a global or whole language level (e.g. overall naming latencies across languages). The results show that proficiency affects local competition, and age of acquisition affects global competition, whereas daily language exposure regulates competition at both the local and the global levels. My third study examines the processing of pronouns, which are particularly demanding linguistic structures. It shows that active proficiency and age of acquisition, together, define circumstances in which pronoun processing may vary between individuals, independently of structural differences between their languages. This suggests that bilinguals with long-term exposure to more than one language and high active proficiency may use some linguistic structures in the same way as individuals with different linguistic backgrounds, i.e. explicitly interpret them in similar ways, but process them in marginally different ways. Through these studies, this thesis brings together the study of linguistic and cognitive aspects of bilingualism by identifying three dimensions of the bilingual experience – proficiency, exposure and age of acquisition – and their effects on language processing, language control and cognitive control.
Article
Despite a growing number of studies on bilingual advantages in executive functions (EF), their findings have been inconsistent. To shed light on this issue, we aimed to address both the conceptual and methodological limitations that have prevailed in the literature: failure to consider diverse bilingual experiences when assessing bilingual advantages or to address the task impurity problems that can arise with EF tasks. Drawing on the adaptive control hypothesis and control process model of code-switching, we adopted theory-driven and latent variable approaches to examine the relations between bilingual interactional contexts and EF. By administering 9 EF tasks to 175 bilingual participants over multiple sessions, we found that bilinguals' dual-language context significantly predicted the latent variable of task-switching, while a dense code-switching context significantly predicted 2 latent variables of inhibitory control and goal maintenance. These findings remained robust after controlling for potential confounds of demographics, socioeconomic status, nonverbal intelligence, and unintended language-switching tendency. Our study suggests that bilingual interactional context is a key language experience that modulates bilingual advantages in EF. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
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The bilingual advantage hypothesis is difficult to test for many reasons and one is the complexity of the executive functioning (EF) construct. The newest wave of meta‐anlayses on the bilingual advantage has minimized the apples and oranges problem by separately analysing results targeting inhibition, updating of working memory, and switching. This chapter presents in detail the results of a meta‐analysis summarized at a meeting of the Psychonomic Society. A complementary part of the narrative that young adults do not show bilingual advantages is that advantages are consistently observed with children and older adults. The key starting point for predictions of bilingual advantages in EF is the plenitude of evidence consistent with the hypothesis that both languages are co‐activated even when the language context supports only one of them and that some general‐purpose aspect of EF is recruited to facilitate the selection of the target language and avoid intrusions from the non‐target language.
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The question whether being bilingual yields cognitive benefits is highly controversial with prior studies providing inconsistent results. Failures to replicate the bilingual advantage have been attributed to methodological factors such as comparing dichotomous groups and measuring cognitive abilities separately with single tasks. Therefore, the authors evaluated the 4 most prominent hypotheses of bilingual advantages for inhibitory control, conflict monitoring, shifting, and general cognitive performance by assessing bilingualism on 3 continuous dimensions (age of acquisition, proficiency, and usage) in a sample of 118 young adults and relating it to 9 cognitive abilities each measured by multiple tasks. Linear mixed-effects models accounting for multiple sources of variance simultaneously and controlling for parents' education as an index of socioeconomic status revealed no evidence for any of the 4 hypotheses. Hence, the authors' results suggest that bilingual benefits are not as broad and as robust as has been previously claimed. Instead, earlier effects were possibly due to task-specific effects in selective and often small samples. Materials: http://www.tatool-web.com/#/doc/lib-bat-uzh-ef.html Data: https://osf.io/d89xh/
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Simultaneous interpretation is an impressive cognitive feat which necessitates the simultaneous use of two languages and therefore begs the question: how is language management accomplished during interpretation? One possibility is that both languages are maintained active and inhibitory control is reduced. To examine whether inhibitory control is reduced after experience with interpretation, students with varying experience were assessed on a three language switching paradigm. This paradigm provides an empirical measure of the inhibition applied to abandoned languages, the n-2 repetition cost. The groups showed different patterns of n-2 repetition costs across the three languages. These differences, however, were not connected to experience with interpretation. Instead, they may be due to other language characteristics. Specifically, the L2 n-2 repetition cost negatively correlated with self-rated oral L2 proficiency, suggesting that language proficiency may affect the use of inhibitory control. The differences seen in the L1 n-2 repetition cost, alternatively, may be due to the differing predominant interactional contexts of the groups. These results suggest that language control may be more complex than previously thought, with different mechanisms used for different languages. Further, these data represent the first use of the n-2 repetition cost as a measure to compare language control between groups.
Chapter
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Inhibition has been assumed to account for various findings in research on task switching. This chapter provides an overview concerning the various inhibitory processes considered to play a role in research using the task switching paradigm. Furthermore, potentially problematic assumptions which may lead to an erroneous assumption of inhibitory mechanisms at work are discussed. In two empirical sections, response-repetition effects as well as n–2 repetition costs are focused. While the discussion of response-repetition costs is thought to provide a model case for alternative memory-based and inhibitory accounts of the same phenomenon, namely the costs arising when switching the task but not the response, the discussion of n – 2 repetition costs focusses on the triggering conditions of inhibition in task switching. Both empirical sections point to the large field of unanswered questions concerning the nature and impact of inhibitory mechanisms in task switching.
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In an ongoing debate, bilingual research currently discusses whether bilingualism enhances non-linguistic executive control. The goal of this study was to investigate the influence of language-switching experience, rather than language proficiency, on this bilingual executive control advantage. We compared the performance of unbalanced bilinguals, balanced non-switching, and balanced switching bilinguals on two executive control tasks, i.e. a flanker and a Simon task. We found that the balanced switching bilinguals outperformed both other groups in terms of executive control performance, whereas the unbalanced and balanced non-switching bilinguals did not differ. These findings indicate that language-switching experience, rather than high second-language proficiency, is the key determinant of the bilingual advantage in cognitive control processes related to interference resolution.
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The hypothesis that managing two languages enhances general executive functioning is examined. More than 80% of the tests for bilingual advantages conducted after 2011 yield null results and those resulting in significant bilingual advantages tend to have small sample sizes. Some published studies reporting significant bilingual advantages arguably produce no group differences if more appropriate tests of the critical interaction or more appropriate baselines are used. Some positive findings are likely to have been caused by failures to match on demographic factors and others have yielded significant differences only with a questionable use of the analysis-of-covariance to "control" for these factors. Although direct replications are under-utilized, when they are, the results of seminal studies cannot be reproduced. Furthermore, most studies testing for bilingual advantages use measures and tasks that do not have demonstrated convergent validity and any significant differences in performance may reflect task-specific mechanism and not domain-free executive functions (EF) abilities. Brain imaging studies have made only a modest contribution to evaluating the bilingual-advantage hypothesis, principally because the neural differences do not align with the behavioral differences and also because the neural measures are often ambiguous with respect to whether greater magnitudes should cause increases or decreases in performance. The cumulative effect of confirmation biases and common research practices has either created a belief in a phenomenon that does not exist or has inflated the frequency and effect size of a genuine phenomenon that is likely to emerge only infrequently and in restricted and undetermined circumstances. Copyright © 2015 Elsevier Ltd. All rights reserved.
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The relation between bilingualism and cognition is informative about the connection between language and mind. From the perspective of language, the question is how bilingualism might help or hinder cognition – narrowly interpreted here as executive function. From the perspective of higher cognition, the question is what kinds of experiences improve executive function. Reported cognitive benefits from bilingualism range from none to substantial as a function of age, type of bilingualism (e.g., life-long balanced vs later-onset or infrequent use of the other language), syntactic relation between the two languages, socio-economic and immigrant status, task, and laboratory. To understand the variability and inconsistencies in results with bilingualism, I analyze concepts of executive function and cognitive reserve and examine the range of factors (such as active video game playing, education, musical training, and aerobic exercise) that are known to correlate with or to improve executive function. I suggest that a) “executive function” is a complex set of cognitive processes, the components of which are sometimes minimally correlated with each other, depending on the task; b) bilingualism is inconsistently correlated with superior executive function and delayed onset of dementia; c) all speakers (mono- or bilingual) have non-linguistic ways of improving executive function; and d) benefits from bilingualism – and all cognitively challenging activities – are inconsistent because individuals vary in the number and kinds of experiences they have that promote superior executive function.
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There has been increasing criticism of the way psychologists conduct and analyze studies. These critiques as well as failures to replicate several high-profile studies have been used as justification to proclaim a "replication crisis" in psychology. Psychologists are encouraged to conduct more "exact" replications of published studies to assess the reproducibility of psychological research. This article argues that the alleged "crisis of replicability" is primarily due to an epistemological misunderstanding that emphasizes the phenomenon instead of its underlying mechanisms. As a consequence, a replicated phenomenon may not serve as a rigorous test of a theoretical hypothesis because identical operationalizations of variables in studies conducted at different times and with different subject populations might test different theoretical constructs. Therefore, we propose that for meaningful replications, attempts at reinstating the original circumstances are not sufficient. Instead, replicators must ascertain that conditions are realized that reflect the theoretical variable(s) manipulated (and/or measured) in the original study. © The Author(s) 2013.
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Research suggests that being bilingual results in advantages on executive control processes and disadvantages on language tasks relative to monolinguals. Furthermore, the executive function advantage is thought to be larger in older than younger adults, suggesting that bilingualism may buffer against age-related changes in executive function. However, there are potential confounds in some of the previous research, as well as inconsistencies in the literature. The goal of the current investigation was to examine the presence of a bilingual advantage in executive control and a bilingual disadvantage on language tasks in the same sample of young and older monolingual anglophones, monolingual francophones, and French/English bilinguals. Participants completed a series of executive function tasks, including a Stroop task, a Simon task, a sustained attention to response task (SART), the Wisconsin Card Sort Test (WCST), and the digit span subtest of the Wechsler Adult Intelligence Scale, and language tasks, including the Boston Naming Test (BNT), and category and letter fluency. The results do not demonstrate an unequivocal advantage for bilinguals on executive function tasks and raise questions about the reliability, robustness and/or specificity of previous findings. The results also did not demonstrate a disadvantage for bilinguals on language tasks. Rather, they suggest that there may be an influence of the language environment. It is concluded that additional research is required to fully characterize any language group differences in both executive function and language tasks.
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A sample of 58 bilingual and 62 monolingual university students completed four tasks commonly used to test for bilingual advantages in executive functioning (EF): antisaccade, flanker, Simon, and color-shape switching. Across the four tasks, 13 different indices were derived that are assumed to reflect individual differences in inhibitory control, monitoring, or switching. The effects of bilingualism on the 13 measures were explored by directly comparing the means of the two language groups and through regression analyses using a continuous measure of bilingualism and multiple demographic characteristics as predictors. Across the 13 different measures and two types of data analysis there were very few significant results and those that did occur supported a monolingual advantage. An equally important goal was to assess the convergent validity through cross-task correlations of indices assume to measure the same component of executive functioning. Most of the correlations using difference-score measures were nonsignificant and many near zero. Although modestly higher levels of convergent validity are sometimes reported, a review of the existing literature suggests that bilingual advantages (or disadvantages) may reflect task-specific differences that are unlikely to generalize to important general differences in EF. Finally, as cautioned by Salthouse, assumed measures of executive functioning may also be threatened by a lack of divergent validity that separates individual or group differences in EF from those in general fluid intelligence or simple processing speed.
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Paap and Greenberg concluded that there is no coherent evidence for bilingual advantages in executive processing. More optimistic researchers believe that the advantages may be restricted to certain types of bilinguals. Recent large-scale and lifespan investigations that tested highly fluent bilinguals from communities where the same two languages are spoken by most residents reported no bilingual advantages in any age group or in any of the tasks used to measure executive functioning. The present study takes a complementary approach by examining a sample that is quite homogeneous in terms of current life experiences, but heterogeneous in terms of its exposure to second languages. The composite database of 168 bilinguals and 216 monolinguals is used to explore for differences based on: (1) the age of acquiring a second language (L2), (2) the relative proficiency of an L2 and (3) the number of languages used. Across 12 different measures of executive function, derived from 4 different nonverbal tasks, there was no consistent evidence supporting the hypotheses that either early bilingualism, highly fluent balanced bilingualism, or trilingualism enhances inhibitory control, monitoring or switching. In fact, when statistically significant effects did occur, they more often disconfirmed than confirmed these hypotheses.
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Bilinguals have been shown to outperform monolinguals in a variety of tasks that do not tap into linguistic processes. The origin of this bilingual advantage has been questioned in recent years. While some authors argue that the reason behind this apparent advantage is bilinguals' enhanced executive functioning, inhibitory skills and/or monitoring abilities, other authors suggest that the locus of these differences between bilinguals and monolinguals may lie in uncontrolled factors or incorrectly matched samples. In the current study we tested a group of 180 bilingual children and a group of 180 carefully matched monolinguals in a child-friendly version of the ANT task. Following recent evidence from similar studies with children, our results showed no bilingual advantage at all, given that the performance of the two groups in the task and the indices associated with the individual attention networks were highly similar and statistically indistinguishable.
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We investigated the relationship between language control and executive control by testing three groups of bilinguals (104 participants) and 54 monolinguals in a training and transfer paradigm. Participants practiced either a language or a non-linguistic color/shape switching task and were tested one week later on both tasks. The color-shape task produced significant immediate improvement with training, which was maintained a week later, but exhibited no cross-task transfer effects. In the dominant-language, training effects did not persist after one week, and there were no transfer effects. In the non-dominant language there were significant training effects that lasted a week, and there was also transfer facilitation from prior practice with the color/shape task, which was limited to a reduction in mixing costs. Despite limited transfer, there were significant correlations between tasks in mixing costs for bilinguals, in switching costs for monolinguals, and in intrusion errors for all participants. Finally, the pattern of costs observed for the two tasks exhibited both similarities and differences across participants. These results imply a limited but significant role for executive control in bilingual language control, possibly playing a stronger role in facilitating non-dominant language production and in supporting the ability to monitor response outcomes to avoid errors.
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Objective: The current study investigated the combined effect of ADHD, previously associated with executive function (EF) deficits, and of bilingualism, previously associated with EF enhancement, on EF. Method: Eighty University students, Hebrew monolinguals and Russian Hebrew bilinguals, with and without ADHD participated. Inhibition tasks were a Numeric Stroop task and a Simon arrows task. Shifting tasks were the Trail Making Test (TMT) and a task-switching paradigm. Results: Participants with ADHD performed worse than controls, but we did not find a bilingual advantage in EF. The negative impact of ADHD was more pronounced for bilinguals than for monolinguals, but only in interference suppression tasks. Bilingual participants with ADHD had the lowest performance. Conclusion: Bilingualism might prove to be an added burden for adults with ADHD, leading to reduced EF abilities. Alternatively, the current findings might be ascribed to over- or under-diagnosis of ADHD due to cultural differences between groups. These issues should be pursued in future research.
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The aim of the present study is two-fold. First, we investigate age-related changes to bilingual language control (bLC) mechanisms across lifespan. Second, we explore the relation between bLC mechanisms and those of the domain-general executive (EC) system by looking at age effects on these two systems. To do so, we compare the performances of the three age groups of bilinguals (young, middle-aged and elderly) in a language switching task to those of non-linguistic switching task. We found an age-related change in the non-linguistic switch cost but not in the language switch cost. Moreover, we did not find any correlation between the magnitudes of the switch costs. Taken together these results indicate that bLC is not affected by age as the EC system is, and interestingly, we add new evidence that the bLC mechanisms are not fully subsidiary to those of the domain-general EC system.
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Previous research has documented advantages and disadvantages of early bilinguals, defined as learning a 2nd language by school age and using both languages since that time. Relative to monolinguals, early bilinguals manifest deficits in lexical access but benefits in executive function. We investigated whether becoming bilingual after childhood (late bilinguals) can produce the cognitive advantages and disadvantages typical of early bilinguals. Participants were 30 monolingual English speakers, 30 late English-Spanish bilinguals, and 30 early Spanish-English bilinguals who completed a picture naming task (lexical access) and an attentional network task (executive function). Late and early bilinguals manifested equivalent cognitive effects in both tasks, demonstrating lexical access deficits and executive function benefits. These findings provide support for the hypothesis that cognitive effects associated with bilingualism arise as the result of proficient, habitual use of 2 languages and not of developmental changes associated with becoming bilingual during childhood. (PsycINFO Database Record (c) 2013 APA, all rights reserved).
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In recent decades several authors have suggested that bilinguals exhibit enhanced cognitive control as compared to monolinguals and some proposals suggest that this main difference between monolinguals and bilinguals is related to bilinguals' enhanced capacity of inhibiting irrelevant information. This has led to the proposal of the so-called bilingual advantage in inhibitory skills. However, recent studies have cast some doubt on the locus and generality of the alleged bilingual advantage in inhibitory skills. In the current study we investigated inhibitory skills in a large sample of 252 monolingual and 252 bilingual children who were carefully matched on a large number of indices. We tested their performance in a verbal Stroop task and in a nonverbal version of the same task (the number size-congruency task). Results were unequivocal and showed that bilingual and monolingual participants performed equally in these two tasks across all the indices or markers of inhibitory skills explored. Furthermore, the lack of differences between monolingual and bilingual children extended to all the age ranges tested and was not modulated by any of the independent factors investigated. In light of these results, we conclude that bilingual children do not exhibit any specific advantage in simple inhibitory tasks as compared to monolinguals.
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Three studies compared bilinguals to monolinguals on 15 indicators of executive processing (EP). Most of the indicators compare a neutral or congruent baseline to a condition that should require EP. For each of the measures there was no main effect of group and a highly significant main effect of condition. The critical marker for a bilingual advantage, the Group×Condition interaction, was significant for only one indicator, but in a pattern indicative of a bilingual disadvantage. Tasks include antisaccade (Study 1), Simon (Studies 1-3), flanker (Study 3), and color-shape switching (Studies 1-3). The two groups performed identically on the Raven's Advanced Matrices test (Study 3). Analyses on the combined data selecting subsets that are precisely matched on parent's educational level or that include only highly fluent bilinguals reveal exactly the same pattern of results. A problem reconfirmed by the present study is that effects assumed to be indicators of a specific executive process in one task (e.g., inhibitory control in the flanker task) frequently do not predict individual differences in that same indicator on a related task (e.g., inhibitory control in the Simon task). The absence of consistent cross-task correlations undermines the interpretation that these are valid indicators of domain-general abilities. In a final discussion the underlying rationale for hypothesizing bilingual advantages in executive processing based on the special linguistic demands placed on bilinguals is interrogated.
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Recent behavioral data have shown that lifelong bilingualism can maintain youthful cognitive control abilities in aging. Here, we provide the first direct evidence of a neural basis for the bilingual cognitive control boost in aging. Two experiments were conducted, using a perceptual task-switching paradigm, including a total of 110 participants. In Experiment 1, older adult bilinguals showed better perceptual switching performance than their monolingual peers. In Experiment 2, younger and older adult monolinguals and bilinguals completed the same perceptual task-switching experiment while functional magnetic resonance imaging (fMRI) was performed. Typical age-related performance reductions and fMRI activation increases were observed. However, like younger adults, bilingual older adults outperformed their monolingual peers while displaying decreased activation in left lateral frontal cortex and cingulate cortex. Critically, this attenuation of age-related over-recruitment associated with bilingualism was directly correlated with better task-switching performance. In addition, the lower blood oxygenation level-dependent response in frontal regions accounted for 82% of the variance in the bilingual task-switching reaction time advantage. These results suggest that lifelong bilingualism offsets age-related declines in the neural efficiency for cognitive control processes.
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Replication is one of the most important tools for the verification of facts within the empirical sciences. A detailed examination of the notion of replication reveals that there are many different meanings to this concept and the relevant procedures, but hardly any systematic literature. This paper analyzes the concept of replication from a theoretical point of view. It demonstrates that the theoretical demands are scarcely met in everyday work within the social sciences. Some demands are just not feasible, whereas others are constricted by restrictions relating to publication. A new classification scheme based on a functional approach that distinguishes between different types of replication is proposed. Next, it will be argued that replication addresses the important connection between existing and new knowledge. To do so it has to be applied explicitly and systematically. The paper ends with a description of procedures how this could be done and a set of recommendations how to handle the concept of replication in the future to exploit its potential to the full. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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This study investigated the possibility that lifelong bilingualism may lead to enhanced efficiency in the ability to shift between mental sets. We compared the performance of monolingual and fluent bilingual college students in a task-switching paradigm. Bilinguals incurred reduced switching costs in the task-switching paradigm when compared with monolinguals, suggesting that lifelong experience in switching between languages may contribute to increased efficiency in the ability to shift flexibly between mental sets. On the other hand, bilinguals did not differ from monolinguals in the differential cost of performing mixed-task as opposed to single-task blocks. Together, these results indicate that bilingual advantages in executive function most likely extend beyond inhibition of competing responses, and encompass flexible mental shifting as well.
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Bilingual advantages in executive control tasks are well documented, but it is not yet clear what degree or type of bilingualism leads to these advantages. To investigate this issue, we compared the performance of two bilingual groups and monolingual speakers in task-switching and language-switching paradigms. Spanish-English bilinguals, who reported switching between languages frequently in daily life, exhibited smaller task-switching costs than monolinguals after controlling for between-group differences in speed and parent education level. By contrast, Mandarin-English bilinguals, who reported switching languages less frequently than Spanish-English bilinguals, did not exhibit a task-switching advantage relative to monolinguals. Comparing the two bilingual groups in language-switching, Spanish-English bilinguals exhibited smaller costs than Mandarin-English bilinguals, even after matching for fluency in the non-dominant language. These results demonstrate an explicit link between language-switching and bilingual advantages in task-switching, while also illustrating some limitations on bilingual advantages. (JINS, 2011, 17, 682-691).
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Inhibitory control and monitoring abilities of Hebrew-English bilingual and English monolingual university students were compared, in a paradigm requiring participants to switch between performing three distinct tasks. Inhibitory control was gauged by lag-2 task repetition costs, namely decreased performance on the final trial of sequences of type ABA relative to CBA, due to persisting inhibition of the recently abandoned task. Bilinguals had larger lag-2 repetition costs, which reflect stronger inhibition of a no-longer relevant task to facilitate a switch into a new task. Monitoring ability was measured by the fadeout effect, which reflects adaptation to simpler task demands when a single task block immediately and unexpectedly follows mixed task blocks. Bilinguals did not differ from monolinguals in the magnitude or trajectory of the fade-out effect. Thus, results support the notion of increased bilingual inhibitory control, even when it is detrimental to performance, and do not demonstrate a specific bilingual advantage in monitoring. These findings are discussed in the context of the recent debate concerning the locus of bilingual advantages.
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The regular use of two languages by bilingual individuals has been shown to have a broad impact on language and cognitive functioning. In this monograph, we consider four aspects of this influence. In the first section, we examine differences between mono-linguals and bilinguals in children's acquisition of language and adults' linguistic processing, particularly in terms of lexical retrieval. Children learning two languages from birth follow the same milestones for language acquisition as mono-linguals do (first words, first use of grammar) but may use different strategies for language acquisition, and they generally have a smaller vocabulary in each language than do monolin-gual children learning only a single language. Adult bilinguals typically take longer to retrieve individual words than monolin-guals do, and they generate fewer words when asked to satisfy a constraint such as category membership or initial letter. In the second section, we consider the impact of bilingualism on nonverbal cognitive processing in both children and adults. The primary effect in this case is the enhancement of executive control functions in bilinguals. On tasks that require inhibition of distract-ing information, switching between tasks, or holding information in mind while performing a task, bilinguals of all ages outperform comparable monolinguals. A plausible reason is that bilinguals recruit control processes to manage their ongoing linguistic per-formance and that these control processes become enhanced for other unrelated aspects of cognitive processing. Preliminary evi-dence also suggests that the executive control advantage may even mitigate cognitive decline in older age and contribute to cognitive reserve, which in turn may postpone Alzheimer's disease. In the third section, we describe the brain networks that are responsible for language processing in bilinguals and demon-strate their involvement in nonverbal executive control for bilinguals. We begin by reviewing neuroimaging research that identifies the networks used for various nonverbal executive control tasks in the literature. These networks are used as a ref-erence point to interpret the way in which bilinguals perform both verbal and nonverbal control tasks. The results show that bilinguals manage attention to their two language systems using the same networks that are used by monolinguals performing nonverbal tasks. In the fourth section, we discuss the special circumstances that surround the referral of bilingual children (e.g., language delays) and adults (e.g., stroke) for clinical intervention. These referrals are typically based on standardized assessments that use normative data from monolingual populations, such as vocabulary size and lexical retrieval. As we have seen, however, these measures are often different for bilinguals, both for children and adults. We discuss the implications of these linguistic differences for standardized test performance and clinical approaches. We conclude by considering some questions that have important public policy implications. What are the pros and cons of French or Spanish immersion educational programs, for example? Also, if bilingualism confers advantages in certain respects, how about three languages—do the benefits increase? In the healthcare field, how can current knowledge help in the treatment of bilingual aphasia patients following stroke? Given the recent increase in bilingualism as a research topic, answers to these and other related questions should be available in the near future.
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Language switching is omnipresent in bilingual individuals. In fact, the ability to switch languages (code switching) is a very fast, efficient, and flexible process that seems to be a fundamental aspect of bilingual language processing. In this study, we aimed to characterize psychometrically self-perceived individual differences in language switching and to create a reliable measure of this behavioral pattern by introducing a bilingual switching questionnaire. As a working hypothesis based on the previous literature about code switching, we decomposed language switching into four constructs: (i) L1 switching tendencies (the tendency to switch to L1; L1-switch); (ii) L2 switching tendencies (L2-switch); (iii) contextual switch, which indexes the frequency of switches usually triggered by a particular situation, topic, or environment; and (iv) unintended switch, which measures the lack of intention and awareness of the language switches. A total of 582 Spanish-Catalan bilingual university students were studied. Twelve items were selected (three for each construct). The correlation matrix was factor-analyzed using minimum rank factor analysis followed by oblique direct oblimin rotation. The overall proportion of common variance explained by the four extracted factors was 0.86. Finally, to assess the external validity of the individual differences scored with the new questionnaire, we evaluated the correlations between these measures and several psychometric (language proficiency) and behavioral measures related to cognitive and attentional control. The present study highlights the importance of evaluating individual differences in language switching using self-assessment instruments when studying the interface between cognitive control and bilingualism.
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Previous research has shown that highly proficient bilinguals have comparable switch costs in both directions when they switch between languages (L1 and L2), the so-called "symmetrical switch cost" effect. Interestingly, the same symmetry is also present when they switch between L1 and a much weaker L3. These findings suggest that highly proficient bilinguals develop a language control system that seems to be insensitive to language proficiency. In the present study, we explore whether the pattern of symmetrical switch costs in language switching tasks generalizes to a non-linguistic switching task in the same group of highly proficient bilinguals. The end goal of this is to assess whether bilingual language control (bLC) can be considered as subsidiary to domain-general executive control (EC). We tested highly proficient Catalan-Spanish bilinguals both in a linguistic switching task and in a non-linguistic switching task. In the linguistic task, participants named pictures in L1 and L2 (Experiment 1) or L3 (Experiment 2) depending on a cue presented with the picture (a flag). In the non-linguistic task, the same participants had to switch between two card sorting rule-sets (color and shape). Overall, participants showed symmetrical switch costs in the linguistic switching task, but not in the non-linguistic switching task. In a further analysis, we observed that in the linguistic switching task the asymmetry of the switch costs changed across blocks, while in the non-linguistic switching task an asymmetrical switch cost was observed throughout the task. The observation of different patterns of switch costs in the linguistic and the non-linguistic switching tasks suggest that the bLC system is not completely subsidiary to the domain-general EC system.
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Monitoring and controlling 2 language systems is fundamental to language use in bilinguals. Here, we reveal in a combined functional (event-related functional magnetic resonance imaging) and structural neuroimaging (voxel-based morphometry) study that dorsal anterior cingulate cortex (ACC), a structure tightly bound to domain-general executive control functions, is a common locus for language control and resolving nonverbal conflict. We also show an experience-dependent effect in the same region: Bilinguals use this structure more efficiently than monolinguals to monitor nonlinguistic cognitive conflicts. They adapted better to conflicting situations showing less ACC activity while outperforming monolinguals. Importantly, for bilinguals, brain activity in the ACC, as well as behavioral measures, also correlated positively with local gray matter volume. These results suggest that early learning and lifelong practice of 2 languages exert a strong impact upon human neocortical development. The bilingual brain adapts better to resolve cognitive conflicts in domain-general cognitive tasks.
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Previous research has found an advantage for bilinguals relative to monolinguals on tasks of attentional control. This advantage has been found to be larger in older adults than in young adults, suggesting that bilingualism provides a buffer against age-related declines in executive functioning. Using a computerized Stroop task in a nonimmigrant sample of young and older monolinguals and bilinguals, the current investigation tried to replicate previous findings of a bilingual advantage. A bilingual advantage would have been demonstrated by smaller Stroop interference (i.e., smaller increases in response time for incongruent than for neutral trials) for bilinguals than for monolinguals. The results showed that bilingual young adults showed a general speed advantage relative to their monolingual counterparts, but this was not associated with smaller Stroop interference. Older adults showed no effect of bilingualism. Thus, the present investigation does not find evidence of a bilingual advantage in young or older adults and suggests limits to the robustness and/or specificity of previous findings.
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To explore the effect of exogenous processes on cognitive control, we used a cueing task-switching paradigm with two spatial judgement tasks and added an irrelevant colour attribute to the task-relevant spatial attribute of the target. The colour was not related to any specific Stimulus-Response relation in the tasks. A correlation was created between stimulus colour and task identity. This correlation was strong but imperfect in Experiment 1 and perfect in Experiment 2. As a result of the colour-task correlation, stimuli contained redundant information about task identity. By changing the correlation pattern every few blocks we caused this information to be sometimes invalid. In both experiments, performance was worse when the information carried by the target was invalid than when it was valid. However, this effect was exclusive to conditions with short task preparation time. By comparing performance with a control group, which had no colour - task correlation (in Experiment 2) we established that the colour manipulation did not cause a qualitative change in preparation strategy, and that the exogenous effect was stronger in switch trials than in repetition trials. We conclude that exogenous processes that are related to task set affect performance primarily if they are presented before endogenous processes of task set preparation have been launched.
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Flexible control of action requires the ability to disengage from previous goals or task sets. The authors tested the hypothesis that disengagement during intentional shifts between task sets is accompanied by inhibition of the previous task set ("backward inhibition"). As an expression of backward inhibition the authors predicted increased response times when shifting to a task set that had to be abandoned recently and, thus, suffers residual inhibition. The critical backward inhibition effect on the level of abstractly defined perceptual task sets was obtained across 6 different experiments. In addition, it was shown that backward inhibition can be differentiated from negative priming (Experiment 2), that it is tied to top-down sequential control (Experiment 3), that it can account at least partially for "residual shift costs" in set-shifting experiments (Experiment 4), and that it occurs even in the context of preplanned sequences of task sets (Experiment 5).
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Knowledge about aging of perceptual-motor skills is based almost exclusively on cross-sectional studies. We examined age-related changes in the retention of mirror-tracing skills in healthy adults who practiced for 3 separate days at baseline and retrained 5 years later at follow-up. Overall, the speed and accuracy of an acquired skill were partially retained after a 5-year interim, although the same asymptote was reached. Analyses with individual learning curves indicated that the effects of age on mirror-tracing speed were greater at longitudinal follow-up than at baseline, with older adults requiring more training to reach asymptote. Thus, although the long-term retention of acquired skills declines with age, older adults still retain the ability to learn the skill. Moreover, those who maintained a processing speed comparable with that of the younger participants evidenced no age-related performance decrements on the mirror-drawing task.
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We explored the overlap between bilingual language control (bLC) and domain-general executive control (EC) by focusing on inhibitory control processes. We tested 62 bilinguals in linguistic and non-linguistic switching tasks for two types of costs, such as the n-1 shift cost and the n-2 repetition cost. In order to explore the involvement of inhibitory control in bLC and EC, we assessed the pattern of switch costs in the two tasks and then we correlated them between tasks. Results showed reduced n-2 repetition costs as compared to n-1 shift costs in the linguistic task only, suggesting that small amount of inhibition were deployed when switching between languages. Importantly, neither the n-1 shift costs nor the n-2 repetition costs were correlated between tasks. These results, supported by additional evidence from the ex-Gaussian analysis, suggest that inhibitory control is differently involved in bLC and in EC.
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Drawing on the adaptive control hypothesis (Green & Abutalebi, 2013), we investigated whether bilinguals’ disparate interactional contexts modulate task-switching performance. Seventy-five bilinguals within the single-language context (SLC) and 58 bilinguals within the dual-language context (DLC) were compared in a typical task-switching paradigm. Given that DLC bilinguals switch between languages within the same context, while SLC bilinguals speak only one language in one environment and therefore rarely switch languages, we hypothesized that the two groups’ stark difference in their interactional contexts of conversational exchanges would lead to differences in switch costs. As predicted, DLC bilinguals showed smaller switch costs than SLC bilinguals. Our diffusion-model analyses suggest that DLC bilinguals’ benefits in switch costs are more likely driven by task-set reconfiguration than by proactive interference. Our findings underscore the modulating role of the interactional context of conversational exchanges in task switching.
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We present a study examining cognitive functions in late non-balanced bilinguals with different levels of second language proficiency. We examined in two experiments a total of 193 mono- and bilingual university students. We assessed different aspects of attention (sustained, selective and attentional switching), verbal fluency (letter and category) as well as picture-word association as a measure of language proficiency. In Experiment 2 we also compared students in their first/initial (Y1) and fourth/final (Y4) year of either language or literature studies. There were no differences between both groups in category fluency. In selective attention, bilinguals outperformed monolinguals in Y1 and this difference remained significant in Y4 despite overall improvement in both groups. Contrasting results were found in attentional switching and letter fluency: while no differences were found in Y1 in both tasks, in Y4 there was an advantage for bilinguals in attentional switching and for monolinguals in letter fluency. We conclude that overall late-acquisition non-balanced bilinguals experience similar cognitive effects as their early-acquisition balanced counterparts. However, different cognitive effects may appear at different stages of adult second language acquisition. Copyright © 2015 Elsevier B.V. All rights reserved.
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Many bilinguals routinely switch between their languages, yet mixed evidence exists about the transfer of language switching skills to broader domains that require attentional control such as task switching. Monolingual and bilingual young adults performed a nonverbal task-switching paradigm in which they viewed colored pictures of animals and indicated either the animal or its color in response to a cue. Monolinguals and bilinguals performed similarly when switching between tasks (local switch cost) in a mixed-task block, but bilinguals demonstrated a smaller mixing effect (global switch cost) than monolinguals, indicating better ability to reconfigure stimulus–response associations. These results suggest that regular practice using multiple languages confers a broader executive function advantage shown as improved flexibility in task switching.
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The basal ganglia are critically involved in language control (LC) processes, allowing a bilingual to utter correctly in one language without interference from the non-requested language. It has been hypothesized that the neural mechanism of LC closely resembles domain-general executive control (EC). The purpose of the present study is to investigate the integrity of bilingual LC and its overlap with domain-general EC in a clinical population such as individuals with Parkinson's disease (PD), notoriously associated with structural damage in the basal ganglia.We approach these issues in two ways. First, we employed a language switching task to investigate the integrity of LC in a group of Catalan–Spanish bilingual individuals with PD, as compared to a group of matched healthy controls. Second, to test the relationship between domain-general EC and LC we compared the performances of individuals with PD and healthy controls also in a non-linguistic switching task. We highlight that, compared to controls, individuals with PD report decreased processing speed, less accuracy and larger switching costs in terms of RT and errors in the language switching task, whereas in the non-linguistic switching task PD patients showed only increased switching cost in terms of errors. However, we report a positive correlation between the magnitudes of linguistic and non-linguistic mixing costs in individuals with PD. Taken together, these results support the notion of a critical role of the basal ganglia and connected structures in LC, and suggest a possible link between LC and domain-general EC.
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Contemporary research on bilingualism has been framed by two major discoveries. In the realm of language processing, studies of comprehension and production show that bilinguals activate information about both languages when using one language alone. Parallel activation of the two languages has been demonstrated for highly proficient bilinguals as well as second language learners and appears to be present even when distinct properties of the languages themselves might be sufficient to bias attention towards the language in use. In the realm of cognitive processing, studies of executive function have demonstrated a bilingual advantage, with bilinguals outperforming their monolingual counterparts on tasks that require ignoring irrelevant information, task switching, and resolving conflict. Our claim is that these outcomes are related and have the overall effect of changing the way that both cognitive and linguistic processing are carried out for bilinguals. In this article we consider each of these domains of bilingual performance and consider the kinds of evidence needed to support this view. We argue that the tendency to consider bilingualism as a unitary phenomenon explained in terms of simple component processes has created a set of apparent controversies that masks the richness of the central finding in this work: the adult mind and brain are open to experience in ways that create profound consequences for both language and cognition.
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Based on previous reports of bilinguals’ reduced non-linguistic switch cost, we explored how bilingualism affects various task-switching mechanisms. We tested different groups of Spanish monolinguals and highly-proficient Catalan–Spanish bilinguals in different task-switching implementations. In Experiment 1 we disengaged the restart cost typically occurring after a cue from the switch cost itself using two cue–task versions varying in explicitness. In Experiment 2 we tested bilingualism effects on overriding conflicting response sets by including bivalency effects. In Experiment 3 we attempted to replicate the reduced switch cost of bilinguals with the same implementation as in previous studies. Relative to monolinguals, bilinguals showed a reduced restart cost in the implicit cue–task version of Experiment 1 and overall faster response latencies in Experiment 2. However, bilinguals did not show reduced switch cost in any experiment – not even in an omnibus analysis combining the standardized switch cost scores of 292 participants across the three experiments. These results qualify previous claims about bilingualism reducing non-linguistic switch costs.
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Objective: Implicit skill learning is hypothesized to depend on nondeclarative memory that operates independent of the medial temporal lobe (MTL) memory system and instead depends on cortico striatal circuits between the basal ganglia and cortical areas supporting motor function and planning. Research with the Serial Reaction Time (SRT) task suggests that patients with memory disorders due to MTL damage exhibit normal implicit sequence learning. However, reports of intact learning rely on observations of no group differences, leading to speculation as to whether implicit sequence learning is fully intact in these patients. Patients with Parkinson's disease (PD) often exhibit impaired sequence learning, but this impairment is not universally observed. Method: Implicit perceptual-motor sequence learning was examined using the Serial Interception Sequence Learning (SISL) task in patients with amnestic Mild Cognitive Impairment (MCI; n = 11) and patients with PD (n = 15). Sequence learning in SISL is resistant to explicit learning and individually adapted task difficulty controls for baseline performance differences. Results: Patients with MCI exhibited robust sequence learning, equivalent to healthy older adults (n = 20), supporting the hypothesis that the MTL does not contribute to learning in this task. In contrast, the majority of patients with PD exhibited no sequence-specific learning in spite of matched overall task performance. Two patients with PD exhibited performance indicative of an explicit compensatory strategy suggesting that impaired implicit learning may lead to greater reliance on explicit memory in some individuals. Conclusion: The differences in learning between patient groups provides strong evidence in favor of implicit sequence learning depending solely on intact basal ganglia function with no contribution from the MTL memory system.
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An advantage for bilingual relative to monolingual young adults has been found for cognitive control tasks, although this finding is not consistent in the literature. The present investigation further examined this advantage using three tasks previously found to be sensitive to the effect. Furthermore, both behavioral and event-related brain potential (ERP) measures were included. Monolingual (n=25) and highly proficient bilingual (n=26) young adults completed a Stroop, Simon, and Eriksen flanker task while electrophysiological recording took place. Behaviorally there were no language group differences on any of the tasks. The ERP measures demonstrated differences between monolinguals and bilinguals with respect to conflict monitoring, resource allocation, stimulus categorization, and error-processing; however, these differences were not consistent across tasks. Given the similar behavioral performance across the groups the observed differences in brain responses may not represent an advantage for bilinguals. The results are discussed with respect to previous findings.
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A total of 104 six-year-old children belonging to 4 groups (English monolinguals, Chinese-English bilinguals, French-English bilinguals, Spanish-English bilinguals) were compared on 3 verbal tasks and 1 nonverbal executive control task to examine the generality of the bilingual effects on development. Bilingual groups differed in degree of similarity between languages, cultural background, and language of schooling. On the executive control task, all bilingual groups performed similarly and exceeded monolinguals; on the language tasks the best performance was achieved by bilingual children whose language of instruction was the same as the language of testing and whose languages had more overlap. Thus, executive control outcomes for bilingual children are general but performance on verbal tasks is specific to factors in the bilingual experience.
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We ask whether bilingualism aids cognitive control over the inadvertent guidance of visual attention from working memory and from bottom-up cueing. We compare highly-proficient Catalan-Spanish bilinguals with Spanish monolinguals in three visual search conditions. In the working memory (WM) condition, attention was driven in a top-down fashion by irrelevant objects held in WM. In the Identify condition, attention was driven in a bottom-up fashion by visual priming. In the Singleton condition, attention was driven in a bottom-up fashion by including a unique distracting object in the search array. The results showed that bilinguals were overall faster than monolinguals in the three conditions, replicating previous findings that bilinguals can be more efficient than monolinguals in the deployment of attention. Interestingly, bilinguals were less captured by irrelevant information held in WM but were equally affected by visual priming and unique singletons in the search displays. These observations suggest that bilingualism aids top-down WM-mediated guidance of attention, facilitating processes that keep separate representations in WM from representations that guide visual attention. In contrast, bottom-up attentional capture by salient yet unrelated input operates similarly in bilinguals and monolinguals.
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Using two languages on an everyday basis appears to have a positive effect on general-purpose executive control in bilinguals. However, the neural correlates of this effect remain poorly understood. To investigate the brain bases of the bilingual advantage in executive control, we tested 21 Spanish monolinguals and 19 Spanish-Catalan early bilinguals in a non-verbal task-switching paradigm. As expected based on previous experiments on non-verbal task switching, we found activation in the right inferior frontal cortex and the anterior cingulate of monolingual participants. While bilingual participants showed a reduced switching cost, they activated the left inferior frontal cortex and the left striatum, a pattern of activation consistent with networks thought to underlie language control. Overall, these results support the hypothesis that bilinguals' early training in switching back and forth between their languages leads to the recruitment of brain regions involved in language control when performing non-linguistic cognitive tasks.
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We report two experiments exploring more in detail the bilingual advantage in conflict resolution tasks. In particular, we focus on the origin of the bilingual advantage on overall reaction times in the flanker task. Bilingual and monolingual participants were asked to perform a flanker task under different task versions. In Experiment 1, we used two low-monitoring versions where most of the trials were of just one type (either congruent or incongruent). In Experiment 2, we used two high-monitoring versions where congruent and incongruent trials were more evenly distributed. An effect of bilingualism in overall reaction times was only present in the high-monitoring condition. These results reveal that when the task at hand recruits a good deal of monitoring resources, bilinguals outperform monolinguals. This observation suggests that bilingualism may affect the monitoring processes involved in executive control.
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A battery of cognitive tests, specifically designed to assess verbal and skill learning, was administered to healthy volunteer subjects of different ages. Although there were age-related declines in initial and terminal performance in both a pursuit rotor and a mirror reading task, the increase in performance with practice on these tasks was little affected by age. Recall, but not recognition, of verbal material was also impaired in the elderly, as were some measures of frequency estimation. These findings are compatible with the contention that, although acquisition of declarative tasks, which requires conscious processing, is impaired in the elderly, acquisition of nondeclarative tasks, which can be learned without conscious awareness, is not affected by age. However, classical conditioning may be an exception to this generalization for reasons that are at the present time unknown.
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The need of bilinguals to continuously control two languages during speech production may exert general effects on their attentional networks. To explore this issue we compared the performance of bilinguals and monolinguals in the attentional network task (ANT) developed by Fan et al. [Fan, J., McCandliss, B.D. Sommer, T., Raz, A., Posner, M.I. (2002). Testing the efficiency and independence of attentional networks. Journal of Cognitive Neuroscience, 14, 340-347]. This task is supposed to tap into three different attentional networks: alerting, orienting and executive control. The results revealed that bilingual participants were not only faster in performing the task, but also more efficient in the alerting and executive control networks. In particular, bilinguals were aided more by the presentation of an alerting cue, and were also better at resolving conflicting information. Furthermore, bilinguals experienced a reduced switching cost between the different type of trials compared to monolinguals. These results show that bilingualism exerts an influence in the attainment of efficient attentional mechanisms by young adults that are supposed to be at the peak of their attentional capabilities.