On the bilingual advantage in conflict processing: Now you see it, now you don’t
Introduction
Bilingualism has been shown to have a positive effect on the functioning of an individual’s attentional system across the life-span (e.g., Bialystok, 1999, Bialystok and Martin, 2004, Carlson and Meltzoff, 2008, Costa et al., 2008, Martin-Rhee and Bialystok, 2008; see full list of studies in Appendix A). The bilingual advantage has been explored mainly by means of tasks that involve ignoring distracting and conflicting information, such as the Simon task and the flanker task. There are two effects that have been taken as indexing a bilingual advantage:
- (a)
The conflict produced by incongruent distractors is larger for monolinguals than for bilinguals (e.g., Bialystok et al., 2004, Bialystok et al., 2008, Costa et al., 2008).
- (b)
Bilinguals perform tasks involving conflict resolution overall faster than monolinguals (e.g., Bialystok, 2006, Costa et al., 2008, Martin-Rhee and Bialystok, 2008).
Consider, for example, the flanker task in which participants are asked to indicate whether a central arrow (→) points to the right or to the left. This arrow is presented along with four flanker arrows pointing to the same (congruent trials →→→→→) or different direction (incongruent trials ←←→←←). Responses tend to be slower for incongruent than for congruent trials (the conflict effect), revealing the time needed to resolve the conflict between the target and the flankers. The bilingual advantage in this task was indexed by a reduced conflict effect for bilinguals in comparison to monolinguals (Costa et al., 2008). Interestingly, bilinguals were also overall faster in performing the task. That is, bilinguals in comparison to monolinguals responded faster both in congruent and incongruent trials. This effect may reflect an impact of bilingualism on the efficiency of other cognitive processes than conflict resolution per se, as has already been suggested by several authors (e.g., response suppression and switching; Bialystok, Craik, & Ryan, 2006).
The reliability and robustness of the two effects associated to bilingualism mentioned above appear to be somewhat different. A review of the literature is complex, given the different types of populations, tasks and designs used. However, in a large number of studies the magnitude of the conflict effect is similar for bilinguals and monolinguals (see Appendix A). Most of these studies have used mixed designs (25/37 studies) in which congruent and incongruent trials were randomly presented. Out of these 25 experiments only 6 led to a bilingual advantage in the magnitude of the conflict effect. However, there was a significant difference in overall reaction times (RTs) between the two groups in about 12 of these 25 experiments. It is worth mentioning that most of these studies used mixing contexts in which congruent and incongruent trials were presented evenly (22/25), and in only 12 of the 22 there was a bilingual effect whatsoever. Importantly, however, when the design is blocked differences associated to bilingualism are extremely difficult to detect (3/12).
Two empirical generalizations can be derived from these results. A bilingual advantage is more likely to be present in: (a) overall RTs than on the magnitude of the conflict effect, (b) in mixing contexts where congruent and incongruent trials are randomly presented, than in blocked designs. In this article, we explore the relationship between these two empirical generalizations. We do so by assessing how the percentage of congruent and incongruent trials in mixed designs affect the detectability of the bilingual impact on both overall RTs and the magnitude of conflict effects.
Section snippets
On the origin of the Bilingual advantage on overall RTs and on the conflict effect
From the theoretical point of view, the bilingual advantage on the magnitude of the conflict effect and on the overall RTs may index the impact of bilingualism on different components of the attentional system. The first effect may be related to processes recruited in suppressing interference from irrelevant conflicting information. The need of bilinguals to continuously control their two languages, focusing on the relevant linguistic representation while avoiding interference from the
The present study
In this study we test the hypothesis that the bilingual advantage in overall RTs stems from a more efficient monitoring system. The rationale of the study is the following: if the bilingual advantage is in some way related to the functioning of the monitoring system, then it should be present in conditions requiring high monitoring demands, and reduced or absent in those condition in which the monitoring system is less taxed. To manipulate the involvement of the monitoring system, the
General method
In this version of the ANT
Experiment 1: Is there a bilingual advantage in low monitoring contexts?
This experiment included two tasks versions. In the first version, most of the trials were congruent (92% congruent version −88 congruent trials and 8 incongruent trials per block) while in the second version most of them were incongruent (8% congruent version −8 congruent trials and 88 incongruent trials per block). An effect of bilingualism will be indexed either by a main effect of “Group of Participants” or by an interaction of this variable with the “Type of flanker” variable, since this
Results and discussion
RTs faster than 200 ms or slower than 1200 ms were excluded from the analyses (0.52% of the trials). We conducted a general analysis of variance (ANOVA) with “Block” (1 vs. 2 vs. 3) and “Flanker type” (congruent vs. incongruent) as within-subject factors, and “Group of Participants” (bilingual vs. monolingual) and “Task version” (8% congruent version vs. 92% congruent version) as between-subjects factors (see Appendix C for a description of the orienting and alerting effects).
In the RTs analyses
Experiment 2: Is there a bilingual advantage in high monitoring contexts?
This experiment included two tasks versions. In the first version, half of the trials were congruent and the other half incongruent (50% congruent version −48 congruent trials and 48 incongruent trials per block). In the second version, only 25% of the trials were incongruent (75% congruent version −72 congruent trials and 24 incongruent trials per block). An effect of bilingualism would be indexed either by a main effect of “Group of participants” in any of these versions or by an interaction
Results
The same criteria as in Experiment 1 to remove outliers were applied here (0.4% of the trials). Also, the same general analysis of variance (ANOVA) as in the previous study was performed.
In the RT analyses the main effect of “Task version” was not significant. The main effects of “Block” (F(2, 240) = 4.63, MSE = 921.93, p = .011) and “Flanker type” (F(1, 120) = 1482.84, MSE = 1667.65, p < .0001) were significant. Crucially, the main effect of “Group of Participants” was significant (F(1, 120) = 11.86, MSE =
Discussion
Several interesting results were observed in this experiment. First, bilinguals tended to be overall faster than monolinguals (Fig. 2, Panel B). This effect was clearly significant across the whole experiment in the condition in which the monitoring system is maximally recruited (50% congruent version) and was present
General discussion
The experiments reported in this article aimed at exploring some of the conditions that lead to a bilingual advantage in tasks that involve conflict processing. In particular, we focused on the origin of the bilingual advantage in overall speed. We hypothesized that such an effect might reveal an impact of bilingualism on the efficiency of the conflict monitoring system, and that consequently, its detectability would depend on the extent to which the experimental conditions tax the monitoring
The bilingual advantage on overall RTs
One of the indexes of a bilingual advantage in conflict resolution tasks is the overall faster RTs of bilinguals in comparison to monolinguals. Arguably, this effect cannot be attributed merely to a more efficient conflict resolution processing, given that no conflict resolution is required when dealing with congruent stimuli (target and flankers call for the same response). We hypothesized that this bilingual advantage could be the result of a more efficient monitoring processing system, in
The bilingual advantage on the magnitude of the conflict effect
The results presented here are also relevant for the other signature effect of a bilingual advantage in conflict processing tasks, namely the reduction in the magnitude of the conflict effect in bilinguals. Although this effect has received much attention, it appears not to be very robust (see Appendix A), leading some authors to question its usefulness for drawing strong conclusions (Colzato et al., 2008). Our results add evidence to this concern. This is because a difference in the magnitude
Language processing, conflict resolution and conflict monitoring
In the Introduction we argued that the advantage in the magnitude of the conflict effect may stem from the need of bilinguals to lexicalize words in the intended language while preventing massive interference from the other language. There are several proposals regarding how this lexicalization is achieved, but all of them agree on assuming that some sort of language control is needed (Costa et al., 2006, Finkbeiner et al., 2006, Finkbeiner et al., 2006, Green, 1998, La Heij, 2005) (in fact, it
Acknowledgements
This research was supported by two grants from the Spanish Government (PSI2008-01191/PSIC with EC Fondos FEDER Consolider Ingenio 2010 CE-CSD2007-00121). Mireia Hernández was supported by a Pre-doctoral fellowship from the Catalan Government. (SGR-2005). We thank Elin Runnquist for her comments.
References (31)
- et al.
Bilingual language production: The neurocognition of language representation and control
Journal of Neurolinguistics
(2007) - et al.
Effect of bilingualism on cognitive control in the Simon task: Evidence from MEG
NeuroImage
(2005) - et al.
Bilingualism aids conflict resolution: Evidence from the ANT task
Cognition
(2008) - et al.
Lexical access in bilingual speech production: Evidence from language switching in highly proficient bilinguals and L2 learners
Journal of Memory and Language
(2004) - et al.
Bilingual language switching in naming: Asymmetrical costs of language selection
Journal of Memory and Language
(1999) Cognitive complexity and attentional control in the bilingual mind
Child Development
(1999)Effect of bilingualism and computer video game experience on the Simon task
Canadian Journal of Experimental Psychology
(2006)- et al.
Bilingualism, aging, and cognitive control: Evidence from the Simon task
Psychology & Aging
(2004) - et al.
Cognitive control and lexical access in younger and older bilinguals
Journal of Experimental Psychology: Learning, Memory and Cognition
(2008) - et al.
Executive control in a modified anti-saccade task: Effects of aging and bilingualism
Journal of Experimental Psychology: Learning, Memory, and Cognition
(2006)
Attention and inhibition in bilingual children: Evidence from the dimensional change card sort task
Developmental Science
Bilingualism across the lifespan: The rise and fall of inhibitory control
International Journal of Bilingualism
Bilingual experience and executive 651 functioning in young children
Developmental Science
How does bilingualism improve executive control? A comparison of active and reactive inhibition mechanisms
Journal of Experimental Psychology: Learning, Memory and Cognition
The dynamics of bilingual lexical access
Bilingualism: Language and Cognition
Cited by (585)
Executive function skills account for a bilingual advantage in English novel word learning among low-income preschoolers
2023, Journal of Experimental Child PsychologyDo bilinguals get the joke? Humor comprehension in mono- and bilinguals
2023, Bilingualism