Bilingual advantage is the notion that the practice of employing two languages, choosing one while inhibiting the other enhances executive function. Executive function is a faction of top-down psychological processes vital in attention, inhibition, and planning (Diamond, 2013). Bilinguals have been shown to have advantages in tasks concerning interference repression- inhibition of inappropriate tasks (Bunge et al, 2002). But research on the bilingual advantage in executive function has often generated contradictory evidence. The Simon, Stroop, Flanker and Attentional Network tasks have frequently been employed as a measure of executive function. For the purpose of this written piece, one will focus on the Simon task, which is a measure of inhibition, with children as the target population. One will also examine reasons behind the conflicting evidence for the bilingual advantage regardless of studies often utilising similar tasks and target populations. Additionally, the methodological issues that may have affected the contradictory outcomes will be considered.
As previously pointed out, the simon task is commonly used as an assessment of inhibition in bilingual advantage studies. For instance, De Cat, Gusanto and Serratrice (2017) assessed inhibition using 174 children. A computer-based version of the simon task was used where the compatibility of stimulus and response was according to its shape and position. Two conditions were involved, a mismatching condition where the square was aligned by the button with the wrong colour and a matching condition where the colour of the square was corresponded with the position of the button. There were 8-practice trials along with 48 critical trials and children were instructed to press the button as quickly and accurately as possible. Children’s responses were noted. They found that bilingualism did not have an effect in inhibition. However, a fascinating discovery from this study was that children in the highly heterogeneous bilingual group benefitted from a socioeconomic advantage. This suggests that an advantage in executive function may stem from an advantage background rather than solely based on bilingualism.
Nevertheless, using a similar methodology, Ross and Melinger (2017) provide support for the bilingual advantage. In their study using the Simon task, there were 174 children between the ages of 6 and 9 years- there were 54 bilingual speakers, 45 monolinguals and 48 bidialectal speakers. There were 48 trials evenly allocated between the two colours (red and blue squares) and locations(left vs right). The precision and speed of responses were assessed. Findings showed that bilinguals made fewer errors than monolinguals in the Simon task but no evidence for 8-year-olds were found. This indicate that the bilingual effect on executive function might be age-specific-implying that not children of all ages show the bilingual advantage.
These refuting results suggest that there are methodological issues concerning bilingual advantage studies. One of these problems might be sample size. For example, Ross and Melinger used a smaller sample compared to Decat and colleagues. Small sample sizes are argued to generate positive outcomes. But this is problematic because small samples decrease the statistical power of studies. It means that findings from such studies cannot be generalised to every bilingual child because the samples used in such studies are not representative of bilingual children. Moreover, the refuting evidence is perhaps due to the impurity of cognitive control tasks. For example, the simon task may not offer a pure measure of a sole control skill instead, it might stem from several components of cognitive control.
Nevertheless, Namazi & Thordardottir (2010) did not find supporting evidence for the bilingual advantage in EF irrespective of using a smaller sample. In a study involving 45 children, the Simon task was employed where children were required to push a red button when a red square appeared on the computer screen and press a blue button when a blue square emerged. The test-trials contained 36 congruent and 36 incongruent trials shown at random. Children’s reaction time was assessed. A bilingual advantage was not found because bilingual and monolingual children demonstrated similar performance on the Simon task. However, it was found that children with enhanced visual working memories performed considerably better on the Simon task as they were more precise and quicker. This suggests that an advantage in executive function might not be due to a bilingual advantage effect but other factors affecting it.
The fact that the same task was used in this study and Melinger and Ross’ study yet conflicting evidence was discovered demonstrates that factors other than the sample size or task swayed the outcomes. It is argued that, children for these studies are often designated to dichotomous groups but bilingualism is a multidimension and continuous phenomenon so this might have an influence on the outcomes. Although, it is claimed that small sample sizes often generate positive findings, Melinger and Ross used a sample larger than Namazi and Thordardottir yet found evidence for the bilingual advantage which implies that factors other than sample size impacts the outcomes of bilingual advantage studies. For example, since random assignment is not feasible in quasi-experimental studies, it may be possible that comparing monolinguals to bilinguals leads to a possibility of bilingualism covarying other factors that affect EF.
In a study exploring non-linguistic effects of language control in early second language learners, bilinguals, and trilingual, Poarch and Van Hell (2012) found evidence for the bilingual advantage in German children. This study consisted of 75 German children aged between 5 and 8 years old. The Simon task was used with twenty-four practice trials and 84 critical trials. Participants were examined on their speed and precision. They found the Simon effect advantage for bilingual children over monolinguals. Bilinguals also had a greater conflict resolution over monolinguals and second-language learners. These findings suggest that bilinguals have an advantage in certain tasks of EF. The refuting results is possibly due to the number of trials used. While Namazi & Thordardottir (2010) used only 36 critical trials, Poarch and Hell used 84 critical trials. This means that children could have improve on their accuracy as the trials progressed. Moreover, cultural influences may have affected the outcomes of this study. For instance, While Namazi and Thordardottir used French and English monolinguals and bilinguals, Poarch and Hell used German children.
Comparable to Namazi & Thordardottir findings, Morton and Harper (2007) found no evidence for the bilingual advantage in 6- and 7-year olds. But socioeconomic status was taken into consideration. There were 34 children (17 monolinguals and 17 bilinguals) whose socioeconomic status was assessed through a parental information questionnaire. All children were from a well‐educated middle‐class family. Subjects were required to complete a computer‐based version of the Simon task with 28 trials. It was found that both bilingual and monolingual children exhibited comparable performance in the Simon task. For the incongruent trials, both groups were slower and more prone to make errors than the congruent trials. Moreover, bilingual children failed to demonstrate an advantage regardless of their control of two languages. However, socioeconomic status had an effect- children from higher economic backgrounds demonstrated smaller cost of conflict in the Simon task in terms of errors. These findings demonstrate that, it may not be bilingualism that influence executive function, but rather external factors such as socioeconomic status.
These inconsistent findings indicate that there are issues of reliability in research on the bilingual advantage. Perhaps it could be the fact that tests for bilingual advantage in EF often employ mixed-factorial designs with two language groups and two types of trials. For instance, in the Simon task, interference outcomes are the difference between the congruent and incongruent trials. As a result, if bilinguals have better inhibitory control, the interference scores should be smaller for bilinguals compared to monolinguals, but this is not the case. Additionally, the study by Morton and Harper was not representative because it only focused on children from well-educated middle-class families. This is an issue because children from lower socioeconomic backgrounds may perform differently from those from middle-class families so the results cannot be generalised to all children. Furthermore, academics such as Paap et al (2015) argue that there is a small proportion of supporting outcomes on the bilingual advantage which may be due to factors such as type 1 errors or confounds. For example, Baker et al (2012) found that it is easy for scholars to exaggerate type 1 errors when they apply hidden degrees of freedom in their analyses. Thus, researchers may select the most desirable outcomes by letting the sample size depend on the results of significance tests. A meta-analysis by Zhou and Krott involving 68 experiments showed that researchers also use data trimming procedures where longer responses in their analysis often yield a bilingualism effect. All these issues influence the outcomes of the bilingual advantage in EF.
In conclusion, this essay has explored the empirical evidence for the Bilingual Advantage in Executive Function-specifically focusing on inhibition in children. Based on the studies evaluated, one has concluded that there is no bilingual advantage in executive function. studies that often find evidence faces methodological scrutiny such as the use of small samples, task impurity and individual differences. Although there is some evidence to support the bilingual advantage, it seems like it is both task-specific and social economic factors as well as cultural factors seem to influence it-implying that further research in bilingual advantage in children is essential.