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.

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.

A bilingual advantage in a form of a better performance of bilinguals in tasks tapping into executive function abilities has been reported repeatedly in the literature. However, recent research defends that this advantage does not stem from bilingualism, but from uncontrolled factors or imperfectly matched samples. In this study we explored the potential impact of bilingualism on executive functioning abilities by testing large groups of young adult bilinguals and monolinguals in the tasks that were most extensively used when the advantages were reported. Importantly, the recently identified factors that could be disrupting the between groups comparisons were controlled for, and both groups were matched. We found no differences between groups in their performance. Additional bootstrapping analyses indicated that, when the bilingual advantage appeared, it very often co-occurred with unmatched socio-demographic factors. The evidence presented here indicates that the bilingual advantage might indeed be caused by spurious uncontrolled factors rather than bilingualism per se. Secondly, bilingualism has been argued to potentially affect working memory also. Therefore, we tested the same participants in both a forward and a backward version of a visual and an auditory working memory task. We found no differences between groups in either of the forward versions of the tasks, but bilinguals systematically outperformed monolinguals in the backward conditions. The results are analysed and interpreted taking into consideration different perspectives in the domain-specificity of the executive functions and working memory.