Facultad de Lenguas y Educación, Universidad Nebrija; Madrid, Spain.
BCBL. Basque Center on Cognition, Brain and Language; Donostia, Spain.
PLoS One. 2019 Feb 13;14(2):e0206770. doi: 10.1371/journal.pone.0206770. eCollection 2019.
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.
双语优势表现为双语者在执行功能任务中的表现优于单语者，这在文献中已经被反复报道。然而，最近的研究认为，这种优势并非源自双语，而是源自不受控制的因素或不匹配的样本。在这项研究中，我们通过测试大量年轻成年双语者和单语者在被广泛报道的优势任务中，探索了双语对执行功能能力的潜在影响。重要的是，我们控制了最近发现的可能破坏组间比较的因素，并对两组进行了匹配。我们发现两组在表现上没有差异。额外的自举分析表明，当出现双语优势时，它经常与不匹配的社会人口因素同时出现。这里呈现的证据表明，双语优势可能确实是由虚假的不受控制的因素而不是双语本身引起的。其次，双语被认为也可能影响工作记忆。因此，我们在视觉和听觉工作记忆任务的正向和反向版本中测试了相同的参与者。我们发现，在任务的正向版本中，两组之间没有差异，但双语者在反向条件下的表现明显优于单语者。我们分析并解释了这些结果，同时考虑了执行功能和工作记忆领域的特异性的不同观点。
