School of Psychology, University of Birmingham, Birmingham B15 2TT, United Kingdom; Centre for Human Brain Health, University of Birmingham, Birmingham B15 2TT, United Kingdom; School of Psychology, University of Bristol, Bristol BS8 1TU, United Kingdom.
School of Psychology, University of Birmingham, Birmingham B15 2TT, United Kingdom; Centre for Human Brain Health, University of Birmingham, Birmingham B15 2TT, United Kingdom; Department of Language and Culture, UiT the Arctic University of Norway, Tromsø 9019, Norway.
Neuroimage. 2023 Jun;273:120085. doi: 10.1016/j.neuroimage.2023.120085. Epub 2023 Apr 3.
Bilinguals have often, but not always, been found to outperform monolinguals on domain-general attentional control. Inconsistent findings have been argued to stem, at least partly, from treating bilingualism as a uniform category and from not considering how neural adaptations to bilingual experiences modulate behavioural outcomes. The present study investigated how patterns of language experience, including language switching behaviour, duration and intensity/diversity of bilingual language use, influence the brain processes underlying cognitive control, and how these in turn translate to cognitive control performance. We examined reaction times and spectral dynamics of the electroencephalograms (EEG) of two-hundred-and-thirty-nine participants (about 70% bilinguals) with diverse language experiences during two cognitive control paradigms testing interference suppression (flanker and Simon task). Using structural equation modelling, we found that different bilingual experience factors were related with neurocognitive measures, which in turn were related with behavioural interference effects, for the flanker but not the Simon task. More specifically, increased frequency of language switching and intensity/diversity of bilingual language usage was negatively related to induced top-down control measures (especially midline-frontal theta), which in turn was beneficial for interference control. In contrast, duration of bilingual engagement correlated negatively with evoked bottom-up control measures (especially P3) and was therefore detrimental to interference control. We demonstrate here for the first time how the different factors of bilingual experience lead to different neural adaptations which impact behavioural outcomes. SIGNIFICANCE STATEMENT: Like other intensive experiences, bilingualism leads to brain adaptations. It results in structural changes in language areas, and, due to demands on language control, in brain areas associated with domain-general cognitive control. Related to this, bilinguals often outperform monolinguals on cognitive control tasks. But what is often ignored is that bilingualism is a multi-dimensional phenomenon, with variations such as diversity of language usage and duration of language use. The present large-scale study of neural functioning in bilingualism revealed for the first time how individual differences in bilingual experience lead to adaptations to brain functioning which in turn affect cognitive control behaviour. It exemplifies how the complexity of individual experiences plays a fundamental role in brain function.
双语者在一般注意控制方面的表现通常优于单语者，但并非总是如此。不一致的发现被认为至少部分源于将双语者视为一个统一的类别，以及没有考虑到对双语经验的神经适应如何调节行为结果。本研究调查了语言经验模式，包括语言转换行为、双语语言使用的持续时间和强度/多样性，如何影响认知控制的大脑过程，以及这些如何转化为认知控制表现。我们在两项认知控制范式中检查了 239 名参与者（约 70%为双语者）的脑电图（EEG）的反应时间和频谱动态，这些参与者具有不同的语言经验，测试了干扰抑制（flanker 和 Simon 任务）。使用结构方程模型，我们发现，不同的双语经验因素与神经认知测量相关，这些因素反过来又与 flanker 任务而不是 Simon 任务的行为干扰效应相关。更具体地说，语言转换的频率增加和双语语言使用的强度/多样性与自上而下控制措施（特别是中线-额theta）呈负相关，这反过来又有利于干扰控制。相比之下，双语参与的持续时间与诱发的自下而上控制措施（特别是 P3）呈负相关，因此不利于干扰控制。我们在这里首次证明了双语经验的不同因素如何导致不同的神经适应，从而影响行为结果。 意义陈述：与其他密集经验一样，双语导致大脑适应。它导致语言区域的结构变化，并且由于对语言控制的需求，导致与一般领域认知控制相关的大脑区域发生变化。与之相关的是，双语者在认知控制任务上的表现通常优于单语者。但人们常常忽略的是，双语是一个多维度的现象，具有语言使用的多样性和持续时间等变化。本研究首次揭示了双语经验的个体差异如何导致大脑功能的适应，进而影响认知控制行为。它例证了个体经验的复杂性如何在大脑功能中起着根本作用。
