Bilingualism as a Source of Experience-Dependent Plasticity: Mechanisms and Limits

双语作为经验依赖性可塑性的来源：机制和限制

• 批准号: RGPIN-2020-06440
• 负责人: Bialystok, Ellen
• 金额: $ 4.74万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=741213
• 关键词: Bilingualism; Source; Experience; Dependent; Plasticity

This research examines bilingualism as a means of investigating the potential for experience-related neuroplasticity to affect cognitive performance across the lifespan. Bilinguals generally outperform monolinguals on executive function (EF) tasks that require avoiding distraction, shifting between goals, and engaging working memory and show differences in brain structure and function. Moreover, bilinguals display symptoms of dementia at a later stage of disease than monolinguals, all else being equal. However, not all studies find these effects so much remains unknown. The proposed studies will use behavioral and neuroimaging methods to examine children, young adults and older adults to address two crucial gaps in this literature. The first gap is identification of the mechanism responsible for the reported effects. The early explanation was based on a componential view of EF and singled out inhibition as most relevant. The idea was that bilingual language use required inhibition to avoid interference from the jointly activated non-target language but new evidence is inconsistent with this view. My hypothesis is that bilingual experience leads to an adaptation in attention networks that follow from navigating a complex linguistic environment. Attention is involved in all aspects of EF but not tied to a single component. Critically, the component and attention views make different predictions about bilingual performance will diverge. From a componential view of EF, bilinguals will outperform monolinguals on tasks that rely on inhibition; from an attention view, bilinguals will outperform monolinguals on tasks that require efficient attention strategies on complex conditions, regardless of the EF component. These studies will manipulate task difficulty across paradigms to compare the effect of component process demands and attention demands for monolingual and bilingual participants. The second gap is identification of the conditions necessary for these adaptations to occur. Individual differences and context clearly interact with these processes to determine outcomes. Fragmentary evidence points to the need for attention systems to be intact for bilingualism to lead to positive outcomes; bilingual adults with ADHD do not show the benefits found for non-ADHD bilinguals, and bilingual older adults with EF deficits do not show any delay of dementia symptoms. The hypothesis is that for individuals with compromised attention systems, bilingualism will exacerbate rather than benefit an already struggling system. Understanding how bilingualism leads to neuroplastic changes in cognition creates the possibility for devising interventions to improve cognition broadly, stimulating essential development in children and mitigating cognitive decline as older adults sit on the threshold between normal aging and dementia. Identifying attention as a relevant bridge between experience and cognition will have clear implications for new directions in intervention.

本研究探讨双语作为一种手段，调查潜在的经验相关的神经可塑性，影响整个生命周期的认知表现。双语者通常在执行功能（EF）任务中表现优于单语者，这些任务需要避免分心，在目标之间转换，并参与工作记忆，并显示大脑结构和功能的差异。此外，在其他条件相同的情况下，双语者比单语者在疾病后期表现出痴呆症状。然而，并不是所有的研究都发现了这些影响，所以还有很多未知数。拟议的研究将使用行为和神经影像学方法来检查儿童，年轻人和老年人，以解决这一文献中的两个关键空白。第一个差距是确定造成所报告的影响的机制。早期的解释是基于EF的成分观点，并挑选出抑制作为最相关的。这个想法是双语使用需要抑制，以避免干扰共同激活的非目标语言，但新的证据是不符合这一观点。我的假设是，双语经验导致了注意网络的适应，这是在复杂的语言环境中导航的结果。注意力涉及到执行功能的各个方面，但不局限于单一的组成部分。关键的是，成分观和注意观对双语成绩的预测存在分歧。从EF的成分观点来看，双语者在依赖于抑制的任务上的表现优于单语者;从注意力观点来看，双语者在复杂条件下需要有效注意策略的任务上的表现优于单语者，无论EF成分如何。这些研究将操纵跨范式的任务难度，比较单语和双语参与者的组件过程要求和注意力要求的效果。第二个差距是确定这些适应发生的必要条件。个体差异和背景显然与这些过程相互作用，以确定结果。零散的证据表明，注意力系统需要保持完整，才能使双语产生积极的结果;患有ADHD的双语成年人没有表现出非ADHD双语者的益处，而患有EF缺陷的双语老年人没有表现出痴呆症状的任何延迟。假设是，对于注意力系统受损的人来说，双语将加剧而不是有益于已经挣扎的系统。 了解双语如何导致认知的神经可塑性变化，为设计广泛改善认知的干预措施创造了可能性，刺激儿童的基本发展，并减轻认知下降，因为老年人处于正常衰老和痴呆症之间的门槛。将注意力确定为经验和认知之间的相关桥梁，将对干预的新方向产生明确的影响。