Executive control of language in young and older bilinguals

越来越多的人需要了解年轻人和老年人的双语能力，因为35%的加拿大人会说两种语言，而60岁以上的人的比例正在增加。双语者的第一语言（L1）和第二语言（L2）之间有不同程度的重叠。当双语者说话或阅读时，这种信息共享需要执行控制来正确地访问和产生适合语言的信息。研究表明，老年双语者的执行控制能力相对来说不受年龄相关衰退的影响。因此，我将研究年轻和老年英语/法语双语者的注意力和执行控制，特别是使用基于语言的任务结合脑电活动（ERPs）。研究1将考察在存在内部和跨语言语音和语义干扰时，母语和第二语言中图片命名过程中的言语自我监测。目的是确定语言自我监控在第二语言中是否比在第一语言中更强（由于来自第一语言的干扰）。研究3将检验双语所带来的执行控制优势是否对词汇歧义词（即拼写相同但含义不同的词）的激活和选择有积极影响。研究3将研究语言作为引导年轻人和老年人注意力的机制（即，通过指定物体之间的关系）。研究4将研究两种语言之间转换的神经机制。这里有一个看似矛盾的不对称成本，即从较弱的L2切换到较强的L1所需的时间要比从较弱的L2切换到较强的L1所需的时间长。这可能是由于需要抑制L2中执行所需的L1，然后必须克服L1才能切换回L1。总的来说，本研究项目将通过研究执行控制在生产（研究1）和理解（研究2、3、4）中的作用，通过将当前的研究成果扩展到老年双语者（他们代表了执行控制重要性的极端测试），并通过阐明涉及语言控制的神经过程，做出新颖而重要的贡献。

There is a growing need to understand bilingualism in younger and older adults because 35% of Canadians are bilingual and the proportion over the age of 60 is increasing. There is a varying degree of overlap between a bilingual's first (L1) and second (L2) language. This sharing of information requires executive control to correctly access and produce language-appropriate information when a bilingual is speaking or reading. Studies have shown that executive control capabilities of older bilinguals are relatively protected against age-related decline. Thus, I will investigate attentional and executive control in younger and older English/ French bilinguals specifically using language-based tasks in combination with electrical brain activity (ERPs). Study 1 will examine verbal self-monitoring during picture naming in L1 and L2 when within- and across-language phonological and semantic distractors are present. The goal is to determine whether verbal self-monitoring is greater in L2 than in L1 (due to interference from L1). Study 3 will examine whether the executive control benefits due to being bilingual have a positive effect on the activation and selection of lexically ambiguous words (i.e., words with the same spelling but two distinct meanings). Study 3 will examine language as a mechanism for directing attention (i.e., by specifying relationship between objects) in younger and older adults. Study 4 will examine the neural mechanisms of switching between two languages. There is a seemingly paradoxical asymmetrical cost, namely that it takes longer to switch from one's weaker L2 to one's stronger L1 than vice versa. This is likely due to the need to suppress L1 that is required to perform in L2, which must then be overcome to switch back to L1. Overall, this research program will make a novel and significant contribution by examining the role of executive control in both production (Study 1) and comprehension (Studies 2, 3, 4), by extending current research findings to older bilinguals who represent an extreme test of the importance of executive control, and by elucidating the neural processes involved in the control of language.