LangDiv: Hypotheses about the sources of bilingual resilience over the lifespan

学习和使用两种语言可能会干扰孩子的语言发展或导致混乱的想法是一个长期存在的神话。研究表明，双语能力，即接触和使用两种语言，会给大脑带来有益的变化，这种变化从婴儿期一直持续到老年。双语者的两种语言总是活跃的，需要一个持续的过程来表达预期的语言，也需要在语言之间轻松切换的能力。在经历了一生的这些过程后，会说两种语言的老年人往往不会出现一些标志着健康和病理性衰老的认知衰退。会说两种语言的老年人似乎比会说一种语言的老年人在更长时间内保持更好的认知功能。这个项目进行了一系列的实验来探索双语的好处。这些实验的目的是发现，虽然双语似乎可以延缓痴呆症症状的发作，但当双语者最终出现症状时，他们往往无法使用第二语言。对于第二语言的丧失，人们提出了两种解释。第一种解释将这种丧失归因于抑制控制能力的下降，抑制控制是控制语言转换能力的过程。第二种解释涉及单词和它们的意思之间的关系的下降。本项目通过比较涉及这些不同进程的语言任务的性能来测试这些备选方案。网络分析用于测量来自语言生成任务的话语是如何连接的，而来自单词生成任务的数据用于测量认知控制和语言调节。这个项目开发了一个通用的协议，将识别语言和认知变化的模式随着年龄的增长。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The idea that learning and using two languages might interfere with a child's language development or cause confusion is a long-standing myth. Research has demonstrated that bilingualism, exposure to and use of two languages, causes beneficial changes in the brain that can be seen across the lifespan, from infancy and into old age. A bilingual person's two languages are always active, requiring a continual process of juggling to speak the intended language but also the ability to switch between languages at ease. After a lifetime of engaging these processes older bilingual adults tend to be protected from some of the cognitive decline that marks both healthy and pathological aging. Older bilingual adults appear to preserve better cognitive function for longer than older monolingual adults. This project conducts a series of experiments that explore the reasons for this benefit of bilingualism. The experiments are oriented around the finding that, while bilingualism appears to delay the onset of dementia symptoms, when bilinguals finally develop symptoms they are often not able to use their second language. Two explanations have been proposed to explain the loss of the second language. The first explanation attributes the loss to a decline in inhibitory control, the process that controls the ability to switch between languages. The second explanation involves a decline in the relationships between words and what they mean. This project tests these alternatives by comparing the performance on language tasks that engage these different processes. Network analysis is used to measure how connected utterances from language production tasks are and data from word production tasks measure cognitive control and language regulation. This project develops a general protocol that will identify patterns of language and cognitive change with aging.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.