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造成困惑，这是一个由来已久的神话。研究表明，双语，接触和使用两种语言，会使大脑发生有益的变化，从婴儿期到老年，这种变化在整个一生中都可以看到。一个双语的人的两种语言总是活跃的，这需要一个持续不断的过程来说想要说的语言，但也需要有在两种语言之间轻松切换的能力。在经历了一生的这些过程之后，会说两种语言的老年人往往会受到保护，不会受到健康和病理性衰老标志的一些认知衰退的影响。双语老年人似乎比只会说一种语言的老年人保持更好的认知功能的时间更长。这个项目进行了一系列实验，探索双语带来这种好处的原因。这些实验旨在发现，尽管双语似乎可以延缓痴呆症症状的出现，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的下降，抑制控制是控制在语言之间切换的能力的过程。第二种解释涉及词语与其含义之间关系的下降。这个项目通过比较参与这些不同过程的语言任务的表现来测试这些替代方案。网络分析被用来衡量来自语言产生任务的话语的连通性，而来自词汇产生任务的数据则用来衡量认知控制和语言调控。这个项目开发了一个通用方案，它将确定语言和认知随年龄变化的模式。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.