Being bilingual opens up new worlds to speakers. It also appears to delay the onset of dementia…
In the Hyderabad region, a language called Telugu is spoken by the majority Hindu group, and another called Dakkhini by the minority Muslim population. Hindi and English are also commonly spoken in formal contexts, including at school. Most people who grow up in the region, then, are bilingual, and routinely exposed to at least three languages.
The patients who contributed data to the study, then, are surrounded by multiple languages in everyday life, not primarily as a result of moving from one location to another. This turns out to be an important factor, as the authors explain:
In contrast to previous studies, the bilingual group was drawn from the same environment as the monolingual one and the results were therefore free from the confounding effects of immigration. The bilingual effect on age at dementia onset was shown independently of other potential confounding factors, such as education, sex, occupation, cardiovascular risk factors, and urban vs rural dwelling, of subjects with dementia.
In other words, thanks in large part to the study’s cultural context, these researchers made great progress zeroing in on bilingualism as the specific reason for the delay in dementia symptoms.
What exactly is it about the ability to speak in two languages that seems to provide this protective effect? Alladi and co-authors explain:
The constant need in a bilingual person to selectively activate one language and suppress the other is thought to lead to a better development of executive functions and attentional tasks with cognitive advantages being best documented in attentional control, inhibition, and conflict resolution.
Read the study in Neurology (behind a paywall). Or check out these open source links:
- Delaying the onset of Alzheimer disease, Neurology 2010.
- Language Control in Different Contexts: The Behavioral Ecology of Bilingual Speakers, Frontiers in Psychology.
- A Longitudinal Study of Memory Advantages in Bilinguals, PLOS ONE.
Links via Nicodin Bogdan on Science in Google+.