Very interesting research of the mental and cognitive values of being bilingual.

It is established that learned knowledge and habitual procedures (crystallized intelligence) hold up well as people age, said lead author Ellen Bialystok, Ph.D., of York University, but abilities that depend on keeping one’s attention on a task (fluid intelligence) actually decline as people get older. But in her study, Bialystok found that those who have been bilingual most of their life were better able to manage their attention to complex set of rapidly changing task demands as measured by an experimental task – The Simon Task – that purposely distracts the test takers.