The latest evidence from the bilingualism-is-good-for-you crew comes from Brian Gold, a neuroscientist at the University of Kentucky College of Medicine in Lexington. To test the idea, he had older people who grew up bilingual do an attention-switching task, a skill that typically fades with age. Earlier research has found that people bilingual since childhood are better at the high-order thinking called executive function as they age.

Gold found that his bilingual seniors were better at the task, which had them quickly sorting colors and shapes, than their monolingual peers. He then added an extra dimension by sticking the people’s heads in scanners to see what was happening inside their brains. The brains of the monolingual seniors were working harder to complete the task, while the bilingual seniors’ brains were much more efficient, more like those of young adults.

Neuroscientists think that having more reserve brain power helps compensate for age-related declines in thinking and memory, and may help protect against the losses caused by Alzheimer’s and other forms of dementia. The study was published in the Journal of Neuroscience.