Fiocco and her colleagues followed 2, 509 healthy men and women over an eight-year period.

CNN: Experts reveal best ways to save an aging brain

But studies like Fiocco's suggest that it may be possible to turn "decliners" into "maintainers" by encouraging social and intellectual engagement.

CNN: Experts reveal best ways to save an aging brain

However, even if you didn't finish high school or have other factors you can't change, you can still challenge your brain to preserve mental function, Fiocco says.

CNN: Experts reveal best ways to save an aging brain