There's our stereotypical image of the elderly creeping around slowly, enjoying quiet hobbies, and battling various medical complaints, and then there are the portraits of people in their 80s and 90 included in Sharon Jayson's recent Washington Post article on "superagers."

These inspiring elders include a National Senior Games badminton champion, an 88-year-old lawyer who in addition to continuing to practice sits on no less than six community boards, and a comedian who hasn't let his 90th birthday slow him down.

Their heartwarming stories are worth a read just to put a smile on your face, but they also raise one basic question -- what sets people this this who are perpetually mentally young apart from the average Joe who experiences an earlier and more severe mental decline.

Luck and genetics certainly play their part, but as Jayson discovered speaking to experts, mindset is one of the biggest factors when it comes to keeping your brain young.

Years don't make you old; stereotypes do.

You might think we feel older when our joints get creaky and our memories less reliable, but according to a new study out of the Columbia Aging Center at Columbia University, the process of mental aging depends less than you might expect on physical changes that you can't control, and more on mental ones you can.

The study found that refusing to accept the negative stereotypes about aging that swirl around in our culture.can actually help protect your mind from the ravages of the years. Or, to put it simply, refusing to get old actually works -- mentally at least.

"Adults who believe age is just a number showed better memory performance, but adults who believed aging is set in stone and fixed had a decrease in memory performance and a stronger stress reaction," David Weiss, the researcher behind the Columbia study, explained to Jayson.

Other research apparently backs up these findings. Low expectations for your mental performance as you age tend to become a self-fulfilling prophecy, these studies find. Setting yourself new challenges and believing in your capabilities no matter how many candles you have on your birthday cake tends to keep your mind in peak form longer.

Do your brain a few favors too.

Of course, while mindset is clearly a key piece of the puzzle when it comes to keeping your brain sharp as you age, living a healthy lifestyle is certainly going to help too. Science suggests that specific practices -- like meditation and regular weight training -- can help your brain stay in peak condition longer.

So add those to your regime of refusing to act your age for the best chances of becoming a superager yourself.