Secret #7: Protect the future you

As you age your brain undergoes subtle changes that can affect how you manage money. For example, you'll probably become more optimistic -- a phenomenon known as the positivity effect. In hunter-gatherer days, when you got older, you were no longer called upon to grab a spear and defend the tribe. "You no longer needed to be so focused on all the things that could go wrong," says Laura Carstensen, director of the Stanford Center on Longevity.

Hey, what's wrong with a little optimism? It's one reason old folks tend to be happier than younger ones, according to recent studies. But the positivity effect can also make the 2030 you -- or maybe your parents right now -- less attuned to threats and therefore more vulnerable to scammers.

It's not that older people find the idea of losing money any easier, but that they're more likely to think, "That nice young man would never cheat me."

The more serious risk, of course, is an outright decline in mental abilities. New studies show that this decline is more common than you may realize. After 60, the rate of dementia doubles every five years. By the time they reach their mid-eighties, half of people have some cognitive impairment.

Yet older people are increasingly expected to manage their portfolios on their own -- a fact that has helped make cognitive decline a hot topic among behavioral scientists. Facing the risks now, while you're at the peak of your powers, is a good thing, says Harvard economics professor David Laibson: It means you can act today to protect yourself tomorrow.

Put these findings into action:

Stay active. Researchers have not yet discovered a prescription for staving off cognitive decline. But so far, studies indicate that working out both your body and your brain -- through regular walks, reading books, and solving puzzles, for example -- may help.

Simplify your finances when you retire, suggests Rosanne Rogé, a financial adviser in Bohemia, N.Y.: "It will be harder to mess things up."

Be hard to find. Discourage scam artists from getting to you (or your parents) by keeping the latest spam filters installed on your computers, putting yourself on the national Do Not Call registry, and using caller ID in case any telemarketers slip past.

Arrange now for help later. You need a durable power of attorney, which gives a person you name the authority to make financial decisions for you if it becomes necessary. Assuming you have a will, you probably already have a DPA: They're typically drawn up at the same time. But many financial firms require you to fill out their own forms too. Do so by the time you retire, suggests New York elder-law attorney Daniel Fish. Your future self may thank you.

Tali Yahalom contributed to this article.