Everyone's lost a lot of money on their 401k plans. I've heard some people calling them 201k plans. So it's even more important to get people to be saving more for retirement. Behavioral economics has helped us learn a lot about how to do that.

Most people start claiming benefits within a year of when they become eligible, although benefits increase substantially if they wait.

Rip Van Winkle would be the ideal stock market investor: Rip could invest in the market before his nap and when he woke up 20 years later, he'd be happy. He would have been asleep through all the ups and downs in between. But few investors resemble Mr. Van Winkle. The more often an investor counts his money - or looks at the value of his mutual funds in the newspaper - the lower his risk tolerance.

The lesson from behavioral economics is that people only save if it's automatic.

he card companies will often, as a courtesy, honor that credit card, but hit you with a penalty. And you keep swiping your card for $3 at Starbucks for your latté, and you're getting hit with a $25 penalty because it's over your credit limit.

LTCM lost money when Russia defaulted on a certain class of bonds, and then they had other investments like on the spread between two different kinds of shares of Royal Dutch Shell Oil Company. Now that seems completely unrelated to Russian bonds. But they were related because other hedge funds saw similar discrepancies and they were all making similar bets.

A company invites their employees to sign up for a plan where every time they get a raise, some part of that raise goes to increasing their contribution rate to the 401k plan. In the first company we convinced to adopt this plan, saving rates tripled.