It turns out, that men, when they're taking care of their business, they're not fully attending to the task at hand, but, I'm sure there's an evolutionary explanation for this, if you give them a target, they will aim.

I think one lesson we have to learn is that there's a lot more risk than we're giving credit to, a lot more what economist calls systematic risk.

Credit cards have been extremely profitable to banks. They're profitable not from the fees they collect from the retailers that use the credit cards, that pays the bills, but the real profits come from the interest payments and the charges to users that are unexpected.

The same with the mortgage brokers that were selling people mortgages they couldn't afford. We shouldn't pay them on each mortgage they write. They should have what they call "skin in the game," where they've got to reimburse us if the guy who sold the mortgage defaults.

Investors must keep in mind that there's a difference between a good company and a good stock. After all, you can buy a good car but pay too much for it.

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.

Retirement savings is probably behavioral economists' greatest success story. It is a prototypical behavioral-economics problem because saving for retirement is cognitively hard - figuring out how much to save - and requires self-control.