Lotteries are just one way to provide positive reinforcement. Their power comes from the fact that the chance of winning the prize is overvalued.

Arthur Laffer's idea, that lowering taxes could increase revenues, was logically correct. If tax rates are high enough, then people will go to such lengths to avoid them that cutting taxes can increase revenues. What he was wrong about was in thinking that income tax rates were already so high in the 1970s that cutting them would raise revenues.

Real people have trouble balancing their checkbooks, much less calculating how much they need to save for retirement; they sometimes binge on food, drink, or high-definition televisions. They are more like Homer Simpson than Mr. Spock.

If you're not putting enough away for emergencies or retirement, making commitments in advance, such as signing up for payroll withholding, can help.

Countries all around the world, starting with the U.K., have started behavioural insight teams, often referred to as nudge units. And they seem to be doing lots of good.

We all need a lot of humility, and especially about the economy.

The lesson of my field, behavioral economics, is that we need to understand the ways in which we differ from the rational human assumed in standard economic theory.

In the 1940s, economics started getting highly mathematical. It was basically because economists weren't smart enough to write down models of real behavior that they started writing down models of highly rational behavior - and they kind of forgot about humans.

Whenever I'm asked to autograph a copy of 'Nudge,' the book I wrote with Cass Sunstein, the Harvard law professor, I sign it, 'Nudge for good.' Unfortunately, that is meant as a plea, not an expectation.

Behavioral economics offers a plausible explanation for overreactions by the market. For example, a long period of bad performance can lead to stereotyping.

If you want to encourage some activity, make it easy.

Tonight - to you, the great silent majority of my fellow Americans - I ask for your support.

Tonight - to you, the great silent majority of my fellow Americans - I ask for your support.

I am not a crook.

I am not a crook.

There are some people, you know, they think the way to be a big man is to shout and stomp and raise hell-and then nothing ever really happens. I'm not like that I never shoot blanks.

There are some people, you know, they think the way to be a big man is to shout and stomp and raise hell-and then nothing ever really happens. I'm not like that I never shoot blanks.

If you think the United States has stood still, who built the largest shopping center in the world?

If you think the United States has stood still, who built the largest shopping center in the world?

I played by the rules of politics as I found them.

I played by the rules of politics as I found them.

A president can ask for reconciliation in the racial conflict that divides Americans. But reconciliation comes only from the hearts of people.

A president can ask for reconciliation in the racial conflict that divides Americans. But reconciliation comes only from the hearts of people.

It's a piece of cake until you get to the top. You find you can't stop playing the game the way you've always played it.