Coruscation

a bubble is a form of psychological malfunction. And like mental illness there's a tricky gray area between being really sick and just having a few problems, Mr. Shiller said during a panel discussion at the World Economic Forum in Davos, Switzerland.

The solution: a checklist like psychologists use to determine if someone is suffering from, say, depression. So here is Mr. Shiller's checklist.

• Sharp increases in the price of an asset like real estate or dot-com shares
• Great public excitement about said increases
• An accompanying media frenzy
• Stories of people earning a lot of money, causing envy among people who aren't
• Growing interest in the asset class among the general public
• "New era" theories to justify unprecedented price increases
• A decline in lending standards