What we can learn from past stock market crashes

The stock market took another nerve-wracking ride on Thursday, with the Dow Jones Industrials dropping more than 1,000 points. One explanation of this week's jitters is the idea that market prices are out of whack. So how low could we go? Economics correspondent Paul Solman puts today's market in historical perspective -- and it isn't especially reassuring.

Despite all of this, the worse thing one can do is panic sell!