Marketplace host David Brancaccio asks Yale economist Robert J. Shiller about the swings in the stock market since April 2000. Shiller asserts that despite several months of volatility, investors remain unjustifiably overconfident because of the long bull market. Shiller argues that as a result, they aren't ready for a dramatic market collapse and to think otherwise ignores the lessons of history. Shiller explains that the New Economy isn't so new, as history is filled with periods of increased productivity that do not lead to increased corporate profits. In fact, Shiller thinks that the long term outlook for the current market is less positive than in 1929.Listen to Robert J. Shiller's Irrational Exhuberance, a Random House Audible audio exclusive!