Robert Shiller – Destroyer of Efficient Market Hypothesis (EMH)

Efficient market hypothesis states that the market price reflect all information available and consistent alpha generation is impossible.

Rober shiller demonstrates that short-term price movement is substantially driven by psychology and cannot be reasonablely justified by all availble public information.

Shiller's perspective can be illustrated by his definition of bubble:
"A situation in which news of price increases spurs investor enthusiasm which spreads by psychological contagion from person to person, in the process amplifying stories that might justify the price increase and bringing in a larger and larger class of investors, who, despite doubts about the real value of the investment, are drawn to it partly through envy of others’ successes and partly through a gambler’s excitement."