We introduce a new model of aggregate information cascades where only one of two possible actions is observable to others. When called upon, agents (who decide in some random order that they do not know) are only informed about the total number of others who have chosen the observable action...

We test the no-trade theorem in a laboratory nancial market where subjects can trade an asset whose value is unknown. Subjects receive clues on the asset value and then set a bid and an ask at which they are willing to buy or to sell from the other participants. In treatments with no gains from...

We study herd behavior in a laboratory ?nancial market with ?- nancial market professionals. An important novelty of the experi- mental design is the use of a strategy-like method. This allows us to detect herd behavior directly by observing subjects?decisions for all realizations of their...

We study social learning by boundedly rational agents. Agents take a decision in sequence, after observing their predecessors and a private signal. They are unable to understand their predecessors’ decisions in their finest details: they only understand the relation between the aggregate...

We study the effect of transaction costs (e.g., a trading fee or a transaction tax, like the Tobin tax) on the aggregation of private information in financial markets. We analyze a financial market à la Glosten and Milgrom, in which informed and uninformed traders trade in sequence with a...