Clear irrationality on online auctions:
We employ a novel approach to identify overbidding in auctions. We compare online auction prices to fixed prices for the same item on the same webpage. In detailed data on auctions of a board game, 42 percent of auctions exceed the simultaneous fixed price. The result replicates in a broad cross-section of auctions (48 percent overbidding). A small fraction of overbidders, 17 percent of bidders, suffices to generate the large fraction of auctions with overbidding. We show that the observed behavior is inconsistent with rational behavior, even allowing for uncertainty about prices and switching costs, since the expected auction price also exceeds the fixed price. Limited attention best explains our results.
Malmendier, U. and Y. H. Lee “The Bidder’s Curse.” American Economic Review 101(2): 749-87.