An experimental investigation of the explosive effect in almost common value auctions

With only two bidders, a slight private value advantage in a common value auction is predicted to have an explosive effect on the allocation and revenue of the auction when using a second price and/or English clock mechanism. This paper uses the “wallet game” in an English clock mechanism with two players to test these predictions. The results show that the effect is proportional, not explosive, confirming the results of past experiments. A behavioral model with two types of players, naive and sophisticated, is developed and tested against the experimental data. In the model, naive players use a rule of thumb bidding function, while the sophisticated players are fully rational and, when forming their strategy (choosing the best response), correctly account for the probability that a rival is naive or sophisticated. We use cluster analysis to classify the players in the symmetric auctions as naive or sophisticated and a strict win/lose criteria to classify players in the asymmetric auctions. We find that those players classified as sophisticated are more aggressive in responding to high signals or advantaged status than their naive counterparts, but do not lower their bids relative to the naive players when receiving low signals or when regular.