We consider an auction in which the behavior of one potential bidder depart
s mildly from full rationality. We show that the presence of such an inexpe
rt bidder can be enough to discourage all of an infinitely large population
of fully rational potential bidders from entering an auction. Furthermore,
this departure from full rationality does not reduce the inexpert bidder's
payoff. (C) 2001 Elsevier Science B.V. All rights reserved.