We study the effect of interim feedback policies in a dynamic all-pay auction where two players bid over two stages to win a common-value prize. We show that sequential equilibrium outcomes are characterized by Cheapest Signal Equilibria, wherein stage 1 bids are such that one player bids zero while the other chooses a cheapest bid consistent with some signal. Equilibrium payoffs for both players are always zero, and the sum of expected total bids equals the value of the prize. We conduct an experiment with four natural feedback policy treatments -- full, rank, and two cutoff policies -- and while the bidding behavior deviates from equilibrium, we fail to reject the hypothesis of no treatment effect on total bids. Further, stage 1 bids induce sunk costs and head starts, and we test for the resulting sunk cost and discouragement effects in stage 2 bidding.

翻译：本研究探讨了在动态全支付拍卖中，中期反馈策略对竞标行为的影响。该拍卖模型设定两名参与者在两个阶段中竞标，以获取具有共同价值的奖品。我们证明，序贯均衡结果可由"最廉价信号均衡"刻画：在第一阶段，一名参与者出价为零，而另一名参与者则选择与特定信号相容的最低可行出价。双方参与者的均衡收益始终为零，且预期总出价之和等于奖品价值。我们设计了包含四种自然反馈策略（完全反馈、排名反馈及两种阈值反馈）的实验。虽然实际竞标行为偏离了均衡预测，但我们未能拒绝"不同反馈策略对总出价无显著影响"的原假设。此外，第一阶段出价会产生沉没成本效应和先发优势，我们在第二阶段竞标中检验了由此引发的沉没成本效应与士气挫败效应。