Rewards, Experience and Decision Costs in First Price Auctions

Consistent with a model of asymmetric risk aversion, subjects in first price auctions consistently bid above the risk neutral Nash prediction. It has been argued that this is due to low opportunity cost of deviating from the risk neutral bid. We increase opportunity cost (and payoff levels) by factors of 0, 1, 5, 10, and 20, from the normal levels generating payoffs up to 250 for risk neutral subjects and observe an insignificant increase in the slope of individual bid functions. The RMSE of bids declines significantly. This is consistent with a reward/decision cost model of bidding behavior.