Does anonymity affect the willingness to accept and willingness to pay gap? A generalization of Plott and Zeiler

Conventional value-elicitation experiments often find subjects provide higher valuations for items they posses than for identical items they may acquire. Plott and Zeiler (Am Econ Rev 95:530-545, 2005) replicate this willingness-to-pay/willingness-to-accept "gap" with conventional experimental procedures, but find no gap after implementing procedures that provide for subject anonymity and familiarity with the second-price mechanism. This paper investigates whether anonymity is necessary for their result. We employ both types of procedures with and without anonymity. Contrary to predictions of one theory-which suggest social pressures may cause differences in subject valuations-we find, regardless of anonymity, conventional procedures generate gaps and Plott and Zeiler's does not. These findings strongly suggest subject familiarity with elicitation mechanisms, not anonymity, is responsible for the variability in results across value-elicitation experiments. As an application to experimental design methodology, there appears to be little need to impose anonymity when using second-price mechanisms in standard consumer good experiments.