Hypothetical bias for private goods: does cheap talk make a difference?

Economists and market researchers often need to accurately gauge consumers' willingness-to-pay for private goods. The experimental literature has identified a problem of hypothetical bias when using stated preferences techniques, such as open-ended questions. It has been suggested that using a cheap talk script has the potential to resolve this bias. Yet, few empirical studies on the efficiency of cheap talk for private goods exist. This study uses a between-subjects experimental design to compare consumers' willingness-to-pay for DHA-enriched milk using three elicitation methods: 1) Hypothetical open-ended stated preference question, without monetary consequence for the respondent; 2) Idem to the first with the addition of a cheap talk script; and 3) A Vickrey auction with real monetary consequences. In this experiment subjects have the choice to participate, or not, at each period. Our results indicate a significant hypothetical bias. While the use of cheap talk has no impact on this bias, it does however increase the level of participation to the market.