Testing hypothetical bias with a real choice experiment using respondents' own money

The investigation of hypothetical bias in choice experiments (CEs) has typically been conducted in the laboratory with only minimal field experiments. Moreover, it is common practice to provide an initial endowment (money or coupons) to respondents. In this research, we employed a between-subject CE in a supermarket with three different treatments (i.e. hypothetical, hypothetical with cheap talk script and real). With the real treatment, we required respondents to use their own money when making a payment. The proposed incentive-compatible mechanism mimics as close as possible the everyday purchasing situation. Results confirm the presence of hypothetical bias and the mixed effectiveness of a cheap talk script.