Measuring Hypothetical Bias in Choice Experiments: The Importance of Cognitive Consistency

A choice experiment eliciting environmental values with both real and hypothetical trade-offs is set up in order to test for hypothetical bias. A larger hypothetical bias was found in a between-subject than in a within-subject design, using otherwise identical scenarios, which can explain previous diverging results in the literature. We argue that people strive for consistency between their attitudes and behaviors, leading them to act in ways that correspond with their prior hypothetical statements. People hence seem to prefer to do what they say they would do, although this may not always reflect their true preferences regarding the good being valued.