Justification aversion: The road to more effective defaults

Default options are one of the most frequently used tools of choice architecture, yet the factors that influence their effectiveness remain imperfectly understood. As a way to improve the effectiveness of defaults, this paper explores the idea of adding a justification requirement if people want to switch away from the default. Across six pre-registered studies, we find a consistent justification aversion effect: Depending on the context, the requirement to justify one's choice results in a 22% to 58% increase in default adherence relative to comparable (non-justification) requirements. This effect is robust to different decision contexts and alternative switching requirements. We test various potential mechanisms, and the evidence is most consistent with image concerns associated with having to justify a socially undesirable deviation from the default. Importantly, image concerns do not appear to undermine socially desirable deviations from defaults.