糖心原创

Title: Does voluntariness affect the cost of breaking a promise?

Abstract: Promises foster trust and cooperation if they are believed and kept. A large experimental literature shows that promises are frequently kept in the absence of contractual or reputational incentives, even when doing so comes at a monetary cost. Two main explanations have been proposed: (1) avoidance of guilt arising from failing to meet the promisee’s expectations; (2) an intrinsic cost of breaking a promise per se. This study focuses on the latter and aims to answer a question that has received no systematic attention yet: does the degree to which a promise is given voluntarily affect the magnitude of the cost when breaking it? We address this question in two steps. First, we develop a theoretical model that characterizes how the voluntariness of a promise as well as the cost of breaking a promise jointly affect people’s promise-making and promise-keeping behaviour. We then derive predictions that differ depending on whether the cost of breaking a promise increases with the voluntariness of the promise. Second, we design a lab experiment in which the degree of voluntariness is exogenously manipulated by varying the attractiveness of the non-promise alternative available to subjects, who are asked to choose between giving a promise and sending a non-promise message, allowing us to test our main research question.