Contributions in linear public goods experiments with stranger matching: two motivations

Abstract

ABSTRACTWe investigated why subjects contribute to the public good in a linear public goods game with stranger matching. In this experiment, subjects were asked to determine their contributions to the public good and also their beliefs about their partners’ contributions. Additionally, the subjects were asked to note the reason for their decisions in real time. We used the subjects’ descriptions for a coding analysis, which is a classification method of the motivations. Integrating this coding methodology and behavioural data revealed that full contributions are the result of two motives. One is the conditional cooperation motive to achieve the socially optimal outcome. The other is the motive to lead the other group member to contribute all of their endowment in the following periods by signalling one’s own act (i.e. a teaching motive). The study further reveals that the two identified motives play a key role in driving cooperative behaviour, and that other motives (such as confusion and altruism) play a minor role.