Increasing benefits in one-time public goods does not promote cooperation.

The long tradition of research on cooperation includes a well-established finding that individuals respond to the degree of conflict between self- and collective interests (that is, the relative benefits from cooperation) in providing public goods. Existing empirical evidence builds upon settings where participants make multiple decisions or strategically consider alternative scenarios. Here, we consider a decision setting where participants face a one-time (single-decision) setting. One-time cooperative encounters often occur in volunteering or donating to immediate needs for crisis relief. For these distinct and highly relevant settings, we report a lack of responsiveness to increases in cooperation benefits, thereby highlighting limits to our understanding of the determinants of one-time cooperation encounters. Across two studies, n = 2,232 individuals participate in treatments where we vary across participants the relative benefit from contributing to a public good (that is, the marginal per capita return, the MPCR). We examine decisions from alternative participant pools (UK general population vs. students), implementations varying the physical distance between participants (online vs. in the laboratory), and more complex decision settings considering group-to-group interactions including not only providers but also donors to public goods. Throughout, neither average contribution levels, nor the distribution of contributions are significantly affected by the increases in cooperation benefits. The mechanism behind these results can be explained by the close correlation between expectations of other's cooperation and own cooperation, and the fact that these expectations do not increase with higher benefits from cooperation.