Dr. Felix Koelle, a research fellow at the Faculty of Management, Economics, and Social Sciences at the University of Cologne, led a team studying how the paradigm of reciprocity influences public goods. Participants (n = 876) in a series of experiments and simulations were asked to either maintain a public good or create a new one. Examples for the maintenance of public goods are sustaining natural resources like water, limiting CO2 emissions and fostering biodiversity. Examples for the provision of public goods are engagement in political activities, charity and volunteering.