Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
This paper reports an experimental study of the public goods game in which contributions are not submitted all at once but incrementally as coordinated in real time by a clock. Individuals press a button as soon as the clock equals their willingness to contribute. By providing information about the point at which subjects stop further contributions we find evidence for conditionally cooperative behaviour: A subject's decision to stop contributing induces an immediate reaction of the other group members.