Cycles of conditional cooperation in a real-time voluntarycontribution mechanism

This paper provides a new way to identify conditional cooperationin a real-time version of the standard voluntary contribution mechanism. Ourapproach avoids most drawbacks of the traditional procedures because it relieson endogenous cycle lengths, which are defined by the number of contributors aplayer waits before committing to a further contribution. Based on hypotheticaldistributions of randomly generated contribution sequences, we provide strongevidence for conditionally cooperative behavior. Moreover, notwithstanding adecline in contributions, conditional cooperation is found to be stable over time.