Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
Global and local cooperation in supplying global public goods is often insufficient. In this respect, laboratory experiments show that peer punishment is an effective cooperation‐enhancing instrument. However, it is unclear whether peer punishment would facilitate cooperation and public good provision even under congruent heterogeneities in wealth and punishment effectiveness. To this end, we experimentally study the effect of peer punishment under joint heterogeneities, where either the richest or the poorest member is also the most effective punisher. We compare these joint heterogeneities to treatments with single heterogeneities in either endowment or punishment effectiveness and to a baseline symmetry treatment with homogeneous parties. We find that heterogeneity in punishment effectiveness does not matter for cooperation, whereas endowment heterogeneity reduces cooperation compared to symmetry. This is because rich members contribute a lower portion of their endowment to the public good than their poorer counterparts. We also observe that cooperation is higher under joint heterogeneities in endowment and punishment effectiveness than under endowment heterogeneity (with no differences than under symmetry). This holds even when the rich party gains less from cooperation and is the most effective punisher. (JEL C92, D74, H41)