When do the expectations of others matter? Experimental evidence on distributional justice and guilt aversion.

Distributional justice-measured by the proportionality between effort exerted and rewards obtained-and guilt aversion-triggered by not fulfilling others' expectations-are widely acknowledged fundamental sources of pro-social behavior. We design three experiments to study the relevance of these sources of behavior when considered in interaction. In particular, we investigate whether subjects fulfill others' expectations also when this could produce inequitable allocations that conflict with distributional justice considerations.

The stability of conditional cooperation: beliefs alone cannot explain the decline of cooperation in social dilemmas.

An often-replicated result in the experimental literature on social dilemmas is that a large share of subjects choose conditionally cooperative strategies. Cooperation generated by such choices is notoriously unstable, as individuals reduce their contributions to the public good in reaction to other subjects' free-riding. This has led to the widely-held conclusion that cooperation observed in experiments (and its decline) is mostly driven by imperfect reciprocity.