Public good provision, in-group cooperation and out-group descriptive norms: A lab experiment

We use a public good experiment to study how in-group cooperation is affected by payoff-irrelevant information about cooperation in other groups (i.e., descriptive out-group feedback). We find that positive out-group feedback, indicating above-average cooperation, deters low in-group contributors from increasing their contribution towards the in-group average. By contrast, negative out-group feedback, which informs participants about below-average cooperation, deters high in-group contributors from decreasing their contribution towards the in-group average. These two effects work together to dampen contribution patterns associated with conditional cooperation. Further, we show that the effects are stronger for individual-level feedback (comparing individual contributions with the out-group average) than for group-level feedback (comparing total contributions by in-group members with that of other groups). Interestingly, when allowed to avoid out-group feedback information, the propensity to consult the feedback is similar for high and low in-group contributors, suggesting that information acquisition is not always self-serving.