While inequality in resource endowments has been shown to affect cooperation levels in groups, much of this evidence comes from studies of within-group inequality. In an online public goods experiment, we instead examine the effects of payoff-irrelevant inequality in resources between groups on...

Using a dictator game experiment, we examine whether the introduction of group identities affects giving. Group identities can activate feelings of in-group love and out-group hate to create an in-group bias. In addition, group identities may spawn social sanctions that are designed to reinforce...