Put your money where your mouth is: Reciprocity, social preferences, trust and contributions to public goods

It is argued that trust and positive social preferences promote public goods production. However, public goods produced by any in-group may have favourable or unfavourable consequences for out-groups (called benign' and malignant' public goods, respectively). I develop a theoretical model of heterogeneous reciprocity preferences and report two experiments relating trust, social preferences and in-group bias to contributions to benign and malignant public goods. The results allow four general conclusions: (i) contributions to benign public goods are (weakly) higher than contributions to malignant ones; (ii) general trust is at best weakly related to contributions to both types of public goods; (iii) the expectation that others contribute is positively related to contributions to both types of public goods; and (iv) social preferences are positively related to contributions to benign public goods and unrelated to contributions to malignant public goods, while in-group bias is negatively related to contributions to both public goods.