Because I want to share, not because I should: Prosocial implications of gratitude expression in repeated zero-sum resource allocation exchanges

The current research examines how gratitude (vs. neutral) expression indirectly reinforces prosocial resource-allocation decisions in repeated zero-sum social exchanges. Drawing upon the emotion as social information (EASI) model, we found in four experiments that counterpart (recipient) gratitude (vs. neutral) expression regarding participants’ (allocators’) resource-allocation proposal in Exchange 1 evoked participants’ perception of their counterpart’s benevolence (when the proposal was accepted). Consistent with self-determination theory, participants’ perception of their counterpart’s benevolence led to their prosocial resource-allocation decision toward their counterpart in Exchange 2 due to their prosocial motivation, independently from and jointly with their obligatory motivation. Notably, in three experiments (“Study 1b”–“Study 3” sections), participants’ obligatory motivation attenuated the positive link between their prosocial motivation and prosocial resource-allocation decision in Exchange 2. Taken together, our findings highlight that expressing gratitude in repeated zero-sum social exchanges is a desirable strategy for shaping a counterpart’s benevolence perception and motivating the counterpart to make a prosocial resource-allocation decision.